Charles E. Bemis

Right ventricular infarction complicated by right to left shunt

A case of right ventricular infarction complicated by a right to left shunt through a patent foramen ovale is presented. The diagnosis was confirmed by two-dimensional echocardiography with contrast injection and indicator dye-dilution curve and oximetry at cardiac catheterization.

Left ventricular end-systolic pressure-volume relation. A combined radionuclide and hemodynamic study.

Abstract This study examines the effect of increasing heart rate by atrial pacing on the left ventricular endsystolic pressure-volume relation and determines whether peak pressure can be used instead of end-systolic pressure. Measurements were made of cardiac output (by thermodilution), pulmonary arterial pressure, ejection fraction (by radionuclide angiography), and aortic pressure (by intraarterial catheter). End-systolic pressure was measured at the dicrotic notch. The end-diastolic and end-systolic volumes were determined from the ejection fraction and cardiac output. There was excellent correlation in pressure-volume relation determined by peak pressure and end-systolic pressure (r = 0.95). In 8 normal subjects there was

Ventricular systolic and diastolic impairment during pacing-induced myocardial ischemia in coronary artery disease: Simultaneous hemodynamic, electrocardiographic, and radionuclide angiographic evaluation

This study examined the impairment in systolic and diastolic performance of both ventricles during pacing-induced myocardial ischemia in 12 men with coronary artery disease. Simultaneous hemodynamic, ECG, and radionuclide angiographic assessments were made: pre pacing (pre-P); intermediate pacing (P-1); maximum pacing (P-2); and immediately after pacing (post pacing (P-P). The prepacing measurements were made with the patient in the supine position and during leg elevation. Pacing produced a leftward and upward shift in the diastolic pressure-volume relation, a progressive decrease in left ventricular (LV) end-diastolic volume (p less than 0.003) and right ventricular (RV) end-diastolic volume (p less than 0.01), concomitant with an increase in the pulmonary artery wedge pressure (p less than 0.004) and the right atrial pressure (p less than 0.04). The shift in the LV pressure-volume relation was associated with an initial increase (P-1), followed by a decrease (P-2) in the peak filling rate (p less than 0.001). Pacing also resulted in systolic dysfunction: abnormal LV ejection fraction responses in eight patients, LV regional wall motion abnormalities in eight patients, and abnormal RV ejection fraction responses in seven patients. Leg elevation resulted in a 7% increase in cardiac output, a 20% increase in RV end-diastolic volume, a 28% increase in right atrial pressure, a 29% increase in pulmonary artery wedge pressure, and a 10% increase in LV end-diastolic volume (p less than 0.05). Thus, the ischemic response to pacing results in systolic and diastolic LV and RV dysfunction, with the diastolic impairment being more frequent than the systolic impairment.

Correlation between changes in R wave amplitude and left ventricular volume induced by rapid atrial pacing

To examine the Brody effect in humans, we studied 15 patients by means of coronary sinus pacing. We measured left ventricular (LV) volumes from the cardiac output (measured by the thermodilution technique) and LV ejection fraction (measured by radionuclide ventriculography). Pulmonary blood volume was determined by means of cardiac output and mean pulmonary transit time. In six patients, pacing was performed at two different rates, resulting in 21 pacing measurements. The heart rate increased with pacing from 73 +/- 11 to 119 +/- 19 bpm (mean +/- standard deviation, p less than 0.001). The end-diastolic volume (EDV) and the end-systolic volume (ESV) decreased with pacing (p less than 0.001 each). The R wave amplitude decreased with pacing (1.44 +/- 0.63 mV control vs 1.32 +/- 0.58 mV with pacing; p less than 0.01). R wave amplitude decreased in 19 of the 21 pacing studies (90%); EDV and ESV decreased in all 21 pacing studies, and pulmonary blood volume decreased in 14 of the 15 pacing studies (93%) performed in 11 patients. There was a significant correlation between the percentage of change in R wave amplitude with the percentage of change in EDV (r = 0.54, p less than 0.01) and with the percentage of change in ESV (r = 0.54, p less than 0.01). These results, therefore, validate Brodys hypothesis and indicate that changes in LV volumes affect the R wave amplitude.

Forward ejection fraction: A new index of left ventricular function in mitral regurgitation

Previous studies have shown that a normal LVEF is not a reliable index of LV function in MR. We hypothesized that the forward EF, which is the forward stroke volume (measured by Fick or thermodilution) divided by end-diastolic volume (measured by contrast ventriculography) may be a useful index of LV function, since it represents LV emptying into the aorta. This index was examined in 54 patients with chronic MR who had normal EF (greater than or equal to 50%). There were significant correlations between the forward EF and the end-diastolic volume index (r = -0.69, p less than 0.001), end-systolic volume index (r = -0.64, p less than 0.001), cardiac index (r = 0.43, p less than 0.01), and the ratio of systolic pressure-to-end-systolic volume (r = 0.65, p less than 0.001). Patients were divided into two groups according to the forward EF: group I (n = 34) had forward EF less than or equal to 35%; and group II (n = 20) had forward EF greater than 35%. Of the 32 patients who subsequently underwent mitral valve replacement, 24 patients were in group I and eight patients were in group II. At a mean follow-up of 35 months, four patients died; all of them were in group I. Improvement in functional class occurred in 75% of surgical survivors (80% in group I and 63% in group II, p = NS). These preliminary data suggest that forward EF may be a useful index of LV performance in patients with MR who have normal EF.

Effect of collateral vessels on prognosis in patients with one vessel coronary artery disease

The prognostic implications of coronary collateral channels were examined in 359 medically treated patients with one vessel coronary artery disease and a normal left ventricular ejection fraction (greater than or equal to 50%). There were 149 patients with isolated left anterior descending coronary artery disease (group I) and 210 patients with isolated left circumflex or right coronary artery disease (group II). Collateral channels were present in 68 patients (46%) in group I and 115 patients (55%) in group II. During a follow-up period of up to 82 months (mean +/- SD 34 +/- 18), there were 23 cardiac events (4 patients died of cardiac causes and 19 patients had a nonfatal acute myocardial infarction). Actuarial survival analysis showed that the risk of cardiac events was not related to the presence of collateral channels in the two groups. Thus, the risk of cardiac events is not related to the presence or absence of collateral channels in patients with one vessel coronary artery disease. Further, the risks of cardiac death (0.3%/yr) and nonfatal myocardial infarction (1.9%/yr) are very low in medically treated patients with one vessel coronary artery disease and a normal left ventricular ejection fraction.

Relation of body habitus to the severity of mitral stenosis in women.

Abstract Wood described wasting and lean body weight in patients with severe mitral stenosis (MS) who had congestive heart failure.1,2 Cardiac cachexia has been attributed to the catabolic effect of congestive heart failure and to the increased work of breathing.3 This report examines the relation between body habitus and the severity of MS in 79 women.