Juan Sieira

Phrenic nerve paralysis during cryoballoon ablation for atrial fibrillation: A comparison between the first- and second-generation balloon

BACKGROUND Phrenic nerve palsy (PNP) is the most frequently observed complication during cryoballoon ablation (CB; Arctic Front, Medtronic, MN) occurring in roughly 7%-9% of the cases. The new second-generation cryoballoon ablation Arctic Front Advance (CB-A) (Arctic Front) has recently been launched in the market. OBJECTIVE To evaluate the incidence of right PNP with the new CB-A in comparison with the first-generation balloon in a series of consecutive patients that underwent pulmonary vein isolation with this modality. METHODS The study was designed as an observational study with a prospective follow-up. In total, 121 consecutive patients were included: 80 patients with the CB (group 1) and 41 with the CB-A (group 2). RESULTS Mean procedural times, fluoroscopic times, and time to pulmonary vein isolation documented by real-time recordings were significantly lower in group 2 (P ≤ .05). The occurrence of PNP was significantly higher in group 2 (6.25% [5 of 80] in group 1 vs 19.5% [8 of 41] in group 2; P = .033). At 7 months, PNP persisted in 1 (2.5%) patient in the CB-A group. CONCLUSIONS Right PNP seems to occur in a significantly larger number of patients with the second-generation CB-A. However, this complication is reversible in nearly all cases on short-term follow-up. More refined phrenic nerve monitoring during right-sided pulmonary vein ablation and less vigorous wedging maneuvers in the pulmonary vein ostia might significantly reduce the occurrence of this complication.

Implantable Cardioverter-Defibrillator Therapy in Brugada Syndrome: A 20-Year Single-Center Experience

BACKGROUND Patients with Brugada syndrome and aborted sudden cardiac death or syncope have higher risks for ventricular arrhythmias (VAs) and should undergo implantable cardioverter-defibrillator (ICD) placement. Device-based management of asymptomatic patients is controversial. ICD therapy is associated with high rates of inappropriate shocks and device-related complications. OBJECTIVES The objective of this study was to investigate clinical features, management, and long-term follow-up of ICD therapy in patients with Brugada syndrome. METHODS Patients presenting with spontaneous or drug-induced Brugada type 1 electrocardiographic findings, who underwent ICD implantation and continuous follow-up at a single institution, were eligible for this study. RESULTS A total of 176 consecutive patients were included. During a mean follow-up period of 83.8 ± 57.3 months, spontaneous sustained VAs occurred in 30 patients (17%). Eight patients (4.5%) died. Appropriate ICD shocks occurred in 28 patients (15.9%), and 33 patients (18.7%) had inappropriate shocks. Electrical storm occurred in 4 subjects (2.3%). Twenty-eight patients (15.9%) experienced device-related complications. In multivariate Cox regression analysis, aborted sudden cardiac death and VA inducibility on electrophysiologic studies were independent predictors of appropriate shock occurrence. CONCLUSIONS ICD therapy was an effective strategy in Brugada syndrome, treating potentially lethal arrhythmias in 17% of patients during long-term follow-up. Appropriate shocks were significantly associated with the presence of aborted sudden cardiac death but also occurred in 13% of asymptomatic patients. Risk stratification by electrophysiologic study may identify asymptomatic patients at risk for arrhythmic events and could be helpful in investigating syncope not related to VAs. ICD placement is frequently associated with device-related complications, and rates of inappropriate shocks remain high regardless of careful device programming.

Pulmonary vein isolation as index procedure for persistent atrial fibrillation: One-year clinical outcome after ablation using the second-generation cryoballoon

