Henrique Horta Veloso

Acute atrial fibrillation during dengue hemorrhagic fever

Dengue fever is a viral infection transmitted by the mosquito, Aedes aegypti. Cardiac rhythm disorders, such as atrioventricular blocks and ventricular ectopic beats, appear during infection and are attributed to viral myocarditis. However, supraventricular arrhythmias have not been reported. We present a case of acute atrial fibrillation, with a rapid ventricular rate, successfully treated with intravenous amiodarone, in a 62-year-old man with dengue hemorrhagic fever, who had no structural heart disease.

Efficacy and safety of sotalol versus quinidine for the maintenance of sinus rhythm after conversion of atrial fibrillation

To compare the efficacy and safety of sotalol and quinidine after conversion of atrial fibrillation (AF) of 5.2 cm were excluded. After 6 months of follow-up, using the Kaplan-Meier method, the probabilities of success were comparable between sotalol (74%) and quinidine (68%), but recurrences occurred later with sotalol than with quinidine (69 vs 10 days, p 72 hours), quinidine was more effective than sotalol (68% vs 33%, p <0.05). During recurrences, the ventricular rate was significantly reduced in patients taking sotalol (98 to 82 beats/min, p <0.05). Independent predictors of therapeutic success were recent-onset AF in the sotalol group (p <0.001) and absence of hypertension in the quinidine group (p <0.05). In conclusion, sotalol and quinidine have comparable efficacy and safety for the maintenance of sinus rhythm in the overall group. In recent-onset AF, sotalol was more effective, whereas in chronic AF, quinidine had a better result. Recurrences occurred later with sotalol when compared with quinidine. Because of proarrhythmia, these drugs should be used judiciously in patients on diuretic therapy.

Effectiveness and costs of chemical versus electrical cardioversion of atrial fibrillation

BACKGROUND Atrial fibrillation is the most common sustained cardiac arrhythmia and has an important impact on costs of medical assistance. Traditional interventions to convert atrial fibrillation to sinus rhythm are antiarrhythmic drugs and external electrical cardioversion. However, the best option for starting the cardioversion is not well established. METHODS In a multicentre randomised trial of 139 patients with persistent atrial fibrillation lasting less than 6 months, we compared the effectiveness and the cost-effectiveness ratio of initial treatment with chemical or electrical cardioversion. Subjects who did not achieve sinus rhythm with chemical cardioversion were considered to undergo electrical cardioversion and vice-versa. RESULTS The efficacy of the initial attempt for cardioversion was similar with chemical or electrical cardioversion (74 vs. 73%, P=0.95). However, the strategy of starting with antiarrhythmic drugs was more effective than with electrical procedure (96 vs. 84%, P=0.0016). Initiating with chemical cardioversion was also less expensive than with electrical cardioversion (1240 US dollars vs. 1917 US dollars ; P=0.002). Life-threatening complications occurred only during chemical cardioversion (5%), all of them in patients with structural heart disease. CONCLUSIONS In patients with persistent atrial fibrillation of less than 6 months, initial chemical or electrical cardioversion appear to be similar but the strategy of starting the cardioversion with antiarrhythmic drugs is more effective and less expensive than starting with the electrical procedure. Patients with structural heart disease undergoing chemical cardioversion seem to be more susceptible to severe complications.

Initial Energy for External Electrical Cardioversion of Atrial Fibrillation

OBJECTIVE To investigate the initial energy level required for electrical cardioversion of atrial fibrillation (AF). METHODS We studied patients undergoing electrical cardioversion in the 1st Multicenter Trial of SOCESP. Patients were divided into 2 groups according to the initial energy level of electrical cardioversion: 100J and >/=150J. We compared the efficacy of the initial and final shock of the procedure, the number of shocks administered, and the cumulative energy levels. RESULTS Eight-six patients underwent electrical cardioversion. In 53 patients (62%), cardioversion was started with 100J, and in 33 patients (38%), cardioversion was started with >/=150J. Groups did not differ regarding clinical features and therapeutical interventions. A tendency existed towards greater efficacy of the initial shock in patients who received >/=150J (61% vs. 42% in the 100J group, p=0.08). The number of shocks was smaller in the >/=150J group (1.5+/-0.7 vs. 2.1+/-1.3, p=0.04). No difference existed regarding the final efficacy of electrical cardioversion and total cumulative energy levels in both groups. In the subgroup of patients with recent-onset AF (</=48h), the cumulative energy level was lower in the 100J group (240+/-227J vs. 324+/-225J, p=0.03). CONCLUSION Patients who were given initial energy of >/=150J received fewer counter shocks with a tendency toward greater success than those patients who were given 100J; however, in patients with recent-onset AF, the average cumulative energy level was lower in the 100J group. These data suggest that electrical cardioversion should be initiated with energy levels >/=150J in patients with chronic AF.

