Barry W. Ramo

Hemodynamic Findings in 123 Patients with Acute Myocardial Infarction on Admission

Hemodynamic and clinical evaluations of 123 patients with acute myocardial infarction were performed during the first hour of admission to the hospital. In the 123 patients, the right atrial pressure was less than 10 mm Hg in 49 patients, the right atrial oxygen saturation was less than 70% in 97 patients, the arteriovenous oxygen difference was greater than 5.0 vol% in 78 patients. The arterial Po2 was less than 90 mm Hg in 101 of 107 patients who could be evaluated while breathing room air. The cardiac index was depressed below 3.0 L/min/m2 in 65 of 98 patients.The hemodynamic findings generally correlated with the clinical status of the patient; however, within each clinical class of patients there was a wide spectrum of values for each measurement evaluated. There was also considerable overlap of the values found within each clinical classification. It is concluded that hemodynamic evaluation of patients with acute myocardial infarction presents a profile of the patient which is frequently different from the profile that clinical evaluation presents. An objective hemodynamic classification of patients with acute myocardial infarction may provide a more useful index for the evaluation of the patients prognosis and for the assessment of preventative therapy.

Coronary Angioplasty for Acute Mitral Regurgitation Due to Myocardial Infarction: A Nonsurgical Treatment Preserving Mitral Valve Integrity

Three patients presented to the cardiac catheterization laboratory with myocardial infarction, severe mitral regurgitation, and pulmonary edema. Two patients were in cardiogenic shock at the time of cardiac catheterization. Percutaneous transluminal coronary angioplasty was done on the occluded artery in all three patients with resolution of the pulmonary edema as well as auscultative evidence of mitral regurgitation. The mean pulmonary wedge pressure dropped from 34 to 10 mm Hg in these patients. Mean follow-up of 11.7 months showed no evidence of clinical heart failure, angina pectoris, or auscultative evidence of mitral regurgitation.

The natural history of right coronary arterial occlusion in the pig: Comparison with left anterior descending arterial occlusion☆

Abstract Gradual occlusion of the right coronary artery in the farm pig produces a much lower mortality rate than occlusion of the left anterior descending artery. The rate and extent of collateral vessel development in these 2 arteries after the gradual occlusion of each were compared in the pig using selective coronary cineangiograms. Serial studies were performed over 42 days after placement of an ameroid constrictor on the right coronary artery in 24 pigs (RCA group) and on the left anterior descending artery in 27 pigs (LADA group). Despite similar rates of occlusion, collateral vessels developed earlier in pigs in the RCA group. With partial occlusion collaterals were seen in 75 percent of those in the RCA group and in 33 percent of those in the LADA group. After total occlusion, the contralateral vessel was completely opacified at 1, 2, 3 and 4 weeks in 40, 71, 87 and 100 percent, respectively, of animals studied in the RCA group, compared to 8, 20, 40 and 100 percent of animals in the LADA group. Histologic evidence of myocardial infarction, although present in all animals, was more extensive in animals in the LAPA group. All myocardial infarctions noted were limited to the left ventricle although blood supply to the right ventricle is almost exclusively from the right coronary artery. The difference in the rapidity and extent of collateral vessel development may be related to the dissimilarity in pressure and mass between the right and left ventricles, and it may explain the lower mortality rate, smaller left ventricular infarction and absent right ventricular infarction following occlusion of the right coronary artery.

Migration of a severed transvenous pacing catheter and its successful removal

Abstract In a patient with complete A-V block with a permanent transvenous pacemaker pacing failure occurred. The insulation of the pacing catheter had eroded and resulted in ineffective pacing. Since the catheter could not be removed from the venous system, it was severed. The proximal end was fixed to the tissue in the neck at its entrance into the external jugular vein. The distal portion remained in the superior vena cava. Subsequently, the catheter dislodged from its sutures and migrated to the inferior vena cava. A safe snare was developed and used to remove the catheter through the saphenous vein. This report points out the need to remove permanent pacing catheters from the heart when they are not to be used and describes a method for removing intravascular foreign bodies.

