CPVT: Arrhythmogenesis, Therapeutic Management, and Future Perspectives. A Brief Review of the Literature.

Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is a primary electrical disease characterized by a normal resting electrocardiogram and induction of malignant arrhythmias during adrenergic stress leading to syncope or sudden cardiac death (SCD). CPVT is caused by mutations in the cardiac ryanodine receptor (RyR2) or in the sarcoplasmic reticulum protein calsequestrin 2 genes (CASQ2). The RyR2 mutations are responsible for the autosomal dominant form of CPVT, while CASQ2 mutations are rare and account for the recessive form. These mutations cause a substantial inballance in the homeostasis of intracellular calcium resulting in polymorphic ventricular tachycardia through triggered activity. Beta blockers were for years the cornerstone of therapy in these patients. Sodium channel blockers, especially flecainide, have an additive role in those not responding in beta blockade. Implantation of defibrillators needs a meticulous evaluation since inappropriate shocks may lead to electrical storm. Finally, cardiac sympathetic denervation might also be an alternative therapeutic option. Early identification and risk stratification is of major importance in patients with CPVT. The aim of the present review is to present the arrhythmogenic mechanisms of the disease, the current therapies applied and potential future perspectives.

Long-term prognosis of drug-induced Brugada syndrome.

BACKGROUND: Patients with drug-induced Brugada syndrome (BS) are considered at a lower risk than those with a spontaneous type I pattern. Nevertheless, they can present arrhythmic events. OBJECTIVE: The purpose of this study was to investigate their clinical characteristics, long-term prognosis and risk factors. METHODS: A consecutive cohort of 343 patients with drug-induced BS was included and compared with 78 patients with a spontaneous type I pattern. RESULTS: The mean age was 40.7 ± 18.3 years. Sudden cardiac death (SCD) was the clinical presentation in 13 (3.8%) and syncope in 86 (25.1%); 244 (71.1%) were asymptomatic. Patients with drug-induced BS were less frequently men (180 (52.5%) vs 63 (80.8%); P < .01), were more frequently asymptomatic (244 (71.1%) vs 44 (56.4%); P < .01), and had less ventricular arrhythmias (VAs) induced during electrophysiology study (41 (13.2%) vs 31 (42.4%); P < .01). An implantable cardioverter-defibrillator was implanted in 128 patients (37.3%). During a median follow-up of 62.5 months (interquartile range 28.9-115.6 months), 34 patients presented arrhythmic events. The event rate was 1.1% person-year (vs 2.3% person-year in patients with a spontaneous type I pattern; P < .01). Presentation as SCD and inducible VAs were independent risk factors significantly associated with arrhythmic events (adjusted hazard ratio 22.0 and 3.5). Drug-induced BS was related to a better prognosis only in asymptomatic individuals. CONCLUSION: Drug-induced BS has a good prognosis if asymptomatic; however, SCD is possible. Clinical presentation as SCD and inducible VAs during electrophysiology study are independent risk factors for arrhythmic events. In asymptomatic patients, proband status and inducible VAs can help to identify patients at higher risk, but further evidence is needed.

A score model to predict risk of events in patients with Brugada Syndrome.

AIMS: Risk stratification in Brugada Syndrome (BS) remains challenging. Arrhythmic events can occur life-long and studies with long follow-ups are sparse. The aim of our study was to investigate long-term prognosis and risk stratification of BS patients. METHODS AND RESULTS: A single centre consecutive cohort of 400 BS patients was included and analysed. Mean age was 41.1 years, 78 patients (19.5%) had a spontaneous type I electrocardiogram (ECG). Clinical presentation was aborted sudden cardiac death (SCD) in 20 patients (5.0%), syncope in 111 (27.8%) and asymptomatic in 269 (67.3%). Familial antecedents of SCD were found in 184 individuals (46.0%), in 31 (7.8%) occurred in first-degree relatives younger than 35 years. An implantable cardioverter defibrillator (ICD) was placed in 176 (44.0%). During a mean follow-up of 80.7 months, 34 arrhythmic events occurred (event rate: 1.4% year). Variables significantly associated to events were: presentation as aborted SCD (Hazard risk [HR] 20.0), syncope (HR 3.7), spontaneous type I (HR 2.7), male gender (HR 2.7), early SCD in first-degree relatives (HR 2.9), SND (HR 5.0), inducible VA (HR 4.7) and proband status (HR 2.1). A score including ECG pattern, early familial SCD antecedents, inducible electrophysiological study, presentation as syncope or as aborted SCD and SND had a predictive performance of 0.82. A score greater than 2 conferred a 5-year event probability of 9.2%. CONCLUSIONS: BS patients remain at risk many years after diagnosis. Early SCD in first-degree relatives and SND are risk factors for arrhythmic events. A simple risk score might help in the stratification and management of BS patients.