Epicardial mapping of sustained ventricular tachycardia in nonischemic heart disease

BACKGROUND The complexity of reentrant circuits related to ventricular tachycardias decreases the success rate of radiofrequency ablation procedures. OBJECTIVE To evaluate whether the epicardial mapping with multiple electrodes carried out simultaneously with the endocardial mapping helps in ablation procedures of sustained ventricular tachycardia (VT) in patients with nonischemic heart disease. METHODS Twenty-six patients with recurrent sustained VT, of which 22 (84.6%) presenting chronic chagasic cardiomyopathy, 2 (7.7%) with idiopathic dilated cardiomyopathy and 2 with right ventricular arrhythmogenic dysplasia (RVAD), were submitted to epicardial mapping with two or three microcatheters, with 8 electrodes each, simultaneously to the conventional endocardial mapping. A catheter with a 4-mm tip was used for the ablation by radiofrequency (RF) carried out during the induced VT. RESULTS Of the 33 induced VT, 25 were mapped and 20 had their origin defined. Eleven had epicardial and 9 had endocardial origin. The programmed ventricular stimulation did not induce sustained VT in 11 (42.0%) of the 26 patients after the ablation. Events such as VT recurrence and death occurred in 10.0% of the patients submitted to successful ablation and in 59.0% of the unsuccessful cases, during a mean ambulatory follow-up of 357 ± 208 days. CONCLUSION Subepicardial circuits are frequent in patients with nonischemic heart disease. The epicardial mapping with multiple catheters carried out simultaneously with the endocardial mapping contributes to the identification of these circuits in a same procedure.BACKGROUND: The complexity of reentrant circuits related to ventricular tachycardias decreases the success rate of radiofrequency ablation procedures. OBJECTIVE: To evaluate whether the epicardial mapping with multiple electrodes carried out simultaneously with the endocardial mapping helps in ablation procedures of sustained ventricular tachycardia (VT) in patients with nonischemic heart disease. METHODS: Twenty-six patients with recurrent sustained VT, of which 22 (84.6%) presenting chronic chagasic cardiomyopathy, 2 (7.7%) with idiopathic dilated cardiomyopathy and 2 with right ventricular arrhythmogenic dysplasia (RVAD), were submitted to epicardial mapping with two or three microcatheters, with 8 electrodes each, simultaneously to the conventional endocardial mapping. A catheter with a 4-mm tip was used for the ablation by radiofrequency (RF) carried out during the induced VT. RESULTS: Of the 33 induced VT, 25 were mapped and 20 had their origin defined. Eleven had epicardial and 9 had endocardial origin. The programmed ventricular stimulation did not induce sustained VT in 11 (42.0%) of the 26 patients after the ablation. Events such as VT recurrence and death occurred in 10.0% of the patients submitted to successful ablation and in 59.0% of the unsuccessful cases, during a mean ambulatory follow-up of 357 ± 208 days. CONCLUSION: Subepicardial circuits are frequent in patients with nonischemic heart disease. The epicardial mapping with multiple catheters carried out simultaneously with the endocardial mapping contributes to the identification of these circuits in a same procedure.

