Clinical Effectiveness and Safety of Transvenous Lead Extraction of Very Old Leads @melchami99 https://t.co/6iCNkqlbBY

EP fellowship tips: Find a program that challenges you 💪, supports you 🤗, and sparks your curiosity ⚡. Your mentors make all the difference! #MedEd #Electrophysiology

The Beatles - Hey Bulldog (1968)

So many fascinating EP phenomena in this, to my knowledge not previously reported, form of "bigeminy of the bigeminy". #EPeeps #Cardiology #ECG

Tracings like this reassure you that left posterior hemiblock (sorry, I'm from Argentina) is a real thing.

Patient with right bundle branch block and atrial bigeminy: blocked or conducted with rare aberrancy, superimposed left posterior fascicular block. #ECG #Cardiology

Gap phenomenon caught in real life! #ECG #EPeeps

This was easily fixed by programming a much shorter sensed AV delay. Subsequent ECG showed appropriate resynchronization (identical QRS), with tracking and atrial pacing.

There is effective resynchronization during atrial pacing but just pseudofusion during tracking, despite a generous V-V offset. This highlights the need for short sensed AV delays with right atrial appendage lead when there is good AV conduction.

CRT may not be dead after all! Look at this ECG. Are we resynchronizing 100%? If not, how to fix it? #ECG #Cardiology #EPeeps

Device was programmed DDDR with long paced AV delay. There was T wave oversensing of every second beat. Why? I don't know. One can trace back the VA escape interval to the exact time of the oversensing. Fixed by reducing ventricular sensitivity.

#ECGChallenge: Female patient in her early 40's with a history of diabetes presents with two hours of right sided chest pain. What is your interpretation of the ECG? https://t.co/Q73vKaBlV9

Interesting bigeminal atrial paced rhythm. What is going on? #Cardiology #ECG

https://t.co/MO3SNXyzMa

Furthermore, there is clear biventricular pacing (2 spikes). If LV adaptive had been operative, there should have been only LV pacing (1 spike), given the rate and relatively short PR.

Patient developed full blown defibrillation lead failure over time. This seemingly innocent ECG was the first clue of a problem in the defibrillation lead. Understanding of timing cycles is crucial to device troubleshooting.

Further testing showed that there was intermittent oversensing of noise in the V channel, triggering PVARP.

There was indeed intermittent "undersensing" of P waves with failure to track and intrinsic AV conduction with LBBB. Atrial "undersensing" could be real or functional, when the A signal falls in PVARP.

Medtronic's (AdaptivCRT) extends the AV delay for one beat every 100 beats. However, unless one turns the default ventricular sense response (VSR) off, there will be the spike at the time of sensing the intrinsic R. So less likely in this case.

Thank you for the participation. Adaptive algorithm was a good thought. Abbott's (SyncAV) extends the AV delay for 3 consecutive beats, so not the case.