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Biomedical subjects

G C Timmis

Publications and source records attributed to G C Timmis.

At least 91 records · Page 5Linked to original sources
PubMed1982

Percutaneous intraaortic balloon counterpulsation. Clinical effectiveness and hazards.

Because of its greater ease and rapidity of insertion, the percutaneous intraaortic balloon in many institutions has become the primary method for implementing counterpulsation. We report the results and complications of 113 attempted procedures in a variety of clinical settings. We had a high (93.8 percent) insertion success rate. However, our 18.6 complication rate was similar to the experience reported for the surgical method of insertion. Thus, the original anticipation of reduced complications with this method has not been realized in this and other recent reports.

Adult↗
PubMed1981

Medical management of ischemic heart disease.

Medical therapy primarily affects myocardial oxygen demands. Nitrates and other vasodilators decrease filling pressure, ventricular diastolic volume and to some extent, impedance to ventricular emptying. Beta blockers decrease myocardial contractility and heart rate through a reduction of sympathetic neural traffic. Afterload reduction by the control of hypertension and preload reduction via the LaPlace relationship through reversal of congestive failure are critical for successful therapy. Modification of smoking habits and personality traits with renunciation of a sedentary life-style are also therapeutically useful. While increases in myocardial blood flow have depended primarily on surgical revascularization procedures, calcium antagonists such as nifedipine have been shown to affect flow by reversing vasospasm, which has been recognized with increasing frequency as a concomitant of even fixed coronary arterial disease. The first therapy, however, is diet since it affects both the supply and demand sides of myocardial oxygen balance. Reduction of body bulk decreases myocardial oxygen demand since both vary in obligate parallel. Religious abstention from saturated fats and cholesterol-containing foods, especially by those with pre-existing coronary heart disease, may arrest the otherwise inexorable deterioration.

Humans↗
PubMed1979

Limitations of exercise testing in critical left coronary artery disease.

Exercise testing was evaluated in 51 patients with critical left coronary artery disease (LCA) documented by coronary arteriography within two weeks of their bicycle ergometer (26 patients) or treadmill (25 patients) electrocardiographic study. Adequate tests, as defined by the patient having reached 85% of predicted maximum heart rate, were achieved in only 16 patients on the ergometer (62%) and in 21 (84%) on the treadmill. Nevertheless mean maximum double product (220 vs 232) and mean exercise time (4.6 min vs 5.0 min.) were similar (p:NS). The sensitivity for ergometry and treadmill testing was 75 and 62% respectively. If however we include those negative studies in which for various reasons patients were unable to achieve 85% of their predicted maximal heart rate (i.e., inadequate studies), sensitivity was only 46 and 52% respectively. Thus a sizable group of patients with critical LCA disease cannot adequately perform exercise tests especially on the ergometer; and over half of all such patients studied will be found for one reason or another to respond negatively, regardless of exercise protocol.

Blood Pressure↗
PubMed1979

Corrected transposition of great vessels and Ebstein's anomaly of tricuspid valve. Echocardiographic findings.

A case is reported concerning echocardiographic findings in a patient with congenital corrected transposition of the great vessels and Ebstein's anomaly of the tricuspid valve. This presented an unusual opportunity to study atrioventricular valve closure in a patient in whom the Ebstein's malformation involved the systemic atrioventricular valve. The mitral to tricuspid valve closure interval was 68 milliseconds and represented significant delay in tricuspid valve closure. This closure interval is similar to closure intervals previously reported for patients with Ebstein's anomaly without ventricular inversion.

Ebstein Anomaly↗
PubMed1976

Reassessment of Q waves in left bundle branch block.

This study disputes a number of recent reports claiming that abnormal Q waves or a QS configuration in inferior leads (II, III and AVF) coexisting with left bundle branch block is highly suggestive of, and indeed specific for, myocardial infarction. Five patients reported herein demonstrate disappearance of Q waves in inferior leads on spontaneous reversal of LBBB to normal conduction. This necessitates the conclusion that these Q waves represent a postdivisional conduction variant most closely equivalent to left anterior fascicular block coexisting with predivisional LBBB. Absence of inferior R waves in the five patients demonstrating LBBB is explicable by as little as a 20 msec conduction delay in the posterior fascicle coexisting with a higher grade conduction defect in the anterior fascicle. It is concluded that LBBB with a QS configuration in II, III and AVF cannot be considered diagnostic of inferior wall infarction since it regularly results from impaired conduction of the left anterior and possibly the left posterior fascicle (to a lesser extent), which may be reversible.

Aged↗
PubMed1975

The basis for differences in ethanol-induced myocardial depression in normal subjects.

The acute effects of ethanol (ETOH) on cardiac function in 32 normal subjects has been studied utilizing systolic time intervals. Seven (group I) 13 (group II), and 12 subjects (group III), reported an average daily consumption of less than 1 oz, 1-2 oz, and more than 2 oz of ETOH, respectively. Progressively higher control values from group I to group III in PEP, PEPI, ICT and PET/LVET were observed (PEP-I vs PEPI-III: P smaller than 0.05; PEP/LVET-I vs PEP/LVET-II and PEP/LVET-III: P smaller than 0.05). There was progressively less change in these variables following acute ETOH (P smaller than 0.02-0.05 in group I; P equals NS in group III, group II intermediate). This indicates some degree of chronic myocardial impairment in group II and especially in group III, which tends to be proportionate to the degree of chronic ETOH exposure. These data are not necessarily disparate with previous reports of little or even a salutary hemodynamic effect of ETOH in normal subjects. Thus, the relative stability of LVET post ETOH, coupled with the observed increase in heart rate, is consistent with previous reports of ETOH-induced rate-dependent increments in cardiac output with unchanging stroke volumes, in spite of the presence of acute myocardial depression. The observations reported herein demonstrate the probable incremental influence of ETOH consumption in a chain of events which may culminate in alcoholic cardiomyopathy.

Adult↗