BACKGROUND No data are available about the clinical outcome of pulmonary vein isolation (PVI) as an index procedure for persistent atrial fibrillation (PersAF) ablation using the second-generation cryoballoon (CB-Adv). OBJECTIVE The purpose of this study was to assess the 1-year efficacy of PVI as an index procedure for PersAF ablation using the novel CB-Adv. METHODS Sixty-three consecutive patients (45 male [71.4%], mean age 62.7 ± 9.7 years) with drug-refractory PersAF undergoing PVI using the novel CB-Adv were enrolled. Follow-up was based on outpatient clinic visits including Holter ECGs. Recurrence of atrial tachyarrhythmias (ATas) was defined as a symptomatic or documented episode >30 seconds. RESULTS A total of 247 PVs were identified and successfully isolated with a mean of 1.7 ± 0.4 freezes. Mean procedural and fluoroscopy times were 87.1 ± 38.2 minutes and 14.9 ± 6.1 minutes, respectively. Among 26 of 63 patients (41.3%) presenting with AF at the beginning of the procedure, 7 of 26 (26.9%) converted to sinus rhythm during ablation. Phrenic nerve palsy occurred in 4 of 63 patients (6.3%). At 1-year follow-up, after a 3-month blanking period (BP), 38 of 63 patients (60.3%) were in sinus rhythm. Because of ATa recurrences, 9 patients underwent a second procedure with radiofrequency ablation showing a pulmonary vein reconnection in 4 right-sided PVs (44.4%) and 3 left-sided PVs (33.3%). Multivariate analysis demonstrated that PersAF duration (P = .01) and relapses during BP (P = .04) were independent predictors of AT recurrences. CONCLUSION At 1-year follow-up, freedom from ATas following PersAF ablation with the novel CB-Adv is 60%. Phrenic nerve palsy is the most common complication. PersAF duration and relapses during the BP appear to be significant predictors of arrhythmic recurrences.

Circumferential pulmonary vein isolation as index procedure for persistent atrial fibrillation: a comparison between radiofrequency catheter ablation and second-generation cryoballoon ablation

AIMS To assess the 1 year efficacy of pulmonary vein isolation (PVI) as index procedure for persistent atrial fibrillation (PersAF) comparing conventional radiofrequency irrigated-tip catheter ablation (RFCA) using contact-force technology and ablation using the second-generation cryoballoon (CB-AdvA). METHODS AND RESULTS One hundred consecutive patients (74 male, 74%; mean age 62.4 ± 9.6 years) with drug-refractory PersAF undergoing PVI using RFCA and CB-AdvA were enrolled. Follow-up was based on outpatient clinic visits including Holter-electrocardiograms. Recurrence of atrial tachyarrhythmias (ATas) was defined as a symptomatic or documented episode >30 s. Among 100 patients, 50 underwent RFCA whereas 50 CB-AdvA. Mean procedure and fluoroscopy times were 90.5 ± 41.7 vs. 140.2 ± 46.9 min and 14.5 ± 6.6 vs. 19.8 ± 6.8 min in the CB-Adv and in the RFCA group, respectively (P < 0.01). At 1 year follow-up, after a 3 months blanking period (BP), freedom from ATas off-drugs after a single procedure was 60% (28/50 patients) in the CB-Adv and 56% (27/50 patients) in the RFCA group (P = 0.71). Multivariate analysis demonstrated that PersAF duration (P = 0.01) and relapses during BP (P = 0.02) were independent predictors of ATa recurrences following the index procedure. CONCLUSION Freedom from ATas following PersAF ablation with RFCA and CB-Adv is comparable at 1 year follow-up after a single procedure. Ablation with the CB-Adv is associated with shorter procedure time and radiation exposure as compared with RFCA. Atrial tachyarrhythmias occurrence during BP and longer time of PersAF seem to be significant predictors of arrhythmia recurrences after the index procedure.

Drug-Induced Brugada Syndrome in Children: Clinical Features, Device-Based Management, and Long-Term Follow-Up

