Key characteristics for effective acute pulmonary vein isolation when using a novel cryoballoon technology: insights from the CHARISMA registry.

PURPOSE: A new cryoballoon (CB) technology (POLARx™; Boston Scientific) for pulmonary vein (PV) isolation in patients with atrial fibrillation (AF) has recently been introduced. The aim of this study was to evaluate procedural and biophysical parameters resulting in acute PV isolation when using this new CB. METHODS: We assessed the first 69 consecutive patients indicated for AF ablation who underwent PV isolation by means of a novel CB system. Procedural metrics were prospectively recorded. RESULTS: A total of 274 PVs were targeted in 69 patients. PV isolation was achieved in all patients by means of cryoablation alone. The median time to isolation (TTI) was 44 [31-68] s (median temperature at TTI = - 49 [- 53 to - 41] °C). The median duration of CB ablation was 180 [180 to 240] s. The median nadir temperature was - 56.0 [- 61 to - 52] °C, and the median thaw time to 0 °C was 18 [15-21] s. The median grade of PV occlusion was 4 [3 to 4]. On the basis of ROC analysis, we defined the following cut-off values for acute PV isolation: - 56 °C for nadir temperature (sensitivity = 73.3%, specificity = 64.6%, AUC = 0.716; positive predictive value = 88.1%), 30 s for TTT (60.2%, 53.3%, 0.578; 79.7%), thaw time > 17 s (65.3%, 70.0%, 0.709; 86.9%), and grade of PV occlusion = 4 (79.4%, 66.7%, 0.738; 88.5%). No major procedure-related adverse events were observed at 30-day post-procedure. CONCLUSIONS: The new POLARx™ CB appears to be effective and safe. A nadir temperature of - 56 °C, a thaw time to 0 °C ≥ 17 s, and complete PV occlusion were the best predictors of acute PV isolation. CLINICAL TRIAL REGISTRATION: Catheter Ablation of Arrhythmias with a High-Density Mapping System in Real-World Practice (CHARISMA). URL: http://clinicaltrials.gov/Identifier : NCT03793998. Registration date: January 4, 2019.

Safety and efficacy of atrial fibrillation ablation guided by Ablation Index module.

PURPOSE: Reconnection of pulmonary veins (PVs) remains common following radiofrequency catheter ablation for atrial fibrillation (AF). Ablation Index (AI) is a novel ablation quality marker that incorporates stability, contact force (CF), time, and power in a weighted formula. Its use seems to improve lesion durability. This is a prospective, single-arm registry to investigate on the safety and mid-term efficacy of AF ablation guided by the AI. METHODS: One hundred fifty-six consecutive patients (mean age 58 ± 10 years, 49% males, 44% with structural heart disease) referred for paroxysmal (124) or persistent (32) AF underwent antral PV isolation using a surround flow CF-sensing catheter guided by the AI. Radiofrequency was delivered targeting interlesion distance ≤ 6 mm and Ablation Index of 330-350 at posterior wall and 400-450 at anterior wall. RESULTS: Mean overall procedure time was 95 ± 30 min with a mean fluoroscopy time of 5 ± 6 min. Mean ablation time was 26 ± 10 min, 627/628 targeted PV were isolated. One pericardial effusion and two groin hematomas were reported; none required intervention. During a mean follow-up of 14 ± 6 months, 17 (10.8%) (9% paroxysmal AF vs 22% persistent AF, p = 0.09) patients had an atrial arrhythmia recurrence. CONCLUSIONS: PV ablation guided by AI resulted feasible, achieving a high rate of isolated PVs, with a low complication rate, and allowed a high single-procedure arrhythmia-free survival at 14 months.

High-density mapping to guide ablation of a right bundle branch morphology premature ventricular contraction from the right outflow tract.

The Rhythmia ultrahigh-density mapping system with a specific algorithm seems to be helpful in identifying the target area to successfully treat multiple morphologies by catheter ablation in the right ventricular outflow tract RVOT. Interestingly, the acquisition process seemed to be extremely faster than a standard manual point-by-point premature ventricular contraction (PVC) mapping.

