Doppler echocardiography. Role in emergency diagnosis of cardiac valve disease.

Doppler echocardiography provides crucial information in the evaluation of a patient with suspected significant heart valve dysfunction. Doppler studies can provide quantitative data on the gradients across the stenotic valves and in many cases derive the actual valve area (with use of the pressure half-time method for stenotic atrioventricular valves or the continuity equation for semilunar valves). When combined with two-dimensional echocardiographic studies, Doppler studies may discern the cause of valve dysfunction. In valvular regurgitation, semi-quantitative estimation of the severity of the problem can be obtained by pulsed Doppler flow mapping or color Doppler echocardiography. These methods show great value for rapid evaluation of valve dysfunction in the emergency setting.

Left ventricular function during stable sustained ventricular tachycardia. Hemodynamic and echo-Doppler analysis.

To assess the left ventricular function during sustained stable ventricular tachycardia (VT), ten patients, aged 58 to 74, underwent simultaneous echo-Doppler and hemodynamic studies during sinus rhythm and induced sustained stable monomorphic VT. The VT cycle length was 447 +/- 92 ms (mean +/- SD). During VT, cardiac index fell from 2.32 +/- 0.54 to 1.62 +/- 0.63 L/min/m2 (p less than 0.001), and systemic systolic blood pressure fell from 129 +/- 18 to 107 +/- 18 mm Hg (p less than 0.001), while left ventricular end-diastolic pressure showed a rising trend from 9 +/- 7 to 15 +/- 12 mm Hg, and pulmonary artery wedge pressure rose from 10.2 +/- 1.6 to 24.2 +/- 2.3 mm Hg (p less than 0.005). By echo-Doppler the ejection fraction and the presence and degree of valvular regurgitation were not significantly changed during VT. The mean maximal left ventricular inflow tract velocities, mean time velocity integrals, and the mean time velocity integrals normalized for heart rate (measures of left ventricular diastolic filling) decreased from 0.59 +/- 0.074 to 0.40 +/- 0.053 m/s (p less than 0.05), from 0.12 +/- 0.029 to 0.021 +/- 0.012 m (p less than 0.001), and from 7.43 +/- 1.20 to 3.21 +/- 1.49 m x beats/min (p less than 0.001) during VT, respectively. We conclude that hemodynamic changes during stable sustained VT are neither associated with significant changes in systolic left ventricular function nor related to valvular regurgitation and are likely caused by impaired left ventricular diastolic filling.

Avoidance of retrograde catheterization by Doppler echocardiographic diagnosis of Björk-Shiley aortic valve dysfunction.

A 74-year-old man with a history of prior Björk-Shiley aortic valve replacement was admitted with chest pain and dyspnea. Results of physical examination and cinefluoroscopy suggested a dysfunction of the prosthetic valve; imaging echocardiography was not helpful. Nonimaging continuous wave Doppler examination confirmed severe prosthetic aortic valve dysfunction, necessitating emergent replacement, and potentially hazardous retrograde catheterization of the prosthesis was avoided.

Cough syncope presenting as Mobitz type II atrioventricular block--an electrophysiologic correlation.

A 34-year-old man with a history of cough syncope exhibited Mobitz type II atrioventricular block with a narrow QRS complex on Holter monitoring. The baseline electrophysiologic study was normal. No significant atrioventricular block could be induced with carotid sinus massage, neck suction, or intravenous propranolol. However, coughing reproduced Mobitz type II atrioventricular block, which was found to be above the His bundle on the His bundle electrogram. A review of the mechanism of cough syncope is also presented.