Combined atrial fibrillation ablation and balloon mitral commissurotomy in patients with rheumatic mitral stenosis.

INTRODUCTION: Ablation of atrial fibrillation (AF) is usually not considered in patients with rheumatic mitral stenosis (RMS). We analyzed the results of a combined procedure of AF ablation and percutaneous balloon mitral commissurotomy (PBMC). METHODS: We prospectively included 22 patients with severe RMS to undergo a combined PBMC + AF ablation procedure. Noninvasive mapping of the atria was also performed. A historical sample of propensity-scored matched patients who underwent PBMC alone was used as controls. The primary endpoint was freedom from AF/AT at 1-year. Multivariate analysis evaluated sinus rhythm (SR) predictors. RESULTS: Successful pulmonary vein isolation and electrocardiographic imaging-based drivers ablation was performed in 20 patients following PBMC. At 1-year, 75% of the patients in the combined group were in SR compared to 40% in the propensity-score matched group (p = 0.004). The composite of AF recurrence, need for mitral surgery and all-cause mortality was also more frequent in the control group (65% vs. 30%; p = 0.005). Catheter ablation (odds ratio [OR] 1.58; 95% confidence interval [CI] [1.17-17.37]; p = 0.04) and AF type (OR 1.46; 95% CI [1.05-82.64]; p < 0.001) were the only independent predictors of SR at 1-year. Noninvasive mapping in the combined group showed that the number of simultaneous rotors (OR 2.10; 95% CI [1.41-10.2]; p = 0.04) was the only independent predictor of AF. CONCLUSION: A combined procedure of AF ablation and PBMC significantly increased the proportion of patients in sinus rhythm at 1-year. Noninvasive mapping may help to improve AF characterization and guide personalized AF treatment.

Successful cryoablation of dual atrioventricular nodal nonreentrant tachycardia: First reported cases.

We describe two consecutive adult males with incessant dual atrioventricular nodal nonreentrant tachycardia and associated severe cardiomyopathy. After invasive diagnosis, this is the first published report showing the successful outcome of this rare tachycardia with effective cryoablation. Cryothermal lesions in the roof of the proximal coronary sinus and right midseptal area lead to complete resolution of the tachycardia-mediated cardiomyopathy in the mid-term follow-up of our patients.

Pediatric Catheter Ablation: Characteristics and Results of a Series in a Tertiary Referral Hospital.

INTRODUCTION AND OBJECTIVES: Catheter ablation has become the treatment of choice in an increasing number of arrhythmias in children and adolescents. There is still limited evidence of its use at a national level in Spain. The aim was to describe the characteristics and results of a modern monocentric series form a referral tertiary care centre. METHODS: Retrospective register of invasive procedures between 2004 and 2016 performed in patients under 17 years and recorded clinical characteristic, ablation methodology and acute and chronic results of the procedure. RESULTS: A total of 291 procedures in 224 patients were included. Median age was 12.2 years, 60% male. Overall, 46% patients were referred from other autonomous communities. The most frequent substrates were accessory pathways (AP) (70.2%,>50% septal AP localization) and atrioventricular nodal reentrant tachycardia (AVNRT) (15.8%). Congenital and acquired heart disease was frequent (16.8%). Cryoablation was used in 35.5% of the cases. Overall acute success of the primary procedure was 93.5% (AP 93.8%; AVNRT 100%). Redo procedures after recurrence were performed in 18.9% of all substrates, with a long-term cumulative efficacy of 98.4% (AP 99.3%; AVNRT 100%). One (0.37%) serious complication occurred, a case of complete atrioventricular block. CONCLUSIONS: Our study replicated previous international reports of high success rates with scarce complications in a high complexity series, confirming the safety and efficacy of pediatric catheter ablation in our environment performed at highly experienced referral centers.

Current Indications for Implantable Cardioverter Defibrillators in Non-Ischemic Cardiomyopathies and Channelopathies.

