Systolic time intervals in diabetes mellitus.

Systolic time intervals (STI) were evaluated in 45 diabetics without any cardiac signs and symptoms in order to study the left ventricular function. The STI parameters revealed an impairment of left ventricular function, thus implying preclinical myocardial involvement. This left ventricular dysfunction was more marked in patients in poor metabolic control and in cases with evidence of microangiopathy in kidney and retina, thus favoring the view that the primary myocardial disease is the result of metabolic and vascular components. Significant improvement in STI parameters was observed when good metabolic control was achieved, thus indicating that strict metabolic control is indeed worthwhile.

Differential effects of autonomic blockade on sinus and atrioventricular nodal function in normals and in intrinsic sinus node dysfunction.

The effect of pharmacologic total autonomic blockade on sinus and atrioventricular nodes was studied in 10 normals and 21 patients with sick sinus syndrome with abnormal intrinsic corrected sinus node recovery time. In normals the intrinsic heart rate (113.3 +/- 11.6 beats/min) was higher than the resting heart rate (87.3 +/- 12 beats/min; P less than 0.001). The AH interval at an identical paced rate decreased from 119 +/- 36 msec to 93 +/- 17.6 msec after autonomic blockade (P less than 0.05). Mean atrial paced cycle length at AH Wenckebach block was not different during control and after drugs (319 +/- 46 msec vs. 311.5 +/- 39 msec; P = NS). Although sinus cycle length shortened in all cases after autonomic blockade, paced cycle length at AH Wenckebach increased (4) or remained unchanged (3) in 7 cases. Maximum normal "intrinsic" paced cycle length at AH Wenckebach was 390 msec (mean +/- 2 SD). In sick sinus syndrome, resting heart rate (66.3 +/- 18.8 beats/min) and intrinsic heart rate (74.6 +/- 16.4 beats/min) were similar (P = NS); AH at identical paced rate: control 136.6 +/- 54 msec, after drugs 130.5 +/- 35 msec (P = NS); cycle length at AH Wenckebach: control 380.5 +/- 73 msec, after autonomic blockade 383 +/- 49 msec (P = NS). Two of 3 cases with abnormal atrioventricular nodal response to atrial pacing during control normalized after autonomic blockade; 9/21 (42.8%) cases developed AH Wenckebach at cycle length greater than 390 msec after autonomic blockade. The data suggest that the autonomic nervous system has differential effects on sinus and atrioventricular nodes. Patients with sick sinus syndrome frequently have abnormalities of "intrinsic" atrioventricular nodal conduction unmasked by autonomic blockade.

Left ventricular false tendons: echocardiographic incidence in India and clinical importance.

In a prospective study of 1012 patients above the age of 12 years, we detected 4 (0.4%) cases of left ventricular false tendon (LVFT) by echocardiography. Two patients had significant heart disease and LVFT was perhaps a chance occurrence; two others had no significant heart disease and LVFT probably had a causal association with S3 gallop in one and systolic murmur in the other. Diagnosis of LVFT may help to explain cardiac findings of uncertain origin.

Atrial septal motion in obligatory right to left shunt.

An adult patient with a hypoplastic right heart with intact ventricular septum, pulmonary atresia, secundum ASD and a PDA was studied by 2-D echocardiography. A striking flap valve motion of the primum portion of the interatrial septum was observed. This is perhaps the first report of its kind in an adult.