Ionic basis of pharmacological therapy in Brugada syndrome.

An implantable cardioverter-defibrillator is considered the only effective therapy to terminate ventricular arrhythmias in symptomatic patients with Brugada syndrome. However, it does not prevent future arrhythmic episodes. Only antiarrhythmic drug therapy can prevent them. There have been several reports of a beneficial effect of oral quinidine in both asymptomatic and symptomatic patients. Other possible beneficial oral agents could be I(to) blockers. Intravenous isoproterenol has been reported to be especially useful in abolishing arrhythmic storms in emergency situations. Also, isolated case reports on the usefulness of cilostazol, sotalol, and mexiletine have been described. The present article reviews the mechanisms by which these drugs may act and their possible role in the pharmacotherapy of this disease.

Electrocardiographic characteristics of patients with Ebstein's anomaly before and after ablation of an accessory atrioventricular pathway.

UNLABELLED: The abnormal development of the tricuspid valve in patients with Ebstein's anomaly results in several activation abnormalities including delayed intraatrial conduction, right bundle branch block (RBBB), and ventricular preexcitation. The aim of the present study was to define the ECG characteristics before and after ablation of an accessory A-V pathway (AP) in patients with Ebstein's anomaly. METHODS: A series of 226 consecutive patients with Ebstein's anomaly was studied. Sixty-four patients (28%) had documented tachycardia. Thirty-three patients with recurrent tachycardia were found to have a single right-sided AP that was successfully ablated (study group). Thirty patients without tachycardia served as the control group. RESULTS: Only 21 of 33 patients (62%) had a typical ECG pattern of preexcitation. In addition, none of the patients had an ECG pattern of RBBB during sinus rhythm. In contrast, 28 of 30 (93%) patients in the control group had RBBB (P < 0.001). Radiofrequency catheter ablation resulted in appearance of RBBB in 31 of 33 (94%) patients. The absence of RBBB in patients with Ebstein's anomaly and recurrent tachycardia had a 98% sensitivity and 92% specificity for the diagnosis of an AP. The positive predictive value was 91% (0.77, 0.97 CI 95%) and the negative predictive value was 98% (0.85, 0.99 CI 95%). CONCLUSION: One-third of patients with Ebstein's anomaly and symptomatic tachyarrhythmias have minimal or absent ECG features of ventricular preexcitation. In these patients, the absence of RBBB pattern is a strong predictor of an AP.

Drug therapy in Brugada syndrome.

Sudden cardiac death in healthy individuals with structurally normal hearts and a characteristic morphology of the QRS complex resembling a right bundle branch block with elevation of the ST segment in V1 to V3 is known as Brugada syndrome (BrS). Although placement of an implantable cardioverter-defibrillator is considered the only effective therapy for symptomatic patients, some authors have repeatedly reported a beneficial effect of quinidine and isoproterenol in patients with BrS. Also, isolated case reports on the usefulness of cilostazol, sotalol, and mexiletine have been described. The present article reviews the mechanisms by which these drugs may act and their role in the pharmacotherapy of BrS. Other possible agents, mainly I(2) blockers, are also reviewed.

[Direct cryothermal ablation eliminates conduction of the slow pathway without inducing ectopic rhythms]. / La ablación criotérmica percutánea directa elimina la conducción a través de la vía lenta intranodal sin inducir ritmos ectópicos.

Radiofrequency catheter ablation of atrioventricular nodal reentrant tachycardia is based on the elimination of conduction of slow or fast intranodal pathway. To avoid potential atrioventricular (AV) block, a new technology has been developed, cryothermal ablation. We report a case of AV nodal reentrant tachycardia in whom direct cryoablation, without previous ice mapping, was successfully performed. Interestingly and as previously described, cryotherapy did not induce ectopic rhythms, the conventional surrogate during radiofrequency ablation.

Doença de Ebstein: ausência de bloqueio de ramo direito como preditor de via anômala manifestada / Ebstein disease: absence of right branch block as a predictor of manifested anomalous way

O desenvolvimento anormal da válvula tricúspide na doença de Ebstein resulta em uma série de anormalidades na ativação, que inclui condução intra-atrial demorada, bloqueio de ramo direito(BRG) e pré-excitação ventricular. O objetivo desse tabalho era definir as características do ECG antes e depois da ablação de uma via anômala atrioventricular. De 226 pacientes consecutivos com anomalia de Ebstein, 64 apresentavam taquicardia documentada...