Decrease in the percentage of biventricular pacing due to non sustained atrial and ventricular arrhythmias
Patient
47 years old man implanted with a triple chamber defibrillator Viva XT for dilated cardiomyopathy with left bundle branch block ; routine follow-up ; several episodes of non sustained VT recorded by the device ;
Trace
Plot
- atrio-ventricular rhythm 1/1 ;
- simultaneous acceleration of the atrial and the ventricular rhythm;
- end of the episode;
Tracing
- atrial detection and biventricular pacing (AS-BV) ;
- the episode starts with a premature atrial contraction (suggesting an atrial tachycardia) ; the first atrial cycle is labeled AR because it falls in the PVARP of the previous AS-BV cycle, and do not trigger a new AV delay, spontaneous AV conduction with a long PR interval, the QRS is sensed and labeled VS ; at the second cycle of the tachycardia, the PR interval prolongs again and the third cycle of the tachycardia falls in the post-ventricular atrial blanking (labeled Ab) ; in the next cycles, the PR interval shortens because the atrial rate slows-down, and the atrial cycles are labeled AR;
- tachycardia at 170bpm with spontaneous ventricular rhythm ;
- the episode ends with no atrial event (in favor of atrial tachycardia) ;
- end of the episode;
Text
- episode wrongly classified as non-sustained VT;
Plot
- atrio-ventricular rhythm;
- acceleration of the ventricular rhythm without any modification of the atrial rhythm, suggesting a non-sustained ventricular arrhythmia;
- end of the episode;
Tracing
- atrial detection and biventricular pacing (AS-BV) ;
- non-sustained VT: onset with a premature ventricular beat; detection of a fast ventricular rhythm at 190 bpm (TS) ; atrio-ventricular dissociation with more V than A ;
- spontaneous termination of the arrhythmia and end of the episode;
Text
- episode diagnosed as « non sustained VT »;
Comments
This patient presented with many episodes of non-sustained VT correctly diagnosed by the device but also many episodes of misdiagnosed atrial tachycardia (false diagnosis of non-sustained VT). This example illustrates the need to review all the episodes and control the diagnosis made by the device. Non-sustained VT and atrial tachycardia are common causes temporary interruption of biventricular pacing. In this case, a treatment with amiodarone was introduced but did not strongly influence the occurrence of the different types of arrhythmias.
