| Abstract: | In eleven patients with isolated mitral stenosis and regular sinus rhythm a right cardiac catheterization was performed and the wedged pulmonary capillary pressure recorded at rest and during electrical pacing of the right atrium at successive frequencies of 100, 120, 140, and, occasionally, 160 and 180 beats/min, while cardiac output was estimated by the Fick's principle. In all cases a significant elevation of pulmonary capillary pressure with a simultaneous reduction in cardiac output was obtained. The rise of wedged pulmonary pressure was proportional to the increment in cardiac frequency and related also to the calculated area of the mitral valve. The influence of active atrial contraction upon pulmonary pressure and cardiac output is discussed and comparisons with other studies are made. Emphasis is made on the value of atrial pacing as a diagnostic method in mitral stenosis, especially in cases in whom classical effort manoeuvres can not be applied or are insufficient to rise cardiac frequency. |
