ecg in pacemaker malfunction sriram rajagopal, southern railway hospital, perambur,chennai

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