BVT and Andersen-Tawil Syndrome. Bidirectional ventricular tachycardia (BVT), although a rare arrhythmia in the general population, is frequently observed in patients with Andersen-Tawil syndrome and long QT interval. However, the pharmacologic treatment of this arrhythmia remains unknown. In the present study, we documented the favorable antiarrhythmic action of flecainide in a young woman with sustained BVT and Andersen-Tawil syndrome. She presented with incessant BVT that could only be terminated with flecainide. During sinus rhythm, a prolonged QT interval was observed. Genetic studies revealed a mutation in the K + channel gene KCNJ2. Over a 4-year follow-up period, recurrence of her arrhythmia occurred twice. The first episode was due to noncompliance and resolved with resumption of flecainide therapy. The second recurrence was associated with a tachycardia-induced cardiomyopathy and resolved when the dose of flecainide was increased from 200 to 300 mg daily. This report suggests that flecainide can be effective in controlling BVT associated with Andersen-Tawil syndrome and indicates that the left ventricular dysfunction is secondary to the arrhythmia and not due to an associated phenotypic manifestation of the disorder. (J Cardiovasc Electrophysiol, Vol. 19, pp. 95-97, January 2008.) bidirectional ventricular tachycardia, long QT syndrome, Andersen-Tawil syndrome, flecainide Case Report A 16-year-old female was referred for evaluation of sustained bidirectional ventricular tachycardia (BVT) associated with dizziness. The patient had no known heart disease, was on no medications, and had no family history of heart disease or sudden death. Physical examination was normal except for mild symmetric lower extremity weakness. Serum laboratory assessments, chest x-ray, echocardiography, and cardiac magnetic resonance imaging were all normal. On admission, an electrocardiogram showed BVT with alternating QRS complexes (Fig. 1). Atrial and ventricular transesophageal stimulation failed to terminate the arrhythmia. Multiple drugs given intravenously were also unsuccessful, including lidocaine, propranolol, diltiazem, potassium chloride, and magnesium sulfate. Administration of oral flecainide 100 mg twice a day suppressed the arrhythmia and allowed resumption of sinus rhythm with a distinct long QT interval and biphasic T waves (Fig. 2). Genetic analysis demonstrated an R67W mutation in the K+ channel gene KCNJ2. The patient refused ICD implantation and was discharged on flecainide therapy. A complete cardiovascular evaluation of her parents and three brothers disclosed no abnormalities. During a 4-year follow-up period, the patient had two recurrences of BVT. The first episode was due to noncompliance and the arrhythmia disappeared when the patient resumed flecainide treatment. The second episode occurred 3 years later while on flecainide and was associated with congestive heart failure and globally depressed left ventricular function (ejection fraction 25%). The arrhythmia was controlled when the daily dose of...

Given that cardiovascular risk factors (CRF), such as smoking, alcoholism and hypertension, may contribute to the development of heart lesions, chronically Trypanosoma cruzi-infected individuals were studied to explore the relationship between the presence of such CRF, cardiomyopathy and antibodies that have been proposed to play a pathogenetic role in Chagas' disease. The targets of these antibodies were T. cruzi antigens such as cruzipain (Cz), a P ribosomal antigen (P2), and a component of myelin sheaths also present in T. cruzi (sulphatide). Individuals were classified into four groups on the basis of specific serology and presence of CRF: subjects with T. cruzi infection and CRF; those with positive serology and no CRF; seronegatives with CRF; and seronegatives without CRF, were analysed. Seronegatives or seropositives with CRF showed a greater occurrence of heart involvement (chest X-ray and/or electrocardiogram abnormalities). Seropositives with CRF displayed significantly higher levels of antisulphatide antibodies than the three remaining groups and higher levels of antibodies against Cz and P2 compared to the seropositives without CRF. Increased amounts of anti-P2 and antisulphatide antibodies were also found in seropositives with marked heart involvement. The presence of CRF is associated with a different profile of antibody responses and degree of cardiac effects.

Among patients preselected for exercise-induced ventricular tachycardia, almost half could be induced into ventricular tachycardia by isoproterenol infusion. Mental stress was a less powerful inducer of ventricular arrhythmias in this study group.

The Andersen-Tawil syndrome is a cardiac ion channel disease that is inherited in an autosomal dominant way and is classified as type 7 of the congenital long QT syndromes. Affected gene is KCNJ2, which forms the inward rectifier potassium channel designated Kir2.1. This protein is involved in stabilizing the resting membrane potential and controls the duration of the action potential in skeletal muscle and heart. It also participates in the terminal repolarization phase of the action potential in ventricular myocytes and is a major component responsible for the correction in the potassium current during phase 3 of the action potential repolarization. Kir 2.1 channel has a predominant role in skeletal muscle, heart and brain. Alterations in this channel produce flaccid paralysis, arrhythmias, impaired skeletal development primarily in extremities and facial area. In this review we address the disease from the point of view of clinical and molecular diagnosis with emphasis on cardiac manifestations.

Sudden death is common in patients with congenital coronary artery anomalies mainly when the left main coronary artery originates from the right coronary sinus. Ventricular fibrillation in these patients is irreversible unless defibrillation can be rapidly performed. We describe a 57-year-old male with an anomalous origin of circumflex and the left anterior descending coronary arteries from the right coronary sinus. He developed two episodes of ventricular fibrillation that terminated spontaneously, 10 hours after percutaneous revascularization of the circumflex coronary artery. Computed tomography angiography, in addition to confirming the anomalous origin of the coronary arteries, showed a muscle bridge over the midportion of the left anterior descending coronary artery. This is the first report of spontaneous termination of ventricular fibrillation in a patient with congenital anomaly of the coronary arteries.