“Nonsignificant” early repolarization pattern on postresuscitation ECG as a harbinger of impending electrical storm

We report a 55‐year‐old man who was resuscitated from out‐of‐hospital cardiac arrest and subsequently developed three episodes of ventricular fibrillation (VF) on the same day. Early repolarization (ER) pattern was not significant (<0.1 mV) on postresuscitation ECG. However, ER pattern became evident (0.25 mV) before the onset of VF and then completely disappeared. The unusual dynamics of ER pattern observed in the present case could be called “masked” ER syndrome.     

The prevalence of early repolarization in patients with noncompaction cardiomyopathy presenting with malignant ventricular arrhythmias

Early Repolarization in Noncompaction Cardiomyopathy. Background: Early repolarization (ER) is associated with malignant ventricular arrhythmias, including ventricular fibrillation (VF) and sudden cardiac death (SCD). One possible mechanism is increased trabeculation with deep intramyocardial invagination, carrying the Purkinje system deeper into the myocardium resulting in delayed depolarization and inhomogenous repolarization. Noncompaction cardiomyopathy (NCCM) is a recently classified, primary cardiomyopathy with excessive trabeculations. In these patients ventricular arrhythmias, including sustained VT and VF, occur frequently. The aim of this study was to determine the prevalence of ER in NCCM patients, especially in those primarily presenting with malignant ventricular arrhythmias or SCD. Methods: We analyzed prospective data from our NCCM registry including 84 patients, median age: 40 (3–79) years. Results: Fourteen patients (17%) initially presented with sustained VT (n = 5) or VF (n = 9) and 70 (83%) with heart failure or else. After the exclusion of 20 patients with the left bundle branch block, 25 (39%) NCCM patients had ER; 3 (6%) located in inferior leads, 14 (27%) in lateral leads, and 8 (15%) in both. None had ER in leads V1 to V3. In those presenting with VT/VF, 9/12 (75%) had ER (2 in inferior leads, 3 in lateral leads and 4 in both), versus 16/52 (31%) in the other patients (P = 0.02). If the NCCM population was dichotomized according to the presence or absence of ER, the long‐term outcome for VT/VF appeared worse in the ER positive patients (P = 0.05). Conclusion: There is a high prevalence of ER in NCCM patients, especially in those who present with malignant ventricular arrhythmias. (J Cardiovasc Electrophysiol, Vol. 23, pp. 938‐944, September 2012)     

Acquired long QT syndrome with torsade de pointes in a patient with primary hypothyroidism

A case of 78 year-old woman with primary hypothyroidism and atrial fibrillation treated with sotalol, complicated with cardiac arrest due to ventricular fibrillation (VF) and torsade de pointes (TdP) is presented. The QT interval was prolonged to 660 msec. Episodes of polymorphic ventricular tachycardia and VF recurred. Lidocaine, tosylate bretylate and betabloker successfully eliminated VF but short-lasting episodes of TdP were still present. Increased doses of hormonal substitution with thyroid hormones successfully eliminated malignant ventricular arrhythmias and normalised QT interval to 430 msec.     

Association of early repolarization pattern and ventricular fibrillation in patients with vasospastic angina: A systematic review and meta‐analysis

BackgroundAn early repolarization (ER) pattern is a risk factor for ventricular fibrillation (VF) in patients with vasospastic angina (VSA) caused by a coronary artery spasm. However, its detailed characteristics and prognostic value for VF remain unclear. Thus, we investigated the relationship between ER and VF in patients with VSA.HypothesisThe ER pattern is associated with VF in patients with VSA.MethodsIn this systematic review and meta‐analysis, we searched PubMed, Embase, Cochrane Library, and Web of Science databases for eligible studies published between January 2011 and December 2020; 8 studies with 1761 patients were included in the final analysis.ResultsThe ER pattern significantly predicted adverse cardiovascular events (ACEs) and VF (odds ratio [OR] = 5.13, 95% confidence interval [95% CI]: 3.16–8.35, p < .00001 and OR = 5.20, 95% CI: 3.05–8.87, p < .00001). The presence of ER in the inferior leads increased the VF risk (OR = 7.80, 95% CI: 4.04–15.05, p < .00001), regardless of the J‐point morphology or type of ST‐segment elevation in the ER pattern. A horizontal/descending ST‐segment elevation was significantly associated with VF in patients with or without an ER pattern during a coronary spasm (OR = 2.28, 95% CI: 1.07–4.88, p = .03). However, obstructive coronary artery disease was unrelated to the ER pattern (OR = 0.82, 95% CI: 0.27–2.53, p = .73).ConclusionsAn ER pattern is significantly associated with an increased risk of ACE in patients with VSA. An inferior ER pattern with horizontal/descending ST‐segment elevation confers the highest risk for VF during VSA onset. Nevertheless, the ER pattern is not associated with obstructive coronary artery disease.     