Twelve-year follow-up of catheter ablation for atrial fibrillation: A prospective, multicenter, randomized study.

BACKGROUND: Randomized and controlled studies have reported the effect of catheter ablation (CA) for atrial fibrillation (AF) over a follow-up of 12-24 months. OBJECTIVE: We report on the effect of CA plus antiarrhythmic drugs in comparison with antiarrhythmic drugs alone on the maintenance of sinus rhythm over 12-year follow-up. METHODS: We extended the follow-up duration of the 137 patients who were enrolled in the Catheter Ablation for the Cure of Atrial Fibrillation Study between February 1, 2002, and June 30, 2003, and randomized to antiarrhythmic drugs (control group) or antiarrhythmic drugs plus CA (ablation group). The primary end point was time to first symptomatic or asymptomatic recurrence of atrial arrhythmia lasting >30 seconds during follow-up. RESULTS: During follow-up, 19 of 68 (27.9%; 95% confidence interval [CI] 18.7%-39.6%) ablation group patients and 3 of 69 (4.3%; 95% CI 1.49%-12.0%) control group patients did not experience any relapse of atrial tachyarrhythmia (P < .001). The Kaplan-Meier analysis performed to determine the probability of survival free from atrial arrhythmias showed a statistical difference in favor of the ablation group (log-rank, P < .001). The effect of CA was consistent in both patients with paroxysmal AF and those with persistent AF. In the multivariate Cox regression analysis, belonging to the control group (hazard ratio 2.95; 95% CI 1.896-4.726; P < .001) and longer time since first AF episode (hazard ratio 1.004; 95% CI 1.002-1.084; P = .041) were predictors of atrial tachyarrhythmia recurrence. CONCLUSION: In patients with paroxysmal and persistent AF, CA significantly increased time to first recurrence of atrial arrhythmias during 12-year follow-up.

Hypertonic Saline in Conjunction with High-Dose Furosemide Improves Dose-Response Curves in Worsening Refractory Congestive Heart Failure.

INTRODUCTION: Diuretic responsiveness in patients with chronic heart failure (CHF) is better assessed by urine production per unit diuretic dose than by the absolute urine output or diuretic dose. Diuretic resistance arises over time when the plateau rate of sodium and water excretion is reached prior to optimal fluid elimination and may be overcome when hypertonic saline solution (HSS) is added to high doses of furosemide. METHODS: Forty-two consecutively hospitalized patients with refractory CHF were randomized in a 1:1:1 ratio to furosemide doses (125 mg, 250 mg, 500 mg) so that all patients received intravenous furosemide diluted in 150 ml of normal saline (0.9%) in the first step (0-24 h) and the same furosemide dose diluted in 150 ml of HSS (1.4%) in the next step (24-48 h) as to obtain 3 groups as follows: Fourteen patients receiving 125 mg (group 1), fourteen patients receiving 250 mg (group 2), and fourteen patients receiving 500 mg (group 3) of furosemide. Urine samples of all patients were collected at 30, 60, and 90 min, and 3, 4, 5, 6, 8, and 24 h after infusion. Diuresis, sodium excretion, osmolality, and furosemide concentration were evaluated for each urine sample. RESULTS: After randomization, 40 patients completed the study. Two patients, one in group 2 and one in group 3 dropped out. Patients in group 1 (125 mg furosemide) had a mean age of 77 ± 17 years, 43% were male, 6 (43%) had heart failure with a preserved ejection fraction (HFpEF), and 64% were in New York Heart Association (NYHA) class IV; the mean age of patients in group 2 (250 mg furosemide) was 80 ± 8.1 years, 15% were male, 5 (38%) had HFpEF, and 84% were in NYHA class IV; and the mean age of patients in group 3 (500 mg furosemide) was 73 ± 12 years, 54% were male, 6 (46%) had HFpEF, and 69% were in NYHA class IV. HSS added to furosemide increased total urine output, sodium excretion, urinary osmolality, and furosemide urine delivery in all patients and at all time points. The percentage increase was 18,14, and 14% for urine output; 29, 24, and 16% for total sodium excretion; 45, 34, and 20% for urinary osmolarity; and 27, 36, and 32% for total furosemide excretion in groups 1, 2, and 3, respectively. These findings were translated in an improvement in the furosemide dose-response curves in these patients. CONCLUSION: These results may serve as new pathophysiological basis for HSS use in the treatment of refractory CHF.

