Early Detection and Treatment of Atrial Arrhythmias Alleviates the Arrhythmic Burden in Paced Patients: The SETAM Study.

BACKGROUND: Remote monitoring (RM) can remotely detect atrial tachyarrhythmias (ATAs). The benefit of RM compared to conventional follow-up in the detection and management of ATA was assessed in recipients of dual-chamber pacemakers. METHODS: The multicenter randomized SETAM study enrolled 595 patients in sinus rhythm with a CHA2 DS2 -VASc score ≥2, without ATA history and untreated with antiarrhythmics and antithrombotics, randomly assigned to RM (RM-ON; n = 291) versus ambulatory follow-up (RM-OFF; n = 304) during 12.8 ± 3.3 months. ATA occurrence, burden, and management were analyzed together with adverse clinical events. RESULTS: Patients were 79 ± 8 years old, 63% men, with a CHA2 DS2 -VASc score of 3.7± 1.2. ATA were detected in 83 patients (28%) in the RM-ON versus 66 (22%) in the RM-OFF group (P = 0.06). The median time between the pacemaker implantation and the first treated ATA was 114 days [44; 241] in the RM-ON versus 224 days [67; 366] in the RM-OFF group (hazard ratio [HR] = 0.56; 95% confidence interval [CI]: 0.37-0.86; P = 0.01). Therapies for ATA were initiated in 92 patients and the time to treatment of ATA was shortened by 44% in the RM-ON group (HR = 0.565; 95% CI: 0.37-0.86; P = 0.01). Over the last 4 months of follow-up, the mean ATA burden was alleviated by 4 hours/day (18%) in the RM-ON group. The rate of adverse clinical events was similar in both groups. CONCLUSION: Remotely monitored patients were diagnosed and treated earlier for ATA, and subsequently had a lower ATA burden.

A randomized study of remote follow-up of implantable cardioverter defibrillators: safety and efficacy report of the ECOST trial.

AIMS: The ECOST trial examined prospectively the long-term safety and effectiveness of home monitoring (HM) of implantable cardioverter defibrillators (ICD). METHODS AND RESULTS: The trial's primary objective was to randomly compare the proportions of patients experiencing ≥ 1 major adverse event (MAE), including deaths from all causes, and cardiovascular, procedure-related, and device-related MAE associated with HM (active group) vs. ambulatory follow-ups (control group) in a sample of 433 patients. The 221 patients assigned to the active group were seen once a year, unless HM reported an ICD dysfunction or a clinical event requiring an ambulatory visit, while the 212 patients in the control group underwent ambulatory visits every 6 months. The characteristics of the study groups were similar. Over a follow-up of 24.2 months, 38.5% of patients in the active and 41.5% in the control group experienced ≥ 1 MAE (P < 0.05 for non-inferiority). The overall number of shocks delivered was significantly lower in the active (n = 193) than in the control (n = 657) group (P < 0.05) and the proportion of patients who received inappropriate shocks was 52% lower in the active (n = 11) than in the control (n = 22) group (P < 0.05). At the end of the follow-up, the battery longevity was longer in the active group because of a lower number of capacitor charges (499 vs. 2081). CONCLUSION: Our observations indicate that long-term HM of ICD is at least as safe as standard ambulatory follow-ups with respect to a broad spectrum of MAE. It also lowered significantly the number of appropriate and inappropriate shocks delivered, and spared the device battery. Clinical trials registration NCT00989417.

Atrial fibrillation with a very rapid ventricular response as the first clinical arrhythmia in a 76-year-old man.

The interest of electrohysiological study for the prognostic evaluation of asymptomatic Wolff-Parkinson-White (WPW) syndrome remains controversial. We report the case of an asymptomatic 67-year-old man without heart disease in whom a type A WPW syndrome was noted. Because the WPW was unchanged during exercise testing, transesophageal EPS was performed. In basal state, 1/1 conduction through the Kent bundle was noted up to a rate of 210 beats/min. After infusion of 30 microg of isoproterenol, atrial pacing was associated with a 1/1 conduction throughout the Kent bundle at a rate at 300 beats/min and induced rapid atrial fibrillation which was stopped by flecainide. No treatment was indicated. Nine years later, at age 76, the patient developed syncope related to rapid atrial fibrillation requiring cardioversion. In conclusion, the occurrence of a potentially lethal supraventricular tachyarrhythmia in a previously asymptomatic patient with WPW syndrome might be encountered in elderly patients. Transesophageal electrophysiological evaluation is a useful means to predict this risk.

Contributions of high resolution electrograms memorized by DDDR pacemakers in the interpretation of arrhythmic events.

The accuracy of information retrievable from the memories of DDDR pacing systems has been limited by the absence of actual electrograms confirming the proper sensing of spontaneous cardiac activity versus that of extraneous signals. This study examined the diagnostic power of a new arrhythmia interpretation scheme, which includes the recording and storage of high resolution endocavitary atrial and ventricular electrograms (HREGM). HREGM stored in the memories of new generation pacemakers (PM) in response to nonsustained ventricular tachycardia (NSVT), sustained VT, and atrial arrhythmias were analyzed in a follow-up registry of 520 patients at 1 month, and 3 to 6 months after implantation of a PM for standard indications. For each sequence of stored HREGM, the accuracy of the PM response was examined, classified as accurate (true positive), versus inaccurate (false positive), versus undetermined, and the relative contribution of the HREGM in verifying the PM diagnosis was measured. During a follow-up of 4.9 +/- 2 months, 256 (49%) of the 520 patients had an event recorded, which was confirmed to be arrhythmic on the basis of HREGM. Overall, approximately 34% of atrialtachy response (ATR) episodes were confirmed to be appropriate. Similar percentages of episodes were prompted by oversensing of signals unrelated to cardiac arrhythmias, while nearly 12% of the episodes could not be clarified because of such brief duration as to preclude recording of their onset. Approximately one-third of NSVT, and one-half of VT detections were false positive. Ventricular oversensing, most often due to myopotential interference in presence of unipolar sensing, and atrial undersensing were both identified as sources of false-positive detections of ventricular events. The proportion of true-positive detections was significantly higher in the bipolar (83%) than unipolar configuration. Among 520 PM recipients, miscellaneous episodes of atrial arrhythmias were confirmed by HREGM in 37% of patients within 3 to 6 months of follow-up. Atrial fibrillation was confirmed in only 6% of patients, of whom over 50% already had histories of atrial fibrillation. The prevalence of unsuspected atrial arrhythmia in this unselected population was lower than previously reported.