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Biomedical subjects

J C O'Keefe

Publications and source records attributed to J C O'Keefe.

10 recordsLinked to original sources
PubMed1987

Efficacy of nisoldipine combined with beta-adrenergic-blocking drugs in the treatment of chronic stable angina.

A double-blind, placebo-controlled study was performed to assess whether a new calcium antagonist, nisoldipine, in doses of either 5 mg or 10 mg daily, in combination with beta-adrenergic-blocking drugs (combination therapy) was more effective than beta-adrenergic-blocking drugs alone (single therapy) in the treatment of chronic stable angina. Treatments were assessed at two-week intervals, using exercise electrocardiography and patients' anginal diaries. A significant improvement in exercise capacity and reduction in anginal attacks occurred only during nisoldipine (10 mg daily) combination therapy compared with single therapy. Mean exercise time increased from 419 +/- 146 s (single) to 454 +/- 158 s (p less than 0.02) after combination therapy. Exercise time to onset of 1 mm ST-segment depression improved from 326 +/- 145 s (single) to 331 +/- 139 s after combination therapy, although the change was not significant. Mean number of anginal attacks decreased from 21 +/- 22 (single to 15 +/- 19 (p less than 0.01) during combination treatment, with an associated significant reduction in glyceryl trinitrate consumption. Adverse effects during combined therapy were minor and tolerable. Thus patients limited by exertional angina despite beta-adrenergic-blocking drugs may obtain supplemental relief of angina and myocardial ischemia with the addition of nisoldipine in a dose of 10 mg daily.

Adrenergic beta-Antagonists↗
PubMed1987

Effects of nisoldipine on left ventricular function during exercise or cold pressor stress.

The effects of a single oral dose of nisoldipine, 10 mg, were investigated in two groups of patients. Firstly, the effects of nisoldipine on exercise left ventricular function were assessed in 20 patients with chronic stable angina and coronary disease. Secondly, the effects of nisoldipine on the left ventricular response to cold pressor stimulation were examined in 12 patients with normal coronary arteries, who presented with typical ischaemic chest pain and abnormal exercise tests. All studies were performed using first pass radionuclide angiography and the new short half-life radiopharmaceutical, gold-195m. In patients with coronary disease, mean exercise time improved after nisoldipine (P less than 0.01). Both at the identical workload to that before treatment, and at a new peak workload, mean exercise left ventricular ejection fraction (LVEF) improved significantly after nisoldipine (P less than 0.01 and P less than 0.05 vs pretreatment levels, respectively). At the identical workload to that before treatment, 10 of 16 patients, who had initially developed angina, did not develop angina after nisoldipine, and 23 of 46 exercise-induced regional left ventricular abnormalities had normalized. In the patients with normal coronary arteries undergoing cold pressor stimulation, imaging was carried out at rest, and after 1 and 2.5 minutes of cold stimulation, before and one hour after oral nisoldipine. LVEF fell significantly during cold stimulation before nisoldipine administration, with 10 of the 12 patients showing an abnormal response. Nisoldipine did not lead to any attenuation of the heart rate and blood pressure response to cold, but mean LVEF did not fall at any cold pressor stage and only three patients showed an abnormal response.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

The adequacy of radioisotope mixing from bolus injections in first-pass radionuclide angiographic assessment of right ventricular function: a study using gold-195m.

The adequacy of radioisotopic mixing in first-pass radionuclide studies of right ventricular function was assessed in 27 patients using multiple injections of gold-195m (half-life 30.5 sec). A theoretical disadvantage of the first-pass technique is inadequate mixing of the injected bolus with blood prior to entry into the right ventricle. Since the calculation of ejection fraction is based on the assumption of complete mixing, this would lead to errors. In order to assess the effects of bolus injection rates and bolus duration on the calculation of right ventricular ejection fraction, multiple, rapid, sequential studies were performed using gold-195m at four bolus injection rates (10, 5, 2 and 1 ml/sec). Slowing the injection rate caused a significant increase in bolus duration, and a significant increase in the number of cardiac cycles available for analysis. Mean ejection fraction, however, was not significantly changed. There was good correlation between right ventricular ejection fraction at all injection rates when compared to 10 ml/sec, and no injection rate led to a consistent over or underestimate of right ventricular ejection fraction. There was no significant relationship between change in bolus duration and variation in ejection fraction. These data indicate that mixing is adequate for first-pass studies of right ventricular function using a rapid bolus.