Impact of the high-frequency cutoff of bandpass filtering on ECG quality and clinical interpretation: A comparison between 40Hz and 150Hz cutoff in a surgical preoperative adult outpatient population.

BACKGROUND: In 1990 the American Heart Association (AHA) established a standard 0.05 to 150Hz bandwidth for the routine recording of 12-lead electrocardiograms (ECGs). However, subsequent studies have indicated a very high prevalence of deviations from the recommended cutoffs. OBJECTIVE: This prospective observational study investigates the impact of 40Hz compared to 150Hz high-frequency cutoffs on ECG quality and clinical interpretation in a single-center surgical outpatient population. METHODS: 1582 consecutive adult patients underwent two standard 12-lead ECG tracings using different high-frequency cutoffs (40Hz and 150Hz). Two blinded cardiologists randomly reviewed and interpreted the recordings according to pre-defined parameters (PR and ST segment, Q and T wave abnormalities). An arbitrary score, ranging from 1 to 3, was established to evaluate the perceived quality of the recordings and the non-interpretable ECGs were noted. The tracings were then matched to compare interpretations between 40 and 150Hz filters. RESULTS: A 40Hz high-frequency cutoff resulted in an increased rate of optimal quality ECGs compared to the 150Hz cutoff (93.4% vs 54.6%; p<0.001) and a lower rate of non-interpretable traces (0.25% vs 4.80%; p<0.001). Analyzing the morphologic parameters, no significant differences between the filter settings were found, except for a higher incidence of the J-point elevation in the 40Hz high-frequency cutoff (p=0.007) and a higher incidence of left ventricular hypertrophy in the 150Hz high-frequency cutoff (7.4% vs 5.4%, p<0.001). The latter was noted only in ECGs with borderline QRS amplitudes (between 3.3 and 3.7mV; p<0.001). CONCLUSION: Despite current recommendations, the large deviation from standard high-frequency cutoff in clinical practice does not seem to significantly affect ECG clinical interpretation and a 40Hz high-frequency cutoff of the band-pass filtering may be acceptable in a low risk population, allowing for a better quality of tracings.

Prevalence and Clinical Impact of Early Repolarization Pattern and QRS-Fragmentation in High-Risk Patients With Brugada Syndrome.

BACKGROUND: The phenotypic heterogeneity of Brugada syndrome (BrS) can lead some patients to show an additional inferolateral early repolarization pattern (ERP), or fragmented QRS (f-QRS). The aim of the study was to investigate the prevalence and clinical impact of f-QRS, ERP or combined f-QRS/ERP in high-risk patients with BrS. METHODS AND RESULTS: Patients with spontaneous or drug-induced BrS and an indication to receive an implantable cardioverter-defibrillator (ICD) were considered eligible for this study. From 1992 to 2012, a total of 176 consecutive patients with BrS underwent ICD implantation. Among them, 48 subjects (27.3%) presented with additional depolarization and/or repolarization abnormalities. f-QRS was found in 29 (16.5%), ERP in 15 (8.5%), and combined f-QRS/ERP in 4 patients (2.3%). After a mean follow-up of 95.2±51.9 months, spontaneous sustained ventricular arrhythmias were documented in 8 patients (16.7%). No significant difference was found in the rate of appropriate shocks between patients presenting with f-QRS or ERP and those without abnormalities. Patients with both f-QRS and ERP had a significantly higher rate of appropriate shocks (HR: 4.1; 95% CI: 1.1-19.7; P=0.04). CONCLUSIONS: Fragmented QRS and ERP are common ECG findings in high-risk BrS patients, occurring in up to 27% of cases. When combined, f-QRS and ERP confer a higher risk of appropriate ICD interventions during a very long-term follow-up. (Circ J 2016; 80: 2109-2116).

Single 3-Minute versus Double 4-Minute Freeze Strategy for Second-Generation Cryoballoon Ablation: A Single-Center Experience.

