Catheter Ablation for Atrial Fibrillation with Heart Failure.

BACKGROUND: Mortality and morbidity are higher among patients with atrial fibrillation and heart failure than among those with heart failure alone. Catheter ablation for atrial fibrillation has been proposed as a means of improving outcomes among patients with heart failure who are otherwise receiving appropriate treatment. METHODS: We randomly assigned patients with symptomatic paroxysmal or persistent atrial fibrillation who did not have a response to antiarrhythmic drugs, had unacceptable side effects, or were unwilling to take these drugs to undergo either catheter ablation (179 patients) or medical therapy (rate or rhythm control) (184 patients) for atrial fibrillation in addition to guidelines-based therapy for heart failure. All the patients had New York Heart Association class II, III, or IV heart failure, a left ventricular ejection fraction of 35% or less, and an implanted defibrillator. The primary end point was a composite of death from any cause or hospitalization for worsening heart failure. RESULTS: After a median follow-up of 37.8 months, the primary composite end point occurred in significantly fewer patients in the ablation group than in the medical-therapy group (51 patients [28.5%] vs. 82 patients [44.6%]; hazard ratio, 0.62; 95% confidence interval [CI], 0.43 to 0.87; P=0.007). Significantly fewer patients in the ablation group died from any cause (24 [13.4%] vs. 46 [25.0%]; hazard ratio, 0.53; 95% CI, 0.32 to 0.86; P=0.01), were hospitalized for worsening heart failure (37 [20.7%] vs. 66 [35.9%]; hazard ratio, 0.56; 95% CI, 0.37 to 0.83; P=0.004), or died from cardiovascular causes (20 [11.2%] vs. 41 [22.3%]; hazard ratio, 0.49; 95% CI, 0.29 to 0.84; P=0.009). CONCLUSIONS: Catheter ablation for atrial fibrillation in patients with heart failure was associated with a significantly lower rate of a composite end point of death from any cause or hospitalization for worsening heart failure than was medical therapy. (Funded by Biotronik; CASTLE-AF ClinicalTrials.gov number, NCT00643188 .).

Remote monitoring of implantable cardioverter-defibrillators and resynchronization devices to improve patient outcomes: dead end or way ahead?

Remote monitoring (RM) has become a new standard of care in the follow-up of patients with implantable pacemakers and defibrillators. While it has been consistently shown that RM enables earlier detection of clinically actionable events compared with traditional in-patient evaluation, this advantage did not translate into improved patient outcomes in clinical trials of RM except one study using daily multiparameter telemonitoring in heart failure (HF) patients. Therefore, this review, focusing on RM studies of implantable cardioverter-defibrillators and cardiac resynchronization therapy defibrillators in patients with HF, discusses possible explanations for the differences in trial outcomes. Patient selection may play an important role as more severe HF and concomitant atrial fibrillation have been associated with improved outcomes by RM. Furthermore, the technical set-up of RM may have an important impact as a higher level of connectivity with more frequent data transmission can be linked to better outcomes. Finally, there is growing evidence as to the need of effective algorithms ensuring a fast and well-structured clinical response to the events detected by RM. These factors re-emphasize the potential of remote management of device patients with HF and call for continued clinical research and technical development in the field.

Daily remote monitoring of implantable cardioverter-defibrillators: insights from the pooled patient-level data from three randomized controlled trials (IN-TIME, ECOST, TRUST).