OBJECTIVES The goal of this study was to investigate the clinical features, management, and long-term follow-up of children with drug-induced Brugada syndrome (BS). BACKGROUND Patients with BS <12 years of age with a spontaneous type I electrocardiogram have a higher risk of arrhythmic events. Data on drug-induced BS in patients <12 years of age are lacking. METHODS Among 505 patients with ajmaline-induced BS, subjects ≤12 years of age at the time of diagnosis were considered as children and eligible for this study. RESULTS Forty children (60% male; age 8 ± 2.8 years) were included. Twenty-four children (60%) had a family history of sudden death. Two (5%) had a previous episode of aborted sudden death, and 8 (20%) had syncope. Children experienced more frequent episodes of sinus node dysfunction (SND) compared with older subjects (7.5% vs. 1.5%; p = 0.04) and had a comparable incidence of atrial tachyarrhythmias. Children more frequently experienced episodes of ajmaline-induced sustained ventricular arrhythmias (VAs) compared with older patients (10.0% vs. 1.3%; p = 0.005). Twelve children (30%) received an implantable cardioverter-defibrillator (ICD). After a mean follow-up time of 83 ± 51 months, none of the children died suddenly. Spontaneous sustained VAs were documented in 1 child (2%). Among children with ICD, 1 (8%) experienced an appropriate shock, 4 (33%) had inappropriate ICD shocks, and 4 (33%) experienced device-related complications. CONCLUSIONS Drug-induced BS is associated with atrial arrhythmias and SND. Children are at higher risk of ajmaline-induced VAs. The rate of device-related complications, leading to lead replacement or inappropriate shocks, is considerable and even higher than with appropriate interventions. Based on these findings, the optimal management of BS in childhood should remain individualized, taking into consideration the patients clinical history and familys wishes.

Prognostic Value of Programmed Electrical Stimulation in Brugada Syndrome 20 Years Experience

Background—The prognostic value of electrophysiological investigations in individuals with Brugada syndrome remains controversial. Different groups have published contradictory data. Long-term follow-up is needed to clarify this issue. Methods and Results—Patients presenting with spontaneous or drug-induced Brugada type I ECG and in whom programmed electric stimulation was performed at our institution were considered eligible for this study. A total of 403 consecutive patients (235 males, 58.2%; mean age, 43.2±16.2 years) were included. Ventricular arrhythmias during programmed electric stimulation were induced in 73 (18.1%) patients. After a mean follow-up time of 74.3±57.3 months (median 57.3), 25 arrhythmic events occurred (16 in the inducible group and 9 in the noninducible). Ventricular arrhythmias inducibility presented a hazard ratio for events of 8.3 (95% confidence interval, 3.6–19.4), P<0.01. Conclusions—Programmed ventricular stimulation of the heart is a good predictor of outcome in individuals with Brugada syndrome. It might be of special value to guide further management when performed in asymptomatic individuals. The overall accuracy of the test makes it a suitable screening tool to reassure noninducible asymptomatic individuals

Asymptomatic Brugada Syndrome: Clinical Characterization and Long Term Prognosis

Background—Among Brugada syndrome patients, asymptomatic individuals are considered to be at the lowest risk. Nevertheless, arrhythmic events and sudden cardiac death are not negligible. Literature focused on this specific group of patients is sparse. The purpose of this study is to investigate the clinical characteristics, management, and long-term prognosis of asymptomatic Brugada syndrome patients. Methods and Results—Patients presenting with spontaneous or drug-induced Brugada type I ECG and no symptoms at our institution were considered eligible. A total of 363 consecutive patients (200 men, 55.1%; mean age, 40.9±17.2 years; 41 [11.3%] with spontaneous type I ECG) were included. Electrophysiological study was performed in 321 (88.4%) patients, and ventricular arrhythmias were induced in 32 (10%) patients. An implantable cardioverter defibrillator was implanted in 61 (16.8%) patients. After a mean follow-up time of 73.2±58.9 months, 9 arrhythmic events occurred, accounting for an annual incidence rate of 0.5%. Event-free survival was 99.0% at 1 year, 96.2% at 5 years, and 95.4% at 10 and 15 years. Univariate analysis identified as risk factors: electrophysiological study inducibility (hazard ratio, 11.4; P<0.01), spontaneous type I (hazard ratio, 4.0; P=0.04), and previous sinus node dysfunction (hazard ratio, 8.0; 95% confidence interval, 1.0–63.9; P=0.05). At the multivariate analysis, only inducibility remained significant (hazard ratio, 9.1; P<0.01) Conclusions—Arrhythmic events in asymptomatic Brugada syndrome patients are not insignificant. Ventricular arrhythmia inducibility, spontaneous type I ECG, and presence of sinus node dysfunction might be considered as risk factors and used to drive long-term management.

On the Quest for the Best Freeze: Predictors of Late Pulmonary Vein Reconnections After Second-Generation Cryoballoon Ablation.