J‐Wave Disappearance Immediately After an Episode of Ventricular Fibrillation in a Patient With Resuscitated Sudden Cardiac Death and Brugada Syndrome

J‐Wave Disaapearance After an Episode of Ventricular Fibrillation . Early repolarization (ER) abnormalities in the inferior‐lateral leads are a matter of intense scientific debate because of their demonstrated association with Brugada syndrome (BS) and idiopathic ventricular fibrillation (VF). To add fuel to the fire, we present a case in which ER abnormalities are associated with BS but in which, more importantly, they were shown to be transient and strictly correlated with an episode of VF. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1413‐1415, December 2010)     

Quantifying ventilatory reserve to predict respiratory failure in exacerbations of COPD

We developed a concept of VR in patients with acute exacerbation of advanced COPD and tested the hypothesis that it is predictable and clinically useful in the ER. Our concept of VR was based on the idea that a threshold VF and a MSV capacity are measurable; ie, VR = MSV - VF. We measured resting minute ventilation, the 15-s MVV, FEV1 and ABG values in 13 patients with exacerbation of COPD in the ER and 11 stable subjects with similar degrees of COPD. We tested if measures of VR could distinguish between ER patients progressing to respiratory failure, ER patients who avoided progression to respiratory failure and stable patients. There were significant differences in measures of the mean VR between various groups of patients. We conclude that in this COPD population, VR can be accurately predicted in the ER and that it may be a clinically valid predictor of patient outcomes.     

Successful radiofrequency catheter ablation for electrical storm of ventricular fibrillation in a patient with Brugada syndrome.

The case of a 41-year-old man with Brugada syndrome (BS) who suffered electrical storms (ES) of ventricular fibrillation (VF) is presented. Although intravenous infusion of isoproterenol (ISP) suppressed the VF occurrence, he consistently experienced recurrence of VF following discontinuation of ISP infusion. Quinidine and cilostazol were ineffective. An analysis of VF episodes on electrocardiogram monitoring revealed that the QRS morphology of the first beat of all VF episodes was identical to that of premature ventricular complexes (PVCs) with a left bundle branch-block morphology and inferior axis, which occurred repetitively before the episodes of VF and were recorded throughout the day. In addition, stored electrograms from the implantable cardioverter defibrillator showed that the first beat of all VF episodes had the same morphology. On electrophysiological study, the VF-triggering PVC was found to originate from the posterior portion of the right ventricular outflow tract area and their elimination, which was achieved with radiofrequency catheter ablation (RFCA), resulted in the suppression of ES. Although several other PVCs were still observed, the patient has been free of VF during the 29-month follow-up period. This case indicates that RFCA of VF-triggering PVCs may be useful in the treatment of drug-resistant ES in patients with BS.     

ECG repolarization syndrome abnormalities (J wave syndromes) and idiopathic ventricular fibrillation

Early repolarization (ER) pattern has been recognized for several decades and was interpreted as a variant of the normal electrocardiogram (ECG) as it was frequently observed in young healthy subjects or athletes. It is characterized by a J point elevation and ST-segment elevation inscribed as a QRS slurring or a notch of the S wave in the inferior leads or/and the lateral leads. The ER pattern has been the subject of increased interest since the report of its higher prevalence in subjects resuscitated from cardiac arrest related to idiopathic ventricular fibrillation (VF). Furthermore, population-based studies showed in healthy young adults that ER pattern was associated with an increased cardiovascular mortality and total mortality. A relationship between ER pattern and malignant arrhythmias is also supported by the experimental work of Antzelevitch et al. which provided the cellular and ionic basis for the J point elevation and its arrhythmogenic potential. The ER pattern may coexist with a number of cardiac or extracardiac conditions such as hypothermia. But this review will focus attention on the “isolated ER pattern” in healthy individuals. Antzelevitch and Yan proposed because of a number of similarities between the “ER syndrome” and the Brugada syndrome to group both syndromes under the heading of “J wave syndromes”. The management of ER syndrome (associated with idiopathic VF) is clearly the insertion of an implantable cardioverter defibrillator (ICD). The ER pattern associated with symptoms such as syncope or a familial history of sudden cardiac death requires a complete work-up. Caution should be raised not to generate anxiety in the subject with asymptomatic “isolated ER pattern” as the odds of developing malignant ventricular arrhythmias or to suffer sudden death in this case are extremely low.     

