Biomedical subjects

M D Goddard

Publications and source records attributed to M D Goddard.

4 recordsLinked to original sources

PubMed1989

Sustained effect of and lack of development of tolerance to controlled-release isosorbide-5-mononitrate in chronic stable angina pectoris.

Tolerance has been shown to develop when nitrate preparations are used in such a manner as to produce plasma levels within the therapeutic range continuously over a 24-hour period. However, a period of reduced or low nitrate plasma levels of a few hours per day may limit or completely prevent tolerance development. In 18 patients with chronic stable angina pectoris, a single 60-mg daily dose of a controlled-release preparation of isosorbide-5-mononitrate (ISMN) was compared with the administration of 30 mg, 4 times daily, of immediate-release isosorbide dinitrate (ISDN) in a double-blind, randomized, placebo-controlled, crossover study. The comparisons were carried out on the first day of therapy and after 11 to 14 days of continuous therapy to assess the duration of effectiveness and the development of tolerance. On short-term therapy, both drugs produced a significant improvement in treadmill walking times to moderate angina in comparison with placebo. The values for ISMN were 87 +/- 99 seconds (23%) at 12:30 P.M., 72 +/- 91 seconds (19%) at 5 P.M. and 51 +/- 81 seconds (13%) at 8:30 P.M. For ISDN, the respective values were 71 +/- 83 seconds (19%), 89 +/- 98 seconds (24%) and 79 +/- 87 seconds (21%). There were no significant differences between drugs. Plasma nitrate levels for each drug paralleled the improvements in exercise performance.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1985

Dopamine: its potential for inducing ischemic left ventricular dysfunction.

As an agent potentially capable of inducing ischemia in patients with coronary artery disease, dopamine administered intravenously was evaluated as a pharmacologic stress agent by supine radionuclide angiography, and the results were compared with ergometer exercise. In a preliminary group of 11 subjects (4 normal subjects and 7 patients with coronary disease), dopamine alone was administered in increments of 2.5 micrograms/kg per min to a maximum of 15 micrograms/kg per min. There were significant differences between exercise and dopamine in maximal stress heart rates, 129.3 +/- 30.0 versus 88.0 +/- 35.8 beats/min (p less than 0.05) in normal subjects and 118.9 +/- 21.1 versus 87.6 +/- 22.6 beats/min (p less than 0.05) in patients with coronary disease, as well as in maximal stress rate-pressure products, 213.3 +/- 51.4 versus 155.0 +/- 52.5 mm Hg/min X 10(2) (p less than 0.02) in normal subjects and 216.0 +/- 45.6 versus 161.0 +/- 48.6 mm Hg/min X 10(2) (p less than 0.003) in patients with coronary disease. As a result, in these patients the ejection fraction response was significantly different: -3.3 +/- 4.5% with exercise versus + 6.3 +/- 4.6% with dopamine (p less than 0.05). In a second group of 41 subjects (9 normal subjects and 32 patients with coronary disease), atropine (0.6 mg) was administered intravenously before and after every second dopamine dose increment. This produced statistically similar maximal stress heart rates as compared with exercise in all subjects, rate-pressure products in normal subjects and slightly higher values with dopamine in patients with coronary disease: 200.3 +/- 47.2 versus 183.1 +/- 43.0 (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Abdominal Muscles↗

PubMed1984

Effects on ventricular function of disopyramide, procainamide and quinidine as determined by radionuclide angiography.

To evaluate the effects of the 3 commonly used antiarrhythmic agents--disopyramide, procainamide and quinidine--on left ventricular (LV) function, these 3 agents were administered in random sequence after control radionuclide angiography performed at rest and during exercise in 17 patients. Drug dosages were tailored to achieve therapeutic blood levels 5 minutes before and 2 to 3 hours after drug administration. The mean dose of disopyramide was 141 +/- 26 mg every 6 hours, procainamide, 441 +/- 100 mg every 4 hours, and quinidine, 401 +/- 101 mg of the gluconate preparation every 6 hours. The patients received the appropriate dosage for 7 or more days before repeat radionuclide angiography was performed. The ejection fraction at rest was: control 60 +/- 13%, disopyramide 55 +/- 11%, procainamide 58 +/- 11%, and quinidine 59 +/- 12%. The exercise ejection fraction was: control 61 +/- 14%, disopyramide 58 +/- 13%, procainamide 58 +/- 12% and quinidine 61 +/- 13%. In neither case, at rest nor during exercise was there any significant difference observed between any of the agents or between any individual agent and control. However, at rest 8 subjects had a 5% or more decrease from the control value with disopyramide, 5 had a 5% or more decrease with procainamide and 6 had a 5% or more decrease with quinidine, whereas during exercise the decreases were 8, 6 and 5%, respectively. These values were not statistically different but suggest that caution should be taken in administering all 3 agents, particularly to patients with impaired LV function, because individual sensitivity to a given agent may precipitate a significant decline in LV function.

Adult↗

PubMed1980

Temporary transvenous pacing and femoral vein thrombosis.

The true incidence of thrombosis and pulmonary embolism in patients requiring temporary transvenous pacing via the femoral vein in unknown. Twenty-nine patients, mean age 66.2 years (range 38-79 years) who required temporary pacing were studied by bilateral contrast venography and perfusion lung scanning after removal of the pacing catheter. The patients were subdivided into two subgroups based on hemodynamic status. There was no statistical difference between the two groups with respect to mean age or the time the pacer catheter was in place and all patients were placed on low-dose heparin therapy. Ten patients (34%) had venographic evidence of thrombosis; six of them (60%) showed lung scan evidence of pulmonary emboli. The hemodynamically compromised group consisted of seven patients, six (85%) of whom had thrombosis; three of these six (50%) had pulmonary emboli. Of the 22 patients in the hemodynamically stable group, four (18%) had thrombosis and two of these (50%) had pulmonary emboli. Venous thrombosis, with subsequent pulmonary emboli, is a serious complication of temporary transvenous pacing using the femoral approach, despite the use of prophylactic low-dose heparin.

Adult↗