Coughing produces pulsatile changes in the thorax and abdomen which are transmitted to the heart chambers, arteries and veins. These pulsatile pressure waves are superimposed on the underlying pressures in each compartment. Closure of competent venous valves at the thoracic inlet prevents these pressure waves from being propagated into the brachiocephalic venous bed, resultIng In augmentation of tlte arteriovenous pressure gradient and flow to that bed. These perturbations can produce effective circulation during Itypotensive rhythm disturbances including asystole and ventricular fibrillation, and may affect conversion to sinus rhythm from ventricular tachycardia. Preliminary observations of the effects of coughing in severe mitral regurgitation suggest thai significanl haemodynamfc benefit occurs.
Aortic regurgitation (AR) increases the magnitude and duration of reverse flow in peripheral arteries. In this study a 9,5 MHz bidirectional Doppler ultrasound system was used to evaJuate the blood velocity waveform to determine whether a non-invasive assessment of AR couJd be made based on the relative reverse to forward components in the common carotid and femoral arteries. Blood velocity waveforms were recorded from the femoral artery in 6 control subjects and 19 patients with varying degrees of AR. The median ratio of the reverse to forward .~elocity in the control subjects was 0,22 (range 0,02 - O) and in the patients 0,47 (95 % confidence limits, 0,39 - 0,65). The difference was statistically significant (P <: 0,01, Mann Whitney U test). The simultaneous forward and reverse velocity comp6nents in the common carotid artery of 7 control subjects and 25 patients with AR was also measured, and the AR index calculated. The index was <: 1 in all control subjects (median 0,65, range 0,5 - 0,8) and> 1 in all patients (median 2,6, 95% confidence limits, 1,5 - 2,6). The difference is statistically significant (P <: 0,001). The results of tbis study suggest that the measurement of reverse blood velocity in peripberal arteries may provide a useful method of non-invasively assessing aortic valve disease.
Severe aortic stenosis in infants has a high early mortality after aortic valvotomy, whether done by surgery or balloon. Part of this mortallity might be that some left ventricles in these infants are too small to support an adequate circulation post-valvotomy. Both empirical studies of valvotomy results and a physiological model suggest that even in the absence of associated lesions, survival is unlikely for infants with left ventricular volumes much below 20 ml/m1. These infants shouJd he prepared for a univentricular repair by some operation like the Norwood procedure, followed later by a Footan-type procedure.
Mitral regurgitation (MR) in acute infarction may be sudden and catBstrophic as a result of papillary muscle rupture. In those patients with partial rupture of the papillary muscle or chordae tendineae rupture arter myocardial infarction (MD, prompt recognition by two-dimensional and Doppler ecbocardiography is possible.