Inducibility of ventricular arrhythmia and tachyarrhythmia recurrences in patients with implantable defibrillator.

INTRODUCTION: We evaluated the potential ability of the electrophysiological (EP) inducibility of ventricular arrhythmias to predict the likelihood of appropriate ICD intervention over the long-term in ischemic and nonischemic patients with current primary prevention indications for ICD implantation. METHODS: Between 2006 and 2008, 206 consecutive heart failure patients who were candidates for ICD implantation for the primary prevention of sudden cardiac death according to standard indications underwent EP testing, usually on ICD implantation. RESULTS: On EP testing, 15 (7%) patients had inducible monomorphic ventricular tachycardia (VT) and 14 (7%) ventricular fibrillation (VF). Over 24 months, 64 (31%) patients received appropriate ICD therapies: 51 (25%) for VT and 16 (8%) for VF. The time to the first appropriate ICD therapy trended to be shorter in the group of patients who were inducible on EP testing (p=0.072). Among patients receiving appropriate therapies, the median number of arrhythmic episodes was 2, and the proportion of patients with 2 treated arrhythmic episodes was higher in the group of inducible patients (34% versus 14%, p=0.005). On multivariate analysis, inducibility proved to be an independent predictor of frequent (2) arrhythmic episodes, as did a history of coronary artery bypass grafting. Moreover, patients with 2 treated arrhythmic episodes showed higher mortality (log-rank test, p=0.042). CONCLUSION: Patients with inducibility of VT or VF are more likely to experience frequent appropriate ICD therapies during follow up.

Remote monitoring improves outcome after ICD implantation: the clinical efficacy in the management of heart failure (EFFECT) study.

AIMS: Internet-based remote interrogation systems have been shown to reduce emergency department and in-office visits in patients with implantable cardioverter defibrillators (ICDs), resulting in increased efficiency for healthcare providers. Nonetheless, studies sized to demonstrate the impact of remote monitoring on patients' outcome have been lacking. METHODS AND RESULTS: The EFFECT study was a multicentre clinical trial aimed at measuring and comparing the outcome of ICD patients conventionally followed-up by means of in-clinic visits (Standard arm) or by remote monitoring (Remote arm) in the clinical practice of 25 Italian centres. From 2011 to 2013, 987 consecutive patients were enrolled and followed up for at least 12 months. The primary endpoint was the rate of death and cardiovascular hospitalizations. Remote monitoring was adopted by 499 patients. Patients in the Standard and Remote arms did not differ significantly in terms of baseline clinical characteristics, except for a more frequent use of ICD with cardiac resynchronization therapy (CRT-D) in the Remote arm (48 vs. 36%, P < 0.001). One-year rates of the primary combined endpoint were 0.27 events/year for patients in the Standard arm and were 0.15 events/year for those in the Remote arm (incident rate ratio, 0.55; 95% CI, 0.41-0.73; P < 0.001). The endpoint rates in the Standard and Remote arms were 0.27 and 0.08 events/year, respectively, among CRT-D recipients (P < 0.001), and 0.28 vs. 0.21 among ICD patients (P = 0.094). The rates of in-office visits were 1.9 per year in the Standard arm and 1.7 per year in the Remote arm. CONCLUSION: Compared with the standard follow-up through in-office visits, remote monitoring is associated with reduced death and cardiovascular hospitalizations in patients with ICD in clinical practice. CLINICAL TRIAL REGISTRATION: URL: http://clinicaltrials.gov/ Identifier: NCT01723865.

Geometrical and electrical predictors of cardiac resynchronization therapy response.

