Right atrial flutter due to lower loop reentry: mechanism and anatomic substrates.

Background: The mechanisms of an atrial flutter (AFL) that is more rapid and at times more irregular than typical AFL are unknown.

Methods And Results: Twenty-nine patients with AFL were studied. Atrial electrograms were recorded from a 20-pole catheter placed against the tricuspid annulus (TA), with its distal electrodes lateral to the isthmus between the TA and the eustachian ridge (ER), and from the His bundle and coronary sinus catheters.

Cardiac involvement in myotonic muscular dystrophy (Steinert's disease): a prospective study of 25 patients.

The presence, degree and frequency of disorders of cardiac conduction and rhythm and of regional or global myocardial dystrophy or myotonia have not previously been studied prospectively and systematically in the same population of patients with myotonic dystrophy. Accordingly, 25 adults with classic Steinert's disease underwent electrocardiography, 24-hour ambulatory electrocardiography, vectorcardiography, chest x-rays, echocardiography, electrophysiologic studies, and technetium-99m angiography. Clinically important cardiac manifestations of myotonic dystrophy reside in specialized tissues rather than in myocardium.

Prevalence and clinical correlates of pulmonary arterial hypertension in progressive systemic sclerosis.

Forty-nine patients with progressive systemic sclerosis who had undergone extensive studies including pulmonary artery catheterization as part of an ongoing prospective study of the natural course of progressive systemic sclerosis were evaluated. The overall prevalence of pulmonary arterial hypertension in this population of patients with progressive systemic sclerosis was 33 percent, and among 10 subjects with the CREST syndrome the prevalence of pulmonary hypertension was 50 percent. The relation between pulmonary arterial hypertension documented at catheterization and abnormal results of noninvasive studies suggesting pulmonary hypertension, including physical examination, chest x-ray, electrocardiography, echocardiography, single-breath diffusing capacity, and vital capacity, was studied.

Sodium efflux in rabbit myocardium: relationship to sodium-calcium exchange.

1. The washout of (22)Na, (45)Ca and (58)CoEDTA(-) has been observed in arterially perfused rabbit interventricular septa both in the presence and absence of intoxicating doses of the aglycone, 3 acetylstrophanthidin (ACS).2.

The relationship arrhythmias and conduction disturbances to other manifestations of cardiopulmonary disease in progressive systemic sclerosis (PSS).

Disorders of rhythm and conduction are characteristic of the cardiac involvement in progressive systemic sclerosis (PSS), but their over-all frequency in PSS is not well established. Therefore, 46 ambulatory patients with PSS underwent several tests of cardiopulmonary function, including a 24-hour continuous electrocardiogram (Holter monitor). Conduction disturbances (sinus node dysfunction, first-degree heart block, pre-excitation), supraventricular arrhythmias (supraventricular tachycardia, atrial fibrillation, premature contractions of atrial or junctional origin) and ventricular arrhythmias (ventricular tachycardia, multifocal premature contractions) were observed on Holter monitoring in 26 subjects.