telemetry ecg monitoring during cardiac …
TRANSCRIPT
TELEMETRY ECG MONITORING DURING CARDIAC REHABILITATION TO
DETECT MYOCARDIAL ISCHEMIA
A MANUSCRIPT STYLE TKESIS PRESENTED
TO
THE GRADUATE FACULTY
UNIVERSITY OF WISCONSIN - LA CROSSE
IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE
MASTER OF SCIENCE DEGREE
BY
BEN CRENSHAW
DECEMBER 2000
ABSTRACT
Crenshaw B. D. Telemetry ECG Monitoring During Cardiac Rehabilitation to Detect Mvocardial Ischemia. MS in Adult FitnesslCardiac Rehabilitation, December 2000.42 pp (J. Porcari)
Historically, telemetric ECG monitoring (TELE) has been thought to be incapable of detecting ST-segment changes during exercise. One hundred and nine patients underwent a diagnostic exercise test. A 12-lead ECG (12L) and TELE (modified Lead 11) were recorded simultaneously throughout the exercise test. A total of 1041 temporally correlated tracings were blinded, then interpreted by a cardiologist. ST depression was defined as 2 lmm horizontal or downsloping at .08 mm from the J point in 2 or more adjacent leads. One hundred and twenty-nine tracings (in 36 patients) were positive for ST depression on 12L. Corresponding changes (same time and lead group) were seen on TELE 61% (791129) of the time. In normal 12L tracings, there were 29 ST abnormalities observed in TELE (e.g. false positive). When changes were observed on TELE, corresponding changes were observed on 12L 73% (791108) of the time. TELE matched 12L in magnitude of ST depression within + 0.5 mm 54% of the time. In conclusion, TELE missed ST changes seen on 12L 39% of the time, and does not appear to be a sensitive marker of ischemia. However, when changes are seen on TELE, they indicate that ischemia may be present in a high percentage (73%) and should be taken seriously.
COLLEGE OF HEAL.Tq PHYSICAL EDUCATION, RECREATION, AND
TEACHER EDUCATION
UNIVERSITY OF WISCONSIN - LA CROSSE
THESIS ORAL DEFENSE FORM
Candidate: BenCmshaw
W e rrcommend rcceptutce of this thuis in partial llfillmmt of this candidate's l q l k m t s f o r t h c d ~ :
Master of Scieace - Adult FiWCardiac R e h a b i o n
This candidate has successlllv COm~Ieted the thesis final oral defarse.
/Day'
e . ( h /c- Date
This thesis approved by the College of I-Ierlth. ~hysical ducati ion, ~ e a u t i o n , and TercbaEduution
ACKNOWLEDGEMENTS
I would like to thank the following persons, without whose assistance the
completion of this thesis would not have been possible:
Dr. Porcari and Dr. Foster for giving me the opportunity to take on this study, and
for their patience and perseverance in assisting with the completion of this project.
Dr. Seebach for sewing on my thesis committee.
Dr. Backes for expeditiously reading the seemingly endless mounds of ECG and
telemetry tracings and for his willingness to serve as a committee member.
The cardiac rehabilitation staff at FranciscanISkemp Healthcare for their patience.
and hospitality during the four long months of testing.
iii
TABLE OF CONTENTS
PAGES
... ACKNOWLEDGEMENTS 111 .............................................................................................. LIST OF APPENDICES v ................................................................................................... INTRODUCTION 1 ............................................................................................................. METHODS 2 ....................................................................................................................... RESULTS 4 .......................................................................................................................... DlSCUSSION 7 .................................................................................................................... REFERENCES 11 ................................................................................................................... APPENDICES 13 ...................................................................................................................
LIST OF APPENDICES
APPENDIX PAGE
A. Informed Consent Form - For Study Participation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
B. Informed Consent Form - For GXT . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
C. Raw Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
D. Comparison Between Individual Leads and Telemetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Telemetry vs. Inferior Leads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Telemetry vs. Lateral Leads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Telemetry vs. Anterior Leads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Telemetry vs. Anterior and Lateral Leads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Telemetry vs. Combination of Inferior, Anterior, and Lateral Leads . . . . . . . . . 25
E. Difference in Magnitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
F. Review of Literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Significance of ST Segment Changes During Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Sensitivity of Telemetry Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Conclusion . . ....... .... . ..... ..... . ..... . ..... . ...... . ..... . . ....... . ......... . . ........ . . . ...... . . ...... .... . ... 39
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
INTRODUCTION
Multidisciplinary cardiac rehabilitation is widely used following a cardiac event
to help patients recover their functional ability. Exercise is a central component of this
restoration and has been shown to result in favorable improvements in cardio-respiratory
function, blood lipids, blood pressure, glucose tolerance, body composition, and
psychological well-being.5v7 While exercise training during phase I1 cardiac
rehabilitation is considered safe (1.3 fatalities per million patient-hours'6), the potential
for residual ischemia and significant rhythm changes during the first several months post
cardiac eventlintervention have lead to the use of telemetric heart monitoring systems
during rehabilitation.14
Indeed, the economic basis of phase 11 cardiac rehabilitation depends upon the
perceived value of telemetric monitoring. It is widely accepted that ECG monitoring is
use l l for detecting potentially dangerous arrhythmias during However,
debate continues about the usehlness of continuous ECG monitoring during exercise for
the detection of ST-segment changes suggestive of ischemia. Most programs use some
variation of a lead I1 or Vs configuration, but the sensitivity and accuracy of these
telemetry systems to adequately detect ST-segment changes has been questioned for
several reasons. First, the reliance on a single lead to detect ischemia may not pick up all
of the ischemia that is present. Although ST-segment depression docs not localize the
arca of ischemia,'. " nor indicate which coronary artery is involved, the more leads with
(apparent) ischemic ST-segment shifts, the higher the sensitivity of ECG testing. 10, 17
Second, possible distortion of the ECG signal, compared to hardwire ECG signals, is not
clearly defined. Finally, signal processing techniques have made it possible to average
ECG waveforms and to remove noise. However, this process can actually distort the
signal1' and most manufacturers do not specify to what degree these procedures modify
the ECG.~
One study has shown a high risk of cardiac arrest or sudden death during cardiac
rehabilitation in patients who display significant ST-segment depression during exercise
testing6 Unfortunately, there are not well-documented data that indicate whether or not
ST-segment depression seen during telemetric monitoring is similar to that seen on a 12-
lead ECG or what percentage of ST-segment depression is missed during telemetry.
Therefore, the purpose of this study is to determine the usehlness of telemetry
monitoring, using a single modified lead 11, for detecting ischemia during exercise. This
would then translate to a better understanding of the potential value of ST-segment
changes seen during phase I1 cardiac rehabilitation.
METHODS
The patients involved in this study were referred by their primary physician for
diagnostic exercise testing at Franciscan Skemp Health Care in La Crosse, WI between
January 1,2000 and April 15,2000. The exercise testing was performed using standard
protocols based on age and fictional capacity of the patient. Prior to testing, informed
consent (Appendix A, B) was obtained, and patients were prepped for standard 12-lead
ECG exercise testing (Marquette system) according to guidelines established by
Franciscan Skemp Health Care. Patients were additionally prepped using a modified lead
II. Twelve-lead (l2L) and telemetry (TELE) ECGs were taken in the supine and standing
positions, and during each stage of exercise and recovery.
All ECG and telemetry tracings were blinded, then read and interpreted by a
cardiologist. ST-segment depression was determined to be significant if it was horizontal
or downsloping and lmm or greater .08 mm h m the J point. The results from the
telemetry strips were compared to the 12-lead to see how well they agreed with the
"hardwire" tracing in terms of magnitude of ST-segment depression and frequency of
occurrence.
