A Pacing Puzzle: Can you put the pieces together?
Charlotte Mehegan Chief Cardiac Physiologist and Clinical Scientist – West Suffolk NHS FT, UK
Disclosure: The author has no conflict of interests to declare.
An 82-year-old male attended the eye treatment clinic for a routine cataract procedure. He was not known to Cardiology and declared himself to be generally fit and well. On further questioning during his pre-procedure assessment, he reported a 12-month history of declining exercise tolerance.
A routine 12-lead Electrocardiogram was performed as part of the procedure work-up, showing a junctional bradycardia at 50bpm. Blood pressure was 135/78mmHg and he was not taking any relevant medication.
The patient was subsequently seen in Cardiology outpatient clinic for review of his bradycardia, where a referral was made for permanent pacemaker implantation. A Boston Scientific dual chamber pacemaker was implanted two weeks later, with an active fixation atrial lead secured in the right atrial appendage, and an active fixation ventricular lead secured in the right ventricular septum. The procedure was without complication and the device was programmed DDD 50-130bpm.
Implant parameters: R wave 9.8mV and no P wave at 30ppm. Both thresholds 0.5V at 0.4ms.
Two hours post-implant a routine device check was performed. Parameters remained within normal range and the following presenting EGM was recorded (Figure 1). No concerns were apparent at this point.
Figure 1 – Presenting EGM at post-implant device check. Channels top to bottom: near-field atrial EGM, near-field ventricular EGM and marker channel
The patient was recovering well post-procedure but did complain of transient postural dizziness. A blood pressure of 139/68mmHg (supine) and 130/60mmHg (standing) was recorded and a rhythm strip from telemetry printed (Figure 2).
Figure 2 – Telemetry strip featuring a Lead II rhythm trace