Idiopathic ventricular tachycardia arising from the right ventricular apex.

We present a rare case of idiopathic ventricular tachycardia arising from the right ventricular apex. The electrocardiographic and electrophysiological characteristics of this tachycardia are discussed.

Novel indexes of heterogeneity of ventricular repolarization in subjects with early repolarization pattern.

AIM: The presence of early repolarization (ER) in inferior or inferolateral leads has been associated with malignant arrhythmias and increased mortality. Transmural dispersion of repolarization (TDR) has been proposed to underlie arrhythmogenesis in J-wave syndromes. The present study investigated specific electrocardiographic (ECG) markers including Tpeak-Tend interval and (Tpeak-Tend)/QT ratio that reflect TDR in subjects with ER. METHODS AND RESULTS: The ECGs of 47 healthy individuals (43 males, mean age: 45.7 ± 13.1 years) with an ER pattern in lateral (n = 15) or infero-lateral leads (n = 32) who successfully completed an exercise stress test were analysed at rest, peak workload, and recovery. The ER pattern was defined as slurring or notching of the terminal part of the QRS complex (J-point) ≥ 1 mm, in at least two contiguous leads. Thirty-five age- and sex-matched healthy subjects without ER (28 males, mean age: 48.6 ± 10.2 years) served as comparative controls. Subjects with ER displayed increased Tpeak-Tend interval in lead V(2), Tpeak-Tend dispersion of the precordial leads, and (Tpeak-Tend)/QT ratio in lead V(2) compared with those without ER in all three phases of the exercise test (P < 0.05). In addition, Tpeak-Tend dispersion and the (Tpeak-Tend)/QT ratio in lead V(2) were significantly increased at recovery phase compared with peak exercise only in subjects with ER (P< 0.05). There were no significant differences among the studied ECG parameters regarding the ER location (lateral vs. infero-lateral), the ER type (slurring or notching), or the maximum J-point amplitude (≥ 1.5 vs. <1.5 mm) at baseline ECGs. CONCLUSIONS: Individuals with ER display an increased TDR that may be related to an increased arrhythmic risk.

Long-term prognosis of asymptomatic individuals with spontaneous or drug-induced type 1 electrocardiographic phenotype of Brugada syndrome.

BACKGROUND: Risk stratification of asymptomatic individuals with type 1 electrocardiogram (ECG) phenotype of Brugada syndrome (BS) still remains controversial. This study investigated the long-term prognosis of asymptomatic subjects with spontaneous or drug-induced type 1 ECG pattern of BS. METHODS AND RESULTS: Data from 33 apparently healthy individuals (30 males; age, 43.6 ± 13.4 years) with spontaneous (n = 12) or drug-induced (n = 21) type 1 ECG pattern of BS were retrospectively analyzed. Thirteen subjects (39.4%) displayed a positive family history of BS and/or sudden cardiac death. Electrophysiologic study was performed in 16 subjects, and programed right ventricular stimulation induced polymorphic ventricular tachycardia in 9 (56.3%) of them. A cardioverter defibrillator was implanted in 6 cases. During a mean follow-up period of 5.3 ± 2.8 years, all subjects remained asymptomatic. None of them had syncope or cardioverter defibrillator discharges due to ventricular arrhythmias. CONCLUSIONS: Asymptomatic individuals with spontaneous or drug-induced type 1 ECG phenotype of BS display a benign clinical course during long-term follow-up.

Mechanisms of drug-induced proarrhythmia in clinical practice.

Drug-induced proarrhythmia represents a great challenge for those involved in the development of novel pharmaceuticals and in the regulatory bodies for drug approval as well as for the prescribing clinicians. Our understanding of the mechanisms that underlie drug-induced proarrhythmia has grown dramatically over the last two decades. A growing number of cardiac and non-cardiac agents have been shown to alter cardiac repolarization predisposing to fatal cardiac arrhythmias such as ventricular tachycardia or ventricular fibrillation and sudden cardiac death. These agents may induce the phenotype of long QT syndrome and less commonly of short QT syndrome and Brugada syndrome (BS). Although, genetic susceptibility underlie drug-induced proarrhythmia in certain cases, current data are limited regarding this topic. The present review surveys the current published literature on the mechanisms and the offending medical agents that predispose to drug-induced long QT syndrome, short QT syndrome and BS. Drug-induced proarrhythmia should be considered as a predictor of sudden cardiac death and should prompt critical re-evaluation of the risks and benefits of the suspicious medication. Survivors of drug-induced proarrhythmia and family members require careful examination and possibly genetic testing for the presence of a channelopathy. Treating physicians are advised to follow the lists of agents implicated in drug-induced proarrhythmia in order to minimize the risk of arrhythmia and sudden cardiac death.