Identification of electrocardiographic risk markers for the initial and recurrent episodes of ventricular fibrillation in patients with Brugada syndrome

1 Introduction

New onset of ventricular fibrillation (VF) in asymptomatic patients with Brugada‐type ECG is not frequent, but it cannot be negligible. Risk markers for predicting VF are usually based on results of analysis in symptomatic patients, and they have not been determined for asymptomatic patients. We analyzed ECG markers in patients with Brugada syndrome to differentiate the risk factors for VF in both symptomatic and asymptomatic patients.

2 Methods

The subjects were 471 patients with Brugada syndrome and we divided the subjects into two groups: Asymptomatic group (n = 326) and Symptomatic group (syncope: n = 122, VF: n = 23). We analyzed the following ECG markers: RR, PQ, QRS, QT and Tpeak‐Tend (Tpe) intervals, ST level, atrial fibrillation (AF), atrioventricular block, spontaneous type 1 ECG, early repolarization (ER) and fragmented QRS (fQRS).

3 Results

During follow‐up (91 ± 64 months), 41 patients experienced VF (Asymptomatic: n = 10, Symptomatic: n = 31). Univariable analysis showed that spontaneous type 1 ECG, Tpe interval (≥95 milliseconds), high ST level (≥0.52 mV) and fQRS were common predictors for VF in both the Asymptomatic and Symptomatic groups. In addition to the common risk factors, wide QRS (≥107 milliseconds), long QT interval (≥420 milliseconds), ER and AF were predictors for VF in Symptomatic group. Multivariable analysis of the Symptomatic group showed fQRS, Tpe and ER were independent predictors of prognosis.

4 Conclusions

fQRS and Tpe interval are common risk factors for VF in both asymptomatic and symptomatic patients, whereas ER is a predictor for recurrent VF.     

The effect of spironolactone on ventricular tachyarrhythmias in patients with implantable cardioverter-defibrillators

Background- Previous studies have suggested that aldosterone blockade can reduce the incidence of ventricular tachycardia (VT) or ventricular fibrillation (VF) in patients with heart failure. The SPIronolactone to Reduce ICD Therapy (SPIRIT) trial was designed to test the hypothesis that spironolactone reduces the incidence of VT/VF in patients with implantable cardioverter-defibrillators (ICDs) who are at moderately high risk for recurrent VT/VF. Methods and Results- Ninety patients who had ICDs who were at moderately high risk for recurrent VT/VF and who were not candidates for spironolactone by current heart failure guidelines were randomized to receive spironolactone 25 mg daily or placebo in a double-blind fashion. All patients had previously received ICD therapy (shock or antitachycardia pacing) for VT/VF within 2 years of randomization or an ICD for secondary prevention of VT/VF within 6 months of randomization. The primary end point was time to first recurrence of VT/VF requiring ICD therapy. After a median follow-up of 35 months, the Kaplan-Meier probability estimates for VT/VF requiring ICD therapy were 68.7% in the placebo group and 84.7% in the spironolactone group. Compared with placebo, spironolactone was associated with a similar risk of VT/VF (hazard ratio, 1.01; 95% CI, 0.64-1.83; P=0.71). There was no significant difference between the median times to first VT/VF recurrence requiring ICD therapy in the 2 groups. Conclusions- In patients with ICDs who were at moderately high risk for recurrent VT/VF on account of a recent VT/VF event that was either sustained or treated by the ICD and who were not candidates for spironolactone by current heart failure guidelines, spironolactone did not delay the first recurrence of VT/VF or reduce the risk of recurrent VT/VF.     

Long-term efficacy and toxicity of high-dose amiodarone therapy for ventricular tachycardia or ventricular fibrillation

