Laser coronary angioplasty: experience with 9 cadaver hearts

Experience with laser angioplasty in 16 coronary arteries in 9 cadaver hearts is presented. Coronary obstructions were due to experimentally created thrombi as well as to naturally occurring calcified plaques. Successful laser angioplasty was achieved in 14 of 15 arteries. One artery was sacrificed to etermine factors necessary for deliberate perforation of the arterial wall. This procedure required more than 30 seconds of laser energy at 3.0 W with the catheter tip almost perpendicular to the wall. Penetration of the arterial wall occurred only in the second left anterior descending artery which was plaque-occluded because of operator inexperience.     

Comparison of antihypertensive and hormonal effects of captopril and propranolol at rest and during exercise

Captopril and propranolol were given alone and in combination to 13 hypertensive men and the effects studied at rest (seated, supine and standing) and during exercise. The two drugs were equipotent at rest, and individual patients showed similar blood pressure responses to the two drugs. Both produced slight reduction of urinary aldosterone; when given in combination, both blood pressure and aldosterone were further reduced. During exercise the increase in blood pressure was unaffected by captopril but reduced by propranolol, and there was no correlation between individual responses to the two drugs. It is concluded that the similar effects of the two drugs on resting blood pressure are consistent with their effects on the renin-angiotensin system.     

Duration of ejection in aortic stenosis: effect of stroke volume and pressure gradient

The theoretical effect of variable ventricular function on left ventricular ejection time in aortic stenosis was predicted by applying data measured in 52 patients with pure aortic stenosis to equations derived from the relations of Gorlin and Gorlin and Weissler et al. Ejection time and aortic valve area are not, of necessity, linearly related because (Formula: see text) where LVET is left ventricular ejection time, k is a constant, SV is stroke volume, PG is mean aortic pressure gradient and AVA is aortic valve area. When the patients were separated into performance groups on the basis of cardiac index (at 2.8 liters/min per m2), the linear regression relating the measured SV/square root PG with valve area in 18 patients with normal function (SV/square root PG = 11.1 AVA + 2.0, r = 0.969, p less than 0.001) predicted ejection time prolongation with decreasing valve area. In 34 patients with poor function, however, the decrease in SV/square root PG with decreasing valve area was more marked (SV/square root PG = 12.6 AVA + 0.4, r = 0.894, p less than 0.001), predicting a shorter ejection time at any given valve area in this group. As predicted by the effect of valve area on the equation, ejection time becomes most variable at a small aortic valve area. Independent ejection time measurement in these patients validated the predicted effect.     

Noninvasive diagnosis of persistent fetal circulation versus congenital cardiovascular defects

Congenital cardiovascular anomalies associated with right-left atrial or ductal shunts must be excluded before a diagnosis of persistent fetal circulation (PFC) can be made. Despite the advent of 2-dimensional echocardiography (2-D echo), this differentiation can be difficult and may require cardiac catheterization with selective angiography. Fifteen consecutive cases were analyzed in which difficulty was encountered with this differential diagnosis, and experience with the use of cardiac auscultation, the 12-lead electrocardiogram (ECG), arterial blood gas determinations and 2-D echo, both alone and with injection of venous contrast material, is reviewed. Electrocardiographic abnormalities of ventricular axis, hypertrophy or dominance (p = 0.002) and suspicion of cardiovascular disease on 2-D echo (p = 0.011) were the most useful findings in differentiating patients with PFC from those with congenital cardiovascular abnormalities. The ECG was the most sensitive test (100% sensitivity, 90% specificity), while 2-D echo was the most specific (100% specificity, 75% sensitivity). Evidence of right-left shunting at atrial or ductal levels or both did not differentiate between the groups; both groups had evidence of such shunts. A decision tree was developed to facilitate this differential diagnosis, which uses the ECG and 2-D echo. If the ECG reveals no abnormalities of ventricular axis, dominance or hypertrophy, the 2-D echo shows no structural abnormalities, and total anomalous pulmonary venous return and coarctation/interruption of the aorta are specifically excluded, a congenital cardiovascular anomaly is effectively eliminated. We suggest that this approach can optimize the management of the cyanotic newborn with suspected PFC by eliminating the risks of cardiac catheterization and angiography without missing the diagnosis of a major structural cardiovascular anomaly.