The impact of vagotonic, adrenergic, and random type of paroxysmal atrial fibrillation on left atrial ablation outcomes.

BACKGROUND: Accumulating data have shown that the autonomic nervous system is strongly implicated in the genesis of atrial fibrillation (AF). The aim of this study was to assess the efficacy of a single ablation procedure in patients with vagotonic, adrenergic and random type of paroxysmal AF. METHODS AND RESULTS: The clinical records of consecutive patients with symptomatic, drug-refractory paroxysmal AF who underwent pulmonary vein antral isolation were analysed. The study population consisted of 104 patients (64 males, mean age 57.9 ± 10.9 years) with paroxysmal AF. Based on AF triggers, patients were classified in those with vagotonic (31.7%), adrenergic (17.3%) and random AF (51%). Subjects with adrenergic and random AF tended to be older (p: 0.104) and displayed a higher incidence of hypertension (p: 0.088) compared with those with vagotonic AF. Following a mean follow-up period of 14.7 ± 7.4 months, 74 patients were free from arrhythmia recurrence (71.2%). Late arrhythmia recurrence (>3 months from the index procedure) occurred in 33.3%, 16.7% and 30.2% of patients with vagotonic, adrenergic and random AF, respectively (p: 0.434). Cox regression analysis showed that early AF recurrence [hazard ratio (HR) 15.76; 95% confidence interval (CI) 5.456-45.566, p: <0.001], left atrial volume (HR 0.969; 95% CI 0.942-0.996, p: 0.025) and statin use (HR 6.828; 95% CI 2.078-22.437 p: 0.002) were independent predictors of late arrhythmia recurrence. CONCLUSIONS: In this study cohort, the type of paroxysmal AF was not associated with arrhythmia recurrence following left atrial ablation.

Pacing-facilitated proarrhythmia.

The implantable cardioverter-defibrillator (ICD) has been proven to reduce the mortality of patients with life-threatening ventricular arrhythmias, and has become the therapy of choice for patients with aborted sudden cardiac death or poorly tolerated ventricular tachycardias. Abrupt changes in ventricular cycle lengths or short-long-short (S-L-S) sequences might precede the initiation of ventricular tachycardia and ventricular fibrillation. The S-L-S sequences might be passively permitted or actively facilitated by pacing. We present a case of ICD-facilitated ventricular tachycardia.

A case of severe asymptomatic aortic coarctation in an adult female.

Coarctation of the aorta is typically a disease of childhood and early adulthood, and there is a reduced life expectancy in patients who have not undergone correction. Survival to older age is rare, due to severe cardiovascular complications. We describe the case of a woman first diagnosed with coarctation of aorta at an advanced age.

Current ablation strategies for persistent and long-standing persistent atrial fibrillation.

Atrial fibrillation (AF) is associated with an increased risk of cardiac and overall mortality. Restoration and maintenance of sinus rhythm is of paramount importance if it can be accomplished without the use of antiarrhythmic drugs. Catheter ablation has evolved into a well-established treatment option for patients with symptomatic, drug-refractory AF. Ablation strategies which target the pulmonary veins are the cornerstone of AF ablation procedures, irrespective of the AF type. Ablation strategies in the setting of persistent and long-standing persistent AF are more complex. Many centers follow a stepwise ablation approach including pulmonary vein antral isolation as the initial step, electrogram-based ablation at sites exhibiting complex fractionated atrial electrograms, and linear lesions. Up to now, no single strategy is uniformly effective in patients with persistent and long-standing persistent AF. The present study reviewed the efficacy of the current ablation strategies for persistent and long-standing persistent AF.

Low back pain following intravenous administration of amiodarone.

Amiodarone is a widely used antiarrhythmic drug whose use is significantly limited by numerous undesirable effects following long-term administration. In the literature so far, it has been reported that the most common acute adverse effect of the intravenous administration of amiodarone requiring intervention is hypotension. We present the case of a female patient who experienced low back pain after an intravenous loading dose of amiodarone.