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.

Incidence of sudden cardiac death after ventricular fibrillation complicating acute myocardial infarction: a 5-year cause-of-death analysis of the FAST-MI 2005 registry.

AIMS: Limited data are available on long-term prognosis or causes-of-death analysis among survivors of acute myocardial infarction (MI) according to whether or not they developed ventricular fibrillation (VF) during the acute stage of MI. METHODS AND RESULTS: Among 3670 MI patients hospitalized in France in 2005 and enrolled in this prospective follow-up cohort study, we assessed in-hospital mortality and 5-year cause of death among those who survived to hospital discharge, according to whether they developed VF (116 cases) or not, during the acute stage. 94.5% of patients had complete follow-up at 5 years. In-hospital mortality was significantly higher among VF patients (adjusted OR 7.38, 95% CI 4.27-12.75, P < 0.001). Among 3463 survivors at hospital discharge, 1024 died during a mean follow-up of 52 ± 2 months. The overall survival rate at 5 years was 74.4% (95% CI 72.8-76.0). In Cox multivariate analysis, occurrence of VF during the acute phase of MI was not associated with an increased mortality at 5 years (HR 0.78, 95% CI 0.38-1.58, P = 0.21). The distribution of causes of death at 5 years did not statistically differ according to the presence or absence of VF, especially for sudden cardiac death (13.1% in VF group vs.12.9% in non-VF group), despite a very low rate of implantation of cardioverter defibrillator in both groups (Overall rate 1.2%). CONCLUSION: Patients developing VF in the setting of acute MI are at higher risk of in-hospital mortality. However, VF is not associated with a higher long-term all-cause or sudden cardiac death mortality.

Risk factors related to infections of implanted pacemakers and cardioverter-defibrillators: results of a large prospective study.

BACKGROUND: The Prospective Evaluation of Pacemaker Lead Endocarditis study is a multicenter, prospective survey of the incidence and risk factors of infectious complications after implantation of pacemakers and cardioverter-defibrillators. METHODS AND RESULTS: Between January 1, 2000, and December 31, 2000, 6319 consecutive recipients of implantable systems were enrolled at 44 medical centers and followed up for 12 months. All infectious complications were recorded, and their occurrence was related to the baseline demographic, clinical, and procedural characteristics. Among 5866 pacing systems, 3789 included 2 and 117 had >2 leads; among 453 implantable cardioverter-defibrillators, 178 were dual-lead systems. A total of 4461 de novo implantations occurred and 1858 pulse generator or lead replacements. Reinterventions were performed before hospital discharge in 101 patients. Single- and multiple-variable logistic regression analyses were performed to identify risk factors; adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated. At 12 months, device-related infections were reported in 42 patients (0.68%; 95% CI, 0.47 to 0.89). The occurrence of infection was positively correlated with fever within 24 hours before the implantation procedure (aOR, 5.83; 95% CI, 2.00 to 16.98), use of temporary pacing before the implantation procedure (aOR, 2.46; 95% CI, 1.09 to 5.13), and early reinterventions (aOR, 15.04; 95% CI, 6.7 to 33.73). Implantation of a new system (aOR, 0.46; 95% CI, 0.24 to 0.87) and antibiotic prophylaxis (aOR, 0.4; 95% CI, 0.18 to 0.86) were negatively correlated with risk of infection. CONCLUSIONS: This study identified several factors of risk of device infection and confirmed the efficacy of antibiotic prophylaxis in recipients of new or replacement pacemakers or implantable cardioverter-defibrillators.

Reversal of dilated cardiomyopathy by the elimination of frequent left or right premature ventricular contractions.

