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Biomedical subjects

D D Waters

Publications and source records attributed to D D Waters.

At least 145 records · Page 8Linked to original sources
PubMed1979

Coronary artery spasm during exercise in patients with variant angina.

Seven patients with typical variant angina without coronary stenoses greater than 50% developed angina and ST-segment elevation during treadmill exercise testing. In all cases the ST-segment elevation occurred in the same leads during exercise testing as during spontaneous attacks at rest. Five of the patients had developed spontaneous coronary spasm during coronary arteriography, in each case in the artery corresponding to the site of ST-segment elevation. In five patients, thallium was injected during the exercise test during which angina and ST-segment elevation occurred. In each case, a large perfusion defect not present at rest was found in the zone corresponding to the site of ST-segment elevation. These findings suggest that coronary artery spasm may occur during exercise in patients with variant angina.

Adult↗
PubMed1979

Left main coronary artery stenosis in young patients.

Among 1,041 patients less than 45 years old who underwent coronary arteriography from 1972 to 1977, left main coronary stenosis greater than or equal to 50 percent was present in 31 men (3.4 percent) and in 10 women (7.2 percent, P less than 0.05). The degree of stenosis did not correlate with the duration of symptoms, the severity of angina, the presence of a previous myocardial infarction, nor with the number of risk factors. The clinical and angiographic features in young men did not seem to differ from those described in unselected populations; however, in young women, left main coronary stenosis was often an isolated lesion associated with a short duration of symptoms, a high prevalence of hypertension, no previous myocardial infarction, and a normal ventriculogram, suggesting the possibility that a different pathophysiologic mechanism might be involved. Two deaths occurred at angiography (4.9 percent). Thirty patients underwent coronary artery bypass surgery, with one operative death and one late death; good functional results were obtained, and 21 out of 28 survivors (75 percent) were asymptomatic after a mean follow-up of 29 months.

Adult↗
PubMed1978

Coronary artery disease in young women: clinical and angiographic features and correlation with risk factors.

Coronary arteriography was performed because of suspected coronary disease in 239 women less than 45 years of age. Normal coronary arteries were found in 112 women, and a further 23 had insignificant stenosis (less than 50 percent narrowing of luminal diameter). Of the remaining 104 women, 56 had one vessel, 22 two vessel and 26 three vessel disease. Hyperlipidemia, hypertension, diabetes, smoking and a family history of coronary disease were significantly more frequent in women with significant stenosis than in women with normal arteries. Significant coronary disease was found in 55 percent (100 of 182) of women with more than two risk factors but in only 7 percent (4 of 57) of those with less than two risk factors (P less than 0.0001). Evaluation of symptoms and the resting electrocardiogram also discriminated between women with and without coronary disease, but exercise testing was of little value. Only 4 of the 46 women with previous myocardial infarction had normal or near-normal coronary arteries. Among women with segmental wall motion abnormalities on ventriculography, the site was anterior in 90 percent (19 of 21) of women who used oral contraceptive drugs but in only 60 percent (21 of 35) of nonusers (P less than 0.05). However, in most respects, coronary artery disease in young women does not appear to differ from coronary disease in other patients.

Adult↗
PubMed1978

Hospital treatment of congestive heart failure. Management according to hemodynamic profile.

Selection of therapy for subjects with acute congestive dardiac failure usually involves a choice among a diuretic, a vasodilator and an inotropic agent. Three principal questions are involved in the decision: (1) Is cardiac out normal or depressed? (2) Is blood pressure normal or depressed? (3) is regional myocardial ischemia present? Diuretics are safe and easy to administer, but they do not increase cardiac output or relieve hypoperfusion. Inotropic agents increase cardiac output but differ widely in their effects on blood pressure: selection of specific agents is influenced by their blood pressure effect. All inotropic agents, however, potentially aggravate regional myocardial ischemia. In ischemic heart failure, therefore, vasodilators which also increase cardiac output, may be chosen. Vasodilator administration is in turn limited by the decrease in arterial pressure which accompanies increasing infusion rate. When these three questions are considered in combination, an effective therapeutic regimen can be identified. Thus, congestion without hypoperfusion requires a diuretic if blood pressure is normal; and a vasodilator when blood pressure is increased. In the presence of congestion with hypoperfusion, a vasodilator is employed if blood pressure is normal; and a positive inotropic drug when blood pressure is depressed.

Blood Pressure↗
PubMed1978

Prediction of multivessel disease after inferior myocardial infarction.