Análise da recorrência de fibrilação atrial durante terapia com sotalol ou quinidina

PURPOSE To analyze the recurrences of atrial fibrillation in patients treated with sotalol or quinidine. METHODS After conversion to sinus rhythm, 121 patients with paroxysmal atrial fibrillation were randomized to sotalol (58 patients) or quinidine (63 patients) and followed-up during 6 months. Symptoms and ventricular rates on the 12 lead electrocardiogram of the arrhythmic events were compared between the two groups. Clinical and echocardiographic characteristics were analyzed as predictors of atrial fibrillation recurrence. RESULTS Seventeen (14%) patients relapsed into atrial fibrillation; 7 (12%) were treated with sotalol and 10 (16%) with quinidine. Recurrence occurred later in the sotalol group (median 69 days) in comparison with the quinidine group (median 10 days) (p = 0.04). Symptoms were present in 14 (82%) patients during the initial crisis and in 10 (47%) during recurrence. Recurrence was less symptomatic during antiarrhythmic therapy (p < 0.04), with no statistical differences between the two groups. Only patients treated with sotalol had ventricular rates during the recurrences lower than during initial crisis (p < 0.02). All variables failed to predict recurrence of atrial fibrillation. CONCLUSIONS It was not possible demonstrate differences between sotalol and quinidine for the prevention of atrial fibrillation. Recurrence was less symptomatic during antiarrhythmic therapy. Patients treated with sotalol relapsed to atrial fibrillation later and had ventricular rates during recurrences significantly lower than during the initial crisis.OBJETIVO: Analisar a incidencia e as caracteristicas das crises de recorrencia de fibrilacao atrial (FA) em pacientes sob terapia com sotalol ou quinidina. METODOS: Cento e vinte e um pacientes receberam de forma randomica sotalol (58 pacientes) ou quinidina (63 pacientes) apos reversao de FA paroxistica e foram acompanhados, ambulatorialmente, por 6 meses. As sintomatologias e as frequencias ventriculares ao eletrocardiograma de 12 derivacoes da crise inicial e da recorrencia foram comparadas entre os grupos de drogas. As caracteristicas clinicas e os dados do ecocardiograma foram analisados como preditores de recorrencia. RESULTADOS: Dezessete (14%) pacientes apresentaram recorrencia da arritmia, 7 (12%) em uso de sotalol e 10 (16%) em uso de quinidina. A recorrencia ocorreu mais tardiamente no grupo tratado com sotalol (mediana de 69 dias) em comparacao ao grupo tratado com quinidina (mediana de 10 dias) (p=0,04). A sintomatologia esteve presente em 14 (82%) pacientes na crise inicial e em 8 (47%) pacientes na recorrencia. O tratamento antiarritmico proporcionou recorrencias menos sintomaticas (p<0,04), nao sendo possivel demonstrar diferenca significante entre as terapias. Somente os pacientes tratados com sotalol apresentaram menor frequencia ventricular na recorrencia em comparacao a crise inicial (p<0,02). Todas as variaveis falharam em predizer recorrencia da FA. CONCLUSAO: Nao foi possivel demonstrar diferenca entre o sotalol e a quinidina na prevencao de FA. O tratamento antiarritmico proporcionou a ocorrencia de recorrencias menos sintomaticas. Os pacientes tratados com sotalol apresentaram recorrencia mais tardiamente e frequencia ventricular significantemente menor na recorrencia em comparacao a crise inicial.

Mapeamento epicárdico da taquicardia ventricular sustentada em cardiopatias não isquêmicas