BACKGROUND: RF ablation of frequent premature ventricular contractions (PVC) has recently been shown to improve left ventricular (LV) systolic function and dimensions in a few patients, however mainly when they originated from the right ventricular outflow tract. METHODS: RF ablation was performed at various ventricular locations in six consecutive patients with frequent, isolated PVC associated with idiopathic dilated cardiomyopathy (DCM). Baseline clinical status, PVC counts, LV ejection fraction (EF) and end-diastolic diameter (EDD) were recorded at baseline and at 6 months of follow-up. RESULTS: PVC ablation was performed in the right ventricle in four patients, the left ventricle in two patients. Before RF ablation, five patients were in New York Heart Association (NYHA) functional class I, and one patient was in class II. After RF ablation, the mean PVC count/24 h decreased from 17,717 +/- 7,100 to 268 +/- 366 (p = 0.006) while LVEF increased from 42 +/- 2.5% to 57 +/- 3% (p = 0.0001) and LVEDD decreased from 60.0 +/- 3.5 to 54.0 +/- 3.7 mm (p = 0.0009). The clinical status normalized with regression of palpitations and NYHA class. CONCLUSIONS: Elimination of frequent isolated PVC in patients with DCM with RF can normalize the clinical status and LV systolic function and dimensions, regardless of the morphology or origin of the PVC.

Management of Takotsubo cardiomyopathy in non-academic hospitals in France: The Observational French SyndromEs of TakoTsubo (OFSETT) study.

BACKGROUND: Takotsubo cardiomyopathy (TTC) is a rare condition characterized by a sudden temporary weakening of the heart. TTC can mimic acute myocardial infarction and is associated with a minimal release of myocardial biomarkers in the absence of obstructive coronary artery disease. AIMS: To provide an extensive description of patients admitted to hospital for TTC throughout France and to study the management and outcomes of these patients. METHODS: In 14 non-academic hospitals, we collected clinical, electrocardiographic, biological, psychological and therapeutic data in patients with a diagnosis of TTC according to the Mayo Clinic criteria. RESULTS: Of 117 patients, 91.5% were women, mean ± SD age was 71.4 ± 12.1 years and the prevalence of risk factors was high (hypertension: 57.9%, dyslipidaemia: 33.0%, diabetes: 11.5%, obesity: 11.5%). The most common initial symptoms were chest pain (80.5%) and dyspnoea (24.1%). A triggering psychological event was detected in 64.3% of patients. ST-segment elevation was found in 41.7% of patients and T-wave inversion in 71.6%. Anterior leads were most frequently associated with ST-segment elevation, whereas T-wave inversion was more commonly associated with lateral leads, and Q-waves with septal leads. The ratio of peak B-type natriuretic peptide (BNP) or N-terminal prohormone BNP (NT-proBNP) level to peak troponin level was 1.01. No deaths occurred during the hospital phase. After 1 year of follow-up, 3 of 109 (2.8%) patients with available data died, including one cardiovascular death. Rehospitalizations occurred in 17.4% of patients: 2.8% due to acute heart failure and 14.7% due to non-cardiovascular causes. There was no recurrence of TTC. CONCLUSIONS: This observational study of TTC included primarily women with atherosclerotic risk factors and mental stress. T-wave inversion was more common than ST-segment elevation. There were few adverse cardiovascular outcomes in these patients after 1-year follow-up.

Impact of early statin therapy on development of atrial fibrillation at the acute stage of myocardial infarction: data from the FAST-MI register.

BACKGROUND: Atrial fibrillation developing at the acute stage of myocardial infarction is associated with untoward clinical outcomes. The aim of this study was to determine correlations between early statin therapy and atrial fibrillation in acute myocardial infarction. METHODS: Patients (3396) with sinus rhythm developing acute myocardial infarction were enrolled in the French registry of Acute ST-elevation and non-ST-elevation Myocardial Infarction (FAST-MI). RESULTS: Atrial fibrillation developed in 7.0% of patients without and 3.9% of patients with early (≤48 h of admission) statin therapy (p<0.001). Multivariable analysis, including the propensity score for early statin treatment, showed that statin therapy was associated with reduced risk of atrial fibrillation (OR 0.64; 95% CI 0.45 to 0.92, p=0.017). Compared to patients without early statin therapy, the OR for atrial fibrillation were 0.72 (0.49 to 1.04, p=0.080), 0.52 (0.28 to 0.95, p=0.034) and 0.40 (0.18 to 0.92, p=0.030) in patients on conventional, intermediate and high doses respectively. CONCLUSIONS: This study is the first to document a correlation between early statin therapy and atrial fibrillation at the early stage of acute myocardial infarction.

