ecg in pacemaker malfunction sriram rajagopal, southern railway hospital, perambur,chennai
TRANSCRIPT
ECG in Pacemaker Malfunction
Sriram Rajagopal,
Southern Railway Hospital,
Perambur,Chennai
ECG in “Pacemaker Malfunction”(ECGs in Pacemaker Function
Assessment)
Sriram Rajagopal,
Southern Railway Hospital,
Perambur,Chennai
Implantable pulse generator (IPG)
Lead wire(s)
Implantable Pacemaker Systems Contain the Following Components:
Pseudomalfunctions
Pseudomalfunctions are defined as: Unusual Unexpected Eccentric
ECG findings that appear to result from pacemaker malfunction but that represent normal pacemaker function
ECGs in Patients with Pacemakers
• Basic principles of pacing
• Background information required
• Systematic approach
• Examples with single chamber pacing
• Examples with dual chamber pacing
Overview :
ECGs in Patients with Pacemakers
• Basic principles of pacing
• Background information required
• Systematic approach
• Examples with single chamber pacing
• Examples with dual chamber pacing
Overview :
ECGs in Patients with Pacemakers
• Pace
• Sense – ( what ? )
• Respond – Inhibit , Trigger or Dual
• Respond to increased metabolic demand
by providing rate responsive pacing
• Provide diagnostic information stored by
the pacemaker
What do pacemakers do ?
Timing Intervals Are Expressed in Milliseconds
• One millisecond = 1 / 1,000 of a second
60,000
ms BPM
Rate Conversion
• Conversion– Pacing rate in PPM divided by 60,000 = ms
• 60,000 / 60 PPM = 1000 ms
– Interval in ms divided by 60,000 = PPM• 60,000 / 1000 ms = 60 PPM
Paced Rhythm Recognition
VVI / 60
Paced Rhythm Recognition
VVI / 60
Paced Rhythm Recognition
AAI / 60
Noncapture is Exhibited By:• No evidence of depolarization after pacing artifact
Loss of capture
No Output
• Pacemaker artifacts do not appear on the ECG; rate is less than the lower rate
Pacing output delivered; no evidence of pacing spike is seen
Fusion Beat
• Definition: The combination of an intrinsic beat and a paced beat.
• The morphology varies; in other words, a fusion beat doesn’t really look like a paced beat or an intrinsic beat.
• The pacemaker and the patient contribute to depolarization in Fusion beats.
Fusion
• Ventricular Fusion
Pseudofusion Beat
• Definition: A pacing pulse falls on an intrinsic beat. The pacing pulse is ineffective and the intrinsic complex is not altered.
• The pacemaker does NOT contribute to depolarization in Pseudofusion beats.
Pseudofusion
• Ventricular Pseudofusion
• One lead implanted in the atrium
• One lead implanted in the ventricle
Dual-Chamber Systems Have Two Leads:
Paced Rhythm Recognition
DDD / 60 / 120
Paced Rhythm Recognition
DDD / 60 / 120
Paced Rhythm Recognition
DDD / 60 / 120
Paced Rhythm Recognition
DDD / 60 / 120
Sensing
• Sensing is the ability of the pacemaker to “see” when a natural (intrinsic) depolarization is occurring– Pacemakers sense cardiac depolarization by
measuring changes in electrical potential of myocardial cells between the anode and cathode
Sensitivity – The Greater the Number, the Less Sensitive the Device to
Intracardiac Events
SensitivityA
mp
litu
de
(mV
)
Time
5.0
2.5
1.25
SensitivityA
mp
litu
de
(mV
)
Time
5.0
2.5
1.25
SensitivityA
mp
litu
de
(mV
)
Time
5.0
2.5
1.25
Undersensing . . .
• Pacemaker does not “see” the intrinsic beat, and therefore does not respond appropriately
Intrinsic beat not sensed
Scheduled pace delivered
VVI / 60
Oversensing
• An electrical signal other than the intended P or R wave is detected
Marker channel shows intrinsic
activity...