INTRODUCTION: Second-generation cryoballoon (CB-Adv) ablation is highly effective in achieving pulmonary vein isolation (PVI) with promising mid-term clinical outcome. However, the ideal freezing strategy is still under debate. The aim of this study was to assess the efficacy of a single 3-minute approach compared to the conventional 4-minute plus bonus application using CB-Adv. METHODS AND RESULTS: One hundred and sixty patients (67% male; mean age 58.0 ± 13.3 years) underwent PVI using CB-Adv for paroxysmal atrial fibrillation (PAF). Among 160 patients, 80 received a single 3-minute approach (3-mns group), while the remaining 80 conventional 4-minute plus bonus-freeze (4-mns group). Mean procedure and fluoroscopy times were 90.6 ± 15.8 and 18.3 ± 6.9 in the 4-mns group, 75.2 ± 17.1 and 13.5 ± 8.7 in the 3-mns group (P < 0.001, respectively). First-freeze isolation rate was 91.6% in the 4- versus 90.6% in the 3-mns group (P = 0.78). Persistent phrenic nerve palsy (PNP) occurred in 6/80 (3.5%) in the 4-mns group and 4/80 in the 3-mns group (P = 0.75). The overall freedom from ATas 2 years after the procedure was 78.1% (125/160): 77.5% (62/80 patients) in the 3-mns and 78.8% (63/80 patients) in the 4-mns group (P = 0.82). In multivariate analysis, time to PVI and nadir temperature independently predicted ATa recurrences (P < 0.001). CONCLUSIONS: CB-Adv ablation for PAF is highly effective, resulting in 78% 2-year freedom from arrhythmic recurrences. A "single 3-minute strategy" showed equal efficacy as compared to the conventional 4-minute plus bonus freeze approach at 2-year follow-up, providing shorter procedure and fluoroscopy time. Nadir temperature and time to PVI were predictors of arrhythmic recurrences. "Bonus-freeze" strategy might be unnecessary.

Clinical characterisation and long-term prognosis of women with Brugada syndrome.

OBJECTIVES: Brugada syndrome (BS) in women is considered an infrequent condition with a more favourable prognosis than in men. Nevertheless, arrhythmic events and sudden cardiac death (SCD) also occur in this population. Long-term follow-up data of this group are sparse. The purpose of the present study was to investigate the clinical characteristics and long-term prognosis of women with BS. METHODS: A consecutive cohort of 228 women presenting with spontaneous or drug-induced Brugada type I ECG at our institution were included and compared with 314 men with the same diagnosis. RESULTS: Mean age was 41.5±17.3 years. Clinical presentation was SCD in 6 (2.6%), syncope in 51 (22.4%) and the remaining 171 (75.0%) were asymptomatic. As compared with men, spontaneous type I ECG was less common (7.9% vs 23.2%, p<0.01) and less ventricular arrhythmias were induced during programmed electrical stimulation (5.5% vs 22.3%, p<0.01). An implantable cardioverter defibrillator (ICD) was implanted in 64 women (28.1%). During a mean follow-up of 73.2±56.2 months, seven patients developed arrhythmic events, constituting an event rate of 0.7% per year (as compared with 1.9% per year in men, p=0.02). Presentation as SCD or sinus node dysfunction (SND) was risk factor significantly associated with arrhythmic events (hazard risk (HR) 25.4 and 9.1). CONCLUSION: BS is common in women, representing 42% of patients in our database. Clinical presentation is less severe than men, with more asymptomatic status and less spontaneous type I ECG and prognosis is more favourable, with an event rate of 0.7% year. However, women with SCD or previous SND are at higher risk of arrhythmic events.

'The role of novel oral anticoagulants in patients undergoing cryoballoon ablation for atrial fibrillation'.

AIM: Peri-procedural thromboembolic (TE) and hemorrhagic events are complications of major concern for patients undergoing cryoballoon (CB) ablation for atrial fibrillation (AF). While peri-procedural anticoagulation management could decrease the incidence of these complications, data on CB ablation are scarce. The role of novel oral anticoagulants (NOACs) has not been thoroughly tested in this population. METHODS: In the present study, we sought to assess acute peri-procedural complications in patients undergoing CB ablation for AF under different anticoagulation regimens; anticoagulation administration was performed according to the CHA2DS2-VASc score guidelines. To the best of our knowledge, this is the first study that compares 1) uninterrupted warfarin, 2) bridging therapy with low molecular weight heparin (LMWH), 3) aspirin and 4) NOACs in this subgroup of patients. RESULTS: NOACs were as effective as uninterrupted warfarin in terms of bleeding complications and TE events. Surprisingly, the aspirin group had more hemorrhagic complications than both the warfarin and NOACs groups. CONCLUSION: In the current study, the use of NOACs was an effective and safe approach in CB ablation.

