Wavelets for QRS detection.

This paper examines the use of different wavelet functions for QRS complex detection in ECG. Wavelets provide time and frequency analysis simultaneously and offer flexibility with a number of wavelet functions with different properties available. This research has examined wavelet functions with different properties to determine the effects of orthogonality and time/frequency compactness of the wavelet on the ability to correctly detect the QRS. The error in detection (false negatives and positives) is the criterion for determining the efficacy of the wavelet function. The paper reports a significant reduction in error in detection of QRS complexes with mean error reduced to 0.75%. It also reports that wavelet functions that support symmetry and compactness provide better results.

Dilated cardiomyopathy as an early and rapidly progressive presentation in a woman with acquired immunodeficiency syndrome.

Cardiac disease associated with AIDS is common and is manifested by a variety of lesions. With the advances in therapy for common opportunistic infections, AIDS-associated cardiac abnormalities will play a prominent role in morbidity and mortality. This case illustrates a rapidly progressive and fetal course of AIDS-associated dilated cardiomyopathy in an HIV-infected young woman in relatively stable condition. It is important to be aware of the cardiac manifestations of AIDS so that one can undertake a rational diagnostic and therapeutic approach.

Efficacy of propafenone compared with quinidine in chronic ventricular arrhythmias.

A double-blind, randomized study was designed to evaluate the efficacy of oral propafenone and oral quinidine in suppressing premature ventricular complexes (PVCs). Twenty-five men were studied for 3 weeks. Twelve were randomized to the quinidine group and 13 to the propafenone group. Small doses of the drugs were administered for 1 week (200 mg of quinidine every 6 hours or 300 mg of propafenone every 12 hours) and large doses were administered for another week (400 mg of quinidine every 6 hours or 300 mg of propafenone every 8 hours). Strict criteria were used to define responders to antiarrhythmic therapy. For more than 85% reduction in total PVCs per hour: During the low-dose week, 36% in the quinidine group and 50% in the propafenone group were responders (difference not significant [NS]), while during the high-dose week 33% and 64% were responders (NS). For more than 95% reduction of ventricular couplets per hour: During the low-dose week, 45% in each group were responders, while during the high-dose week, 56% and 60% were responders (NS). For 100% abolition of ventricular tachycardia (VT) beats per 24 hours: During the low-dose week, 60% in the quinidine group and 56% in the propafenone group were responders (NS); during the high-dose week 80% and 67% were responders (NS). There was no significant difference in the 2 groups in incidence of side effects. This study shows comparable efficacy and tolerance of propafenone and quinidine for the control of ventricular arrhythmias in ambulatory patients with diverse forms of heart diseases.