Several studies have demonstrated the beneficial effect of cardiac resynchronization therapy (CRT) in patients with drug-refractory heart failure. A variable proportion, up to 30%, of CRT patients do not benefit from treatment. The lack of response to CRT has a variety of potential causes. The implantation process is fundamental to the success of CRT, since little can subsequently be done to improve the CRT response. The authors reviewed all the geometrical and electrical parameters that could guide the CRT implant and predict its response.

Remote monitoring for implantable defibrillators: a nationwide survey in Italy.

BACKGROUND: Remote monitoring (RM) permits home interrogation of implantable cardioverter defibrillator (ICD) and provides an alternative option to frequent in-person visits. OBJECTIVE: The Italia-RM survey aimed to investigate the current practice of ICD follow-up in Italy and to evaluate the adoption and routine use of RM. METHODS: An ad hoc questionnaire on RM adoption and resource use during in-clinic and remote follow-up sessions was completed in 206 Italian implanting centers. RESULTS: The frequency of routine in-clinic ICD visits was 2 per year in 158/206 (76.7%) centers, 3 per year in 37/206 (18.0%) centers, and 4 per year in 10/206 (4.9%) centers. Follow-up examinations were performed by a cardiologist in 203/206 (98.5%) centers, and by more than one health care worker in 184/206 (89.3%) centers. There were 137/206 (66.5%) responding centers that had already adopted an RM system, the proportion of ICD patients remotely monitored being 15% for single- and dual-chamber ICD and 20% for cardiac resynchronization therapy ICD. Remote ICD interrogations were scheduled every 3 months, and were performed by a cardiologist in 124/137 (90.5%) centers. After the adoption of RM, the mean time between in-clinic visits increased from 5 (SD 1) to 8 (SD 3) months (P<.001). CONCLUSIONS: In current clinical practice, in-clinic ICD follow-up visits consume a large amount of health care resources. The results of this survey show that RM has only partially been adopted in Italy and, although many centers have begun to implement RM in their clinical practice, the majority of their patients continue to be routinely followed-up by means of in-clinic visits.

Antiarrhythmic therapy following ablation of atrial fibrillation.

Antiarrhythmic drugs (AADs) are often used after ablation for atrial fibrillation (AF); the drugs employed vary, but most common are the drugs that were unsuccessful prior to ablation since it seems that the efficacy of AADs might substantially increase after catheter ablation of AF. AADs reduce early recurrences of atrial tachyarrhythmias after AF catheter ablation, whereas they did not prevent arrhythmia recurrences occurring later. Several upstream therapies (angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, statins, corticosteroids and colchicine) have been tested with conflicting results. To date, there is no sufficient evidence to support the use of any upstream therapy after AF catheter ablation. Larger registries and controlled clinical trials in well-defined patient groups and with well-defined outcome parameters are required to further elucidate the role of AADs after AF ablation.

Feasibility and efficacy of electrical cardioversion after cardiac resynchronization implantation in patients with permanent atrial fibrillation.

PURPOSE: Patients with permanent atrial fibrillation (AF) who undergo cardiac resynchronization therapy (CRT) may spontaneously recover sinus rhythm during follow-up. We tested the feasibility and efficacy of electrical cardioversion attempted after 3 months of CRT in patients with permanent AF and measured the long-term maintenance of sinus rhythm. METHODS: Twenty-eight consecutive patients with permanent AF in whom CRT defibrillators had been implanted were scheduled for internal electrical cardioversion after 3 months (group A) and were compared with a control group of 27 patients (group B). RESULTS: In group A, 22 patients (79 %) were eligible for cardioversion; sinus rhythm was restored in 18 (82 %) of these, with no procedural complications. After 12 months, 16 patients (58 %) in group A were in sinus rhythm, compared with one group B patient who spontaneously recovered sinus rhythm (4 %, p < 0.001). On 12-month evaluation, ejection fraction had improved in both groups, but a reduction in left ventricular end-systolic volume was recorded only in group A patients (p = 0.018 versus baseline). CONCLUSIONS: In patients with permanent AF, the rhythm control strategy consisting of internal cardioversion, performed by means of the implanted cardioverter-defibrillator after 3 months of CRT, was associated with a high rate of sinus rhythm resumption on long-term follow-up and with a better echocardiographic response to CRT than that seen in patients treated according to a rate control strategy.