P-wave indices as predictors of atrial fibrillation recurrence after pulmonary vein isolation in normal left atrial size.

AIMS: Prolonged P-wave duration and dispersion are universally accepted noninvasive markers for atrial electrical remodeling. Our aim was to analyze P-wave indices as predictors of atrial fibrillation recurrence after pulmonary vein isolation in patients with normal left atrial size. METHODS: From January 2008 to December 2011, 426 patients with drug-resistant symptomatic paroxysmal atrial fibrillation underwent pulmonary vein isolation as an index procedure by conventional radiofrequency or cryoballoon ablation in our center. Patients with left atrial dilatation, poor-quality electrocardiograms, atrial pacemaker stimulation, and those undergoing repeat procedures were excluded. A total of 201 patients were analyzed during a mean follow-up of 22 ±â€Š16 months. RESULTS: Patients with prolonged P-wave duration had higher rates of atrial fibrillation recurrences compared with those without prolonged P-wave duration (49 vs. 14%; P < 0.001). Atrial fibrillation recurrence was significantly associated with prolonged P-wave duration (129 ±â€Š13 vs. 119 ±â€Š11 ms; P < 0.001) and P-wave dispersion (54 ±â€Š12 vs. 42 ±â€Š10 ms; P < 0.001) compared with those who remained in sinus rhythm. P-wave duration and dispersion were independently associated with atrial fibrillation recurrence (hazard ratio 1.045, 95% confidence interval 1.027-1.063, P < 0.001; and hazard ratio 1.049, 95% confidence interval 1.022-1.078, P < 0.001, respectively), after adjusting for left atrial size and age. CONCLUSION: Prolonged P-wave duration and dispersion were found to be independently associated with higher recurrence rates of atrial fibrillation after pulmonary vein isolation in patients with normal left atrial dimension. Therefore, a prolongation of P-wave indices may help to identify those patients in whom electrical remodeling has already occurred and a more extensive ablation may be indicated.

Electrophysiological findings following pulmonary vein isolation using radiofrequency catheter guided by contact-force and second-generation cryoballoon: lessons from repeat ablation procedures.

AIMS: To assess the incidence of late pulmonary vein (PV) reconnection following index PV isolation (PVI) procedure initially achieved with radiofrequency contact-force catheter ablation (CFCA) and second-generation cryoballoon ablation (CB-AdvA). METHODS AND RESULTS: A total of 56 consecutive patients (41 male, 73.2%; mean age 60.8 ± 11.8 years) underwent a repeat ablation because of recurrent atrial tachyarrhythmias (ATas) after index PVI achieved with CFCA (30 patients) or CB-AdvA (26 patients). All repeat procedures were performed by the means of CFCA. In the CFCA group, among 119 PVs, 43 (36.1%) showed conduction gaps in 24 patients (1.8 per patient), whereas in the CB-AdvA group among 103 veins, 21 (20.4%) showed a PV reconnection in 18 patients (1.2 per patient) (P = 0.01). The left superior pulmonary vein was less frequently reconnected following CB-AdvA when compared with CFCA (2/25, 8% vs. 11/29, 37.9%; P = 0.01). In the CFCA group, the mean CF per-vein was lower in reconnecting veins when compared with those persistently isolated (10.9 ± 2.7 vs. 18.6 ± 3.1 g; P < 0.001). In the CB-AdvA group, late PV reconnection was associated with warmer nadir temperature (-48.9 ± 5.1 vs. -51.2 ± 4.7°C; P = 0.05) and longer time-to-isolation (71.1 ± 20.2 vs. 50.2 ± 32.9 s; P = 0.03). CONCLUSION: The rate of late PV reconnection is significantly lower following CB-AdvA when compared with CFCA as index procedure. Lower CF values and warmer nadir temperature with longer time to effect were more frequently associated with PV reconnections in the setting of CFCA and CB-AdvA.

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.

Pneumoretroperitoneum and Pneumomediastinum Revealing a Left Colon Perforation.

