Effects of disopyramide on left ventricular function: assessment by radionuclide cineangiography.

To determine the effects of disopyramide on resting systolic left ventricular (LV) function and LV functional reserve, gated equilibrium radionuclide cineangiography was performed at rest and during maximal symptom-limited supine bicycle exercise in 12 patients after a single 300 mg oral loading dose of disopyramide, and in 22 patients (including the 12 patients just mentioned) after they received disopyramide 150 mg 4 times daily for 5 to 10 days (average 7). The oral loading dose (average serum level 3.6 +/- 1.3 micrograms/ml [standard deviation] produced decreases in ejection fraction in 9 of 12 patients with a decrease in average resting ejection fraction from 40 +/- 15% to 33 +/- 11% (p less than 0.005). However, the lower, sustained dosage of disopyramide was associated with a lower average serum level of 2.5 +/- 0.8 micrograms/ml and with smaller but significant decreases in ejection fraction in 3 of 22 patients during exercise only. At this dosage there was no significant decrease in average ejection fraction for the group at rest or during exercise. Adverse effects of disopyramide on ejection fraction occurred even in patients with previously normal LV function at rest. Hence, disopyramide may be associated with significant decreases in LV systolic function, particularly when given in high, oral "loading" doses. However, sustained therapy with lower dosages as well as lower drug levels is also associated with less depression of LV function.

Small cell lung cancer: radionuclide bone scans for assessment of tumor extent and response.

Radionuclide bone scans were performed before and during combination chemotherapy in 119 systematically staged patients with small cell carcinoma of the lung. Before therapy, 49 patients (41%) had positive scans. Scan positivity was significantly associated with the presence of metastatic tumor in the bone marrow, positive skeletal radiographs, and elevated serum alkaline phosphatase levels. Nonosseous distant metastases were significantly more likely to be detected as the number of areas of focal abnormalities on bone scan increased. The survival of patients with documented distant metastases in bone and nonosseous sites was significantly inferior to the survival of patients with limited disease, isolated osseous extensive disease, and extensive disease occurring only in nonbony sites. Of 36 patients with initially abnormal scans and tumor regression documented by other methods, scan findings improved in 24 (67%). In 26 (36%) of 72 scans in patients demonstrating disease progression in extraosseous sites, new areas of increased radionuclide uptake appeared. Improvement or worsening in follow-up scans was associated with nonbony tumor response or progression, respectively, 70% of the time. Serial bone scans provide reasonably accurate staging and prognostic information in patients with small cell lung cancer, although they are probably not sufficiently reliable to be used as the sole parameter in therapeutic decision-making.

Radionuclide angiographic assessment of left ventricular function during exercise in patients with a severely reduced ejection fraction.

To study the effect of exercise on left ventricular ejection fraction in patients with congestive cardiomyopathy and the relation of the response to the origin of the myocardial dysfunction, 30 patients with a severely reduced ejection fraction (30 percent or less) were evaluated with radionuclide angiography. Group I consisted of 16 patients with ischemic cardiomyopathy and a mean (+/- standard deviation) resting ejection fraction of 22.3 +/- 6.1 percent. Group II was composed of 14 patients with primary cardiomyopathy and a mean resting ejection fraction of 19.3 +/- 4.7 percent. The mean age, left ventricular end-diastolic pressure, cardiac index and resting left ventricular ejection fraction of Groups I and II were similar; however, the change in the ejection fraction during similar levels of exercise differed significantly. The mean exercise ejection fraction decreased to 16.7 +/- 6.8 percent in Group I, but increased to 24.6 +/- 6.4 percent in Group II (p less than 0.001). Thus, exercise usually results in a directionally opposite change in left ventricular ejection fraction depending on the origin of the congestive cardiomyopathy.