Current indications for implantable cardioverter defibrillators (ICDs) in patients with channelopathies and cardiomyopathies of non-ischemic origin are mainly based on non-randomized evidence. In patients with nonischemic dilated cardiomyopathy (NIDCM), there is a tendency towards a beneficial effect on total mortality of ICD therapy in patients with significant left ventricular (LV) dysfunction. Although an important reduction in sudden cardiac death (SCD) seems to be clearly demonstrated in these patients, a net beneficial effect on total mortality is unclear mostly in cases with good functional status. Risk stratification has been changing over the last two decades in patients with hypertrophic cardiomyopathy (HCM). Its risk profile has been delineated in parallel with the beneficial effect of ICD in high risk patients. Observational results based on "appropriate" ICD interventions do support its usefulness both in primary and secondary SCD prevention in these patients. Novel risk models quantify the rate of sudden cardiac death in these patients on individual basis. Less clear risk stratification is available for cases of arrhythmogenic right ventricular cardiomyopathy (ARVC) and in other uncommon familiar cardiomyopathies. Main features of risk stratification vary among the different channelopathies (long QT syndrome -LQTS-, Brugada syndrome, etc) with great debate on the management of asymptomatic patients. For most familiar cardiomyopathies, ICD therapy is the only accepted strategy in the prevention of SCD. So far, genetic testing has a limited role in risk evaluation and management of the individual patient. This review aims to summarize these criticisms and to refine the current indications of ICD implantation in patients with cardiomyopathies and major channelopathies.

Safety of Outpatient Implantation of the Implantable Cardioverter-defibrillator.

INTRODUCTION AND OBJECTIVES: Strategies are needed to reduce health care costs and improve patient care. The objective of our study was to analyze the safety of outpatient implantation of cardioverter-defibrillators. METHODS: A retrospective study was conducted in 401 consecutive patients who received an implantable cardioverter-defibrillator between 2007 and 2012. The rate of intervention-related complications was compared between 232 patients (58%) whose implantation was performed in the outpatient setting and 169 patients (42%) whose intervention was performed in the inpatient setting. RESULTS: The mean age (standard deviation) of the patients was 62 (14) years; 336 (84%) were male. Outpatients had lower left ventricular ejection fraction and a higher percentage had an indication for primary prevention of sudden death, compared to inpatients. Only 21 outpatients (9%) required subsequent hospitalization. The rate of complications until the third month postimplantation was similar for outpatients (6.0%) and inpatients (5.3%); P = .763. In multivariate analysis, only previous anticoagulant therapy was related to the presence of complications (odds ratio = 3.2; 95% confidence interval, 1.4-7.4; P < .01), mainly due to an increased rate of pocket hematomas. Each outpatient implantation saved approximately €735. CONCLUSIONS: Outpatient implantation of implantable cardioverter-defibrillators is safe and reduces costs. Close observation is recommended for patients receiving chronic anticoagulation therapy due to an increased risk of complications.

Comparison of the safety and feasibility of arrhythmia ablation using the Amigo Robotic Remote Catheter System versus manual ablation.

The aim of this study is to evaluate the safety and feasibility of using the Amigo Remote Catheter System (RCS) in arrhythmia ablation procedures. Because Amigo allows the physician to operate all catheter function outside of the radiation field, operator exposure time was also evaluated. This is a nonrandomized, prospective clinical trial conducted at 1 site (identifier: NCT01834872). The study prospectively enrolled 50 consecutive patients (mean age 59 ± 15 years, 72% men) with any type of arrhythmia (23 atrial fibrillation ablation, 12 common atrial flutters, 10 patients with other supraventricular tachycardia, 4 ventricular tachycardia, and 1 patient with palpitations with no arrhythmia induced) referred for catheter ablation, in which we used RCS. Fifty matched ablation procedures (mean age 57 ± 14 years, 70% men) performed during the same time period, without RCS, were enrolled into the control group. Acute ablation success was 96% with RCS and 98% in the manual group. In only 2 cases, the physician switched to manual ablation (1 ventricular tachycardia and 1 accessory pathway) to complete the procedure. There were no complications related to the use of RCS. No differences were observed in total procedure time, total fluoroscopy time, or total radiofrequency delivery compared with the manual group. In procedures performed with RCS, the operator's fluoroscopy exposure time was reduced by 68 ± 16%. In conclusion, arrhythmia ablation with RCS is safe and feasible. Furthermore, it significantly reduces operator's exposure to radiation.

