Effects of atenolol on rest and exercise hemodynamics in patients with mitral stenosis.

Beta-blocker therapy remains controversial in patients with mitral stenosis. In this randomized, double-blind, crossover, placebo-controlled study, the effects of atenolol (50 and 100 mg/day) were assessed in 15 patients (aged 46 +/- 11 years) with mitral stenosis (mean valve area 1.0 +/- 0.4 cm2; New York Heart Association class II or III) at rest and during upright bicycle ergometry. Doppler echocardiography was used to compare heart rate, cardiac and stroke volume indexes, diastolic filling period, and peak and mean transmitral gradients; a metabolic cart was used to obtain maximal oxygen consumption, carbon dioxide production, and anaerobic threshold. Beta-blocking therapy did not improve exercise time, external work, maximal oxygen consumption rate, or anaerobic threshold. Compared with placebo, maximal oxygen consumption rate and cardiac index decreased (p < 0.05) > 11% and > 20%, respectively, with atenolol at peak exercise. Although heart rate was reduced > 20% and diastolic filling period prolonged > 40% by atenolol at rest and exercise (p < 0.05), stroke volume index changed little compared with placebo. The data suggest that despite lower transvalvular pressure gradients, little benefit in exercise performance is achieved with beta-blocker therapy in patients with severe mitral stenosis.

Doppler evaluation of cardiac filling and ejection properties in humans during parabolic flight.

The cardiac filling and ejection properties of seven normal human subjects were examined during microgravity created on a National Aeronautics and Space Administration aircraft during parabolic flight. Doppler echocardiography was used to measure intracardiac velocities in sitting and supine subjects during three phases of flight: hypergravity (phase I), early microgravity (phase III), and late microgravity (phase IV). Heart rate declined 6% (P < 0.001) and right ventricular inflow velocities rose (46%, early; 26%, mean; P < 0.01) between phase I and phases III or IV in the sitting position only. Peak left ventricular outflow velocities rose 12% and inflow velocities rose (13%, early; 20%, mean) between phases I and IV while subjects were in the supine position (P < 0.05). A 14% rise in early velocities alone was seen between phases I and IV while subjects were in the sitting position (P < 0.05). In subjects entering microgravity while sitting, right heart chambers can accept additional venous return. When microgravity was entered while subjects were supine, however, venous augmentation was not observed. Left heart filling was more prominently enhanced when microgravity was entered while subjects were supine, suggesting a shift of fluid within the pulmonary vasculature.

Pharmacodynamic Doppler determination of mitral valve area in patients with significant aortic regurgitation.

In patients with combined mitral stenosis (MS) and aortic regurgitation (AR), the Doppler-determined mitral valve area (MVA) may be overestimated due to a shorter than expected pressure half-time. We performed Doppler echocardiography at baseline and after inhalation of amyl nitrite in 10 patients with combined MS and AR (Group I) and in five patients with MS alone (Group II). AR severity was reduced by amyl nitrite inhalation in all Group I patients, with a decrease in mean jet height/LVOT ratio from 32% to 21% (p < 0.01). Pressure half-time increased in Group I after amyl nitrite, with a mean reduction in the calculated MVA of 0.15 cm2 (p < 0.01). Group II had no significant changes in pressure half-time or Doppler-determined MVA after amyl nitrite, whereas both groups had comparable increases in heart rate, mean transmitral velocity, and mean transmitral pressure gradient. In patients with combined MS and AR, we conclude that amyl nitrite significantly increases pressure half-time while reducing the severity of AR. These findings support earlier reports of MVA overestimation when pressure half-time is used in the presence of AR.

Comparison of exercise electrocardiography and dobutamine echocardiography.

It is uncertain whether dobutamine echocardiography is a better test than exercise electrocardiography for the detection of coronary disease in patients who can exercise. We compared the hemodynamics, sensitivity, and specificity of these tests in 24 patients, 16 with coronary disease and 8 controls. The tests were performed within six weeks of one another and were interpreted without knowledge of other clinical data. The exercise electrocardiogram was considered abnormal if the patient developed one mm of ST-segment depression, while the dobutamine test (up to 40 micrograms/kg/min) was considered abnormal if the patient developed ST-segment depression or a left ventricular wall motion abnormality. Exercise testing resulted in a higher heart rate (145 +/- 29 vs. 110 +/- 24, p less than 0.001) and blood pressure (176 +/- 31 vs. 148 +/- 24, p less than 0.001). Dobutamine testing was 25% more sensitive than exercise testing (94 vs. 69%, 95% confidence interval for difference is 0 to 50%, p = 0.09), while exercise testing was 38% more specific (88 vs. 50%, 95% confidence interval for difference is -3 to 79%, p = 0.14). We conclude that exercise results in a higher heart rate and blood pressure than dobutamine infusion. Differences in sensitivity and specificity are inconclusive, but indicate that the sensitivity of exercise testing is, at best, equivalent to dobutamine testing, while any increase in specificity with dobutamine testing, compared with exercise testing, would not be clinically significant.

Valvular heart disease: medical therapy and experimental and animal models.

Vasodilators have been advocated for the treatment of regurgitant valvular heart diseases for more than 12 years, and new information on their mechanisms of action is available. Anticoagulants continue as a mainstay of therapy for patients with prosthetic heart valves, and the most desirable levels of anticoagulation for different conditions have been examined. Clinical and animal research studies of cardiac adaptation to mitral and aortic valve diseases are discussed.