Aims: Remote monitoring of implantable cardioverter-defibrillators may improve clinical outcome. A recent meta-analysis of three randomized controlled trials (TRUST, ECOST, IN-TIME) using a specific remote monitoring system with daily transmissions [Biotronik Home Monitoring (HM)] demonstrated improved survival. We performed a patient-level analysis to verify this result with appropriate time-to-event statistics and to investigate further clinical endpoints. Methods and results: Individual data of the TRUST, ECOST, and IN-TIME patients were pooled to calculate absolute risks of endpoints at 1-year follow-up for HM vs. conventional follow-up. All-cause mortality analysis involved all three trials (2405 patients). Other endpoints involved two trials, ECOST and IN-TIME (1078 patients), in which an independent blinded endpoint committee adjudicated the underlying causes of hospitalizations and deaths. The absolute risk of death at 1 year was reduced by 1.9% in the HM group (95% CI: 0.1-3.8%; P = 0.037), equivalent to a risk ratio of 0.62. Also the combined endpoint of all-cause mortality or hospitalization for worsening heart failure (WHF) was significantly reduced (by 5.6%; P = 0.007; risk ratio 0.64). The composite endpoint of all-cause mortality or cardiovascular (CV) hospitalization tended to be reduced by a similar degree (4.1%; P = 0.13; risk ratio 0.85) but without statistical significance. Conclusion: In a pooled analysis of the three trials, HM reduced all-cause mortality and the composite endpoint of all-cause mortality or WHF hospitalization. The similar magnitudes of absolute risk reductions for WHF and CV endpoints suggest that the benefit of HM is driven by the prevention of heart failure exacerbation.

"Largest amplitude ablation" is the optimal approach for typical atrial flutter ablation: a subanalysis from the AURUM 8 study.

INTRODUCTION: The recently proposed "maximum voltage-guided" (MVG) technique for radiofrequency catheter ablation of atrial flutter targets high-voltage electrograms along cavotricuspid isthmus (CTI) to ablate the functionally important anatomic muscle bundles alone, without drawing a complete anatomic line across the CTI. This innovative approach may shorten ablation time and procedure duration. METHODS AND RESULTS: Within the multicenter AURUM 8 study, which compared 8-mm gold- and Pt-Ir-tip catheters in atrial flutter ablation, we made a post hoc comparison of procedural data from 72 patients treated with MVG technique with data from 281 patients undergoing anatomic CTI ablation (unmatched) and with data from 72 patients selected from among those 281 patients such that they were matched with the MVG group with respect to selected baseline parameters and catheter type (matched). The MVG technique markedly reduced (P < 0.001) ablation time (mean 6.9 minutes vs 10.9/9.7 minutes [unmatched/matched]), number of lesions (8.3 vs 13.7/12.9), fluoroscopy time (9.5 minutes vs 20.6/17.9 minutes), procedure duration (59 minutes vs 93/86 minutes), and energy delivered (19 kJ vs 34/30 kJ) compared with anatomic CTI ablation. The incidence of charring was higher for MVG than for anatomic ablation technique (31.9% vs 18.5/15.3%, P < 0.05), where Pt-Ir tip catheters were 6-fold more susceptible to charring than gold-tip catheters (P < 0.001), likely because of a lower thermal conductivity of the Pt-Ir material. The acute success rate was slightly better for MVG than for anatomic ablation technique (97.2% vs 92.2/91.7%, P = n.s.). CONCLUSION: Major procedural parameters are remarkably improved with MVG technique. Gold-tip catheters are substantially less susceptible to charring and may therefore be preferred over Pt-Ir-tip catheters for MVG ablation technique.

Detection of atrial high-rate events by continuous home monitoring: clinical significance in the heart failure-cardiac resynchronization therapy population.