The data were analyzed on a tracing by tracing and a patient by patient basis with
regard to individual lead correlation for the extent of ST-segment depression to test the
hypothesis that there would be no difference between telemetric and hardwire monitoring
systems. The analysis also compared the value of multiple leads by comparing all leads
of the hardwire system verses the telemetric system. The greatest magnitude of ST-
segment change observed on 12L verse magnitude observed on TELE was compared by
individual tracings. Sensitivity, specificity, and predictive values were also analyzed on a
patient by patient basis to evaluate whether or not ischemic abnormalities are detected.
Finally, a comparison of ST-segment depression that occurred on 12L at or below 60%
and also at or below 85% of maximal heart rate was compared to corresponding TELE on
a patient by patient bases.
RESULTS
A total of 1041 temporally correlated 12L and TELE tracings were collected and
analyzed from 109 patients (age range: 32-84, ave. 57.7 years; 74 males, 35 females)
(Appendix C). The first major question to be answered was how likely was it for ST-
segment changes to show up on TELE if there were ST-segment changes on 12L. There
were 129 positive 12L strips. Overall, positive changes were matched 61% (791129) of
the time.
Individual lead correlation was also analyzed (Appendix D). Out of 129 positive
12L, 22 had inferior lead (11,111, aVF) changes with TELE matching 41% (9122) of the
time. Lateral lead (I, aVL, Vs, Vg) changes were found in 7 12L with TELE matching
14% (117). There was only 1 12L with anterior lead (V1-V4) changes and TELE failed to
sense the changes. A combination of anteriorllateral changes (I, aVL, V1-V6) were seen
in 32 12L, with TELE matching 31% (10132) of the time. Wide spread changes
throughout the 12 lead were seen in 75 12L, with TELE matching 80% (60175) of the
time.
The second major question to be answered was if ST-segment changes occurred
on TELE, how likely were ST-segment changes to be seen on 12L. Overall, there were
108 positive TELE strips. Of these, 29 strips were false positives, meaning that there
were no corresponding changes in 12L. Thus, 73% (791108) of the time, if TELE showed
changes, positive changes were seen on 12L.
Additionally, the relationship between the magnitude of ST-segment changes
seen on TELE and 12L was analyzed (Appendix E). The magnitude of TELE ST-
segment depression was conipared to greatest change in magnitude observed on 12L.
35 (1, 30
Under Read
25 Over Read .- 20 H Matched
15 u- 0 10 a9 5
0 0 0.5 1.0 1.5 2.0
mrn
Figure 1. Magnitude Comparison Between TELE and 12L (N = 158)
As can be seen in Figure 1.33% (521158) of the time TELE and 12L matched in
magnitude of ST-segment depression; 54% (861158) of the time TELE was within 0.5
mm. TELE significantly (1 1.0 mm) under read 12L 31% (4911 58) of the time, meaning
there was greatet ST-segment depression on the 12L than what is showing on the TELE.
This is consistent with the previous data that showed that TELE correctly identified 12L
changes only 61% of the time.
The sensitivity, specificity, and predictive value of TELE were also analyzed on a
patient by patient basis. Out of the 109 patients, there were 70 patients with negative 12L.
and TELE (true negative), 23 patients with positive 12L and TELE (true positive), 3
patients with negative 12L and positive TELE (false positive), and 13 patients with
positive 12L and negative TELE (false negative). Sensitivity of TELE was defined as the
percent of patients with positive 12L who had positive TELE. Specificity was defined as
the percent of patients without positive 12L who had a negative TELE. Positive
predictive value was defined as the percent of patients with positive TELE who had
positive 12L and negative predictive value was defined as the percent of patients with
negative TELE who did not have positive 12L.
Sensitivity = TP =64% TP + FN
Specificity = TN =96% TN + FP
Positive Predictive Value = TF' = 88% TP + FP
Negative Predictive Value = TN = 84% TN + FN
Finally, because patients in phase I1 cardiac rehabilitation do not exercise to
maximal levels, ST-segment depression at 60% and 85% of maximal heart rate was
analyzed. Five out of the 36 positive patients (14%) had changes on 12L at or below
60% of their maximal heart rate. TELE correctly detected 2 of 5 of these patients (40%).
Seventeen out of the 36 positive patients (47%) had changes on 12L at or below 85% of
their maximal heart rate. TELE detected 9 out of these 17 patients (53%).
DISCUSSION
There are questions surrounding the reliability of telemetry ECG monitoring to
detect ST-segment changes during cardiac rehabilitation. Most of these questions have to
do with how much of the ST-segment is filtered with telemetry and how many changes
are missed with monitoring with only one view. Therefore, most professionals working
in cardiac rehabilitation who see ST-segment changes base their decisions on clinical
experience and patient si, is and symptoms. Questions posed to the telemetry industry in
regards ?o the significance of ST-segment changes noted during exercise sessions are
often answered with the statement that telemetry is not to be used for diagnostic purposes
due to the filtering of the ECG and the lack of multiple lead views, so a 12-lead should be
gathered.
Several practical questions were posed by this study. The first question to be
answered was how likely was there for ST-segment changes to show up on TELE if there
were ST-segment changes on 12L. This was analyzed on an overall tracing by tracing
bases and then by individual lead correlation. Overall, positive changes seen on 12L
were matched 61% of the time by TELE. The implication of this finding, from a
practical point of view is that during cardiac rehabilitation if changes are not seen on
telemetry during exercise, it does not mean that nothing is occurring on the 12L. TELE
does not seem to be very sensitive to detecting changes.
Individual lead relationship between 12L and TELE was also analyzed. Although
it is known that there is no relationship between ST-segment changes observed in
individual leads and the area of ischemia,'. lo. " ~t ' 1s ' known that in certain leads, such as
the lateral leads, it is more highly correlated. 1.13.15 Also, the more wide spread the ST-
segment changes that are observed, the greater the likelihood of disease. When changes
observed in individual leads were compared with TELE, a poor comelation was shown
when TELE was compared to lateral lead changes (14%) and anterior lead changes (0%).
Even when TELE was compared to a combination of changes of the anterior and lateral
leads it only matched 31% of the time. Inferior lead changes had the best correlation
between TELE individual leads, but with only 41% success. However, when a 12L had
wide spread changes throughout the tracing, TELE matched 80%. It is generally
accepted that widespread ST-segment changes during a GXT indicates more significant
disease." Thus, TELE may detect these people who have more critical disease.
The second question to be answered was if ST-segment changes occurred on
TELE, how likely was it to represent ci~mges on 12L. This study showed that if ST-
segment changes are observed on TELE, 73% of the time significant ST-segment
changes (2 1.0 mm) would be observed on 12L during exercise training. Therefore,
changes that are observed during telemetry monitoring should not be overlooked,
especially if these changes are new onset.
In addition, this study looked at the relationship between the magnitude of ST-
segment depression seen on TELE and 12L. TELE matched the greatest change observed
in 12L 33% of the time and, if given measurement leeway of 2 0.5 mm, TELE matched
54% (861158) of the time. Thus, these data suggests that if ST-segment changes that are
occurring on TELE correlate with 12L, it will be similar in magnitude to what is seen on
12L the majority of the time and will not be in error of more than 1.0 mm.
Data were also analyzed on a patient by patient basis. Sensitivity, specificity,
positive and negative predictive values were calculated. Sensitivity, the percent of
patients with positive 12L who will have positive TELE, was 64%. Specificity, the
percent of patients without a positive 12L who hxl a cegaiive TELE, was 96%. The
positive predictive value, meaning rhe percent of patients with positive TELE who had
positive 12L, equaled 88% while the negative predictive value, meaning the percent of
patients with negative TELE who did not have positive 12L, equaled 84%. The
sensitivity on a patient by patient basis did not differ much from how often positive
changes were matched between 12L and TELE on a tracing by tracing basis (64% vs.
61%). However, the percentage of patients with positive TELE who had positive 12L
(positive predictive value) was greater than what was seen if changes were observed on
TELE compared to 12L on a tracing by tracing basis (88% vs. 73%). The difference in
percentage is due to the fact that in calculating positive predictive value the number of
false positives that occurred on a tracing by tracing basis came primarily from 3 patients.