Does catheter ablation cure atrial fibrillation? Single-procedure outcome of drug-refractory atrial fibrillation ablation: a 6-year multicentre experience.

Aims In the last decade, several approaches to ablating triggers and substrates of atrial fibrillation (AF) have been developed. However, most studies have reported data only on short- or medium-term follow-up. The aim of this study was to investigate whether the 1-year efficacy of catheter ablation for AF is predictive of long-term clinical success. Methods and results Between February 2001 and October 2003, 229 consecutive patients affected by drug-refractory paroxysmal or persistent AF underwent a single radiofrequency catheter ablation procedure (anatomical approach in 146 patients and electrophysiologically guided approach in 83 patients). Of these patients, 177 (mean age 59.1 +/- 10.5 years, 57.6% with paroxysmal AF) were free from any atrial arrhythmia recurrence after 12 months. These 177 patients were subsequently followed up for at least another 24 months, by means of electrocardiogram and 24 h Holter monitoring. After a mean follow-up of 49.7 +/- 13.3 months (range 36-83 months), 58.2% of the patients were free from any atrial arrhythmia recurrence (39.5% without antiarrhythmic drugs). The actuarial atrial arrhythmia recurrence rate was 13.0% at 2 years, 21.8% at 3 years, 35.0% at 4 years, 46.8% at 5 years, and 54.6% at 6 years. Atrial arrhythmia-free survival was similar in patients with paroxysmal or persistent AF, with and without antiarrhythmic drugs during the follow-up, who underwent electrophysiologically guided pulmonary vein (PV) isolation or anatomical PV ablation. Conclusion Even patients in whom catheter ablation prevents AF recurrence for 1 year should not be considered 'cured', since >40% of them will suffer AF recurrence over a long-term clinical follow-up.

Clinical and technical determinants of long-term performance of coronary sinus leads.

OBJECTIVES: Little is known about coronary sinus lead performance in patients with cardiac resynchronization therapy devices. We evaluated the impact of clinical and technical parameters on coronary sinus lead performance over long-term follow-up. METHODS: From February 1999 to July 2004, 235 patients (181 men; mean age, 68 +/- 9 years; mean left ventricular ejection fraction, 26.5 +/- 6.5%; idiopathic dilated cardiomyopathy, 49%; ischemic, 48%; and other cause, 3%) underwent cardiac resynchronization therapy (pacemaker or defibrillator) implantation. RESULTS: On implantation, the only statistically significant difference was observed in mean pacing impedance, which was lower for unipolar leads than for bipolar leads (763 +/- 250 vs. 847 +/- 270 Omega, P = 0.02), and lower in patients with ischemic cardiomyopathy than in those with idiopathic cardiomyopathy (758 +/- 204 vs. 837 +/- 291 Omega, P = 0.03). After a mean follow-up of 41.7 +/- 14.7 months, a significant decrease was observed in mean pacing impedance (from 811 +/- 261 to 717 +/- 284 Omega, P = 0.0026) and mean R-wave amplitude (from 13.2 +/- 6.7 to 10.5 +/- 5.5 mV, P = 0.002), whereas the mean pacing energy threshold increased from 3.6 +/- 10.4 to 9.5 +/- 28 microJ (P = 0.004). On analysis of variance, unipolar lead (P = 0.016) and posterior coronary sinus position (P = 0.049) were related to a greater energy threshold increase. On multivariate analysis (Cox regression), only posterior coronary sinus lead position (P = 0.013) proved to be an independent predictor of long-term significant increase in the stimulation energy threshold. CONCLUSION: Over the long-term follow-up of coronary sinus leads, pacing impedance and R-wave amplitude decreased, whereas the energy threshold increased; unipolar leads and posterior lead location in the coronary sinus were related to a greater energy threshold increase.

