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Thirty-seven patients with ventricular tachyarrhythmias refractory to antiarrhythmic drug treatment, guided by electrophysiological testing, were submitted to implantation of a cardioverter-defibrillator by the transvenous technique. Mean age was 55 +/- 14 years and the underlying heart disease was coronary heart disease in 24 patients, cardiomyopathy or other etiologies in 11 patients. In 2 patients ventricular arrhythmias were idiopathic. Left ventricular ejection fraction was < or equal to 40% in 65% of the patients. The following devices were implanted: CPI Ventak P in 2 patients, Ventak P2 in 9 patients, Ventak PRx in 9 patients, Ventak PRxII in 2 patients, Telectronics Guardian ATP III 4215 in 9 patients, Siemens Siecure in 5 patients, Medtronic Jewel PCD in 1 patient. At implantation defibrillation threshold was lower with biphasic shocks than with monophasic shocks (17.0 +/- 3.2 vs 20.9 +/- 3.8 J, p < 0.003) and the need for subcutaneous patches was lower when biphasic shocks were employed. Operative and perioperative mortality were 0% and no significant complications were observed. During the follow-up (16 +/- 11 months) 35% of the patients had appropriate shocks and 93% of the patients with antitachycardia pacing availability (n = 15) had effective antitachycardia pacing interventions. The following complications were observed: lead failure in 4 patients (3 insulation breaks and 1 elongation for stretching), late lead dislodgement in 2 patients, lead recall in 1 patient, all of which required reintervention. Inappropriate shocks occurred in 30% of the patients and were related to lead failure, supraventricular arrhythmias or alternating current interference. During the follow-up one patient died of sudden death and one was submitted to heart transplantation. In conclusion, implantation of a cardioverter-defibrillator by the transvenous technique is a procedure relatively free from complications. During the follow-up lead failure appears to be one of the most relevant complications. Antitachycardia pacing allows effective termination of ventricular tachycardias without cardioversion, with a better compliance.

Ninety-two patients with diagnosis of lone atrial fibrillation (AF) were retrospectively identified by our in-hospital records. Among the 92 patients, 62 were males and 30 females. Mean age was 50 +/- 15 years (range 13-81). In 30% of the patients mild to moderate systemic hypertension was present. None had thyroid dysfunction. At the time of our first clinical observation, AF showed the following characteristics: recurrent AF in 58% of the cases (53 patients), chronic AF in 16% of the cases (15 patients) and first episode of AF in 26% of the cases (24 patients). Patient's symptoms were: palpitation in 73% of the cases, dyspnea in 24%, asthenia in 22%, chest pain in 19%, dizziness in 19% and syncope in 9% of the cases. In 9% of the subjects AF was asymptomatic. Recurrent AF presented with more than one episode per day in 12% of the cases, one per week in 16% of the cases, one-two episodes in 1 month in 8% of the cases and between two and six episodes in 1 year in 33% of the cases. Cross-sectional echocardiography, evidenced a higher prevalence of left atrial enlargement in patients with chronic AF (7/15 cases = 47%) either compared to subjects with recurrent AF (5/53 cases = 9%, p < 0.005) or compared to subjects with a first episode of AF (3/24 cases = 11%, p < 0.05). Echocardiographic signs of left ventricular dysfunction (left ventricular enlargement or hypokinesia) were found in 27% of the patients with chronic AF and in 8% of the other two groups (NS).(ABSTRACT TRUNCATED AT 250 WORDS)