Left atrial far-field sensing by left ventricular leads: a potential hazard in cardiac resynchronisation therapy.

BACKGROUND: Cardiac resynchronisation therapy (CRT) requires a lead advanced through the coronary sinus (CS) to pace the left ventricle (LV). Left atrial far-field signals (LAFFS) may be sensed by the LV lead at the time of implant or after lead dislodgement, and may inhibit ventricular pacing. OBJECTIVE: To assess the incidence of detection of LAFFS > 2 mV and its correlation with the CS lead position. METHODS: Data from the first 75 consecutive patients enrolled in the InSync III multicentre study were analysed. The position of the LV lead was recorded at implant. During follow-up, pacing was temporarily inhibited and the LV channel electrogram was recorded. The amplitude of LAFFS observed before discharge from the hospital and at 1 month of follow-up was retrospectively analysed. A LAFFS > 2 mV was considered clinically significant. RESULTS: CRT systems were successfully implanted in 71 of 75 patients. A LAFFS > 2 mV was recorded by the LV lead channel in six of 71 patients (8.5%). This phenomenon developed between hospital discharge and 1 month of follow-up in two of these patients and in one case disappeared within 1 month. It was observed in all CS tributaries except the anterior and mid-cardiac veins. CONCLUSIONS: Left atrial far-field signals sensed by the LV lead were not rare. Implanting physicians should be aware of this phenomenon in order to prevent potentially serious complications.

Atrioventricular cross-talk in biventricular pacing: a potential cause of ventricular standstill.

The aim of the study was to evaluate, in recipients of biventricular pacing systems, the risk of asystole due to ventricular pacing inhibition by sensing the left atrial signals by the LV lead at conventional sensitivity. Long-term ventricular sensitivity was programmed at > or = 4 m V in 17 consecutive recipients of ventricular resynchronization systems implanted for chronic management of congestive heart failure. Ventricular pacing inhibition due to AV cross-talk on spontaneous left atrial electrogram (AVCSA) was tested at a 2 mV ventricular sensitivity immediately after implantation of the stimulation system and 1 month later. Pacemaker dependence was also tested during temporary VVI pacing at a rate of 30 beats/min. AVCSA was observed in three patients. It was present on the day of implantation in one patient, and developed within the first month in two others. Asystole was observed in two of the three cases of AVCSA. Three pacemaker nondependent patients at the time of system implantation had become pacemaker dependent at 1 month. AVCSA was observed only with LV leads positioned in the great cardiac vein. In conclusion, asystole due to AVCSA was observed in 11% of recipients of ventricular resynchronization stimulation systems. Care should be taken in these patients to minimize the risk of atrial sensing by the LV lead, preferably avoiding its placement in the great cardiac vein. This phenomenon could be eliminated by the programmability of a right ventricular only sensing configuration.

Atrial pacing for prevention of atrial fibrillation: assessment of simultaneously implemented algorithms.

AIMS: Several preliminary studies indicated that right atrial pacing could prevent atrial tachyarrhythmias (ATA). We sought to compare the safety and the efficacy of atrial-based pacing supplemented by dedicated combined algorithms with conventional atrial pacing in the prevention of ATA. METHODS: Fifty-five patients with a history of recurrent paroxysmal ATA implanted with a dual-chamber pacemaker were studied during two randomized cross-over pacing periods (conventional DDD and DDD with ATA prevention algorithms) of 6 months duration. The primary endpoint was the burden of ATA episodes recorded by the device mode switch algorithm. RESULTS: The cross-over analysis did not demonstrate any significant difference between the two pacing modes: 254+/-533 h of ATA during the control period versus 238+/-518 h during the ATA prevention period. Analysis of a subgroup of patients found that those with the lower percentage of ventricular pacing benefited from ATA prevention algorithms (120+/-182 h versus 225+/-350 h during the control period; P < 0.04). CONCLUSION: When compared with DDD pacing at 70 bpm, ATA prevention algorithms have not demonstrated significant efficacy. However, a subgroup of patients with preserved native AV conduction (low percentage of ventricular pacing) responded to ATA prevention algorithms.