Amiodarone was administered to 154 patients who had sustained, symptomatic ventricular tachycardia (VT) (n = 118) or a cardiac arrest (n = 36) and who were refractory to conventional antiarrhythmic drugs. The loading dose was 800 mg/day for 6 weeks and the maintenance dose was 600 mg/day. Sixty-nine percent of patients continued treatment with amiodarone and had no recurrence of symptomatic VT or ventricular fibrillation (VF) over a follow-up of 6 to 52 months (mean ± standard deviation 14.2 ± 8.2). Six percent of the patients had a nonfatal recurrence of VT and were successfully managed by continuing amiodarone at a higher dose or by the addition of a conventional antiarrhythmic drug. One or more adverse drug reactions occurred in 51% of patients. Adverse effects forced a reduction in the dose of amiodarone in 41 % and discontinuation of amiodarone in 10% of patients. The most common symptomatic adverse reactions were tremor or ataxia (35 %), nausea and anorexia (8%), visual halos or blurring (6%), thyroid function abnormalities (6%) and pulmonary interstitial infiltrates (5%).Although large-dose amiodarone is highly effective in the long-term treatment of VT or VF refractory to conventional antiarrhythmic drugs, it causes significant toxicity in approximately 50% of patients. However, when the dose is adjusted based on clinical response or the development of adverse effects, 75 % of patients with VT or VF can be successfully managed with amiodarone.     

Early repolarization pattern: Innocent finding or marker of risk?

The presence of early repolarization (ER) pattern in the 12-lead ECG, defined as elevation of the QRS–ST junction (J point) often associated with a late QRS slurring or notching (J wave), is a common finding in the general population, particularly in the inferior and precordial lateral leads. In young and healthy individuals, particularly in males, blacks and athletes, this pattern has commonly been considered to represent an innocent finding. However, experimental studies, case reports and studies on healthy subjects surviving a cardiac arrest or with primary ventricular fibrillation (VF) have suggested an association between J-point elevation and/or QRS slurring in the inferior and lateral ECG leads and the risk of VF. On the other hand, in recent epidemiological studies on large general population no significant association between ER patterns and cardiac mortality was found. In athletes, changes of the QRS–ST segment are frequent. We found that in a selected group of 21 young competitive athletes, without underlying heart disease, who experienced cardiac arrest, the prevalence of J wave and/or QRS slurring in the inferior and lateral (V4 to V6) leads was significantly higher in cases than in 365 control athletes. Following sport discontinuation, during the 36-month follow-up arrhythmia recurrences did not differ between subgroups with and without J wave or QRS slurring. Recently, other studies showed that among different patterns of ER rapidly ascending ST segment after the J point seems to be almost universally benign. The conflicting data regarding the prognostic role of ER patterns can be partly due to different definitions of ER used. This emphasizes the need for standardized methods of measurements of QRS end–J point–ST segment and for detailed definitions. The knowledge of the true significance in clinical setting of the various aspects of ER is still unclear and warrants prospective, long-term epidemiological studies.     

Early repolarization pattern: its ECG characteristics,arrhythmogeneity and heritability

Early repolarization (ER) has been accepted as a benign ECG variant for decades. Two seminal studies challenged this notion and have demonstrated that ER pattern is associated with an increased risk of arrhythmic and cardiac mortality in patients with idiopathic ventricular fibrillation (IVF) and in the general population. Recent clinical studies demonstrate its varying impact as an arrhythmogenic substrate on different diseases. For example, in ER syndrome, a primary electrical disease, ER appears as a major arrhythmogenic substrate for development of VF whereas in patients with coronary artery disease, an ER pattern may exist as a silent substrate, increasing the risk of VF during episodes of cardiac ischaemia. Due to the high prevalence of an ER pattern in the general population and a low VF event rate, it remains challenging to differentiate a malignant ER pattern from a benign form. Recent research suggests that a J-wave amplitude of more than 0.1 mV combined with a descending/horizontal ST segment may constitute a malignant ER pattern. Further studies are however necessary to evaluate its prognostic value for cardiac and arrhythmic death in the general population as well as in cases with a malignant ER pattern. While genetic testing has revealed putative causal DNA variants in sporadic cases, the lack of co-segregation with the disease in affected families suggests that ER syndrome is not monogenic but is likely a complex disorder influenced by multiple genetic as well as environmental factors.     

Prognostic value of ventricular tachycardia induced by stimulation in patients without documented tachycardia

