Usefulness of midodrine in patients with severely symptomatic neurocardiogenic syncope: a randomized control study.

INTRODUCTION: The efficacy of midodrine for the management of patients with neurocardiogenic syncope was assessed prospectively in a randomized control study. METHODS AND RESULTS: Patients who had at least monthly occurrences of syncope and a positive tilt-table test were included in the study. A total of 61 patients were randomly allocated to treatment either with midodrine or with fluid, salt tablets, and counseling. Midodrine was given at a starting dose of 5 mg three times a day and increased up to a dose of 15 mg three times a day when required. Midodrine was given during the daytime every 6 hours. Thirty-one patients were assigned to treatment with midodrine; the other 30 patients were advised to increase their fluid intake and were instructed to recognize their prodromes and abort the progression to syncope. Patients were followed-up for at least 6 months. A quality-of-life questionnaire was administered at the time of randomization and 6 months after. At the 6-month follow-up, 25 (81%) of 31 midodrine-treated patients and 4 (13%) of the 30 fluid-therapy patients had remained asymptomatic (P < 0.001). One patient had to discontinue taking midodrine due to severe side effects and another six patients experienced minor side effects that did not require drug discontinuation. CONCLUSION: Midodrine appeared to provide a significant benefit in patients with neurocardiogenic syncope. To prevent recurrence of symptoms, dose adjustments were required in about one third of patients.

First human experience with pulmonary vein isolation using a through-the-balloon circumferential ultrasound ablation system for recurrent atrial fibrillation.

BACKGROUND: Standard mapping and ablation of focal sources of atrial fibrillation are associated with very long procedure times and low efficacy. An anatomic approach to complete pulmonary vein isolation could overcome these limitations. METHODS AND RESULTS: Fifteen patients with atrial fibrillation refractory to medication underwent circumferential isolation of the pulmonary veins by using a novel catheter, with an ultrasound transducer (8-MHz) mounted near the tip, in a saline-filled balloon. Twelve atrial foci and/or atrial fibrillation triggers were identified in 9 patients (pulmonary vein locations: left upper, 3; right upper, 6; right middle, 1; right lower, 1; and left inferior, 1). In 5 patients, lesions were placed in the absence of any mapped triggers. Irrespective of trigger mapping, circumferential isolation of both upper pulmonary veins was attempted in all patients. The lower pulmonary veins were ablated when sinus rhythm activation mapping revealed evidence of a sleeve of atrial muscle in the vein. The median number of lesions per patient required to isolate 1 pulmonary vein was 4 (range, 1 to 29). After ablation, no evidence of narrowing was seen with repeat venography or follow-up computed tomography scan. After a mean follow-up of 35+/-6 weeks, 5 patients had recurrence of atrial fibrillation. Three responded to drugs that were previously ineffective, and 2 remained in atrial fibrillation. CONCLUSIONS: This novel ultrasound ablation system can successfully isolate multiple pulmonary veins. At early follow-up, this approach seems to be effective in preventing recurrent atrial fibrillation in a significant number of patients.

Performance of implantable defibrillator pacing/sensing lead adapters.

The wide variety of implantable defibrillators (ICDs) available from different manufactures and the lack of universal industry standards has resulted in the frequent need for lead adapters at time of ICD implant or change. We analyzed the performance of 81 consecutive ICD sensing/pacing lead adapters used between 1988 and 1993. A total of 66 adapters was used for new epicardial systems, and 15 adapters served as lead connectors during ICD generator replacement. Pacing/sensing lead adapters used were: model LA-201 (n = 28; 34.5%); model 030-308 (n = 26; 32%); model 5866-24 (n = 15; 18.5%); and miscellaneous (n = 12; 15%). After a mean follow-up of 21 +/- 16 months, nine pacing/sensing lead adapters had documented or strongly suspected failure. Most often pacing/sensing lead adapters presented clinically as frequent aborted shocks. Actuarial probability of freedom from failure for model LA-201 was 83% at 1 year, and 72% at 2 and 3 years; this was poorer than for the other sensing leads combined (P = 0.01; hazard ratio = 4.92; 95% confidence intervals = 1.2-20; log-rank test). In conclusion, pacing/sensing lead adapters are a potential source of ICD system complications. Performance is dissimilar among different models; specifically, model LA-201 may not be safe in the long-term, and patients with this lead adapter need to be closely monitored.

Analysis of deaths in patients with an implantable cardioverter defibrillator.

The cause of death and clinical characteristics of 26 patients that died after implantable cardioverter defibrillator placement were reviewed and compared to the 145 patients still living after a mean follow-up of 17 months. Operative mortality was 4% (7/171) and resulted from postoperative ventricular arrhythmias (four patients), heart failure (two patients), and respiratory failure (one patient). Operative mortality was significantly higher (1.7% vs 9.6%, P less than 0.05) following concomitant surgical procedures. Total late mortality was 11% (18/171). Thirteen deaths (75%) occurred in-hospital from progressive deterioration of left ventricular function (nine patients), arrhythmia (two patients), and noncardiac causes (two patients). Outpatient mortality was 3.5% (6/171) and resulted from presumed sudden cardiac death in five of six patients; two of the five had devices that were inactive, one had high defibrillation thresholds, and two had suspected bradyarrhythmic deaths. One postoperative death and one late in-hospital death were also considered sudden cardiac deaths for a total of seven patients with defibrillation system failures. By multivariant analysis, preoperative clinical characteristics associated with a worse prognosis following defibrillator implantation were identified: presentation as ventricular tachycardia (P less than 0.02), induction of sustained monomorphic ventricular tachycardia (P less than 0.05), poor left ventricular performance (P less than 0.01), poor functional status (P less than 0.001), and the use of diuretics (P less than 0.01). Frequent device discharges (P less than 0.001) and concomitant antitachycardia pacing systems (P less than 0.001) were markers for greater arrhythmia recurrence and were potent predictors of a worse prognosis and particularly sudden death.