Collateral vessel development after right ventricular infarction in the pig

Abstract Although the right coronary artery supplies both ventricles in the pig, a gradual proximal right coronary occlusion produces infarction in the left ventricle, whereas the right ventricle is usually spared. This study evaluates the influence of right ventricular hypertension and hypertrophy (RVHH) on the occurrence of right ventricular infarction and the difference in the rate and extent of collateral vessel development after gradual right coronary occlusion in pigs with (RVHH group) and without (control group) increased right ventricular pressure and mass. Right ventricular hypertension and hypertrophy were induced by pulmonary arterial banding which raised right ventricular systolic pressure from 24 to 74 mm Hg and doubled right ventricular mass in 4 weeks. Right coronary occlusion was produced with an ameroid constrictor in 24 control group pigs and 15 RVHH pigs. Serial selective coronary cineangiograms on days 4, 8, 14, 21 and 28 after ameroid constrictor placement showed no difference in first appearance of collateralization to the occluded right coronary artery. Total collateralization, which was present in all pigs studied in the control group by days 21 and 28, was present in only 57 percent of the RVHH group at the same time. Although left ventricular infarction occurred in all animals in both groups, right ventricular infarction was not found in the control group but was seen in 80 percent of the RVHH group. There was no correlation between the degree of collateralization seen and the size of the right ventricular infarction found. Experimentally induced right ventricular hypertrophy and hypertension make the right ventricle susceptible to infarction and impeded total collateral filling of the occluded right coronary artery in some of the animals studied.

Blood-gas and hemodynamic responses to oxygen in acute myocardial infarction.

Blood-gas (Pao2) and hemodynamic responses to the inhalation of oxygen were studied in 60 patients with acute myocardial infarction. Patients who were not in heart failure on admission and did not develop signs of heart failure within the next 5 days achieved the same Pao2 level while breathing 100% oxygen as did patients without acute myocardial infarction. Patients with pulmonary edema or cardiogenic shock had a very poor Pao2 response to oxygen inhalation. Patients in mild heart failure at the time of study and patients who developed heart failure subsequent to the study had a Pao2 response intermediate between the other two groups. This rise of Pao2 with oxygen correlated with the cardiac index and right atrial oxygen prior to inhalation of oxygen. Uncomplicated patients responded to inhalation of oxygen with a decrease of heart rate, cardiac index, stroke index, and cardiac work, and an increase of peripheral resistance. Patients in pulmonary edema or cardiogenic shock or with a low cardiac index or low Pao2 responded with only a slight increase in peripheral resistance. The Pao2 achieved while breathing oxygen appeared to determine the type of hemodynamic response to oxygen. Administration of oxygen to patients with acute myocardial infarction is useful in identifying latent heart failure and in predicting the subsequent clinical course of these patients.

Evaluation of methods of measurement and estimation of left ventricular function after acute myocardial infarction

Using multiple gated cardiac blood pool imaging and single-plane ventriculography from cardiac catheterization, 2 independent measures of left ventricular (LV) ejection fraction (EF) were determined in each of 21 patients. Patients were seen 2 to 6 weeks after their first acute myocardial infarction and were free of electrocardiographic evidence of conduction abnormalities and left or right ventricular hypertrophy. Differences between the 2 measures of LVEF were examined and then compared with the extent of myocardial necrosis estimated from the standard 12-lead electrocardiogram using the complete 54-criteria/32-point Selvester QRS scoring system. Regression analysis yielded an r value of 0.81 (SEE = 8.05) for the overall relation between the 2 measures of LVEF. Correlation coefficients of -0.70, -0.66 and -0.72 were obtained for the relations of radionuclide LVEF, catheterization LVEF and the mean of these 2 determinations, respectively, compared with QRS score. A QRS score 4 or less achieved 100% specificity and that of 8 or less 100% sensitivity for predicting an LVEF greater than 40%. Thus, the Selvester QRS scoring system may be of value in identifying patients with or without markedly impaired LVEF. This risk stratification may be important in reaching optimal postinfarction therapeutic decisions.

Correlation of Left Ventricular Ejection Time with Stroke Index in Patients with Acute Myocardial Infarction.

Excerpt The need for a simple, non-invasive technique for evaluating ventricular function in patients with acute myocardial infarction is apparent. The usefulness of the easily determined left vent...

The Value of Early Hemodynamic Measurements in the Uncomplicated Acute Myocardial Infarction.

Excerpt Forty-five patients with acute myocardial infarction and no clinical evidence of heart failure underwent hemodynamic evaluation during the first hour of admission to the hospital. Catheters...