In order to determine the cause of syncopes or disorders of conduction, 584 programmed stimulations using 2 ventricular extrastimuli delivered during an imposed rhythm were performed, between 1981 and 1985, in patients without ventricular tachycardia (VT) proven by Holter recordings. Eighty-seven non-sustained VT (NSVT) (15%), 8 ventricular fibrillations (VF) (1%), 16 ventricular flutters (VF1) (3%) and 23 sustained VT (SVT) (4%) were induced. To appraise the significance of these responses the patients were followed up for a mean period of 2 +/- 1 years. Among the NSVT patients the first 47 were followed up until 1984 and the others, less numerous, until 1985. Patients who responded to stimulation with NSVT had (4.4%) or did not have an underlying cardiopathy; their mean left ventricular ejection fraction (LVEF) was 53.5 +/- 17% (n = 10); 17% died of heart disease, but the disease was related to VT in only one case; 36% of these patients had cardiac symptoms, but only one presented with episodes of NSVT. Patients who responded with VF had a normal (50%) or abnormal heart; their mean LVEF was 52 +/- 19%; one died of heart failure, the others were asymptomatic. All but one of the patients who responded with VF1 had an underlying cardiopathy and a mean LVEF of 38 +/- 19%; 3 died, 2 of heart failure and 1 of sudden death; 13 were asymptomatic. All patients who responded with SVT had an underlying cardiopathy and a mean LVEF of 37 +/- 13%; 7 (30%) died, including 2 sudden deaths; 2 had episodes of VT and 12 were asymptomatic. In summary, an underlying cardiopathy was present in one-half of the patients who responded with NSVT or VF and in all patients who responded with VF1 or SVT. The risk of VT was low (5%) in patients who responded with NSVT, VF or VF1 and was higher (17%) in those who responded with SVT.     

Spontaneous onset of ventricular fibrillation in Brugada syndrome with J wave and ST-segment elevation in the inferior leads.

We report the case of a 52-year-old man with variant Brugada syndrome who was successfully resuscitated from ventricular fibrillation (VF). Resting ECG showed J wave and ST-segment elevation in the inferior leads but no coved or saddleback ST-segment elevation in the right precordial leads. Pilsicainide infusion provoked coved-type ST-segment elevation in the right precordial leads and mild ST-segment elevation 80 ms after the J point in the inferior leads. During an emergency, 12-lead ECG showed that spontaneous onset of VF was preceded by left bundle branch block and superior axis-type ventricular extrasystoles. The present case provides additional information on the site of origin of VF in patients with Brugada syndrome.     

Insight into specific pro-arrhythmic triggers in Brugada and early repolarization syndromes: results of long-term follow-up

The pro-arrhythmic triggers in Brugada and early repolarization syndromes (BrS, ERS) have not been analyzed systematically except for case reports. We clinically investigated the circumstances which precede/predispose to arrhythmic events in these syndromes during long-term follow-up. A detailed history from the patients/witnesses was taken to investigate the antecedent events in the last few hours that preceded syncope/ventricular fibrillation (VF); medical records, ECG and blood test from the emergency room (ER) were reviewed. 19 patients that fulfilled the investigation criteria were followed up for 71 ± 49 months (34–190 months). Prior to the event (syncope/VF), the patients were partaking different activities in the following decreasing order; drinking alcoholic beverage, having meal, and getting up from sleep, exercise. 3 patients reported mental/physical stress prior to the event and 2 patients developed VF several days after starting oral steroid for treatment of bronchial asthma. In the ER, elevated J-wave amplitude (0.27 ± 0.15 mV) was found with 58 % of the patients having hypokalemia. After electrolyte correction and cessation of steroids, the following day plasma K⁺ (4.2 ± 0.3 mEq/L, P < 0.001) was significantly increased and J-wave amplitude (0.13 ± 0.1 mV, P < 0.001) was remarkably reduced. Three patients were kept on oral spironolactone/potassium supplements. During follow-up for 71 ± 49 (34–190) months, among 4 patients with VF recurrence, one patient developed VF after taking oral steroid. In ERS and BrS, hypokalemia and corticosteroid therapy add substantial pro-arrhythmic effects, but potentially treatable. Stopping steroid therapy and avoiding hypokalemia had excellent long-term outcome.     

甲状腺肿瘤组织中雌激素受体β1和β2的表达及其意义

采用RT-PCR检测10例甲状腺乳头状腺癌(PTC)和10例癌旁正常甲状腺组织雌激素受体(ER)β1、ERβ2以及ERα的表达,同时用免疫组织化学方法检测107例甲状腺癌、56例甲状腺腺瘤和10例正常甲状腺组织中ERβ1和ERβ2表达,并结合甲状腺癌ERα表达及其它主要临床病理参数进行分析.结果显示,ERα mRNA在PTC组织的表达明显高于癌旁正常组织,ERβ2 mRNA在PTC组织的表达明显低于癌旁正常组织(P＜0.05);正常甲状腺组织、甲状腺腺瘤和甲状腺癌中3种ER的表达差异均有统计学意义( P＜0.05);ERβ1和ERβ2在甲状腺癌中的表达与其组织类型有关;甲状腺组织中ERβ1和ERβ2的表达与ERα呈低、中度负相关(ERβ1:r=-0.206,P=0.042;ERβ2:r=-0.545,P＜0.01);ERβ2的表达还与淋巴结转移以及TNM分期有关.提示ERβ2的表达缺失可能导致甲状腺滤泡上皮细胞的增生和癌变以及肿瘤的演进,并且有一定的预后评估价值.     