Finally, because patients arc not exercised to maximal levels during exercise
sessions, changes that occurred at or below 60% and 85% of maximal heart rate were
analyzed. These are typical heart rate ranges between which patients exercise. Only 5 of
the 36 patients had significant changes on 12L 5 60% of heart rate max, and TELE
comctly identified 2 of these. Seventeen of the 36 (47%) patients had significant
changes 5 85% of maximal heart rate, and TELE correctly identified 9 of these patients.
Again, these data suggests that TELE is not a useful tool for diagnosing ischemic changes
but does suggest that changes observed on TELE should not be ignored.
This study suggests that telemetry may have a usefulness in ischemic surveillance
in the cardiac rehabilitation setting. Although telemetry will miss 39% of what is
detected on a 12-lead, ST-segment depression that is observed on telemetry will match
changes seen on a corresponding 12-lead 73% of the time. Telemetry also matches its
corresponding 12-lead in magnitude within 0.5 mm more than half the time, supporting
the fact that the magnitude of depression being observed on telenetry is relatively
reliable. Limitations of this study include the use of only one model of telemetry system
(Quinton Q-Tel). Other telemetry systems may vary in frequency range and the filtering
characteristics of the ECG signal, therefore, further studies on other monitoring systems
need to be conducted.
REFERENCES
1. Blackbum H, Katigbak R: What electrocardiographic leads to take afier exercise? American Heart Journal 1964,67: 184-1 88.
2. Dolatowski RP, Squires RW, Pollock ML, et al: Dysrhythmia detection in myocardial revascularization surgery patients. Medicine and Science in Sports and Exercise 1983;15;4:281-286.
3. Froelicher VF, Myers J, Follansbee WP, et al: Exercise and the Heart, Third Edition. Mosby 1993;120.
4. Froelicher VF, Myers J, Follansbee WP, et al: Exercise and the Heart, Third Edition. Mosby 1993;241.
5. Hahn RA, Teutsch SM, Paffenbarger RS, et al: Excess deaths h m nine chronic diseases in the United States. Journal of the American Medical Association 1986;264:2654-2659.
6. Hossack KF, Hartwig R: Cardiac arrest associated with supervised cardiac rehabilitation. Journal of Cardiac Rehabilitation 1982;2:402-408.
7. Kennedy HI,: Detection of ST-segment depression with Holter system. Ambulatory Electrocardiology 1977; 1 : 1 1.
8. Mahler DA, Froelicher VF, Miller NH, et al: ACSM's Guidelines for Exercise Testing and Prescription, 5" Edition. Williams & Wilkins 1995;s.
9. Mahler DA, Froelicher VF, Miller NH, et al: ACSM's Guidelines for Exercise Testing and Prescription, 5" Edition. Williams & Wilkins 1995;98.
10. Mahler DA, Froelicha VF, Miller NH, et al: ACSM's Guidelines for Exercise Testing and Prescription, 5'h Edition. Williams & Willcins 1995;136.
11. Mark DB. Hlatky MA, Lee KL, et al: Localizing coronary artery obstructions with the exercise treadmill test. Annuals of Internal Medicine 1987;106:53-55.
12. Milliken JA, Abdollah H, Burggraf GW: False-Positive treadmill exercise tests due to computer signal averaging. The American Journal of Cardiology 1990;65:946-948.
13. Miranda CP, Liu J, Kadar A, et al: Usefulness of exercise-induced ST-segment depression in the inferior leads during exercise testing as a marker for coronary artery disease. American Journal ofCardio1og-y 1992;69:303-308.
14. Sennett SM, Pollock ML, Pels AE, et al: Medical problems of patients in an outpatient cardiac rehabilitation program. Journal Cardiopulmonary Rehabilitation 1987;7:458-465.
15. Simoons ML, Block P: Toward the optimal lead system and optimal criteria for exercise electrocardiography. American Journal Cardiology 198 1 ;47: 1366- 1374.
16. Van Camp SP, Peterson RA: Cardiovascular complications of outpatient cardiac rehabilitation programs. Journal of the American Medial Association 1986;256:1160-1163.
17. Weiner DA, McCabe CH, Ryan TJ: Prognostic assessment of patients with coronary artery disease by exercise testing. American Heart Journal 1983;105:749-755.
APPENDIX A
INFORMED CONSENT FORM - FOR STUDY PARTICIPATION
INFORMED CONSENT FOR THE PARTICIPATION IN A STUDY CONCERNING
SENSITIVITY OF HEART MONITORING DURING CARDIAC REHABILITATION TO DETECT ECG CHANGES
Purpose of Study: The purpose of this research project is to determine the sensitivity of
heart monitoring systems used during cardiac rehabilitation.
Procedures: In addition to the 12 lead ECG, I give my permission to allow three extra
electrode patches to be placed on my body, along with another monitoring system which
will be strapped to my back with a small harness. Recordings fkom both the 12 lead and
the additional monitoring system will be taken during each stage of my exercise test. I
give my permission to release a copy of my stress test and telemetry tracing.
Confidentiality: I have been informed any presentation or publication of group results
will be done without identifying me by name. My name will only be known to those
involved in the data collection and the principle investigator.
Benefits: This study may contribute to the scientific knowledge regarding the sensitivity
of heart monitoring in the detection of ECG changes during cardiac rehabilitation. This
knowledge may lead to safer exercise sessions in the future for cardiac patients, and result
in quicker assistance from qualified staff if abnormalities occur during cardiac
rehabilitation.
Risks: There are no known risks associated with this study.
Costs of Tests and Procedures: I have been informed that there will be no additional
cost to me because of participation in this study. Neither 1 nor my insurance company will
be charged for the additional equipment used for this study. Ymy insurance company will
be charged the usual rate for the exercise test.
Voluntary Participation: I have been informed that my participation is voluntary and
that I may withdraw as a subject in this study at any time. I have also been informed that
participation in this study does not in any way affect services provided by Franciscan
Skemp Healthcare.
Any questions regarding this study can be directed to the principle investigator, Ben
Crenshaw (784-7815), or the research advisor Dr. John Porcari , 141 Mitchell Hall, UW -
La Crosse, 785-8684. Questions regarding the protection of human subjects may be
addressed to Dr. Garth Tymeson, Chair, UW-La Crosse Institutional Review Board (608)
785-8155 or Terri Pedace, RN, Medical & Nursing Research Coordinator at Franciscan
Skemp Healthcare (609) 791-9462.
Signature Date
Witness Date
APPENDIX B
INFORMED CONSENT FORM - FOR GXT
Fraodscao Skanp Henlthcuc-Medid Center Human Perfomtuna Laboratory
CONSENT FOR EXERCLSE ECG TEST
I, .authoiizDr. . . andsuchas&mU as he may designarc, to adrmmser and conduct the exercise sms WSL This ~ d e s i g n c d . ~ m a s u n m y f i m e s s f o r w o d c d o r s p o r ~ t o ~ ~ ~ o r a b s e n c e o f c l i n i c a l l ~ -h
~ ; a n d / ~ t o e v a I u a a t h e e f f e c t v m a s o f m y ~ ~ .
I--I will walkm amotor driven aeamnin. hning fhc puformamr of physical activity my elem . el gram wiUk manitond and my blwd pressun willbe measured and rcanded at plicdic inarvals. Excr-
cisewiD.bepDgressively - d u ndIeaptdeeedendpointcvding mmcduamxercise
s t r e s s , o r b e c o m e ~ i n a n y way ordevelop any abndrrspcrmse t h e p h y s i c i a u c m i c k n s i ~
whkkver afttr above cam kt
EvayeEortdbe made m ccnduct the test in M a way as to minimize discanfort and& However. I
undemid thatjust as with other types of diagostic mts there are pormdal riskr (appraxkmly 2 m 3 per
10,000) d d withanexudse mr ?hse include episodes of mnsienrlight-, faineing, cbw ~ l c g c r a m p s a n d v c r y r a r e l y k ~ o r s u d d m d t a t h . IfLnrherlmdcntandmatthem
~ ~ e q u ~ l p c d f o r s u c h ~ andmatirspmfaamlprsdare~dtoadmim'sterany arm-
gency -.n&say. I v M y acccp tht iisks asscciated with the above - - ..
