Evaluation of aortic stenosis by continuous wave Doppler ultrasound.

Twenty-four patients with suspected aortic stenosis (Group I) were evaluated noninvasively by continuous wave Doppler ultrasound before undergoing cardiac catheterization. Twenty normal subjects served as the control group (Group II). Maximal velocity measurements in the ascending aorta ranged from 3.0 to 5.8 m/s (mean 4.34 +/- 0.65) in Group I versus 1.0 to 1.6 m/s (mean 1.28 +/- 0.16) in Group II (p less than 0.001). Using the Bernoulli equation, the peak pressure gradient across the aortic valve was calculated from the maximal velocity in the Group I patients. The results correlated well with the peak aortic valve gradient obtained at cardiac catheterization (r = 0.79). In 20 of these 24 patients, the peak Doppler gradient was within 25% of the gradient found at cardiac catheterization. In three patients, the Doppler study under-estimated the gradient by slightly more than 25% but still detected the presence of significant aortic stenosis. The Doppler technique failed to detect critical aortic stenosis in only one patient. Significant overestimation of the gradient by Doppler measurement did not occur in any patient. The technique was particularly helpful in older patients in whom other noninvasive tests often yield inconclusive results. An important but infrequent limitation of the technique is underestimation of the gradient that occurs when the angle of incidence between the ultrasound beam and aortic blood flow is too large. The findings indicate that continuous wave Doppler ultrasound provides a reliable estimate of the valvular gradient in most patients with aortic stenosis.

Right to left intracardiac shunt: a unique presentation of metastatic cardiac disease.

A 54 year old man presented with signs and symptoms of severe hypoxemia. He had a history of a nasopharyngeal epidermoid carcinoma that was thought to have been totally eradicated 2 years earlier. He was found to have a right to left interatrial shunt through a patent foramen ovale due to tricuspid valve obstruction by a solitary cardiac metastasis. No other such reported case of a metastatic cardiac lesion could be found.

Left ventricular outflow obstruction after aortic valve replacement: detection with continuous wave Doppler ultrasound recording.

A 33 year old woman developed left ventricular outflow obstruction due to a fibrous subvalvular membrane 2 years after insertion of a Hancock modified orifice, porcine aortic valve prosthesis. M-mode and two-dimensional echocardiographic studies failed to detect the membrane. Continuous wave Doppler study revealed a maximal velocity of 4.8 m/s and a calculated peak pressure gradient of 92 mm Hg between the left ventricle and aorta. This finding was in close agreement with the peak gradient of 100 mm Hg obtained at cardiac catheterization. Because of its ability to accurately measure valvular gradients, continuous wave Doppler ultrasound study appears to be a useful noninvasive technique in the evaluation of patients with suspected prosthetic valve dysfunction.

Evaluation of aortic valve endocarditis by two-dimensional echocardiography.

Fourteen patients with aortic valve endocarditis were evaluated. Twelve patients had vegetations detected by two-dimensional echocardiography and two were diagnosed anatomically. M-mode echocardiography was positive in eight patients. Two-dimensional echocardiography was superior to M-mode in determining size, shape, and mobility of vegetations. The following three morphologic types of vegetative lesions were seen on two-dimensional echocardiogram: globular polypoid masses (seven); irregular, elongated lesions with chaotic movement (four); and a cord-like structure (one). Serial two-dimensional echocardiograms performed after completion of antibiotic therapy in seven patients revealed no change in appearance in five and complete disappearance in two patients. Among the 12 patients with vegetations visualized on the two-dimensional echocardiogram, seven responded to medical therapy, four required aortic valve replacement, and one patient died. One of the patients who initially responded to medical therapy eventually required aortic valve replacement following a second episode of aortic endocarditis. In those patients with negative two-dimensional echocardiograms, the vegetations were 3 mm in diameter or less at surgery or autopsy. Vegetations that were visualized on two-dimensional echocardiography were found to be at least 5 mm in diameter at the time of operation. Two-dimensional echocardiography is a valuable noninvasive tool in the evaluation of patients with aortic valve endocarditis.

Intrapericardial instillation of sodium hydroxide: failure to produce pericardial symphysis.

Previously reported clinical studies have suggested sodium hydroxide as an effective agent in causing pleural symphysis. To explore the sclerosing potential of this agent, we instilled 0.5% sodium hydroxide into the pericardium of four dogs. Normal saline was instilled into the pericardium of one control dog. Echocardiograms, 24 hour EKG monitoring and intracardiac pressures were recorded. One dog was sacrificed at the end of 24 hours, another at the end of seven days and three other dogs were sacrificed at the end of 28 days. ST elevations and prolonged episodes of supra-ventricular and ventricular tachycardia were noted during and within 24 hours after the intrapericardial instillation of sodium hydroxide in all the dogs. No arrhythmias were noted in the control dog. None of the dogs showed pericardial symphysis. These results suggest that sodium hydroxide causes serious cardiac arrhythmias when instilled intrapericardially and is of limited value in causing pericardial symphysis.