John Boone

New-Onset Atrial Fibrillation

Background—Although sex differences in coronary artery disease have received considerable attention, few studies have dealt with sex differences in the most common sustained cardiac arrhythmia, atrial fibrillation (AF). Differences in presentation and clinical course may dictate different approaches to detection and management. We sought to examine sex-related differences in presentation, treatment, and outcome in patients presenting with new-onset AF. Methods and Results—The Canadian Registry of Atrial Fibrillation (CARAF) enrolled subjects at the time of first ECG-confirmed diagnosis of AF. Participants were followed at 3 months, at 1 year, and annually thereafter. Treatment was at the discretion of the patients’ physicians and was not directed by CARAF investigators. Baseline and follow-up data collection included a detailed medical history, clinical, ECG, and echocardiographic measures, medication history, and therapeutic interventions. Three hundred thirty-nine women and 560 men were followed for 4.1...

The canadian registry of atrial fibrillation: a noninterventional follow-up of patients after the first diagnosis of atrial fibrillation☆

The Canadian Registry of Atrial Fibrillation (CARAF) is a nondirected, follow-up study of 1,086 patients who are enrolled at 6 centers across Canada at the time of initial electrocardiographically documented diagnosis of atrial fibrillation (AF). Enrollment commenced in 1991 with an intended 10-year follow-up. Comprehensive baseline data, including clinical history, laboratory, and echocardiographic variables were collected. The patients were treated by their own referring physicians and CARAF did not direct their care. Detailed follow-up was performed at 3 months, 1 year, then yearly, with echocardiograms repeated every 2 years. Several studies, which evaluated patient populations, predictors of events, and cardiac structure and functioning, have been performed and are ongoing. Thyroid function was evaluated at baseline, and, of 707 patients evaluated, only 6 patients were found to be hyperthyroid. Symptoms during AF were evaluated and a profile of the types of symptoms and the predictors of symptoms was compiled. Antiarrhythmic drug use is being followed. Sotalol and propafenone were the most commonly used medications, with the use of antiarrhythmic drugs increasing with recurrence of AF. The use of anticoagulants was assessed. The overall use of warfarin was relatively low, but its use increased dramatically with the presence of various risk factors including congestive heart failure, hypertension, and previous stroke. The one risk factor that did not result in increased use of warfarin was hypertension. Therefore, CARAF was able to identify that hypertension appears to be under-recognized and undertreated in its risk for thromboembolic events. CARAF is just now reaching maturity, with the majority of patients having > or=4 years of follow-up. Therefore, extensive investigations are currently under way that will evaluate the baseline characteristics and utilize these as predictors of recurrence of AF, progression to chronicity, and the occurrence of major events such as stroke and death. A very large cohort of patients with serial echocardiograms over 4 years will permit an understanding of the progression of structural and valvular disease. Therefore, CARAF offers a unique opportunity for comprehensive, nondirected follow-up of patients from their initial diagnosis of AF.

Conservative Management of Mitral Valve Aneurysm

A 35-year-old woman had infective endocarditis and an aneurysm of the anterior mitral leaflet. The patient was managed conservatively and the mitral valve aneurysm remained stable over 3 years. Two-dimensional, color flow Doppler, and magnetic resonance images of the aneurysm are presented and features of mitral valve aneurysms are discussed. Conservative management of mitral valve aneurysms with careful follow-up is an acceptable approach.

Efficacy of sotalol guided by programmed electrical stimulation for sustained ventricular arrhythmias secondary to coronary artery disease

Sotalol is a class III antiarrhythmic drug with additional beta-blocker activity that has been shown to be effective in supraventricular and ventricular arrhythmias. Its long-term efficacy for ventricular arrhythmias is not as well described. Patients with documented sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) who had their clinical arrhythmia inducible at baseline electrophysiologic study received sotalol 320 to 640 mg/day. Repeat programmed stimulation was performed after a minimum of 72 hours while receiving the final dose. Of 28 patients (25 men and 3 women) whose arrhythmias were inducible at baseline, 15 had their arrhythmias suppressed with sotalol. Sotalol had greater success in suppressing arrhythmias in those with VF (8 of 9, 89%) than in those with VT (7 of 19, 37%, p < 0.01). In patients with a history of coronary artery disease but no history of myocardial infarction the arrhythmia was suppressed in 7 of 8 (88%) compared with 8 of 20 (40%, p < 0.05) patients with a history of myocardial infarction. All 15 patients in whom ventricular arrhythmias were suppressed continued to take long-term sotalol, and at a follow-up of 10.3 +/- 6.4 months none has had arrhythmia recurrence. Thus, sotalol is an effective drug for the suppression of ventricular arrhythmias as judged by programmed electrical stimulation. It appears to be more effective in patients in whom the clinical arrhythmia is VF rather than VT.

Propafenone-mexiletine combination for the treatment of sustained ventricular tachycardia

OBJECTIVES The purpose of this study was to explore the efficacy of combined therapy with propafenone and mexiletine for control of sustained ventricular tachycardia. BACKGROUND Combination antiarrhythmic drug therapy may enhance efficacy and lead to control of ventricular arrhythmias in some patients. Few reports have studied the combination of class IB and class IC drugs. Thus, this study was designed to investigate a combination of mexiletine and propafenone in patients with refractory ventricular tachycardia. METHODS Sixteen patients with sustained ventricular tachycardia had their clinical arrhythmia induced by programmed stimulation. Procainamide and propafenone alone failed to prevent reinduction of tachycardia in all. Mexiletine was subsequently added to propafenone and programmed stimulation was repeated. RESULTS With combination therapy ventricular tachycardia was noninducible in three patients (19%). A fourth who had presented with polymorphic ventricular tachycardia had slow bundle branch reentry (cycle length 500 ms) induced. In the other 12, tachycardia cycle length increased from 262 +/- 60 ms at baseline to 350 +/- 82 ms with propafenone and to 390 +/- 80 ms with propafenone plus mexiletine (p less than 0.0001 compared with baseline). Hemodynamic deterioration requiring defibrillation occurred in six patients at baseline study, in five taking propafenone and in two taking both drugs. CONCLUSIONS The combination of propafenone and mexiletine is effective in suppressing the induction of ventricular tachycardia in some patients refractory to procainamide and propafenone alone. In those in whom ventricular tachycardia could still be induced, the rate was slower and hemodynamically tolerated.