Left colon perforation usually occurs in complicated diverticulitis or cancer. The most frequent signs are intraperitoneal abscess or peritonitis. In cases of retroperitoneal colonic perforation, diagnosis may be difficult. A 59-year-old woman presented with left thigh pain and with abdominal discomfort associated with mild dyspnea. Computed tomography scan showed air bubbles and purulent collection in the retroperitoneum, with subcutaneous emphysema extending from the left thigh to the neck. Computed tomography scan also revealed portal vein gas and thrombosis with multiple liver abscesses. An emergency laparotomy revealed a perforation of the proximal left colon. No masses were found. A left colectomy was performed. The retroperitoneum was drained and washed extensively. A negative pressure wound therapy was applied. A second-look laparotomy was performed 48 hours later. The retroperitoneum was drained and an end colostomy was performed. Intensive Care Unit postoperative stay was 9 days, and the patient was discharged on the 32nd postoperative day. Pneumoretroperitoneum and pneumomediastinum are rare signs of colonic retroperitoneal perforation. The diagnosis may be delayed, especially in the absence of peritoneal irritation. Clinical, laboratory, and especially radiologic parameters might be useful. Surgical treatment must be prompt to improve prognosis.

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.

Comparison between radiofrequency with contact force-sensing and second-generation cryoballoon for paroxysmal atrial fibrillation catheter ablation: a multicentre European evaluation.

AIMS: Whether pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (PAF) using contact force (CF)-guided radiofrequency (RF) or second-generation cryoballoon (CB) present similar efficacy and safety remains uncertain. METHODS AND RESULTS: We performed a multicentre study comparing procedural safety and arrhythmia recurrence after standardized PVI catheter ablation for PAF using CF-guided RF ablation (Thermocool(®) SmartTouch™, Biosense Webster; or Tacticath™, St Jude Medical) (CF group) with second-generation CB ablation (Arctic Front Advance™, Medtronic) (CB group). Overall, 376 patients (mean age 59.8 ± 10.4 years, 280 males) were enrolled in 4 centres: 198 in CF group and 178 in CB group. Procedure was shorter for CB group than for CF group (109.6 ± 40 vs. 122.5 ± 40.7 min, P = 0.003), but fluoroscopy duration and X-ray exposure were not statistically different (P = 0.1 and P = 0.22, respectively). Overall complication rate was similar in both groups: 14 (7.1%) in the CF group vs. 13 (7.3%) in the CB group (P = 0.93). However, transient right phrenic nerve palsy occurred only in CB group (10 patients, 5.6%; P = 0.001 vs. CF group) and severe non-lethal complications (embolic event, tamponade, or oesophageal injury) occurred only in CF group (5 patients, 2.5%; P = 0.03 vs. CB group). No periprocedural death occurred in either group. Single-procedure freedom from any atrial arrhythmias at 18 months post-ablation was comparable in CF group and CB group (76 vs. 73.3%, respectively, log rank P = 0.63). CONCLUSION: Pulmonary vein isolation using CF-guided RF and second-generation CB leads to comparable single-procedure arrhythmia-free survival at up to 18 months with similar overall complication rate.

Persistence of Phrenic Nerve Palsy Following 28-mm Cryoballoon Ablation: A Four-Year Single Center Experience.

BACKGROUND: Phrenic nerve palsy (PNP) is the most frequently observed complication in the setting of cryoballoon (CB) ablation (Arctic Front, Medtronic Inc., Minneapolis, MN, USA). Although, usually transient, resolving before the end of the procedure, persistent PNP (not resolving before the end of procedure) can occur. Literature on persistent PNP after second generation CB ablation is relatively sparse. METHODS: A total of 316 consecutive patients having undergone large 28-mm CB ablation as index procedure in the Heart Rhythm Management Center, UZ Brussels, Belgium, from January 2009 to December 2013 were retrospectively reviewed for the study. Of these 117 patients were treated with the first generation CB (CB1) and 199 patients with the second generation CB (CB2). RESULTS: PNP occurred in 10% of the total population. Persistent PNP was only observed following CB2 ablation which occurred in 4.5% of the group. At a mean follow-up of 11 months, diaphragmatic contraction in persistent PNP patients resumed in 78% (7/9) of the patients. In a final follow-up at 5 and 20 months, PNP persisted in two patients, respectively. PNP during ablation in the right inferior pulmonary vein was only observed in the CB2 group. No predictors of persistency of PNP were observed. CONCLUSION: Persistence of PNP only occurred in the CB2 group in 4.5% of patients. The majority of patients with persistent PNP were asymptomatic. In most of the patients having persistent PNP after ablation, complete phrenic nerve function resumed during follow-up (78%).

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.

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.