Spontaneous thrombosis of iatrogenic femoral artery pseudoaneurysms: documentation with color Doppler and two-dimensional ultrasonography.

Two-dimensional ultrasonography and color Doppler were used over an 18-month period for the diagnosis and management of femoral artery pseudoaneurysms in six patients with pulsatile groin masses found after catheterization. A diagnosis of pseudoaneurysm was made when color Doppler demonstrated pulsatile systolic flow into echolucent masses. One patient underwent surgical repair of a symptomatic pseudoaneurysm after the initial Doppler study. Serial color Doppler studies were performed in five subjects, all of whom showed resolution of flow after a mean of 18 days (range 7 to 42). Despite an absence of flow, one patient underwent surgical drainage of persistent hematoma. After a mean interval of 233 days (range 84 to 552) all patients have remained free of other complications or symptoms related to the pseudoaneurysm. This experience suggests that urgent surgical repair is not required in all cases of small iatrogenic pseudoaneurysms, and that asymptomatic patients can be safely followed with serial color Doppler examinations.

Hemangiomas of the heart. A clinicopathologic study of ten cases.

The clinical and histopathologic features of 10 cardiac hemangiomas are presented. The patients' ages ranged from 2 weeks to 65 years (mean: 32 years). Eight patients had no other cardiovascular abnormalities, one was associated with intra-atrial lipoma, and one was associated with an anomalous origin of the left coronary artery. One patient had other hemangiomas of the oral cavity and small intestine. The tumors presented as pericardial effusion (2), sudden death (2), shortness of breath (1), incidental finding on chest X-ray (1), asymptomatic murmur (1), syncope (1), and incidental finding at autopsy (2). Location of the tumors included the right ventricle (4), left ventricle (3), atrial septum (2), and right atrium (1). All six tumors presenting in life were resected successfully, one requiring placement of a synthetic graft. Cardiac hemangiomas are usually sporadic; presenting symptoms depend on location in the heart; arrhythmias or sudden death can occur if the tumor is present in the basal region of the ventricular septum; surgical resection is feasible in other locations.

Effects of chronic beta-blockade on rest and exercise hemodynamics in mitral stenosis.

beta-blocker therapy for mitral stenosis is controversial. This study compares right and left heart hemodynamics at rest and supine submaximal exercise in patients (n = 7) receiving chronic beta-antagonists with untreated patients (n = 17) matched for age (mean +/- SD = 51 +/- 12 years) and valve area (0.7 +/- 0.2 cm2/m2). Little benefit was observed with treatment at rest. Although pulmonary capillary wedge pressures (PCWP) were lower during exercise in the beta-blocker group (22 +/- 4 vs. 31 +/- 9 mmHg; P < 0.05), exercise performance was not enhanced and cardiac output response during exercise was reduced (control = 41% increase vs. 12% for beta-blockade). PCWP rose rapidly when diastolic filling periods were < 300 msec in both groups. Pulmonary capillary wedge pressure was found to be a nonlinear functions (P < 0.001) of diastolic filling period (PCWP = 15.9 + 5.84 x 10(5)/dfp2). These data suggest that there is a critical heart rate in patients with mitral stenosis above which hemodynamic compromise rapidly occurs.

Comparison of adenosine, dipyridamole, and dobutamine in stress echocardiography.

OBJECTIVE: To compare adenosine, dipyridamole, and dobutamine in stress echocardiography with regard to sensitivity, specificity, accuracy, and side effects. DESIGN: Crossover, blinded comparison, with coronary angiography serving as the criterion standard. SETTING: U.S. Army tertiary care hospital. PARTICIPANTS: Forty participants, 25 with coronary disease and 15 without coronary disease. Patients were eligible if they had coronary angiography within 6 weeks of stress testing or if they had a risk for coronary disease of less than 5%. MEASUREMENTS: Left ventricular wall motion was recorded after dobutamine (0.38 mg/kg body weight), adenosine (0.84 mg/kg body weight), and dipyridamole (0.84 mg/kg body weight) stress testing. Stress echocardiographic evaluation was considered to be abnormal if the patient developed new or progressive wall motion abnormalities. The rate of side effects for the types of echocardiography and the patient preference were recorded. MAIN RESULTS: The sensitivity of dobutamine stress echocardiography (76%; 95% CI, 59% to 93%) was significantly higher than that of adenosine echocardiography (40%; CI, 21% to 59%; P less than 0.001) and that of dipyridamole echocardiography (56%; CI, 37% to 75%; P = 0.019). The specificity of adenosine testing (93%; CI, 80% to 100%) was significantly higher than that of dobutamine echocardiography (60%; CI, 35% to 85%; P = 0.008) and that of dipyridamole echocardiography (67%; CI, 43% to 91%; P = 0.028). Symptoms were more frequent with adenosine echocardiography (100%) than with dipyridamole (88%; P less than 0.001) or dobutamine (80%; P less than 0.001) echocardiography. Treatment for persistent symptoms was required in more patients after dipyridamole echocardiography (40%) than after dobutamine (12%; P less than 0.001) or adenosine (0%; P less than 0.001) echocardiography. More patients preferred dobutamine (48%) or dipyridamole (40%) echocardiography to adenosine echocardiography (12%; P less than 0.001). CONCLUSIONS: Dobutamine stress echocardiography is more sensitive and is better tolerated than adenosine or dipyridamole stress echocardiography. Adenosine echocardiography is more specific than dobutamine or dipyridamole echocardiography and is less likely to cause persistent symptoms.