AIMS: Uncertainty exists over the importance of device-detected short-duration atrial arrhythmias. Continuous atrial diagnostics, through home monitoring (HM) technology (BIOTRONIK, Berlin, Germany), provides a unique opportunity to assess frequency and quantity of atrial fibrillation (AF) episodes defined as atrial high-rate events (AHRE). METHODS AND RESULTS: Prospective data from 560 heart failure (HF) patients (age 67 ± 10 years, median ejection fraction 27%) patients with a cardiac resynchronization therapy (CRT) device capable of HM from two multi-centre studies were analysed. Atrial high-rate events burden was defined as the duration of mode switch in a 24-h period with atrial rates of >180 beats for at least 1% or total of 14 min per day. The primary endpoint was incidence of a thromboembolic (TE) event. Secondary endpoints were cardiovascular death, hospitalization because of AF, or worsening HF. Over a median 370-day follow-up AHRE occurred in 40% of patients with 11 (2%) patients developing TE complications and mortality rate of 4.3% (24 deaths, 16 with cardiovascular aetiology). Compared with patients without detected AHRE, patients with detected AHRE>3.8 h over a day were nine times more likely to develop TE complications (P= 0.006). The majority of patients (73%) did not show a temporal association with the detected atrial episode and their adverse event, with a mean interval of 46.7 ± 71.9 days (range 0-194) before the TE complication. CONCLUSION: In a high-risk cohort of HF patients, device-detected atrial arrhythmias are associated with an increased incidence of TE events. A cut-off point of 3.8 h over 24 h was associated with significant increase in the event rate. Routine assessment of AHRE should be considered with other data when assessing stroke risk and considering anti-coagulation initiation and should also prompt the optimization of cardioprotective HF therapy in CRT patients.

Potential of remote monitoring to prevent sensing and detection failures in implantable cardioverter defibrillators.

BACKGROUND: Sensing malfunction and misinterpretation of intracardiac electrograms (IEGMs) in patients with implantable cardioverter defibrillators (ICDs) may lead to inadequate device activity such as inappropriate shock delivery or unnecessary mode-switching. Remote monitoring has the potential for early detection of sensing malfunction or misclassification and may thus prevent adverse device activity. Therefore, the authors analyzed the amount, nature, and distribution of misclassification in current ICD and cardiac resynchronization therapy defibrillator technology using the device transmissions of the IN-TIME study population. METHODS: All transmitted tachyarrhythmic episodes in the 664 IN-TIME patients, comprising 2214 device-classified atrial fibrillation (DC-AF) episodes lasting ≥ 30 s and 1330 device-classified ventricular tachycardia or fibrillation (DC-VT/VF) episodes, were manually analyzed by two experienced cardiologists. RESULTS: After evaluation of all DC-VT/VF episodes, a total of 300 VT/VF events (23.1%) were false-positive, with supraventricular tachycardia being the most frequent cause (51.7%), followed by atrial fibrillation (21.3%) and T­wave oversensing (21.0%). A total of 15 patients with false-positive DC-VT/VF received inappropriate shocks. According to the inclusion criteria, 616 IEGMs with DC-AF were assessed. A total of 19.7% were false-positive AF episodes and R­wave oversensing was the most common reason (55.9%). CONCLUSIONS: Remote monitoring offers the opportunity of early detection of signal misclassification and thus early prevention of adverse device reaction, such as inappropriate shock delivery or mode-switching with intermittent loss of atrioventricular synchrony, by correcting the underlying causes.

Gold vs. platinum-iridium tip catheter for cavotricuspid isthmus ablation: the AURUM 8 study.

AIMS: Gold electrodes have the theoretical advantage of creating bigger lesions than platinum-iridium (Pt-Ir) electrodes. We performed a prospective randomized study to compare the clinical efficacy of standard 8 mm Pt-Ir tip catheter (control) and 8 mm gold-tip catheters in the ablation of the cavotricuspid isthmus (CTI)-dependent atrial flutter. METHODS AND RESULTS: A total of 463 patients undergoing CTI ablation in 19 clinical centres were randomized to receive the treatment by gold-tip or control catheter. The primary endpoint was cumulative radiofrequency (RF) application duration until achieving bidirectional CTI block. It did not differ significantly for the two catheters. The gold-tip catheter was, however, associated with a higher ablation success rate (94.3 vs. 89.0%, P = 0.042) and a substantially lower incidence of char and coagulum formation (4.8 vs. 37.9%, P < 0.001), which required exchange of 1 gold-tip (0.4%) and 10 control catheters (4.6%, P = 0.005). The gold-tip catheter delivered more mean power (52 ± 12 W) than the control catheter (48 ± 13 W, P < 0.001). Both mean and maximum temperatures measured by the thermocouple integrated in the catheter tip were statistically significantly lower in the gold (mean: 53.2 ± 4.7°C, max: 68.7 ± 6.6°C) than in the control catheter (54.3 ± 5.2 and 70.2 ± 7.0°C, respectively, P < 0.05). Fluoroscopy time, procedure duration, procedural-related complications, and arrhythmia recurrence during 6 months of follow-up did not differ between the two catheters. CONCLUSION: Owing to a higher primary ablation success rate and reduced incidence of char/coagulum formation, gold may be preferred over Pt-Ir as electrode material for 8 mm tip catheters for CTI ablation. ClinicalTrials.gov: NCT00326001 (http://clinicaltrials.gov/ct2/show/NCT00326001).