Successful treatment of electrical storm with oral quinidine in Brugada syndrome.

A patient implanted with a cardioverter-defibrillator for symptomatic Brugada syndrome was referred to our hospital 17 months later because of recurrent shocks due to ventricular fibrillation (VF). Isoprenaline was intravenously infused and prevented VF episodes, but VF recurred after every attempt of drug discontinuation. A total of 34 shocks were recorded over 25 days. Subsequently, we treated the patient with oral quinidine and the drug suppressed the electrical storm and prevented VF episodes during a follow-up period of 3 years. This case report, together with few others reported in the literature, suggests a role of oral quinidine in the treatment of electrical storm in Brugada syndrome.     

Comparison of arrhythmia recurrence in patients presenting with ventricular fibrillation versus ventricular tachycardia in the Antiarrhythmics Versus Implantable Defibrillators (AVID) trial

Because many episodes of ventricular fibrillation (VF) are believed to be triggered by ventricular tachycardia (VT), patients who present with VT or VF are usually grouped together in discussions of natural history and treatment. However, there are significant differences in the clinical profiles of these 2 patient groups, and some studies have suggested differences in their response to therapy. We examined arrhythmias occurring spontaneously in 449 patients assigned to implantable cardioverter-defibrillator (ICD) therapy in the Antiarrhythmics Versus Implantable Defibrillators (AVID) trial to determine whether patients who receive an ICD after VT have arrhythmias during follow-up that are different from patients who present with VF. ICD printouts were analyzed both by a committee blinded to the patients' original presenting arrhythmia and by the local investigator. During 31 +/- 14 months of follow-up, 2,673 therapies were reported. Patients who were enrolled in the AVID trial after an episode of VT were more likely to have an episode of VT (73.5% vs 30.1%, p <0.001), and were less likely to have an episode of VF (18.3% vs 28.0%, p = 0.013) than patients enrolled after an episode of VF. Adjustment for differences in ejection fraction, previous infarction, and beta-blocker and antiarrhythmic therapy did not appreciably change the results. Ventricular arrhythmia recurrence during follow-up is different in patients who originally present with VT than in those who originally present with VF. These findings suggest there are important differences in the electrophysiologic characteristics of these 2 patient populations.     

Hydroquinidine therapy in Brugada syndrome

OBJECTIVES: We sought to assess hydroquinidine (HQ) efficacy in selected patients with Brugada syndrome (BrS). BACKGROUND: Management of asymptomatic patients with BrS and inducible arrhythmias remains a key issue. Effectiveness of class Ia antiarrhythmic drugs, which inhibit the potassium transient outward current of the action potential, has been suggested in BrS. METHODS: From a cohort of 106 BrS patients, we studied 35 who received HQ (32 men; mean age 48 +/- 11 years). Patients had asymptomatic BrS and inducible arrhythmia (n = 31) or multiple appropriate shocks from an implantable cardioverter-defibrillator (ICD) (n = 4). Asymptomatic patients with inducible arrhythmia underwent electrophysiologic (EP)-guided therapy. When ventricular tachycardia (VT)/ventricular fibrillation (VF) inducibility was not prevented, or in case of HQ intolerance, an ICD was placed. RESULTS: Hydroquinidine prevented VT/VF inducibility in 76% of asymptomatic patients who underwent EP-guided therapy. Syncope occurred in two of the 21 patients who received long-term (17 +/- 13 months) HQ therapy (1 syncope associated with QT interval prolongation and 1 unexplained syncope associated with probable noncompliance). In asymptomatic patients who received an ICD (n = 10), one appropriate shock occurred during a follow-up period of 13 +/- 8 months. In patients with multiple ICD shocks, HQ prevented VT/VF recurrence in all cases during a mean follow-up of 14 +/- 8 months. CONCLUSIONS: Hydroquinidine therapy prevented VT/VF inducibility in 76% of asymptomatic patients with BrS and inducible arrhythmia, as well as VT/VF recurrence in all BrS patients with multiple ICD shocks. These preliminary data suggest that preventive treatment by HQ may be an alternative strategy to ICD placement in asymptomatic patients with BrS and inducible arrhythmia.