Background—The second-generation cryoballoon is effective in achieving acute pulmonary vein isolation (PVI) and favorable clinical outcome. To date, no data are available on factors affecting late PV reconnection after second-generation cryoballoon ablation. Methods and Results—A total of 29 consecutive patients (25 male, 86.2%; mean age 57.8±13.8 years) underwent a repeat procedure, after a mean 11.6±4.5 months (range, 3.5–19.7 months), after index ablation using the 28-mm second-generation cryoballoon. All repeat ablations were performed using a 3-dimensional electroanatomical mapping system. Among all 115 PVs, including 1 left common ostiums (LCOs), 25 (21.7%) showed a PV reconnection in 20 patients (1.25 per patient). Persistent PVI could be documented in 90 of 115 PVs (78.2%). In 9 of 29 patients (31%), all PVs were electrically isolated. In the multivariable analysis, time to PVI (P=0.03) and failure to achieve −40°C within 60 s (P=0.05) independently predicted late PV reconnection. At receiver-operator curve analysis, time to PVI <60 s identified the absence of PV reconduction (sensitivity, 86.7%; specificity, 86.2%; positive predictive value, 59.1%; and negative predictive value, 96.4%; area under the curve, 0.85; confidence interval, 0.73–0.97; P<0.001). Conclusions—The rate of late PV reconnection after second-generation cryoballoon ablation is low (1.25 PVs/patient). Faster time to isolation and achievement of −40°C within 60 s independently predict durable PVI. In addition, 60-s cut-off for time to PVI indicates persistent isolation with 96.4% negative predictive value. These parameters might guide the operator whether to perform further applications to ensure a long-lasting PVI.

Life-threatening ventricular arrhythmias during ajmaline challenge in patients with Brugada syndrome: Incidence, clinical features, and prognosis

BACKGROUND Sustained ventricular arrhythmias (sVAs), such as polymorphic ventricular tachycardia or ventricular fibrillation, can complicate ajmaline challenge in patients with Brugada syndrome (BS). OBJECTIVE To assess the incidence of life-threatening sVAs during ajmaline administration in a large series of patients with BS. In addition, clinical characteristics as well as prognosis of these patients were evaluated. METHODS All consecutive patients with ajmaline-induced diagnosis of BS were eligible for this study. RESULTS A total of 503 patients were included. Nine (1.8%) patients (44% men; mean age 26 ± 18 years) developed a life-threatening sVA during ajmaline challenge. Three patients (33%)were children, and 2 (22%) patients experienced sVAs refractory to the first external defibrillation. One patient underwent venoarterial extracorporeal membrane oxygenation to restore sinus rhythm. Age at the time of ajmaline challenge was significantly lower in patients with sVAs compared with patients without sVAs (26 ± 18 years vs 41 ± 18 years; P = .01). Moreover, patients with sVAs presented more frequently with sinus node dysfunction compared with patients with normal response to ajmaline (22.2% vs 1.4%; P = .01). After a mean follow-up time of 29 ± 8 months, none of the patients who had developed a sVA during ajmaline challenge died suddenly or developed further life-threatening ventricular arrhythmias. CONCLUSIONS sVA during ajmaline challenge is not a rare event in BS occurring in 9 (1.8%) patients. Despite its challenging acute treatment, the occurrence of ajmaline-induced sVAs in patients with BS might not identify a category at higher risk for further arrhythmic events.

Pathogenesis and management of Brugada syndrome

Brugada syndrome is an inherited disease characterized by an increased risk of sudden cardiac death owing to ventricular arrhythmias in the absence of structural heart disease. Since the first description of the syndrome >20 years ago, considerable advances have been made in our understanding of the underlying mechanisms involved and the strategies to stratify at-risk patients. The development of repolarization–depolarization abnormalities in patients with Brugada syndrome can involve genetic alterations, abnormal neural crest cell migration, improper gap junctional communication, or connexome abnormalities. A common phenotype observed on the electrocardiogram of patients with Brugada syndrome might be the result of different pathophysiological mechanisms. Furthermore, risk stratification of this patient cohort is critical, and although some risk factors for Brugada syndrome have been frequently reported, several others remain unconfirmed. Current clinical guidelines offer recommendations for patients at high risk of developing sudden cardiac death, but the management of those at low risk has not yet been defined. In this Review, we discuss the proposed mechanisms that underlie the development of Brugada syndrome and the current risk stratification and therapeutic options available for these patients.