Decrease in the percentage of biventricular pacing due to non-sustained atrial and ventricular arrhythmias

N° 23
Manufacturer Medtronic Device CRT Field Management of atrial arrhythmias

47-year-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.

Graph and trace


  1. 1:1 atrioventricular rhythm;
  2. simultaneous acceleration of the atrial and ventricular rhythms;
  3. end of the episode;


  1. atrial sensing and biventricular pacing (AS-BV);
  2. 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 does 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 due to a slowing of the atrial rate, and the atrial cycles are labeled AR;
  3. tachycardia at 170 bpm with spontaneous ventricular rhythm;
  4. the episode ends with no atrial event (in favor of atrial tachycardia);
  5. end of the episode;


  1. episode erroneously classified as non-sustained VT;


  1. atrioventricular rhythm;
  2. acceleration of the ventricular rhythm without any modification of the atrial rhythm, suggesting a non-sustained ventricular arrhythmia;
  3. end of the episode;


  1. atrial sensing and biventricular pacing (AS-BV);
  2. non-sustained VT: onset with a premature ventricular beat; detection of a fast ventricular rhythm at 190 bpm (TS); atrioventricular dissociation with more V than A;
  3. spontaneous termination of the arrhythmia and end of the episode;


Episode diagnosed as « non-sustained VT ».


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 of the episodes and to control the diagnosis made by the device. Non-sustained VT and atrial tachycardia are common causes of temporary interruption of biventricular pacing. In this instance, a treatment with amiodarone was introduced but did not strongly influence the occurrence of the different types of arrhythmias.

Other articles that may be of interest to you