An 80-year-old man attended the clinic with symptoms of heart failure. Eight years earlier, he received a replacement DDDR pacemaker for Mobitz II atrioventricular (AV) block (lower rate limit, 60; upper tracking rate, 120; sensor rate, 120; automatic mode switching 160; AV delay, sensed 150ms and paced 180ms; bipolar sensing, monopolar stimulation). An electrocardiogram was recorded (Figure).
What do you think was the most likely diagnosis?
- 1.
The patient had circus movement tachycardia (ventricular pacing at the upper rate limit)
- 2.
The patient had atrial fibrillation poorly sensed by the device and mode switching has not occurred.
- 3.
The patient had a dysfunctional device with defective sensing and capture and chaotic pacing via the atrial and ventricular channels.
- 4.
The patient had sinus tachycardia secondary to heart failure, tracked by the pacemaker but with defective atrial sensing.
Suggest a diagnosis to this ECG Contest at http://www.revespcardiol.org/es/electroreto/70/06. The answer will be published in the next issue (July 2017). #RetoECG.