Role of pulmonary veins isolation in persistent atrial fibrillation ablation: the pulmonary vein isolation in persistent atrial fibrillation (PIPA) study.

BACKGROUND: The role of pulmonary veins (PV) isolation in patients with persistent atrial fibrillation (AF) is still debated. The aim of this study was to evaluate the adjunctive role of PV isolation in patients with persistent AF who underwent circumferential PV ablation (anatomical approach). METHODS: We treated 97 consecutive patients presenting with drug-refractory persistent AF by an anatomical approach (group A, n = 36, mean age = 60 +/- 8 years, 29 males) or an integrated approach (group B, n = 61, mean age 59 +/- 10 years, 48 males). In all patients, radiofrequency (RF) ablation was performed by means of a nonfluoroscopic navigation system, in order to anatomically create circumferential lines around the PV. In group B, the persistence of PV potentials was ascertained with a multipolar circular catheter. If PV potentials persisted, RF energy targeting the electrophysiological breakthroughs was delivered to disconnect the PV. Past a 2-month period of observation, success was defined as absence of any atrial tachyarrhythmia recurrence lasting >30 seconds. RESULTS: Total procedure duration (220 +/- 62 minutes vs 140 +/- 43 minutes, P < 0.001), fluoroscopy time (35 +/- 15 minutes vs 17 +/- 9 minutes, P < 0.001), and RF delivery time (48 +/- 22 minutes vs 27 +/- 9 minutes, P < 0.001) were significantly longer in group B than in group A. One cardiac perforation occurred in group A. After 15 +/- 9.1 months, 21 patients in group A (58%) and 34 patients in group B (56%) were free of atrial tachyarrhythmia recurrence (P = 0.9). CONCLUSIONS: In patients with persistent AF, who underwent an anatomical approach, electrophysiological confirmation of PV disconnection significantly increased the fluoroscopy and procedural times, without effect on the long-term outcomes.

Long-term outcomes of CRT-PM versus CRT-D recipients.

OBJECTIVE: To compare the rates of all-cause mortality in recipients of cardiac resynchronization therapy devices without (CRT-PM) versus with defibrillator (CRT-D). METHODS: Between February 1999 and July 2004, 233 patients (mean age = 69 +/- 8 years, 180 men) underwent implantation of CRT-PM or CRT-D devices. New York Heart Association (NYHA) heart failure functional class II was present in 11%, class III in 69%, and class IV in 20% of patients; mean left ventricle ejection fraction (LVEF) was 26.5 +/- 6.5 %, 48% presented with idiopathic dilated cardiomyopathy and 49% with ischemic heart disease. Cox multiple variable regression analysis was performed in search of predictors of death. RESULTS: The clinical characteristics of the 117 CRT-PM and 116 CRT-D recipients were similar, except for LVEF (28.2 +/- 6.2% vs 25.0 +/- 6.5%, respectively; P < 0.001), and ischemic versus nonischemic etiology of heart failure (41% vs 56%, respectively P = 0.02). Over a mean follow-up of 58 +/- 15 months, no significance difference in overall mortality rate was observed between the two study groups. Male sex, NYHA functional class IV, and atrial fibrillation at implant were significant predictors of death. CONCLUSIONS: There was no difference in long-term survival rate among patients with CRT-D versus CRT-PM, although CRT-D more effectively lowered the sudden death rate. Male sex, NYHA functional class IV, and atrial fibrillation predicted the worst prognosis.

Radiofrequency circumferential ablation limited to the left atrium showing fibrillatory activity in a patient with paroxysmal atrial fibrillation.

We report a case of a tailored approach to atrial fibrillation based on the substrate. In a patient with paroxysmal atrial fibrillation, electroanatomic mapping showed that atrial fibrillation was limited to a large area around the ostia of right pulmonary veins. The patient was successfully treated by catheter anatomic isolation of this area from the remaining part of the left atrium.