APPENDIX C
RAW DATA
19
RAW DATA
Pt# T-HR T-ST E-HR I 11 Ill AVR AVL A M V1 V2 V3 V4 V5 V6
1 Stnd 85 -1.5 84 0 -1 -1 0 0 -1 0 0 0 0 0 -0.5 1 - 1 120 -1.5 I19 0 -1.5 -2 0 0 -1 0 0 0 -1 -1 -1 1 4:W 133 -2 134 0 -2 -2 0 0 -1 0 0 0 -1 -1 -1 1 5:26 148 -3 149 0 -2 -2 0 0 -2.5 0 0 0 -1 -1 -1 1 -2 155 -3 155 0 -3 -3 0 0 -3 0 0 0 -1 -2 -2 1 6:18 157 -3 153 0 -3 -3 0 0 -1 0 0 0 -2 -2 -1.5 1 IPE 157 -3 162 0 -3 -3 0 0 -3 0 0 0 -2 -3 -2 I R-2m 121 -1 122 0 -1 -1 0 0 -1 0 0 0 0 0 0 1 R4m I09 -1 109 0 -1 -1 0 0 -1 0 0 0 0 0 -0.5 1 RSm I08 -1.5 109 0 -1.5 -1 0 0 -1.5 0 0 0 0 0 -0.5 2 stage2 153 0 156 0 0 0 0 0 0 0 0 0 -1 -1 -0.5 2 -3 173 -3 173 0 -1.5 -1 0 0 -1 0 0 0 -1.5 -2 -1.5 2 If'E 164 0 1 8 9 0 0 0 0 0 0 0 0 0 - 1 - 1 0 3 R-2m 1 U -0.5 149 0 -1 0 0 0 -1 0 0 0 0 0 0 3 R4m 118 -0.5 117 0 -1 0 0 0 0 0 0 0 0 0 0 4 -1 189 -1 170 0 -1 -1 0 0 -1 0 0 -1 -1 -1 -1 4 -2 181 -1 185 0 -1 -1 0 0 -2 0 0 -1 -1 -1.5 -1 4 Moc 190 -1 192 7 -1 -1 0 0 0 0 0 -1 -1 -1 -1 4 IPE 193 -1 188 0 -1 -1 0 0 -1 0 0 -1 -1 -1 -1 4 R-2m 148 -0.5 152 0 -1 -1 0 0 0 0 0 0 -0.5 -0.5 -0.5 4 R4m 111 -1 114 0 -1 -1 0 0 -1 0 0 0 -0.5 -0.5 -0.5 5 Strpal 84 -1 86 0 -1 0 0 0 0 0 0 0 -0.5-0.5-0.5 5 Sap 2 97 -2 97 0 -1.5 -0.5 0 0 -0.5 0 0 0 -0.5 -1 -1 5 R-0:28m 03 -2 95 0 -1 -1 0 0 -1 0 0 0 -1 -1 1 5 R-2m 86 -2 88 0 -1 -1 0 0 -1 0 0 0 -0.5 -1 -1 5 R4m 81 -2 82 0 -1 -1 0 0 -1 0 0 0 -0.5 -1 -1 5 RSm 73 -2 74 0 -1 0 0 0 -0.5 0 0 0 0 0 -0.5 8 aaga2 134 -1 138 0 -0.5 -0.5 0 0 -0.5 0 0 0 0 -0.5 -0.5 8 -3 in -I 153 o - I -I o o -I o o o -I -I -I 8 RQ:I5m -0.5 152 0 -1 -1 0 0 -0.5 0 0 0 0 -0.5 -0.5 7 5:IO 112 0 108 0 0 0 0 0 0 0 -0.5 -1 -1 -1 -1 7 St.ge2 114 -1 108 0 0 0 0 0 -1 0 -1 -1 -2 -2 -1 7 IPE 109 -1 110 0 0 0 0 0 0 0 -1.5 -2 -2 -2 -1 7 R4:13m 108 -0.5 108 0 0 0 0 0 0 0 -2 -2 -2 -2 -1 7 RQ43m 110 -0.5 104 0 0 0 0 0 0 0 -1 -1 -1.5 -1.5 -1 7 R-2m 94 -1 Q6 0 0 0 0 0 0 0 0 -1 -2 -2 -1 7 R4m 81 -1 81 0 0 0 0 0 0 0 -1 -1 -1 -1 -1 7 R&n 79 -1 80 0 0 0 0 0 0 0 0 -1 -1 -1 -0.5 8 2:U 117 -1 118 0 -1 -1 0 0 -1 0 0 0 0 -1 -1 8 -1 120 I 119 0 -1 -1 0 0 -1 0 0 0 0 -1.5 -1 8 3:41 130 -2 129 0 -1 -1 0 0 - I 0 0 0 -1 -1.5 -1 8 Moc 131) -3 138 0 -2 -2 0 0 -2 0 0 0 -2 -2 -2 8 IPE 141 -2 139 0 -2 -2 0 0 -2 0 0 0 -2 -2 -2 8 RQ36n 133 -2 133 0 -2 -1.5 0 0 -2 0 0 0 -2 -2 -2 8 R Q 5 h 127 -2 129 0 -2 -2 0 0 -2 0 0 0 -2 3 3 0 R-1:23m 112 -2 114 0 -2 -2 0 0 -2 0 0 0 -2 -2 -2 8 R-Zm 105 -2 105 0 -2 -2 0 0 -2 0 0 0 -2 -2 -2
~ -~ ~-~~
Pt # T i T-HR 1-ST E-HR I 11 Ill AVR AVL A M Vl V2 V3 V4 V5 V6 .. .