Cardiac Output↗
PubMed1986

Efficacy of incremental doses of tiapamil on exercise performance in patients with chronic stable angina pectoris.

Ten patients with chronic stable angina were treated with 4 incremental doses of tiapamil (200 mg, 400 mg, 600 mg and 800 mg) in a double-blind, placebo-controlled study. Treadmill exercise electrocardiograms were performed before and after single oral doses of tiapamil. A dose-dependent increase in exercise duration occurred after tiapamil with significant improvement after tiapamil 600 mg and 800 mg. Mean exercise duration increased from 327 +/- 41 seconds (control) to 399 +/- 49 seconds (P less than 0.01) after tiapamil 600 mg and from 314 +/- 39 seconds (control) to 416 +/- 49 seconds after tiapamil 800 mg, P less than 0.001. There was an associated improvement in mean exercise time to onset of 1 mm ST-segment depression from 240 +/- 41 seconds (control) to 300 +/- 48 seconds in 10 patients after tiapamil 600 mg, (P less than 0.02) and from 206 +/- 35 seconds (control) to 272 +/- 51 seconds in 9 patients after tiapamil 800 mg, P less than 0.01. Two patients were free of angina and 1 patient normalized his ST-segments after tiapamil 800 mg. Dose-dependent side-effects were mild and tolerable. Tiapamil is safe and highly effective in improving exercise tolerance and relieving myocardial ischaemia in patients with chronic stable angina.

Adult↗
PubMed1986

Relation between coronary anatomy and serial changes in left ventricular function on exercise: a study using first pass radionuclide angiography with gold-195m.

Serial changes in left ventricular function on exercise were assessed by first pass radionuclide angiography with gold-195m (half life 30.5 s) in 25 men with known coronary anatomy. In the seven patients with three vessel disease, abnormalities of global left ventricular function and regional wall motion occurred earlier during exercise, were of greater extent at peak exercise, and persisted longer after exercise than in the 11 patients with one and two vessel disease or the seven with normal coronary arteries. Although there were significant differences between the groups in absolute change in ejection fraction and the rate of change in ejection fraction related to exercise duration and heart rate, a considerable overlap of values between groups precluded the accurate prediction of coronary anatomy in individuals. These data suggest that the amount of myocardium at risk from ischaemia in some patients with one and two vessel disease may resemble that in patients with three vessel disease. This study shows that an anatomical classification based solely on the number of diseased vessels will not predict the extent of the impairment of left ventricular function on exercise.

Blood Pressure↗
PubMed1985

Ventricular arrhythmias complicating weight reduction therapy in a patient with a prolonged QT interval.

Serious ventricular arrhythmias are known to occur in patients with long QT intervals. We describe a case of torsade de pointes occurring in a patient with a prolonged QT interval while taking a 1000 calorie diet, diethylpropion hydrochloride (Tenuate Dospan) and bendrofluazide. In patients with long QT intervals, hypokalaemia and drugs which further delay repolarization may facilitate the development of life threatening arrhythmias.

Adult↗
PubMed1982

Acromegaly and the heart--echocardiographic and nuclear imaging studies.

Left ventricular mass (LV mass) and function were assessed in 16 acromegalic patients by echocardiography, and rest and exercise gated blood pool scanning (GBPS) respectively. At the time of study, five patients had active acromegaly, five were hypertensive and three had coexisting coronary artery disease. Increased LV mass was found in six (38%) patients, of whom four were hypertensive and two others had active acromegaly of long duration. One normotensive patient, who did not have coronary disease, had increased LV mass associated with persistently elevated growth hormone (GH) levels for the previous 11 years. Abnormal LV function, as detected by GBPS, occurred only in the three patients with coronary disease. Thus, acromegaly is associated with increased LV mass in hypertensive patients and normotensive patients who have prolonged elevation of GH levels prior to adequate treatment. We found no detectable impairment of LV function, at rest or exercise unless other cardiac disease was present.

Acromegaly↗