Mechanisms of fractionated electrograms formation in the posterior left atrium during paroxysmal atrial fibrillation in humans.

OBJECTIVES: The aim of this paper was to study mechanisms of formation of fractionated electrograms on the posterior left atrial wall (PLAW) in human paroxysmal atrial fibrillation (AF). BACKGROUND: The mechanisms responsible for complex fractionated atrial electrogram formation during AF are poorly understood. METHODS: In 24 patients, we induced sustained AF by pacing from a pulmonary vein. We analyzed transitions between organized patterns and changes in electrogram morphology leading to fractionation in relation to interbeat interval duration (systolic interval [SI]) and dominant frequency. Computer simulations of rotors helped in the interpretation of the results. RESULTS: Organized patterns were recorded 31 ± 18% of the time. In 47% of organized patterns, the electrograms and PLAW activation sequence were similar to those of incoming waves during pulmonary vein stimulation that induced AF. Transitions to fractionation were preceded by significant increases in electrogram duration, spike number, and SI shortening (R(2) = 0.94). Similarly, adenosine infusion during organized patterns caused significant SI shortening leading to fractionated electrograms formation. Activation maps during organization showed incoming wave patterns, with earliest activation located closest to the highest dominant frequency site. Activation maps during transitions to fragmentation showed areas of slowed conduction and unidirectional block. Simulations predicted that SI abbreviation that heralds fractionated electrograms formation might result from a Doppler effect on wave fronts preceding an approaching rotor or by acceleration of a stationary or meandering, remotely located source. CONCLUSIONS: During induced AF, SI shortening after either drift or acceleration of a source results in intermittent fibrillatory conduction and formation of fractionated electrograms at the PLAW.

Transient atrioventricular block shortly after uneventful cryoablation of atrioventricular nodal re-entrant tachycardias: report of two cases.

We report two patients with atrioventricular (AV) nodal re-entrant tachycardias who developed transient AV block immediately after uneventful cryoablation of the slow pathway was completed. No tachycardia recurrences were observed after an asymptomatic follow-up of 12 months and 10 months, respectively. This is the first report of this unexpected, transient phenomenon. The exact mechanism(s) remain(s) unclear.

[Treatment of patients with ventricular preexcitation]. / Tratamiento de los pacientes con preexcitación ventricular.

Ventricular preexcitation, due to an accessory pathway that creates an electrical connection between the atria with the ventricles, can provide a substrate for a variety of arrhythmogenic syndromes, from paroxysmal AV junctional tachycardia, to the facilitation or aggravation of atrial tachyarrhythmias that can lead to sudden death. However, statistics show that the most frequent situation is for the individual to remain asymptomatic throughout his or her life. In the asymptomatic individual, population-based studies with very long follow-up periods indicate that the risk of sudden death is minimal. Acute therapy for tachyarrhythmias is based on adenosine/verapamil for regular, narrow-QRS tachycardias and procainamide/electrical cardioversion for preexcited tachyarrhythmias. Chronic pharmacologic therapy with antiarrhythmic drugs is not recommended because its efficacy is not well proven and its risk of side effects can be considerable. In symptomatic patients, the treatment of choice is catheter ablation, with an efficacy of 93%, a complication rate of 1% and a mortality rate of 1 per thousand. Whether catheter ablation should be recommended for asymptomatic individuals remains controversial. The authors recommend that these individuals should be followed with regular clinical evaluation, and that catheter ablation should be advised only for those who become symptomatic.