19 R&n 83 0 8 4 0 - 1 - 1 0 0 - 1 0 0 0 0 0 0 2 0 - 1 120 - 1 1 1 9 0 0 0 0 0 0 0 0 0 0 0 0 20 Mu 182 0 1 8 8 0 0 0 0 0 0 0 0 -1 -1 -1 -1 20 IPE 160 -1 164 0 -1 -1 0 0 -1 0 0 0 -2 -2 -1 20 R0:& 148 0 147 0 -1 -1 0 0 -1 0 0 0 -1 -1 -1 20 R4m 1 0 0 - 1 1 1 5 0 0 0 0 0 0 0 0 0 0 0 0 20 R&n 90 -1 8 9 0 0 0 0 0 0 0 0 0 0 0 0 21 strg.2 155 0 1 5 8 0 -1 -1 0 0 0 0 0 0 -1 -1 -1 21 Stag03 168 0 187 0 0 -1 0 0 0 0 0 0 0 -1 -1 21 Mu 171 0 170 0 -1 -0.5 0 0 -0.5 0 0 0 -0.5 -0.5 -0.5 22 457 214 -3 208 0 0 0 0 0 0 0 0 0 -1 -1 -1 22 R0:2Om 157 0 159 0 -1 -1 0 0 -1 0 0 0 0 0 0 23 strg.1 121 0 1 2 2 0 0 0 0 0 0 0 0 0 -1 -1 0 23 -2 142 0 144 0 -1 -1 0 0 0 0 0 0 -1 -1 -1 23 Mu 139 0 138 0 -1 0 0 0 -1 0 0 0 -1 -1 0 23 R4m 83 0 80 0 0 0 0 0 -1 0 0 0 - 1 -1 24 5:W 188 -1 168 0 -1 -1 0 0 -1 0 0 0 -1 -1 -1 24 Mu 169 -1 170 0 -1 -1 0 0 -1 0 0 0 -1 -1 -1 24 IPE 189 -1 169 0 -1 -1 0 0 0 0 0 0 -1 -1 -1 24 R-2m 144 -1 145 0 0 0 0 0 0 0 0 0 -0.5 -0.5 -0.t 24 R4m 126 -1 127 0 0 0 0 0 0 0 0 0 -0.5-0.5 0 24 RSm 118 -1 118 0 0 0 0 0 0 0 0 0 0 -0.5 0 24 R8m 113 -1 1 1 3 0 0 0 0 0 0 0 0 0 0 0 0 24 R8:45m 113 -1 113 0 0 0 0 0 0 0 0 0 0 0 0 25 -2 133 0 133 0 -1 -1 0 0 -1 0 0 0 0 -1 -1 25 Mu 134 0 134 0 0 0 0 0 0 0 0 0 -1 -1 -1 25 R-2m 00 -1 100 0 -0.5 0 0 0 0 0 0 0 -0.5 -0.5 0 25 R4m 88 -1 93 0 -0.5 0 0 0 -0.5 0 0 0 -0.5 -0.5 -0.5 25 R&n 78 -1 TI 0 0.5 0 0 0 0 0 0 0 0 -0.5 0 2 6 - 3 96 - 1 1 0 7 0 0 0 0 0 0 0 0 0 0 0 0 26 -4 125 -1 125 0 -1 0 0 0 0 0 0 0 -1 -1 -I 28 Mu 130 -1 138 0 -1 -1 0 0 -1 0 0 0 -1 -1 -1 28 IPE 125 -1 132 0 -1 0 0 0 0 0 0 0 0 -1 -1 27 - 3 142 -1 142 0 -0.5 -0.5 0 0 -0.5 0 0 0 0 -0.5 -0.5 27 Mu I60 -1 160 0 -1 0 0 0 0 0 0 0 0 -1 -1 20 Mu 130 0 130 0 0 0 0 0 0 0 0 0 -1 -1 -1 29 IPE 115 -1 114 0 0 0 0 0 0 0 0 0 -1 -1 -1 29 R&n 78 - 1 7 9 0 0 0 0 0 0 0 0 0 0 - 0 . 5 - 0 . 5 30 strg.1 114 -0.5 116 -1 0 0 0 0 0 0 0 0 -0.5 0 0 30 51.0.2 131 0.5 132 -1 0 0 0 0 0 0 0 0 -0.5 -0.5 0 30 st.gl3 150 -1 1 5 0 - 1 0 0 0 0 0 0 0 -1 -1 1 0 30 51.0.4 182 -0.5 163 -1 0 0 0 0 0 0 0 -1.5 -1 1 0 30 IPE 156 0 160 -1 0 0 0 0 0 0 0 -0.5 -0.5 0 0 31 Mu 162 0 191 0 0 0 0 0 0 0 0 0 -1 -0.5-0.5 3 2 s t r g . 3 1 8 8 0 1 5 5 0 0 - 1 0 0 - 1 0 0 0 0 0 0 32 Mu 173 0 1 7 4 0 0 -1 0 0 - 1 0 0 0 0 0 0 33 Ma 112 0 114 0 0.5 0 0 0 -0.5 0 0 0 -1 -1 0 33 IPE 115 0 1 1 3 0 0 0 0 0 0 0 0 0 -1 -1 0 34 IPE 150 0 152 0 -1 -1 0 0 0 .5 0 0 0 0.5 0.5 -0.5 36 Ma 148 0 1 4 8 0 0 0 0 0 0 0 0 0 0 - 1 - 1
Pi # Time T-HR T-ST E-HR I 11 Ill AVR AVL AVF V1 V2 V3 V4 V5 V6 A,--.. -
36 R-6in 83 0 73 0 -0.5 0 0 0 0 0 0 0 -0.5 -': -).5 F-1 753 120 - 1 1 1 9 0 0 0 0 0 0 0 0 0 0 0 0 F-2 IPE 1 4 8 - 1 1 6 0 0 0 0 0 0 0 0 0 0 0 0 0 F-2 R-2m 114 -1 1 2 3 0 0 0 0 0 0 0 0 0 0 0 0 F-2 R4m 1 0 8 - 1 1 0 9 0 0 0 0 0 0 0 0 0 0 0 0 F-3 7:46 1 0 9 - 1 1 0 8 0 0 0 0 0 0 0 0 0 0 0 0 F-3 Max 115 -1 1 1 6 0 0 0 0 0 0 0 0 0 0 0 0 F-3 IPE 116 -1 1 1 6 0 0 0 0 0 0 0 0 0 0 0 0 F-3 R-2m 88 -1 9 0 0 0 0 0 0 0 0 0 0 0 0 0 F-3 R4m 77 -1 7 7 0 0 0 0 0 0 0 0 0 0 0 0 F-3 R-6m 79 -1 7 8 0 0 0 0 0 0 0 0 0 0 0 0
APPENDIX D
COMPARISON BETWEEN INDIVIDUAL LEADS AND TELEMETRY
Telemetry vs. Inferior Leads
P i# Time T-HR T-ST ECG-HR I 11 Ill AVF V l V2 V3 V4 V5 V6
1 Stand 85 -1.5 84 0 -1 -1 -1 0 0 0 0 0 -0.5 1 R-2m 121 -1 122 0 -1 -1 -1 0 0 0 0 0 0 1 R4m 109 -1 109 0 -1 -1 -1 0 0 0 0 0 -0.5 1 R6m 106 -1.5 109 0 -1.5 -1 -1.5 0 0 0 0 0 -0.5 3 R-2m 144 -0.5 149 0 -1 0 -1 0 0 0 0 0 0 3 R4m 116-0 .5 117 0 -1 0 0 0 0 0 0 0 0 4 R-2m 148 -0.5 152 0 -1 -1 0 0 0 0 -0.5 -0.5 -0.5 4 R4m 111 -1 114 0 -1 -1 -1 0 0 0 -0.5 -0.5 -0.5 5 Stage 1 84 -1 86 0 -1 0 0 0 0 0 -0.5 -0.5 -0.5 5 R6m 73 -2 74 0 -1 0 -0.5 0 0 0 0 0 -0.5 6 R-O:l5m 150 -0.5 152 0 -1 -1 -0.5 0 0 0 0 -0.5 -0.5
11Stage2 151 -0.5 148 0 -1 -1 -1 0 0 0 0 0 0 16 R-2117 137 -1 140 0 -1 -1 -1 0 0 0 -0.5 -0.5 -0.5 16 R4m 126 -0.5 127 0 -1 -1 -1 0 0 0 -0.5-0.5-0.5 17 R-2m 100 -1 91 0 -1 -1 -1 0 0 0 -0.5 -0.5 -0.5 17 R-4m 73 -0.5 74 0 -1 -1 -1 0 0 0 0 -0.5 -0.5 19 R6m 83 0 84 0 -1 -1 -1 0 C 0 0 0 0 21 Max 171 0 170 0 -1 -0.5 -0.5 0 0 0 -0.5 -0.5 -0.5 22R-0:20m 157 0 159 0 -1 -1 -1 0 0 0 0 0 0 32Stage3 166 0 155 0 0 -1 -1 0 0 0 0 0 0 32 Max 173 0 174 0 0 -1 -1 0 0 0 0 0 0 34 IPE 150 0 152 0 -1 -1 -0.5 0 0 0 -0.5 -0.5 -0.5
Telemetry vs. Lateral Leads
Pt # Time T-HR T-ST ECG-HR I 11 Ill AVF V1 V2 V3 V4 V5 V6
10 Stage1 114 -0.5 116 -1 0 0 0 0 0 0 -0.5 0 0 10 Stage2 131 -0.5 132 -1 0 0 0 0 0 0 -0.5 -0.5 0 14Stage2 150 -1 153 0 0 0 0 0 0 0 -0.5 -1 -1 30s-1 114 -0.5 116 -1 0 0 0 0 0 0 -0.5 0 0 30 Stage2 131 -0.5 132 -1 0 0 0 0 0 0 -0.5 -0.5 0 35 Max 148 0 148 0 0 0 0 0 0 0 0 -1 -1 36 R6m 83 0 73 0 -0.5 0 0 0 0 0 -0.5 -1 -0.5