Implant-based multi-parameter telemonitoring of patients with heart failure and a defibrillator with vs. without cardiac resynchronization therapy option: a subanalysis of the IN-TIME trial.

AIMS: In the IN-TIME trial, automatic daily implant-based multiparameter telemonitoring significantly improved clinical outcomes in patients with chronic systolic heart failure and implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D). We compared IN-TIME results for ICD and CRT-D subgroups. METHODS: Patients with LVEF ≤ 35%, NYHA class II/III, optimized drug treatment, no permanent atrial fibrillation, and a dual-chamber ICD (n = 274) or CRT-D (n = 390) were randomized 1:1 to telemonitoring or no telemonitoring for 12 months. Primary outcome measure was a composite clinical score, classified as worsened if the patient died or had heart failure-related hospitalization, worse NYHA class, or a worse self-reported overall condition. RESULTS: The prevalence of worsened score at study end was higher in CRT-D than ICD patients (26.4% vs. 18.2%; P = 0.014), as was mortality (7.4% vs. 4.1%; P = 0.069). With telemonitoring, odds ratios (OR) for worsened score and hazard ratios (HR) for mortality were similar in the ICD [OR = 0.55 (P = 0.058), HR = 0.39 (P = 0.17)] and CRT-D [OR = 0.68 (P = 0.10), HR = 0.35 (P = 0.018)] subgroups (insignificant interaction, P = 0.58-0.91). CONCLUSION: Daily multiparameter telemonitoring has a potential to reduce clinical endpoints in patients with chronic systolic heart failure both in ICD and CRT-D subgroups. The absolute benefit seems to be higher in higher-risk populations with worse prognosis.

An optimized approach for right atrial flutter ablation: a post hoc analysis of the AURUM 8 study.

PURPOSE: Radiofrequency catheter ablation of typical atrial flutter can vary largely in duration from patient to patient. The purpose of this work was to determine optimal combination of ablation settings leading to the highest procedural efficacy. METHODS: Our retrospective multivariate analysis comprised 448 patients undergoing atrial flutter ablation with nonirrigated 8-mm catheters at 19 clinical centers. Four procedural variables were included in the prognostic model: preset maximum temperature, preset maximum power, catheter-tip material (gold vs. platinum-iridium), and ablation technique (maximum voltage-guided vs. conventional anatomical approach). Univariate and multivariate analyses were performed using the logistic regression (for acute ablation success) and Cox constant proportional hazard models (for cumulative ablation time). RESULTS: Significant multivariate predictors of acute ablation success were a higher preset maximum temperature (odds 1.083 per 1 °C, P < 0.05) and gold-tip catheter (odds 2.096, P < 0.05). Predictors of cumulative ablation time were the maximum voltage-guided ablation technique (hazard ratio 1.856, P < 0.001), higher preset maximum temperature (hazard ratio 1.039 per 1 °C, P < 0.001), and gold-tip catheter (hazard ratio 1.225, P < 0.05). The combination of optimal settings (70 °C, 70 W, gold-tip catheter, maximum voltage-guided technique) increased the acute success rate from 91.7 % (for the entire study cohort) to 100 %, and reduced median cumulative ablation time from 8.3 to 4.3 min, median total procedure duration from 76 to 55 min, and median fluoroscopy time from 14 to 7 min. CONCLUSIONS: The combination of maximum voltage-guided gold-tip ablation at 70 °C and 70 W was associated with 100 % ablation success and minimal ablation times for nonirrigated ablation of atrial flutter.

