Early use of an implantable loop recorder in syncope evaluation: a randomized study in the context of the French healthcare system (FRESH study).

BACKGROUND: The role of implantable loop recorders (ILRs) in the evaluation strategy for recurrent syncope in France is limited by lack of knowledge of the cost. AIM: To compare a conventional evaluation strategy for syncope with the early use of an ILR in low-risk patients, in terms of diagnostic yield, cost and impact on quality of life (QoL). METHODS: National prospective randomized open-label multicenter study of patients with a single syncope (if severe and recent) or at least two syncopes in the past year. RESULTS: Seventy-eight patients (32 men) were randomized to the ILR strategy (ILR group, n=39) or the conventional evaluation strategy (CONV group, n=39): mean age 66.2±14.8 years; 4.3±6.4 previous syncopes. After 14 months of follow-up, a certain cause of syncope was established in 18 (46.2%) patients in the ILR group and two (5%) patients in the CONV group (P<0.001). Advanced cardiological tests were performed less frequently in the ILR group than in the CONV group (0.03±0.2 vs. 0.2±0.5 tests per patient; P=0.05). Patients in the ILR group were hospitalized for a non-significantly shorter period than patients in the CONV group (5.7±3.2 vs. 8.0±1.4 days). There was no difference between the two groups in terms of QoL main composite score. CONCLUSION: In patients with unexplained syncope, the early use of an ILR has a superior diagnostic yield compared with the conventional evaluation strategy, with lower healthcare-related costs.

Frequency of atrial tachyarrhythmias in patients treated by cardiac resynchronization (from the Prospective, Multicenter Mona Lisa Study).

The continuous measurement of sustained atrial tachyarrhythmia (AT) is now possible with some permanently implanted devices. Data on this subject remain controversial. The aim of this study was to evaluate the incidence of sustained AT in patients treated with cardiac resynchronization therapy using pacemakers without backup defibrillators (CRT-P), within the first year after implantation, using strict definition criteria for sustained AT and a systematic review of all high-quality electrographically recorded episodes. The Mona Lisa study was a prospective, multicenter, cohort study carried out from February 2004 to February 2006, with a 12-month follow-up period. Sustained AT was defined as an episode lasting > or =5 minutes; episodes were confirmed by a systematic review of electrograms in the whole study population. Of the 198 patients who underwent CRT-P device implantation and were enrolled in the study, 173 were in stable sinus rhythm at baseline and were included in the analysis (mean age 70 +/- 9 years, 66% men, 91% in New York Heart Association class III, mean QRS duration 164 +/- 26 ms, mean left ventricular ejection fraction 25 +/- 7%). During a mean follow-up period of 9.9 +/- 3.6 months, 34 patients experienced > or =1 episode of sustained AT, for an incidence rate of 27.5% (95% confidence interval 18.2 to 36.7). Only a history of AT was independently associated with the occurrence of sustained AT within the 12 months after CRT-P device implantation (hazard ratio 2.3, 95% confidence interval 1.2 to 4.4, p = 0.02). In conclusion, this first prospective electrogram-based evaluation of AT incidence demonstrated that 27% of patients developed > or =1 episode of sustained AT lasting > or =5 minutes in the 12 months after CRT-P device implantation.

Physiological approach to monitor patients in congestive heart failure: application of a new implantable device-based system to monitor daily life activity and ventilation.

AIMS: We examine an expert system designed to permanently monitor patients with congestive heart failure (CHF) using data of a dual-sensor pacemaker and to allow warning of significant changes in physiological indices. METHODS AND RESULTS: This study included 67 implanted patients divided into two groups: a control group without history of CHF (n = 19) who had received DDDR pacemakers (DDD group) and a test group (n = 48) who had received cardiac resynchronization therapy systems (CRT group) for severe CHF (NYHA III or IV, LVEF <40%). The embedded monitoring system measures minute ventilation (MV) and activity (ACT) at rest and at exercise. All devices collect data, and all adverse medical events were recorded. Data are stored daily for up to 3 months. The mean ACT was similar for both groups. Mean rest and exercise MV were significantly higher in CRT group. On 195 periods of 1-month follow-up in the CRT group, 31 events were suspected, 22 were true positive, 9 were false-positive, and 3 clinical adverse events were not predicted (sensitivity: 88%, specificity: 94.7%, positive predictive value: 71%, negative predictive value: 98.2%) CONCLUSION: A new diagnostic expert system that holds promise for the long-term ambulatory monitoring of CHF was developed.

Use of a new cardiac pacing mode designed to eliminate unnecessary ventricular pacing.

AIMS: To examine the performance of AAIsafeR2, a new pacing mode to minimize the cumulative proportion of ventricular pacing in patients who do not need regular ventricular support. METHODS AND RESULTS: The safety of AAIsafeR2 was examined in 123 recipients (73 +/- 12 years old, 51% men) of dual chamber pacemakers implanted for sinus node dysfunction, paroxysmal AV block or the bradycardia-tachycardia syndrome. Data were collected from pacemaker diagnostics, and the first 43 patients underwent 24-h Holter recordings before being discharged from the hospital with AAIsafeR2 activated. No adverse event related to AAIsafeR2 was observed. All ventricular pauses detected on Holter tapes triggered immediate back-up ventricular pacing. Appropriate switches to DDD occurred in 97 of 123 patients. In 69 of 123 devices (56%) switches to DDD were non-sustained, and the average % ventricular pacing in this group was 0.2+/-0.5%. CONCLUSION: AAIsafeR2 mode seems to be safe and reliable in patients with infrequent slowing or pauses in ventricular activity, while maintaining ventricular pacing below 1%.

A new dual-chamber pacing mode to minimize ventricular pacing.

Despite the low long-term incidence of high-degree atrioventricular (AV) block and the known negative effects of ventricular pacing, programming of the AAI mode in patients with sinus node dysfunction (SND) remains exceptional. A new pacing mode was, therefore, designed to combine the advantages of AAI with the safety of DDD pacing. AAIsafeR behaves like the AAI mode in absence of AV block. First- and second-degree AV blocks are tolerated up to a predetermined, programmable limit, and conversion to DDD takes place in case of high-degree AV block. From DDD, the device may switch back to AAI, provided AV conduction has returned. The safety of AAIsafeR was examined in 43 recipients (70 +/- 12-year old, 24 men) of dual chamber pacemakers implanted for SND or paroxysmal AV block. All patients underwent 24-hour ambulatory electrocardiographic recordings before hospital discharge and at 1 month of follow-up with the AAIsafeR mode activated. No AAIsafeR-related adverse event was observed. At 1 month, the device was functioning in AAIsafeR in 28 patients (65%), and the mean rate of ventricular pacing was 0.2%+/- 0.4%. Appropriate switches to DDD occurred in 15 patients (35%) for frequent, unexpected AV block. AAIsafeR mode was safe and preserved ventricular function during paroxysmal AV block, while maintaining a very low rate of ventricular pacing. The performance of this new pacing mode in the prevention of atrial fibrillation will be examined in a large, controlled study.