Tekmetry vs. Anterior Leads
Pt# T i T-HR TST ECG-HR I 11 Ill AVF V l V2 V3 ' ~ 4 V5 V6
31 Mox 162 0 I91 0 0 0 0 0 0 0 -1 -0.5 -0.5
Telemetry vs. Anterior 8 Lateral Leads
~t # ~i T-HR T-ST ECG-HR I 11 Ill AVF V1 V2 V3 V4 V5 V6
2S-2 153 0 155 0 0 0 0 0 0 0 -1 -1 -0.5 2 IPE 164 0 169 0 0 0 0 0 0 0 -1 -1 0 7 5:lO 112 0 106 0 0 0 0 0 -0.5 -1 -1 -1 -1 7 IPE 109 -1 110 0 0 0 0 0 -1.5 -2 -2 -2 -1 7 R-0:13m 106 -0.5 106 0 0 0 0 0 -2 -2 -2 -2 -1 7 R-0:43m 110 -0.5 104 0 0 0 0 0 -1 -1 -1.5 -1.5 -1 7 R-2m 94 -1 96 0 0 0 0 0 0 -1 -2 -2 -1 7 R4m 81 -1 81 0 0 0 0 0 -1 -1 -1 -1 -1 7 R-6m 79 -1 80 0 0 0 0 0 0 -1 -1 -1 -0.5
10 Stage1 114 -0.5 116 -1 0 0 0 0 0 0 -0.5 0 0 1OSbg02 131 -0.5 132 -1 0 0 0 0 0 0 -0.5 -0.5 0 10 Stew4 182 -0.5 163 -1 0 0 0 0 0 -1.5 -1 -1 0 10 IPE 155 0 160 -1 0 0 0 0 0 -0.5 -0.5 0 0 14Stew2 150 -1 153 0 0 0 0 0 0 0 -0.5 -1 -1 15Stage2 150 -1 153 0 0 0 0 0 0 0 -1 -1 -1 15 Max 166 -1 169 0 0 0 0 0 0 0 -1 -1 -1 20 Max 162 0 166 0 0 0 0 0 0 -1 -1 -1 -1 22 457 214 -3 208 0 0 0 0 0 0 0 -1 -1 -1 23 Stage I 121 0 122 0 0 0 0 0 0 0 -1 -1 0 25 Max 1 3 4 0 1 3 4 0 0 0 0 0 0 0 - 1 - 1 - 1 28 Max 130 0 130 0 0 0 0 0 0 0 -1 -1 -1 29 IPE 115 -1 114 0 0 0 0 0 0 0 -1 -1 -1 30s-I 114 -0.5 116 -1 0 0 0 0 0 0 -0.5 0 0 30 S-2 131 0 .5 132 -1 0 0 0 0 0 0 -0.5 -0.5 0 30s-3 150 -1 150 -1 0 0 0 0 0 -1 -1 -1 0 30s-4 162 -0.5 163 -1 0 0 0 0 0 -1.5 -1 -1 0 30 IPE 155 0 160 -1 0 0 0 0 0 -0.5 -0.5 0 0 31 Muc 162 0 I91 0 0 0 0 0 0 0 -1 -0.5 -0.5 33 Max 112 0 114 0 -0.5 0 -0.5 0 0 0 -1 -1 0 33 IPE 115 0 113 0 0 0 0 0 0 0 -1 -1 0 35 Max 148 0 148 0 0 0 0 0 0 0 0 -1 -1 36 R&n 83 0 73 0 -0.5 0 0 0 0 0 -0.5 -1 -0.5
Telemetry w. Combination of Inferior. Anterior, & Lateral Leads - Pt# TI~M T-HR T-ST ECG-HR I 11 Ill AVF V1 V2 V3 V4 V5 V6
I Strg. I 120 -1.5 119 0 -1.5 -2 -1 0 0 0 -1 -1 -1 1 4:W 133 -2 134 0 -2 -2 -1 0 0 0 -1 -1 -1 1 528 148 3 149 0 -2 -2 -2.5 0 0 0 -1 -1 -1 l S t r g . 2 155 -3 155 0 -3 3 -3 0 0 0 -1 -2 -2 10:18 157 3 153 0 3 3 -1 0 0 0 -2 -2 -1.5 1 IPE 157 3 162 0 3 -3 -3 0 0 0 -2 -3 - 2 1
190 -1 192 ? -1 -1 0 0 0 -1 -1 -1 -1 193 -1 188 0 -1 -1 -1 0 0 -1 -1 -1 -1
5 Stage 2 97 -2 97 0 -1.5 -0.5 -0.5 0 0 0 -0.5 -1 -1 5 R-0:26m 93 -2 95 0 -1 -1 -1 0 0 0 -1 -1 1
86 -2 88 0 -1 -1 -1 0 0 0 -0.5 -1 -1 81 -2 82 0 -1 -1 -1 0 0 0 -0.5 -1 -1
8Stage1 120 -1 119 0 -1 -1 -1 0 0 0 0 -1.5 -1 130 -2 129 0 -1 -1 -1 0 0 0 -1 1 -1 136 -3 138 0 -2 -2 -2 0 0 0 -2 -2 -2 141 -2 139 0 -2 -2 -2 0 0 0 -2 -2 -2
8R-0:36m 133 -2 133 0 -2 -1.5 -2 0 0 0 -2 -2 -2 8 R-0:54m 127 -2 129 0 -2 -2 -2 0 0 0 -2 -2 -2 8 R-1:23m 112 -2 114 0 -2 -2 -2 0 0 0 -2 -2 -2
105 -2 105 0 -2 -2 -2 0 0 0 -2 -2 -2 8 R-3:28m 104 -2 103 0 -2 -1 -2 0 0 0 -2 -3 -2
82 -2 81 0 -2 -1 -1 0 0 0 -3 -3 -2 83 0 -2 0 -1 0 0 0 -2 -2 -1 85 0 -1 0 -1 0 0 0 -2 -2 -1
76 -2 77 0 -1 0 -1 0 0 0 -2 -2 -1 81 0 -1 0 -1 0 0 0 -2 -2 -1 86 0 -1 0 -1 0 0 0 -1 -1 -1
8R-l2:19m 74 -1 72 0 -1 0 -1 0 0 0 -1 -1 0 78 0 -1 0 -1 0 0 0 -1 -1 0
179 0 178 0 -1 -1 -1 0 0 0 0 -1 0 155 -1 169 0 -1 -1 -1 0 0 0 0 -1 0 157 -0.5 181 0 -1 -1 -1 0 0 0 0 -1 0 157 -0.5 180 0 -1 -1 -0.5 0 0 0 0 -1 0 111 0 112 0 -1 -1 -1 0 0 0 -1 -1 -1 122 -1 122 0 -1 -1 -1 0 0 0 -1 -1 -1 169 -1 170 0 -1 -1 -1 0 0 0 -1.5 -2 -1.5 166 -1 167 0 -1 -1 -1 0 0 0 -1 -2 -1 134 -1 138 0 -1 0 0 0 0 0 -0.5 -2 -1
16 Stage 2 143 -1 143 0 -1 -1 -1 0 0 0 -1 -1 -1 189 -1 167 0 -2 -2 -2 0 0 0 -2 -2 -2 162 -1 168 0 -1 -1 -1 0 0 0 -1 -1 -1
APPENDIX E
DIFFERENCE IN MAGNITUDE
DIFFERENCE IN MAGNITUDE
PI # Time T-ST Greatest Diff
1 Stand -1.5 -1 -0.5 1 Stpoe 1 -1.5 -2 0.5 1 4:w -2 -2 0 1 5:28 -3 -2.5 -0.5 1 Stage2 -3 -3 0 1 6:18 -3 -3 0 1 IPE -3 -3 0 1 R-2m -1 -1 0 1 R4m -1 -1 0 1 RSm -1.5 -1.5 0 2 Stpoe2 0 -1 1 2 Stage3 -3 -2 -1 2 IPE 0 -1 1 3 R-2m -0.5 -1 0.5 3 R-4m -0.5 -1 0.5 4 stage1 -1 -1 0 4 stage2 -1 -2 1 4 MU -1 -1 0 4 IPE -1 -1 0 4 R-2m -0.5 -1 0.5 4 R4m -1 -1 0 5 Stage1 -1 -1 0 5 Stage 2 -2 -1.5 -0.5 5 R-0:26m -2 -1 -1 5 R-2m -2 -1 -1 5 R4m -2 -1 -1 5 RSm -2 -1 -1 6 stage 2 -1 -0.5 -0.5 6 stage3 -1 -1 0 8 R-O:lSm -0.5 1 0.5 7 5:lO 0 -1 1 7 sage2 -1 -2 1 7 IPE -1 -2 1 7 R-0:13m -0.5 -2 1.5 7 R-0:43m -0.5 -1.5 1 7 R-2m -1 -2 1 7 R-4m -1 -1 0 7 RSm -1 -1 0 8 2 : u -1 -1 0 8 1 -1 -1.5 0.5 8 341 -2 -1.5 -0.5 8 Mu -3 -2 -1 0 IPE -2 -2 0 8 R-O:38m -2 -2 0
R-12m -1
R-14m -1 -0.5 -0.5
8- 1 -0.5 -1 0.5 Stage 2 -0.5 -1 0.5
-1 -0.5 -0.
