Pacemaker failure to capture

A 78-years old female came with a history of giddiness on and off and dyspnoea on exertion since last one week. She was also complaining of orthopnoea and paroxysmal nocturnal dyspnoea. Patient was a known case of diabetes mellitus and hypertension since last 20 years. The patient had the history of coronary artery diseases twenty years back for which she underwent CABG at outside hospital. Patient also had history of complete heart block for which she underwent pacemaker implantation (Medtronic ) with VVI mode 25years back. Patient had history of pacemaker battery replacement 4 years back. At the time of admission patient blood pressure was 178/100 mmHg, pulse was 40 beats per minute, Respiratory system examination showed right-sided basal crepitation, CVS S1S2 heard. ECG of the patient is shown below.

ECG (Click on the image to enlarge it)

ECG is showing pacemaker spikes with intermittent intrinsic QRS complexes, Ventricle rate @ 40 beats per minute, absence of QRS complex after few pacemaker spikes suggestive of there is proper pacing by pacemaker (in view of presence of pacemaker spikes) but loss of capture( as spikes are not followed by QRS complexes)

Another ECG of the patient without magnet (Click on the image to enlarge it)

ECG is showing the heart rate of 60 beats per minute. Pacemaker spikes are followed by QRS complex suggestive of both normal pacings, sensing and capture by a pacemaker.

ECG with magnet (Click on the image to enlarge it)

ECG is showing heart rate of 100 beats per minute with normal pacemaker pacing and capture.

Final diagnosis was intermittent failure to capture.

Patient pacemaker device interrogation was done which showed pacemaker battery lifespan of 8 months suggestive of End of life pacemaker with pacing threshold of 5.5V. The patient is presently planned for new pacemaker implantation.


Thank you

Praveen Gupta