BACKGROUND The complexity of reentrant circuits related to ventricular tachycardias decreases the success rate of radiofrequency ablation procedures. OBJECTIVE To evaluate whether the epicardial mapping with multiple electrodes carried out simultaneously with the endocardial mapping helps in ablation procedures of sustained ventricular tachycardia (VT) in patients with nonischemic heart disease. METHODS Twenty-six patients with recurrent sustained VT, of which 22 (84.6%) presenting chronic chagasic cardiomyopathy, 2 (7.7%) with idiopathic dilated cardiomyopathy and 2 with right ventricular arrhythmogenic dysplasia (RVAD), were submitted to epicardial mapping with two or three microcatheters, with 8 electrodes each, simultaneously to the conventional endocardial mapping. A catheter with a 4-mm tip was used for the ablation by radiofrequency (RF) carried out during the induced VT. RESULTS Of the 33 induced VT, 25 were mapped and 20 had their origin defined. Eleven had epicardial and 9 had endocardial origin. The programmed ventricular stimulation did not induce sustained VT in 11 (42.0%) of the 26 patients after the ablation. Events such as VT recurrence and death occurred in 10.0% of the patients submitted to successful ablation and in 59.0% of the unsuccessful cases, during a mean ambulatory follow-up of 357 ± 208 days. CONCLUSION Subepicardial circuits are frequent in patients with nonischemic heart disease. The epicardial mapping with multiple catheters carried out simultaneously with the endocardial mapping contributes to the identification of these circuits in a same procedure.BACKGROUND: The complexity of reentrant circuits related to ventricular tachycardias decreases the success rate of radiofrequency ablation procedures. OBJECTIVE: To evaluate whether the epicardial mapping with multiple electrodes carried out simultaneously with the endocardial mapping helps in ablation procedures of sustained ventricular tachycardia (VT) in patients with nonischemic heart disease. METHODS: Twenty-six patients with recurrent sustained VT, of which 22 (84.6%) presenting chronic chagasic cardiomyopathy, 2 (7.7%) with idiopathic dilated cardiomyopathy and 2 with right ventricular arrhythmogenic dysplasia (RVAD), were submitted to epicardial mapping with two or three microcatheters, with 8 electrodes each, simultaneously to the conventional endocardial mapping. A catheter with a 4-mm tip was used for the ablation by radiofrequency (RF) carried out during the induced VT. RESULTS: Of the 33 induced VT, 25 were mapped and 20 had their origin defined. Eleven had epicardial and 9 had endocardial origin. The programmed ventricular stimulation did not induce sustained VT in 11 (42.0%) of the 26 patients after the ablation. Events such as VT recurrence and death occurred in 10.0% of the patients submitted to successful ablation and in 59.0% of the unsuccessful cases, during a mean ambulatory follow-up of 357 ± 208 days. CONCLUSION: Subepicardial circuits are frequent in patients with nonischemic heart disease. The epicardial mapping with multiple catheters carried out simultaneously with the endocardial mapping contributes to the identification of these circuits in a same procedure.

Mapeo epicárdico de la taquicardia ventricular sostenida en cardiopatías no isquémicas

BACKGROUND The complexity of reentrant circuits related to ventricular tachycardias decreases the success rate of radiofrequency ablation procedures. OBJECTIVE To evaluate whether the epicardial mapping with multiple electrodes carried out simultaneously with the endocardial mapping helps in ablation procedures of sustained ventricular tachycardia (VT) in patients with nonischemic heart disease. METHODS Twenty-six patients with recurrent sustained VT, of which 22 (84.6%) presenting chronic chagasic cardiomyopathy, 2 (7.7%) with idiopathic dilated cardiomyopathy and 2 with right ventricular arrhythmogenic dysplasia (RVAD), were submitted to epicardial mapping with two or three microcatheters, with 8 electrodes each, simultaneously to the conventional endocardial mapping. A catheter with a 4-mm tip was used for the ablation by radiofrequency (RF) carried out during the induced VT. RESULTS Of the 33 induced VT, 25 were mapped and 20 had their origin defined. Eleven had epicardial and 9 had endocardial origin. The programmed ventricular stimulation did not induce sustained VT in 11 (42.0%) of the 26 patients after the ablation. Events such as VT recurrence and death occurred in 10.0% of the patients submitted to successful ablation and in 59.0% of the unsuccessful cases, during a mean ambulatory follow-up of 357 ± 208 days. CONCLUSION Subepicardial circuits are frequent in patients with nonischemic heart disease. The epicardial mapping with multiple catheters carried out simultaneously with the endocardial mapping contributes to the identification of these circuits in a same procedure.BACKGROUND: The complexity of reentrant circuits related to ventricular tachycardias decreases the success rate of radiofrequency ablation procedures. OBJECTIVE: To evaluate whether the epicardial mapping with multiple electrodes carried out simultaneously with the endocardial mapping helps in ablation procedures of sustained ventricular tachycardia (VT) in patients with nonischemic heart disease. METHODS: Twenty-six patients with recurrent sustained VT, of which 22 (84.6%) presenting chronic chagasic cardiomyopathy, 2 (7.7%) with idiopathic dilated cardiomyopathy and 2 with right ventricular arrhythmogenic dysplasia (RVAD), were submitted to epicardial mapping with two or three microcatheters, with 8 electrodes each, simultaneously to the conventional endocardial mapping. A catheter with a 4-mm tip was used for the ablation by radiofrequency (RF) carried out during the induced VT. RESULTS: Of the 33 induced VT, 25 were mapped and 20 had their origin defined. Eleven had epicardial and 9 had endocardial origin. The programmed ventricular stimulation did not induce sustained VT in 11 (42.0%) of the 26 patients after the ablation. Events such as VT recurrence and death occurred in 10.0% of the patients submitted to successful ablation and in 59.0% of the unsuccessful cases, during a mean ambulatory follow-up of 357 ± 208 days. CONCLUSION: Subepicardial circuits are frequent in patients with nonischemic heart disease. The epicardial mapping with multiple catheters carried out simultaneously with the endocardial mapping contributes to the identification of these circuits in a same procedure.

