Gottlieb C. Friesinger

Hemodynamic Consequences of the Injection of Radiopaque Material

The hemodynamic changes resulting from injection of radiopaque material into the left heart in a series of patients undergong cineangiographic studies have been reported. The hypertonicity of radiopaque materials appears to be responsible for much of the observed reaction. The mechanism whereby hypertonic solutions produce the observed physiologic changes remains unknown.Changes observed in patients could be reproduced in experimental animals. The combined experimental and clinical data show that left atrial pressure increases, left atrial pulse contour alters, stroke output increases, heart rate is much unchanged, peripheral artery pressure falls, hematocrit level falls, and myocardial contractile force decreases mildly and transiently.The difference between the physiologic effects of injecting hypertonic media into the right and left sides of the circulation is discussed.Because the pressure changes are easy to monitor and parallel the other features of the hemodynamic reaction, it is good to wait until pressures have returned to the pre-angiographic level before proceeding with the injection of more radiopaque material. This usually requires 15 minutes.

The Effect of Nitroglycerin on the Systemic and Coronary Circulation in Man and Dogs

The pharmacodynamics of nitroglycerin have been studied in dogs and man.In dogs, intravenous nitroglycerin (TNG) caused a decrease in left ventricular work, myocardial blood flow (MFB), and myocardial oxygen consumption, and no significant change in coronary vascular resistance.Intracoronary artery TNG in dogs caused an immediate increase in MBF and a decrease in coronary vascular resistance that persisted until arterial pressure fell.In man, sublingual TNG (0.4 mg.) caused a decrease in left ventricular work, MBF, and myocardial oxygen consumption, and no significant decrease in coronary vascular resistance in patients with and without arteriographically proven coronary artery disease.The injection of doses of 0.1 to 0.2 mg. of TNG directly into the coronary artery in man caused an immediate increase in MBF and a decrease in coronary vascular resistance in patients with and without arteriographically proven coronary artery disease.The hypothesis proposed for the mechanism of action of TNG in the relief of angina pectoris is first, a decrease in coronary vascular resistance due to its effect on the coronary circulation, and, secondly, a decrease in cardiac work due to its effect on the systemic circulation.

Coronary Arteriographic Appearances in Patients with Left Bundle-Branch Block

Left bundle-branch block (LBBB) was found to be associated with an unusually short left main coronary artery in 11 of 12 patients studied by selective coronary arteriography. The average length of the left coronary artery in this group of 12 patients with LBBB was 4.5 ± 1.7 mm as compared to 12.8 ± 0.8 mm in a control group. Four of the 12 had evidence of ischemic heart disease, one had mild aortic regurgitation, one had myocardiopathy, and one had a patent ductus arteriosus. No etiology was discovered for the LBBB in the remaining five patients. Mechanical and hemodynamic explanations for this association of a particular pattern of coronary anatomy with LBBB are proposed.

Myocardial Blood Flow in Pacing-Induced Angina

Current methods of measuring myocardial blood flow using 133xenon have failed to separate normals from patients with ischemic heart disease at rest. In the present study such a separation was attempted by utilizing pacing-induced tachycardia (PIT) to stress the myocardium. 133Xenon was injected into the left coronary artery to measure blood flow in 27 patients at rest and during pacing-induced tachycardia. Oxygen content was simultaneously measured in the aorta and coronary sinus of 13 of these patients. Pacing rates of 150 beats/min or greater were obtained in 21 patients. In 10 patients (group I), who developed ischemia, manifested either by typical angina or ischemic electrocardiographic changes during PIT, myocardial blood flow increased 32 ml/min/100 g of tissue (P < 0.001). In 17 patients (group II), who did not develop ischemia, myocardial blood flow increased 12 ml/min/100 g of tissue (P < 0.02). The increase in group I patients was significantly greater than in group II (P < 0.02). Myocardial oxygen consumption increased 4.63 ml/min/100 g of tissue (P < 0.01) in ischemic responders (group I) and 2.62 ml/min/100 g of tissue in nonischemic responders (group II). It is concluded that patients with an ischemic response to pacing-induced tachycardia had a greater increase in myocardial blood flow and myocardial oxygen consumption than patients who did not develop an ischemic response. This unexpected finding is best explained by an increased myocardial blood flow in the nonischemic areas of the myocardium which may result from a vasodilator response to ischemia.

Effects of intravenously administered digoxin on mild left ventricular failure in acute myocardial infarction in man

Abstract Studies were made in 10 patients with early mild left ventricular failure in acute myocardial infarction to determine the hemodynamic correlates of the condition and evaluate the effects of intravenously administered digoxin. Studies were performed within 72 hours of infarction. Patients with basilar rales, tachycardia and ventricular (S 3 ) gallop sound were selected for study. Findings during the control period were consistent with mild left ventricular failure. Stroke index was below normal (28 ± 7.1 ml/m 2 ), but cardiac index was within normal limits (3.22 ± 0.60 liters/min per m 2 ) because of tachycardia. Stroke work index was low (39 +- 13.7 g-m/m 2 ), and pulmonary arterial end-diastolic pressure was minimally increased (15.2 ± 3.5 mm Hg). After intravenous administration of digoxin (0.75 mg in 7 patients, 1.0 mg in 3 patients), there were no statistically significant changes in any of the measured variables when the whole group was considered. Relating stroke work index to pulmonary arterial diastolic pressure, 2 types of responses were found. Four patients had a distinct inotropic response; the other 6 patients had no significant change, or a worsening of function. The reasons for a variable response in the early phase of infarction may be related to the regional nature of infarction or possibly to humoral factors influencing myocardial performance. Data suggest that digitalis is of limited value during this stage of infarction. Further studies and more precise characterization of patients may provide insight into the role of digitalis in the early phases of acute infarction.

