Incidence of paroxysmal atrial tachycardias in patients treated with cardiac resynchronization therapy and continuously monitored by device diagnostics

AIMS: Little is known about the incidence of paroxysmal atrial tachycardias (PAT) in patients with heart failure (HF). The availability of cardiac resynchronization therapy (CRT) devices with extended diagnostics for AT enables continuous monitoring of PAT episodes. The aim of the study was to assess the incidence over time of PAT in HF patients treated with CRT. METHODS AND RESULTS: Consecutive patients in NYHA functional class III or IV despite optimal drug therapy, QRS duration > or = 130 ms, left ventricular ejection fraction < or = 35%, and left ventricular end-diastolic dimension > or = 55 mm were eligible for enrolment. Patients with permanent or persistent atrial fibrillation (AF) were not included in the study. The first follow-up examination was performed 2 weeks after implantation, to optimize atrial sensing and CRT. Subsequent follow-up examinations were carried out 15 and 28 weeks after implantation, to collect the telemetric data. A total of 173 patients (67 +/- 11 years, M 116) were enrolled. Complete arrhythmia monitoring data were available from 120 patients over a mean follow-up of 183 +/- 23 days. Atrial tachycardia episodes were detected through telemetry in 25 of 120 patients (21%) during at least one follow-up examination. Atrial tachycardia episodes were recorded in 29 and 17% (P = NS) of patients with and without previous history of AF, respectively. CONCLUSION: More than 20% of the overall HF patient population treated with CRT suffer PAT episodes. Paroxysmal atrial tachycardia may interfere with response to CRT. Therefore, telemetric data may be relevant to drive the appropriate therapy in each patient.