Remote monitoring of heart failure patients using implantable cardiac pacing devices and external sensors: results of the Insight-HF study.

AIM: The rapidly increasing prevalence and poor outcome of congestive heart failure have stimulated the development of different telemonitoring technologies. In this study, we monitored remotely self-measured body weight and blood pressure, in parallel with the data automatically transmitted by implantable cardioverter-defibrillators. The primary aim of this study was to evaluate the correlation between different parameters screened by these two telemonitoring systems. METHODS AND RESULTS: Thirty-two patients in NYHA class III heart failure were followed for 164 ± 48 days after cardioverter-defibrillator implantation. In 29 patients, mean heart rate (MHR), resting heart rate (RHR), and patient activity (determined by implanted devices), weight and blood pressure measurements were received on 85% of all days when remote data transmissions were expected. Based on approximately 4,000 daily pairs of measurements pooled for all patients, weight inversely correlated with activity and with the difference between MHR and RHR. By contrast, blood pressure did not correlate with weight, activity, or the difference between MHR and RHR, but it correlated with MHR and RHR individually. CONCLUSION: Body weight, patient activity, and the difference between MHR and RHR are mutually correlated and may reasonably contribute to an algorithm for predicting heart failure deterioration. Blood pressure appears to offer no additional value. As both genesis and symptoms of heart failure exacerbation are non-uniform and complex, the telemonitoring concepts for heart failure patients should employ continuous monitoring of multiple diagnostic parameters, rather than rely on a single parameter. Provided that patient compliance is strictly supervised, reliable data flow from sensors requiring patient involvement is possible.

Potential value of automated daily screening of cardiac resynchronization therapy defibrillator diagnostics for prediction of major cardiovascular events: results from Home-CARE (Home Monitoring in Cardiac Resynchronization Therapy) study.

AIM: To investigate whether diagnostic data from implanted cardiac resynchronization therapy defibrillators (CRT-Ds) retrieved automatically at 24 h intervals via a Home Monitoring function can enable dynamic prediction of cardiovascular hospitalization and death. METHODS AND RESULTS: Three hundred and seventy-seven heart failure patients received CRT-Ds with Home Monitoring option. Data on all deaths and hospitalizations due to cardiovascular reasons and Home Monitoring data were collected prospectively during 1-year follow-up to develop a predictive algorithm with a predefined specificity of 99.5%. Seven parameters were included in the algorithm: mean heart rate over 24 h, heart rate at rest, patient activity, frequency of ventricular extrasystoles, atrial-atrial intervals (heart rate variability), right ventricular pacing impedance, and painless shock impedance. The algorithm was developed using a 25-day monitoring window ending 3 days before hospitalization or death. While the retrospective sensitivities of the individual parameters ranged from 23.6 to 50.0%, the combination of all parameters was 65.4% sensitive in detecting cardiovascular hospitalizations and deaths with 99.5% specificity (corresponding to 1.83 false-positive detections per patient-year of follow-up). The estimated relative risk of an event was 7.15-fold higher after a positive predictor finding than after a negative predictor finding. CONCLUSION: We developed an automated algorithm for dynamic prediction of cardiovascular events in patients treated with CRT-D devices capable of daily transmission of their diagnostic data via Home Monitoring. This tool may increase patients' quality of life and reduce morbidity, mortality, and health economic burden, it now warrants prospective studies. ClinicalTrials.gov NCT00376116.