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 :







Overview :


• 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


VVI / 60


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:


DDD / 60 / 120


DDD / 60 / 120


DDD / 60 / 120


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







Overview :


• 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







Overview :


• 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 :







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


ECG #4

• VVI

• Loss of Ventricular Sensing

• Ventricular Undersensing with Functional loss of capture on the second to last beat

4

5


ECG #5

• VVI

• Loss of Ventricular capture with functional loss of sensing

5

6


ECG #6

• VVI

• Normal Capture

• Ventricular Oversensing

6

10


10


ECG #10

• VVI

• Capture Unknown

• Normal Sensing

• Normal initiation of Hysteresis

10

12


12


ECG #12

• VVI

• Normal Capture

• Ventricular Undersensing

12

13


13


ECG #13

• VVI

• Loss of Ventricular Capture

• Normal Sensing

13

15


ECG #15

• VVIR

• Normal Capture and Sensing under Sensor drive

15

Crosstalk







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


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


ECG # 10



Answer ECG #10

• Normal Atrial Capture with one beat showing functional loss of atrial capture

• Atrial Undersensing• Normal Ventricular Capture• Ventricular Sensing Unknown


ECG # 12



Answer ECG #12• Normal Atrial Capture

• Normal Atrial Sensing

• Normal Ventricular Capture with two beats of functional loss of capture

• Ventricular Undersensing


ECG # 20



Answer ECG #20

• Initiation of 2:1 block upper rate response

• Normal Upper Rate Behavior Operation


ECG # 24


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


• Familiarity with basics of pacemaker function

• Knowledge of clinical background and details of

pacing system

• Programmed parameters – essential

• Familiarity with special features


Conclusions :

Thank you for your kind attention !










ECG in Pacemaker Malfunction Sriram Rajagopal, Southern Railway Hospital, Perambur,Chennai.

Documents

paced beat

intrinsic beat

pacing pulse

pacemaker malfunctionecgs

paced rhythm recognitionaai

evidence of pacing spike

lower rate pacing output

dual chamber