Search PubMed⌕ Search

Biomedical subjects

R D Wiens

Publications and source records attributed to R D Wiens.

26 records · Page 2Linked to original sources
PubMed1984

Chronotropic incompetence in clinical exercise testing.

Chronotropic incompetence has been found to be an important predictor of obstructive coronary artery disease (CAD). However, few data define the normal heart rate response to progressive exercise and allow a clear definition of chronotropic incompetence. In this study, 312 patients who underwent an exercise stress test and coronary angiography were evaluated. The exercise heart rates of 140 normal subjects were used to define the normal mean heart rate at progressive work loads. Two standard deviations of the mean were chosen to represent a normal response at various levels of exercise. Analysis of the exercise heart rates in 172 patients who had CAD revealed 16 patients who had a peak exercise heart rate below 2 standard deviations of the mean. Of the 16 patients, 5 had 1-vessel, 5 had 2-vessel and 6 had 3-vessel CAD. Of 65 patients who had no significant ST-segment shift and who did not reach 85% of age-predicted heart rate, 13 (20%) had an inappropriately low heart rate for the work load performed. Each of the 13 patients had CAD. Of the 172 patients with CAD, those with chronotropic incompetence exercised further than the patients who did not have chronotropic incompetence (9.4 +/- 2.1 vs 7.0 +/- 3.4 METs, p less than 0.01). In conclusion, chronotropic incompetence is a relatively infrequent occurrence in an exercise test population; however, this finding, when present, is relatively specific for CAD, and may be useful in detecting patients with CAD who have an indeterminate exercise test.

Adult↗
PubMed1984

Left-axis deviation and adiposity: the United States Health and Nutrition Examination Survey.

The influence of body fatness on the direction of the electrocardiographic mean frontal plane QRS axis was investigated in a nationally representative population of 6,913 adults aged 25 to 74 years (the U.S. Health and Nutrition Examination Survey). Adiposity was measured as skinfold thickness and the mean frontal QRS axis was determined by computer analysis of limb lead vectors. A significant leftward shift of the mean QRS axis occurred with increasing fatness in both men and women (p less than 0.001) and was independent of age and blood pressure. However, this association was confined to the range of normal QRS axis. The prevalence of left-axis deviation (LAD) (QRS axis of -30 degrees or less) was not higher among those with greater measures of body fatness. There were no significant differences in mean age-adjusted skinfold thickness, height, weight or chest circumference between those with LAD and those with a normal QRS axis. Thus, although the direction of the mean frontal QRS axis is influenced significantly by body fatness throughout the normal QRS axis range, this association is lost as the QRS axis becomes abnormally deviated to the left. An ECG demonstrating LAD obtained from an obese person probably represents a true abnormality and not merely a reflection of adiposity.

Adult↗
PubMed1981

Preservation of the myocardium during coronary artery bypass grafting.

The influence of three methods of myocardial preservation used during coronary artery bypass grafting on operative mortality and perioperative myocardial infarction was evaluated in seven institutions participating in the Coronary Artery Surgery Study (CASS). Both operative mortality and perioperative infarctions were comparable with either normothermic and topical hypothermic myocardial preservation. The addition of potassium cardioplegia to hypothermia lowered both operative mortality and perioperative myocardial infarction (p less than 0.01 and p less than 0.001, respectively). Stepwise multivariate discriminant analysis revealed that the high-risk clinical and angiographic variables were the most important determinants of operative mortality, followed by surgical priority and the use of potassium cardioplegia. However, none of the clinical, angiographic and surgical variables other than the use of potassium cardioplegia influenced the incidence of perioperative myocardial infarction.

Adult↗
PubMed1978

Late sequelae of perioperative myocardial infarction.

The late suquelae of myocardial injury occurring at the time of direct myocardial revascularization are unknown. Fifty of 500 consecutive patients undergoing aortocoronary bypass grafting developed both electrocardiographic and enzymatic evidence of myocardial injury. They were matched with 50 patients of similar age, sex, history of previous infarction, severity of angina, degree of coronary arteriosclerosis, and level of ventricular function as determined by preoperative angiographic studies. The conduct of the operation was identical in each group except for prolongation of total cross-clamp time in those patients with myocardial injury. The total number of vessels grafted, the conduit used, and the operative mean graft flow were similar. Results of treadmill stress testing at 24 to 36 months were not significantly different between groups. Angina status, long-term survival, graft patency, and ventricular function were not adversely affected by intraoperative myocardial injury. However, postoperative ventricular function and stress test performance were related to graft patency.

Adult↗
PubMed1977

Clinical use of echocardiography: a review.

The clinical usefulness of echocardiography can be considered under a few broad categories: (a) measurement of internal structures and their changing relationships to each other throughout the cardiac cycle; (b) demonstration of abnormalities of function which are dependent on motion--for example, the prolapsing mitral leaflet or the paradoxical septal motion in right ventricular volume overload; and (c) changes within the heart such as pericardial effusion which lead to the development of echo-free spaces or the appearance of echo within a normally echo-free chamber as in myxoma.

Adolescent↗
PubMed1975

Myocardial injury and bypass grafting. Value of serum enzymes in diagnosis.

To clarify the value of serum enzymes in the detection of intraoperative and postoperative myocardial injury associated with coronary artery bypass grafting, we evaluated 70 consecutive patients (151 grafts). We used electrocardiograms and serial determinations of serum levels: serum glutamic oxaloacetic transaminase (SGOT), creatinine phosphokinase (CPK), lactic dehydrogenase (LDH), and LDH isoenzymes on Days zero, 1, 3, 5, 7, and 10. Patency of all grafts 1 week postoperatively was 92 per cent. Fourteen patients (20 per cent) had ECG evidence of acute myocardial infarction (AMI) or ischemia lasting longer than 48 hours. This incidence of AMI was attendant with no deaths or discernible changes in postoperative ventriculography. LDH-1 (cardiac fraction) was elevated in all patients with myocardial injury. Late elevation of LDH-1 occurred in 2 patients at the time of postoperative catheterization, 1 of whom had negative findings on ECG. Diagnostic correlation was not observed with total LDH, CPK, or SGOT. Predisposing factors to AMI included preinfarction angina (4 of 14 patients), occluded grafts (4 of 14), and a bypass time greater than 120 minutes.

Angina Pectoris↗