-1 -0.5 -0. -1 -0.5 -0.
R4m -0.5 -1
Pt # Time T-ST Greatest Diff
18 Max 0 -1 1 18 IPE -1 -1 0 18 R-2m -f -1 0 18 R4m -0.5 -1 0.5 19 Stage 1 -1 -1 0 19 Max -1 -2 1 19 IPE -1 -1 0 19 R-2m -1 -1 0 19 R4m -1 -1 0 19 Ram 0 -1 1 20 Stage 1 -1 0 -1 20 Max 0 -1 1 20 IPE -1 -2 1 20 R-O:48m 0 -1 1 20 R4m -1 0 -1 20 Ram -1 0 -1 21 Stage2 0 -1 1 21 Stage3 0 -1 1 21 Max 0 -1 1 22 457 -3 -1 -2 22 R-0:20m 0 -1 1 23 Stage1 0 -1 1 23 S-2 0 -1 1 23 Max 0 -1 1 23 R4m 0 -1 1 24 5:09 -1 -1 0 24 Max -1 -1 0 24 IPE -1 -1 0 24 R-2m -1 -0.5 -0.5 24 R4m -1 -0.5 -0.5 24 RSm -1 -0.5 -0.5 24 R-8m -1 0 -1 24 R-8:45m -1 0 -1 25 S-2 0 -1 1 25 Max 0 -1 1 25 R-2m -1 -0.5 -0.5 25 R4m -1 -0.5 -0.5 25 RSm -1 -0.5 -0.5 26 S-3 -1 0 -1 26 Stage4 -1 -1 0 26 Max -1 -1 0 26 IPE -1 -1 0 27 S W 3 1 -0.5 -0.5 27 Max -1 -1 0 28 M u 0 -1 1 29 IPE -1 -1 0
Pt # Time T-ST Greatest Diff
29 R-6m -1 -0.5 -0.5 30 Stage 1 -0.5 -1 0.5 30 Stage 2 -0.5 -1 0.5 30 Stage3 -1 -1 0 30 Stage 4 -0.5 -1.5 1 30 IPE 0 -1 1 31 Max 0 -1 1 32 Stage 3 0 -1 1 32 Max 0 -1 1 33 Max 0 -1 1 33 IPE 0 -1 1 34 IPE 0 -1 1 35 Max 0 -1 1 38 R-6m 0 -1 1 F-1 753 -1 0 -1 F-2 IPE -1 0 -1 F-2 R-2m -1 0 -1 F-2 R4m -1 0 -1 F-3 7:46 -1 0 -1 F-3 Max -1 0 -1 F-3 IPE -1 0 -1 F-3 R-2m -1 0 -1 F-3 R4m -1 0 -1 F-3 Ram -1 0 -1
APPENDIX F
REVIEW OF LITERATURE
REVIEW OF LITERATURE
Introduction
Monitoring cardiac patients during rehabilitation for arrhythmias and appropriate
heart rate response has been recognized and utilized as standard of care since the 1960's
when exercise was shown to be useful in returning these patients to their best possible
state of health. Although exercising cardiac patients has been shown to be relatively
cardiac events can still occur and as the field of cardiac rehabilitation has emerged,
the question of the ability to identify and intervene in patients suffering from ischemic
disease was put forth. This necessity is alluded to in a study done by Hossack on the
incidence of cardiac events during cardiac rehabilitation that reported that 18 of the 25
patients who went into cardiac arrest had ST-segment depression during exercise
training.' There were three features that these patients shared: above normal exercise
performance; a poor compliance to training heart rate range; and a markedly ischemic
exercise ECG. Questions smunding the ability to detect ischemic changes during
exercise have plagued the cardiac rehabilitation community for some time. Thus, this
review will examine the significance of ST-segment changes seen during exercise and the
reliability of telemetry to detect changes.
Sinnificance of ST-Segment Changes during Exercise
Because of the nature of the left main coronary artery which supplies the left
ventricle, the seriousness of having disease to this vessel and the ability to screen for it
noninvasively has lead to studies that involve exercise testing. There have been several
studies that have attempted to predict left main disease. Weiner et a ~ . ~ ' defined a strongly
positive exercise test as more than 2 mm downsloping ST-segment depression involving
5 or more leads, occurring at less than 5 METs, and which persisted late into recovery.
Blumenthal and co-workers2 validated these findings a year later. Lee, Thomas, and
oldm man'^ found similar results using only three variables: angina type, age, and amount
of exercise-induced ST-segment depression. In other words, the greater the magnitude of
ST-depression, the more wide spread the ST-depression, and the earlier its onset occurs,
the more serious the disease.
Several other studies have been done in attempt to predict deadly cardiac events
by reviewing exercise and electrocardiogram responses in patients with myocardial
infarctions. A study done by Klein and colleagues'0 showed that patients suffering from
an myocardial infarction who underwent a sub-maximal exercise test prior to hospital
discharge and showed exercise-induced ST-segment depression had twice the risk for
suffering rc-infarction or death compared to patients without ST-segment depression.
Also, for those patients without diagnostic Q-waves appearing on their pretest
electrocardiogram, the risk i n c d to 11 times for an abnormal ST-segment response.
Krone et al." PlsO showed a three times higher incidence of cardiac eventi in the year
after an MI in patient8 with exercise induced ischemia (angina or ST depression, or both)
compared to those with a normal pre-discharge exercise test. Sami .md colleagues18
studied 200 post-M1 men who were considered a relatively low-risk group. Each man
was tested serially approximately five times each from 3 to 52 weeks post-MI. Patients
who showed exercise-induced PVCs or ischemic ST-segment depression within 11 weeks
after infarction had an increased risk of subsequent cardiac events.
These studies show the significance of identifying and treating risk factors
aggressively in these patients who continue to show ST-segment depression. Althodgh
new pharmacological interventions may have decreased these odds since the date of these
earlier studies, the increased speed at which patients are discharged from the hospital
post-MI or bypass surgery allows for some of these patients to have potential problems
go undetected, increasing their dependence on telemetry in cardiac rehabilitation to
identify these patients. Unfortunately, there have been few studies that have looked
specifically at the sensitivity of telemetry monitoring to ST-segment changes. Most of
the assumptions in the field of cardiac rehabilitation in regards to the sensitivity of
telemetry to detect ST-segment are based on several factors; the use of a single lead in
monitoring, the unreliability of !!Y kferior lead to detect ischemia, and the fact that the
filtering and signal processing of the ECG in telemetry systems is not clearly defined.