Left Ventricular Preejection Period and Ejection Time in Patients with Acute Myocardial Infarction

The phases of systole were measured in 51 patients with acute myocardial infarction and three control groups: (1) a group of 40 patients without heart disease, (2) a group of 23 patients admitted to a coronary care unit for chest pain, who did not have an acute myocardial infarction, and (3) a group of 16 patients with stable angina pectoris and arteriographically proven coronary atherosclerosis. In addition, serial measurements were made in the acute myocardial infarction group. Total electricalmechanical systole (QS2), the preejection period (PEP), and left ventricular ejection time (LVET) were measured in each patient from simultaneous recordings of the ECG, phonocardiogram, and carotid pulse tracing. The systolic and diastolic blood pressures and QRS duration were also measured. Corrections were made for heart rate where appropriate.The average PEP was elevated on the first day of myocardial infarction but was within normal limits thereafter. The LVET and QS2 were significantly shortened until the fourth week of hospitalization. There was considerable overlap in the PEP values among the four groups. Eight patients died of acute myocardial infarction; the PEP was abnormally short in three (two of whom had cardiogenic shock), normal in two, and abnormally long in three. The PEP/LVET ratio separated the acute MI group from the normal group but not from the other two patient groups. Clinical class, digitalis, and infarct location did not produce characteristic changes in the systolic time intervals.A reduction in stroke volume is the most likely explanation for the reduction in LVET and QS2. The wide range in PEP values observed is best explained by alterations in the multiple determinants of PEP.The systolic time intervals do not appear to be useful as a diagnostic or prognostic tool in acute myocardial infarction.

The Use of Apexcardiography in the Assessment of Left Ventricular Diastolic Pressure

A total of 58 observations of simultaneous left ventricular pressure and apex-cardiograms (ACG) was made on 18 patients. An a wave percentage amplitude (aWPA) of greater than 15% of the total deflection of the ACG indicated an increase in left ventricular end-diastolic pressure (LVEDP). In 12 observations on six patients, an aWPA of less than 15% was associated with a high LVEDP. Patients with high LVEDP and aWPA of less than 15% had a high early left ventricular diastolic pressure with further rise in pressure prior to atrial contraction. These patients had small LV a waves (“atrial kick”). The aWPA of the ACG correlated better with the magnitude of the LV a wave than the absolute level of LVEDP in all patients. Correlation was good between changes in aWPA and changes in LVEDP in individual patients; but the ACG as an indirect means of evaluating left ventricular function is limited by the fact that elevations in LVEDP can exist in the presence of a normal aWPA. The ACG is a complex tracing reflecting not only intracardiac pressures, but changes in left ventricular volume, compliance, position, and perhaps left atrial function as well.

Anatomic and Physiologic Considerations in Measurements of Myocardial Blood Flow

Indicators can be used to measure myocardial blood flow if the myocardial circulation can be isolated from other segments of the systemic circulation.Methods of measuring myocardial blood flow can be divided into groups according to the technic employed to provide “isolation” of the myocardium.There is no practical method of proved accuracy whereby coronary blood flow can be measured in man in absolute terms of ml./min.All the so-called clearance methods measure myocardial blood flow in flow/volume units or ml./min./100 Gm.Myocardial blood flow measurements in these flow/volume units have not proved useful in separation of normal individuals from those with ischemic heart disease at rest, but have been useful in the study of acute intervention such as exercise or the administration of drugs.

Tetralogy of Fallot: Report of case with total correction at 54 years of age

A s the risks of cardiac surgery decrease, new categories of patients can be added to the list of those for whom surgery is indicated. Congenital defects can be corrected before symptoms develop and before irreversible changes occur in the myocardium or pulmonary vasculature. The entire concept of the inoperable lesion or the inoperable situation must be subject to constant review. This is especially true in the case of patients with congenital heart disease who have reached middle age and have, therefore, in many cases, already attained an age in excess of their life expectancy. The surgical risk in the middle-aged patient is increased because of age and associated cardiovascular disease, such as atherosclerosis, as well as by the presence of noncardiac disease. This report documents the case of a 54-year-old man with tetralogy of Fallot in whom the lesions were totally corrected surgically by the use of cardiopulmonary bypass, with good result.

Relation of the ballistocardiogram to left ventricular pressure measurements in man

Abstract 1. 1. An air-supported ballistocardiograph was used to obtain simultaneous recordings of body acceleration and left ventricular pressure in 7 patients. 2. 2. An average correlation of 0.810 was found for the IJ amplitude of the ballistocardiogram and the maximal derivative of the left ventricular pressure. 3. 3. The ballistocardiographic wave measurements displayed a high sensitivity to alterations in the left ventricular maximal pressure derivative of successive heartbeats. 4. 4. These observations suggest the potential application of the ballistocardiogram as a noninvasive method for quantitatively monitoring the mechanical activity of the heart.