...though no activity is present
VVI / 60
ECGs in Patients with Pacemakers
• Basic principles of pacing
• Background information required
• Systematic approach
• Examples with single chamber pacing
• Examples with dual chamber pacing
Overview :
ECGs in Patients with Pacemakers
• Clinical details – age , indication for
pacing, time since implant etc
• Type of pacemaker
• Programmed parameters
• Magnet Behaviour
• Special features
Basic Data :
Magnet Operation
• Magnet application causes asynchronous pacing at a designated “magnet” rate
Rate Responsive Pacing
• An accelerating or decelerating rate may be perceived as anomalous pacemaker behavior
VVIR / 60 / 120VVIR / 60 / 120
Hysteresis
• Allows a lower rate between sensed events to occur; paced rate is higher
Lower Rate 70 ppm Hysteresis Rate 50 ppm
ECGs in Patients with Pacemakers
• Basic principles of pacing
• Background information required
• Systematic approach
• Examples with single chamber pacing
• Examples with dual chamber pacing
Overview :
ECGs in Patients with Pacemakers
• Identify underlying intrinsic rhythm if any ( in each chamber)
• Verify appropriate sensing ( if possible )
• Verify capture
• Measure base rate and check if appropriate
• Identify any variations in intervals and interpret
• Identify causes of inappropriate sensing or pacing
Single chamber pacing :
ECGs in Patients with Pacemakers
• Basic principles of pacing
• Background information required
• Systematic approach
• Examples with single chamber pacing
• Examples with dual chamber pacing
Overview :
1
Single Chamber ECG AnalysisProgrammed Parameters
Mode………………………………………….. VVIBase Rate……………………………………….. 70 ppmMagnet Response…………………….. Battery TestHysteresis Rate………………………………… Off ppm
T Temporary programmed value7 Mar 2000 23:201.0 Second
ECG #1
• VVI
• Normal Capture and Sensing
1
2
Single Chamber ECG AnalysisProgrammed Parameters
Mode………………………………………….. VVIBase Rate……………………………………….. 70 ppmMagnet Response…………………….. Battery TestHysteresis Rate………………………………… Off ppm
T Temporary programmed valueJun 14 1999 2:57 pm1.0 Second
ECG #2
• VVI
• Normal Sensing
• Capture unknown
2
3
Single Chamber ECG Analysis
ECG #3
• VVI
• Normal Capture and Sensing with initiation of Hysteresis
3
4
Single Chamber ECG Analysis
ECG #4
• VVI
• Loss of Ventricular Sensing
• Ventricular Undersensing with Functional loss of capture on the second to last beat
4
5
Single Chamber ECG Analysis
ECG #5
• VVI
• Loss of Ventricular capture with functional loss of sensing
5
6
Single Chamber ECG Analysis
ECG #6
• VVI
• Normal Capture
• Ventricular Oversensing
6
10
Single Chamber ECG Analysis
10
Single Chamber ECG Analysis
ECG #10
• VVI
• Capture Unknown
• Normal Sensing
• Normal initiation of Hysteresis
10
12
Single Chamber ECG Analysis
12
Single Chamber ECG Analysis
ECG #12
• VVI
• Normal Capture
• Ventricular Undersensing
12
13
Single Chamber ECG Analysis
13
Single Chamber ECG Analysis
ECG #13
• VVI
• Loss of Ventricular Capture
• Normal Sensing
13
15
Single Chamber ECG Analysis
ECG #15
• VVIR
• Normal Capture and Sensing under Sensor drive
15
Crosstalk
ECGs in Patients with Pacemakers
• Basic principles of pacing
• Background information required
• Systematic approach
• Examples with single chamber pacing
• Examples with dual chamber pacing
Overview :
A Systematic Approach
• Measure Base Rate• Measure AV/PV (PAV/ SAV) Interval• Verify Atrial capture• Verify Atrial sensing• Verify Ventricular capture• Verify Ventricular sensing• Verify Underlying rhythm• Document
ECG # 3
Dual Chamber ECG Analysis
Base Rate 60 ppm
MTR 120 ppm
AVD 200 ms
PVARP 250 ms
Answer ECG #3
• Loss of Atrial Capture
• Normal Atrial Sensing
• Normal Ventricular Capture
• Ventricular Sensing Unknown
Base Rate 60 ppm
MTR 120 ppm
AVD 200 ms
PVARP 250 ms
ECG # 5
Base Rate 60 ppmMTR 120 ppmAV 200 msPV 150 msPVARP 250 ms
Dual Chamber ECG Analysis
Answer ECG #5• Normal Atrial Capture
– Possible Psuedofusion on 4th atrial output
• Atrial Sensing Unknown• Loss of Ventricular Capture• Normal Ventricular Sensing
– Functional Loss of Ventricular Sensing
Base Rate 60 ppmMTR 120 ppmAV 200 msPV 150 msPVARP 250 ms
ECG # 10
Dual Chamber ECG Analysis
Base Rate 60 ppmMTR 120 ppmAV 200 msPV 200 msPVARP 250 ms
Answer ECG #10
• Normal Atrial Capture with one beat showing functional loss of atrial capture
• Atrial Undersensing• Normal Ventricular Capture• Ventricular Sensing Unknown
Base Rate 60 ppmMTR 120 ppmAV 200 msPV 200 msPVARP 250 ms
ECG # 12
Dual Chamber ECG Analysis
Base Rate 60 ppmMTR 120 ppmAV 200 msPV 200 msPVARP 250 ms
Answer ECG #12• Normal Atrial Capture
• Normal Atrial Sensing
• Normal Ventricular Capture with two beats of functional loss of capture
• Ventricular Undersensing
Base Rate 60 ppmMTR 120 ppmAV 200 msPV 200 msPVARP 250 ms
ECG # 20
Dual Chamber ECG Analysis
Base Rate 60 ppmMTR 120 ppmAV 200 msPV 200 msPVARP 250 ms
Answer ECG #20
• Initiation of 2:1 block upper rate response
• Normal Upper Rate Behavior Operation
Base Rate 60 ppmMTR 120 ppmAV 200 msPV 200 msPVARP 250 ms
ECG # 24
Dual Chamber ECG Analysis
Base Rate 60 ppmMTR 120 ppmAV 200 msPV 150 msMin. PV 88 msPVARP 250 ms
Answer ECG #24• Normal Atrial Capture• Normal Atrial Sensing • Normal Ventricular Capture• Ventricular Sensing Unknown• Initiation of a Pacemaker Mediated
Tachycardia (PMT) with following a PVC
Base Rate 60 ppmMTR 120 ppmAV 200 msPV 150 msMin. PV 88 msPVARP 250 ms
ECGs in Patients with Pacemakers
• Familiarity with basics of pacemaker function
• Knowledge of clinical background and details of
pacing system
• Programmed parameters – essential
• Familiarity with special features
• Systematic approach
Conclusions :
Thank you for your kind attention !
ECGs in Patients with Pacemakers
ECGs in Patients with Pacemakers
ECGs in Patients with Pacemakers
ECGs in Patients with Pacemakers
ECGs in Patients with Pacemakers
ECGs in Patients with Pacemakers
ECGs in Patients with Pacemakers
ECGs in Patients with Pacemakers
ECGs in Patients with Pacemakers