Immediate hemodynamic response of patients with atrioventricular block and cardiac failure to transvenous pacing

Immediate hemodynamic improvement in patients with complete heart block occurs when the ventricular rate is increased by electrical pacing. During pacing, there is reduction in the pulmonary artery wedge, right atrial, and left and right ventricular filling pressures. The mean rate of ejection, stroke volume, and stroke work decreased following pacing, whereas the ejection time per minute increased, and dye curves assumed a more normal configuration. Very little change was noted in the resting cardiac output.

The paced heart is able to obtain greater increases in cardiac output, stroke volume, and mean rate of ejection during exercise than when unpaced. In addition, pacing tends to return elevated exercising filling pressures in the right and left ventricles toward normal.

Acute myocardial infarction secondary to thromboembolism from a fractured prosthetic aortic valve

A case of coronary artery embolism from thrombus in a fracture in an aortic Starr-Edwards prosthesis was documented at necropsy. This 40-year-old white man had replacement of the aortic and mitral valves by ball-valve prostheses 5 years prior to his death. Following surgery, he was able to return to full-time work. He did not return for follow-up for 2 years, and when next seen he had an acute myocardial infarction and left ventricular failure. An embolus to the left anterior descending coronary artery was demonstrated at the postmortem examination. The mitral ball was intact, but the aortic ball had two large fractures which contained thrombi.

Serum lactate dehydrogenase elevation in ambulatory cardiac patients. Evidence for chronic hemolysis

Activity of total lactate dehydrogenase (LDH) and that of the heat-stable isozyme (LDH-1) was measured by the method of Strandjord and Clayson in the serum of 62 cardiac patients with congenital and valvular heart disease before and after cardiac catheterization and at follow-up examination after cardiac surgery. A universal elevation of both total and heat-stable LDH was found in patients with prosthetic heart valves of several types. Lesser degrees of abnormalities were seen in a number of the patients without prosthetic devices. Some patients had a small increase in serum enzyme activity the day after cardiac catheterization. The evidence presented implicates hemolysis in the production of these abnormalities. It is suggested that all patients with prosthetic valves and a significant percentage of patients with severe hemodynamic abnormalities have chronic, usually compensated, intravascular hemolysis secondary to mechanical damage to red blood cells. These findings must be kept in mind in interpreting serum LDH determinations in patients with valvular prostheses or congenital and valvular heart disease who present with complaints of chest pain.

Q-1 interval of the phonocardiogram in patients with atrial septal defect

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