The lack of reliability of the inferior lead (which is commonly used in telemetry)
as an independent marker to detect ischemia is well doc~mented.'~~ 20.27 However, the
inferior lead has been shown to be helpful for diagnosis of severe ischemia because
multiple-lead involvement has been associated with multi-vessel2' and left main
disease?8 Mark and co-workers5. ''s showed that ST-segment depression does not
localize the area of ischemia and most of the studies suggest that VS is the best lead in
indicating true ischemic disease.'. 16* l9 It is with these studies in mind that ST-segment
changes observed on telemetry are often disregarded unless the changes are large in
magnitude and the patient is symptomatic.
Sensitivitv of Telemetrv Monitoring
Another reason that has cast doubt on the reliability of telemetry to detect ST-
segment changes is due to the insufficient frequency response of telemetry in detecting
the ST-segment. A recorder with an inadequate frequency response can either
artifactually induce ST-segment depression in normal individuals or show upsloping
depression when horizontal depression is actually present?9 The majority of 12-lead
exercix testing monitoring equipment has a frequency response of 0.01 to 20-40 Hz.
Monitoring equipment should have a diagnostic bandwidth for ECG frequency response
of 0.05 to 100 Hz to adequately observe ST-segment changes?' Telemetry, specifically
the Quinton Q-Tel which was used in this study, has a frequency response of 0.5 to 40
Hz. Reasoning for the lack of sensitivity has been because the need for ECG monitoring
has been to determine dysrrhythmias and major ischemic response and there is not a great
need for the sensitivity and specificity required during exercise testing?' However, the
reliability of the ST-segment changes that are seen on telemetry are still in question and
there arc no studies that have been done specifically on telemetry that have indicated how
reliable or predicable telemetry is in detecting these changes. The majority of research
done on the d t i v i t y of monitoring the ST-segment other than on the standard 12-lead
ECG has been done on Holter monitoring systems.
Stephen Glasser in his book, The Clinical Approach to Exercise ~ e s t i n ~ , 6 alludes
to the lack of enthusiasm for the evaluation of ST-segment changes from early Holter
recordings systems because they did not accurately reproduce the low frequency ST-
segment changes. This is because of the inadequate characteristics of frequency response
(0.5 to 50 Hz), which has since been rectified with the advancement of technology.25 In
the evolution of Holter monitoring systems, Wolf et al?' compared 24-hour ambulatory
monitoring to a multistage bicycle ergometer test to detect ST-T changes in 47 patients.
Bicycle ergometry tests were preformed and then patients were monitored for one week
after the test. They found a good correlation between the multistage bicycle test (25
positive tests) and 24-hour ambulatory monitoring (24 positive tests), with 21 patients
showing similar changes on both tests. Although Holter monitoring used a Vs
configuration, a discrepancy was found only in seven patients. Wolf et al. attributed this
tc the fact that only one chest lead was being recorded during Holter monitoring and
changes seen during ergometry were confined to the limb leads in three of these patients.
Interestingly, however, in two other patients with ST-T changes confined to the limb
leads had revealed similar changes to seven other patients during monitoring ergometry.
Wolf et al. concluded the combined application of both tests would increase the yield of
ST-T changes in patients with suspected ischemic heart disease, however, they did not do
any follow-up with coronary angiographic data.
In another study done by Crawford and colleagues~ ambulatory monitoring was
compared with graded exercise testing to selective coronary cineangiography in 70
patients (39 with coronary artery disease and 31 without disease). Although they
concluded that continuous ambulatory monitoring is of limited value for detecting or
excluding coronary artery disease, the sensitivity of ambulatory monitoring was similar to
that of a graded exercise test (62% vs. 67%). but specificity was greater in graded
exercise testing than in ambulatory monitoring (75% vs. 61%). In comparing both the
graded exercise test and Holter monitoring, methodology was a little sounder than in the
study done by Wolf et al." Exercise tests were done to maximal levels, and to be sure
that both tests were equisensitive for ST changes, two patients underwent treadmill
exercise while wearing a Holter monitor, which was found to be identical in VS.
Unfortunately, Crawford and colleagues did not specify how well ambulatory monitoring
and graded exercise testing correlated on a test by test basis.
Several of the above studies done on Holter monitoring systems emphasize that
continuous ambulatory ECG monitoring is valuable if used along with exercise testing in
the detection of ischemic heart disease, but none promote it to be equally diagnostic.
Other studies have also suggested the ambulatory ECG monitoring may be more useful in
detecting arrhythmic and ischemic events than exercise testing because of the length of
monitoring that occurs and the ability to word the ECG during specific tasks that are not
as reproducible during an exercise test."' Telemetry may have similar qualities because
of the length of time and frequency of monitoring. In the future, telemetry monitoring
may evolve to be equally as useful in detecting these changes. However, currently, there
are s c v d differences bctwem the Holtcr monitoring system that was being used in the
above studies and telemetry. One, the lead that is ob8ened during Holter monitoring
(VS) is mon reliable for detecting ischemic disease verses the lead that is generally
observed during exercise training (lead 11). 1, 16.19 The second issue is that as the use of
continuous ambulatory monitoring has progressed, the limitation that the frequency
response gave in detecting low frequency ST-segment changes638. '7.13.14.3' was
improved upon, thus the transfer of relative data to the detection of ST-segment changes
observed during telemetry became less relevant because most telemetry systems have not
made these changes. However, as questions and demands were put forth in regards to the
usefulness of continuous ambulatory monitoring, research and advancements were made
by the scientific and commercial industries to meet those needs. These same questions
are now being asked of the capabilities of telemetry systems.
For instance, two studies from the University of Iowa Hospitals and Clinics that
investigated the importance of ECG monitoring during cardiac rehabilitation observed the
incidence of "physician reportable" events that occurred. One study looked at events in
phase I cardiac rehabilitation, the other at events occuning in phase 11. In the study
looking at Phase I;46 of 173 acute myocardial infarction patients had at least one
"physician reportable" event that occurred.22 Forty of these events were ischemic events
and six were arrhythmic in nature. Sixty-seven percent of these patients required a
change in medical management. Telemetry monitoring that was used had a frequency
response of 0.05 Hz and monitored leads I, V1, MCLS, and CMS.
During phase I1 cardiac rehabilitation monitoring, using diagnostic quality bipolar
substitutes for Vs (CMs, MCLs), Lounsbury and co-workers'%trospectively reviewed
the records of 939 patients for three specific events; arrhythmias, ischemic ECG changes,
and exercise-induced hypotension. They proceeded to evaluate how many of these
events resulted in a revision in medical management. They found 242 ischemic episodes
in 161 patients (17%), 255 episodes of significant arrhythmia in 124 patients (13%), and
754 episodes of hypotension in 315 patients (34%). Revision in medical management
due to the findings in this study occurred in 69% of the ischemic patients, 63% in patients
with significant arrhythmias, and 39% in patients with hypotension. This study suggests
that the primary purpose for monitoring in phase I1 cardiac rehabilitation is the detection
of silent ischemia and the secondary purpose for monitoring is the detection of
asymptomatic arrhythmia^.'^ However, monitoring must be of diagnostic quality in
frequency response and lead choice. Additionally, probably of more importance, when
events are detected, they usually result in a revision in medical management.
Conclusion
Because there is still dispute regarding accuracy in cardiac rehabilitation, further
study needs to be conducted to determine the effectiveness of telemetry to detect
ischemic changes, especially those systems commonly used that monitor lead I1 and use a
high frequency response. More importantly, however, further study is needed to indicate
the relevance of ST-segment changes that are currently observed on such systems. Such
studies could lead to better medical management of patients by indicating whether or not
changes seen on telemehy during cardiac rehabilitation are reflective of changes
occurring on a 12-lead.
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