Atrial fibrillation or flutter and stroke: effectiveness of oral anticoagulation in clinical practice.

Dear Sir, In the interesting study of Frost et al. [1], clinical evolution of 5124 patients with nonvalvular atrial fibrillation or atrial flutter in Denmark to define the impact of oral anticoagulation on stroke of any nature was investigated (fatal or nonfatal, ischaemic or haemorrhagic). Diagnoses of atrial fibrillation, atrial flutter and stroke were obtained from the County Hospital Discharge Registry and data on prescriptions of anticoagulation from the National Health Service. The overall incidence of stroke was around 30 per 1000 persons-years of follow-up and the adjusted relative risks of stroke during anticoagulation were 0.6 [95% confidence interval (CI): 0.4–1.0] in men, and 1.0 (95% CI: 0.7–1.6) in women compared with nonuse periods. The authors concluded that the effectiveness of oral anticoagulation might be lesser than the efficacy reported from randomized trials. We think that some considerations must be performed facing the observed results. Current knowledge, supported by several randomized trials, is that adjusted-dose oral anticoagulation is more effective than no treatment or aspirin in the prevention of all stroke (both ischaemic or haemorrhagic) in nonvalvular atrial fibrillation [2, 3] (Table 1). However, it is also well-established that, in comparison with placebo, aspirin promotes a slight but significant reduction in the incidence of stroke in these patients. Consequently, the superiority of anticoagulation over aspirin is less evident than over no treatment (Table 1). In the Danish study, the use of aspirin was not evaluated. In the period out of anticoagulation, certainly many patients were taking this antiplatelet drug, and this may have hindered the demonstration of benefit with oral anticoagulation. Nonvalvular patients with previous stroke or transient ischaemic attack have a rate of subsequent stroke around 13% per year and benefit substantially with oral anticoagulation, whilst patients without previous embolic events have a rate of stroke of 5% per year [2]. In these cases, the decision for anticoagulation must consider other clinical and echocardiographic risk factors [3–6]. In the Danish study, patients with previous diagnosis of stroke or with a stroke occurring in the same month as a diagnosis of atrial fibrillation were excluded. Thus, this investigation was limited to primary prevention. In this setting, the superiority of anticoagulation therapy over no treatment or aspirin has been demonstrated, but with less importance than that for secondary prevention (Table 1). Dr L. Frost and colleagues hypothesized that in the real world , the advantage of anticoagulation may be less pronounced. Results of randomized trials may fail to achieve optimal results in clinical practice because the control of adjusted-dose of oral anticoagulation and patient follow-up are different. The most important evidence investigating the impact of oral anticoagulation in clinical practice with atrial fibrillation patients is the meta-analysis of Evans & Kalra [7]. In this study that included three series [8–10], patients in clinical practice were older and had more comorbid conditions compared with trial participants. However, the ischaemic stroke rate was similar between clinical practice and randomized studies [1.8% (95% CI: 0.9–2.7%) vs. 1.4% (95% CI: 0.9–2.0%)], as it was the occurrence of intracranial haemorrhage [0.1% (95% CI: 0–0.3%) vs. 0.3% (95% CI 0.06–0.5%)] and major bleeding [1.1% (95% CI: 0.4–1.8%) vs. 1.3% (95% CI: 0.8–1.8%)]. There was only a higher rate of minor bleeding in clinical practice than in trials [12.0% (95% CI: 9.7–14.3%) vs. 7.9% (95% CI: 6.6–9.2%)]. In conclusion, we do believe that the observation of a modest reduction of stroke with oral anticoagulation in the study of Frost et al. [1] should be restricted for the primary prevention setting. Journal of Internal Medicine 2003; 253: 92–93