Leonardo Siqueira

Prognostic criteria of success and recurrence in circumferential ablation for the treatment of atrial fibrillation

OBJECTIVES To analyze the success of circumferential ablation of atrial fibrillation and to investigate possible clinical and electroanatomic predictors of recurrence of cardiac arrhythmia. METHODS 104 consecutive patients free of structural heart disease and refractory to at least two antiarrhythmic drugs, and undergoing circumferential ablation for the treatment of paroxysmal/persistent atrial fibrillation were analyzed. Seventy two patients were males and the mean age of the group was 58.6 + 10.9 years. The procedure consisted of a single transseptal puncture and three-dimension mapping using the CARTO system to acquire points in the left atrium and pulmonary veins. Radiofrequency applications were performed encircling the pulmonary vein ostea, up to a > or = 80% reduction of the atrial potential amplitude. One additional line was created in the mitral isthmus and another in the cavotricuspid isthmus. Total left atrium volume, area ablated around the pulmonary veins, and completeness of the ablation line (complete or incomplete line) were analyzed. A line was considered complete when the distance between two contiguous radiofrequency application points was lower than 10mm. RESULTS In a mean 18-month follow-up, 87 patients were in sinus rhythm (84%), and 17 patients presented recurrence (16%). In the multivariate analysis, only the left atrial volume (p<0.0001) and complete ablation (p<0.05) were independent predictors of recurrence. CONCLUSION The results suggest that the left atrial volume and the presence of complete ablation are predictive of recurrence of atrial fibrillation.

Acompanhamento clínico de pacientes portadores de cardioversor-desfibrilador implantável

OBJECTIVE: To report appropriate (AT) and inappropriate (IT) ICD therapies in patients with ischemic and nonischemic heart disease, as well as early and late procedure-related complications. METHODS: One hundred and fifty-five patients (119 male and 36 female), mean age 47 years (21-88), who underwent ICD implantation between 1994 and March 2003 were analyzed. Patients were divided into the following groups: Group I--Post-AMI patients (n = 80); Group II--Patients with nonischemic heart disease and LV ejection fraction < 40% (n = 45), Chagas disease (n = 18), idiopathic dilated cardiomyopathy (n= 12), hypertensive disease (n = 8), hypertrophic cardiomyopathy (n = 4) and valvular heart disease (n = 3); Group III--Patients with arrhythmogenic right ventricular dysplasia (n = 13); and Group IV--Patients with channelopathies: Brugada Syndrome (n = 8) and idiopathic ventricular arrhythmias (n = 9). All patients underwent electrophysiological study (EPS) with induction of sustained ventricular arrhythmia ICD implantation. RESULTS: During the 26-month mean follow up, a high rate of appropriate ICD therapies (antitachycardia pacing and/or shock) was observed (46%) in the four groups, with no statistically significant difference. The four groups did not differ in either overall (8.4%) or arrhythmic mortality (1.3%). There was no correlation between appropriate ICD therapies and initial clinical presentation or inducible ventricular arrhythmia at EPS, and a 4% incidence of early and late procedure-related complications was found. CONCLUSION: The high incidence of appropriate ICD therapy and low rate of sudden death in the patients studied suggest that ICD is a valuable strategy in the management of ischemic and nonischemic patients previously selected by means of EPS.

Intra-His bundle block: clinical, electrocardiographic, and electrophysiologic characteristics

OBJECTIVE To assess the clinical, electrocardiographic, and electrophysiologic characteristics of patients (pt) with intra-His bundle block undergoing an electrophysiologic study (EPS). METHODS We analyzed the characteristics of 16 pt with second-degree atrioventricular block and symptoms of syncope or dyspnea, or both, undergoing conventional EPS. RESULTS Intra-His bundle block was documented in 16 pt during an EPS. In 15 (94%) pt, the atrioventricular block was recorded in sinus rhythm; 4 (25%) pt had intra-His Wenckebach phenomenon, which correlated with Mobitz I (MI) atrioventricular block on the electrocardiogram. Seven (44%) pt had 2:1 atrioventricular block, 2 of whom were asymptomatic (12.5%). One (6%) pt had intra- and infra-His bundle block. Clinically, 11 (68%) pt had syncope or presyncope, 3 (18%) had dyspnea on exertion, and 2 (12.5%) were asymptomatic. Eight (50%) pt had bundle-branch block as follows: 4 (25%) pt had left bundle-branch block, and 4 (25%) had right bundle-branch block. Left anterosuperior divisional block was observed in 3 pt (19%), 2 of whom with associated right bundle-branch block. CONCLUSION Intra-His bundle block was observed in 11% of the pt with second-degree atrioventricular block, syncope or presyncope, or both, it being the most frequent clinical presentation. Intra-His bundle block was more common in the elderly (> 60 years) and among females. The most frequent electrocardiographic presentations were second-degree Mobitz I or type 2:1 atrioventricular block.