Kenneth B. Lewis

Pulmonary Arterial Pulse Wave Velocity and Impedance in Man

The differential pressure method of Womersley and McDonald was used to measure instantaneous blood flow in the main pulmonary artery in ten human subjects. Three subjects had normal pulmonary arterial pressures and flows, seven had mitral stenosis and pulmonary hypertension. The spectrum of input impedance versus frequency was similar to that previously reported for the dog and rabbit, with the modulus decreasing from relatively high values at zero frequency to a minimum between 2 and 5 cycles/sec. Characteristic impedance and phase velocity were lower in the normal subjects than in those with pulmonary hypertension (averages, 23 dyne sec cm-5 and 1.68 m/sec in the normals; 46 dyne sec cm-5 and 4.77 m/sec in the hypertensives). Hydraulic energy dissipated per unit time by pulsations in the pulmonary bed was usually higher in the hypertensive than in the normal cases, because of the greater stiffness of the pulmonary arteries in the subjects with pulmonary hypertension. The elasticity of the pulmonary arterial tree appears to be as important as the state of the arterioles and capillaries in determining the energy required for pulsatile pulmonary blood flow.

Pressure gradients without obstruction. A new concept of "hypertrophic subaortic stenosis".

Summary and Conclusions Significant outflow tract obstruction was notseen byleft ventricular cineangiocardiography in seven patients with hypertrophic subaorticstenosis.Catheter withdrawals through the leftventricle, recorded cinefluorographically, lo-calized the high pressure areas to portions ofthe left ventricle which emptied completely in early systole. Sustained systolic contractionin empty portions of the left ventricle pro-vides an explanation for the pressure gradi-entsinthesepatients.Isoproterenol infusions increased the rate and degree of left ventricular emptying, ob-literating portions of the cavity earlier andincreasingthepressure gradient.Themechanismof gradient production with- out obstruction was similar to the phenome-non observed in dogs receiving isoproterenol infusions. The cardiac muscle in these patients is ab-normally thick and the left ventricle emptiesmorerapidly than normal; therefore a hyper- trophic hyperkinetic cardiomyopathy is present.The nonobstructive

Anomalous Left Coronary Artery Arising from the Pulmonary Artery in an Adult A Review of the Therapeutic Problem

The 29-year-old woman with anomalous left coronary artery arising from the pulmonary trunk whose case is presented is at the time of writing, the oldest patient on record in whom this condition has been diagnosed during life. The diagnosis was made by aortic cineangiography and confirmed by selective injection of contrast material into the right coronary artery. The collateral pathways between the right and the anomalous left coronary artery were thus defined. Vectorcardiographic and electrocardiographic patterns of anterolateral myocardial infarction with periinfarction block have not been observed in any of the previously reported adults with this type of rare congenital anomaly.The 27 cases of ligation of the aberrant left coronary artery arising from the pulmonary artery reported in the literature have been reviewed and the results of this operation discussed.Diagnosis of the anomalous left coronary artery in adult life is possible if it is considered in patients presenting with a continuous murmur at the base and electrocardiographic evidence of myocardial infarction.