We correlated clinical parameters with angiographic findings in 108 men with a previous isolated inferior myocardial infarction, to determine if these parameters could predict accurately which patients had multivessel disease. Of 71 men in angina class 2-3, 42 had three vessel disease versus only seven of the 37 who were either asymptomatic or angina class 1 (P less than 0.001). Multivessel disease was present in 35 of the 36 who had anterior ST-T abnormalities at rest (P less than 0.001) and 16 of the 17 with cardiomegaly. Among men 55 years and older, the incidence of multivessel disease was 94% compared to 70% in men less than 55 (P less than 0.03). We conclude that functional angina class, age, and the presence of resting anterior ST and T abnormalities are highly predictive of associated left system disease in survivors of inferior infarction.

Angina Pectoris↗
PubMed1978

Myocardial ischemia: detection and quantitation.

Myocardial ischemia at rest occurs only late in the course of coronary artery disease, but transient ischemia can often be induced by increasing myocardial oxygen demand with exercise or atrial pacing. Myocardial ischemia causes a series of physiologic abnormalities that can be detected by assessment of myocardial perfusion, regional mechanical function, electrophysiology, and metabolism. Methods of assessment vary widely in sensitivity, specificity, cost, and ease of application. Although the appropriate choice of diagnostic test may be difficult, the morbidity and mortality that result from myocardial ischemia and infarction and the demonstrated potential of coronary artery bypass surgery to reverse myocardial ischemia before the development of permanent sequellae make the detection of ischemia an important clinical problem. Present methods for quantitating myocardial ischemia are imprecise and difficult to apply but have been used successfully to evaluate the efficacy of therapies designed to reduce the size of myocardial infarction.

Animals↗
PubMed1977

Early changes in regional and global left ventricular function induced by graded reductions in regional coronary perfusion.

To determine the sequence of changes in segmental myocardial function, regional lactate metabolism and global left ventricular function induced by mild regional ischemia, blood flow in the left anterior descending coronary artery of 10 dogs was reduced by 10 percent decrements with use of a screw clamp. At each level of flow, segmental mechanical function and regional metabolism were assessed, the former with use of a mercury-in-Silastic length gauge and the latter with transmyocardial lactate balance measurements obtained with sampling from the anterior interventricular vein. Coronary arterial flow at the onset of regional lactate production was 48 +/- 4 percent (mean +/- standard error of the mean) of the control value. The onset of segmental mechanical dysfunction coincided with the onset of lactate production. Epicardial S-T segment abnormalities over the ischemic zone usually could not be detected until coronary flow was further reduced. After the onset of regional ischemia there was a linear correlation between coronary arterial flow and regional lactate production. At the onset of mild regional ischemia, defined as the onset of regional lactate production, no significant or directionally consistent changes were noted in standard measurements of global left ventricular performance, including heart rate, mean aortic pressure, left ventricular end-diastolic pressure, cardiac output, stroke volume, stroke work and peak positive dP/dt (maximal rate of rise of pressure). However, peak negative dP/dt (maximal rate of pressure decrease) decreased from 99 +/- 2 to 89 +/- 3 percent of the control value (P less than 0.0005) coincident with the onset of ischemia. It is hypothesized that dyssynchronous wall motion in the ischemic zone during isometric relaxation accounts for this decrease in peak negative dP/dt.

Animals↗
PubMed1977

Contrasting influences of alterations in ventricular preload and afterload upon systemic hemodynamics, function, and metabolism of ischemic myocardium.

This study of anesthetized, open-chest dogs compares the effects of primary increases in left ventricular preload and afterload upon global and regional myocardial function and metabolism in the presence of a left anterior descending coronary artery stenosis (LAD). When LAD flow was reduced to 40-50% of control, regional systolic shortening declined by 20 to 25% and regional lactate extraction changed to production. In seven control dogs the mechanical abnormalities persisted during the 30 min of observation, but lactate production was reduced spontaneously. In ten dogs, increases in left ventricular end-diastolic pressure (LVEDP) during dextran infusion were associated with increases in cardiac output and regional systolic shortening; however, regional lactate production also increased (P less than 0.05) despite an augmentation in LAD flow. In seven dogs mean arterial pressure increased by an average of 32 mm Hg during angiotensin infusion (0.2 to 0.4 mug/kg/min); LVEDP did not change but cardiac output decreased significantly. LAD artery flow improved markedly and lactate production shifted to extraction (P less than 0.05) while systolic shortening remained unchanged. When angiotensin was discontinued, lactate extraction worsened again. Thus, in the presence of a severe coronary stenosis, a primary increase in preload improves cardiac output but at the expense of aggravated ischemia. In contrast, a primary increase in afterload reduces cardiac output but may improve perfusion and lactate uptake of the ischemic myocardium.

Angiotensin II↗
PubMed1977

Detection of myocardial ischemia.

Myocardial ischemia causes a series of anatomic and physiologic abnormalities that can be detected and quantified by assessment of myocardial perfusion, mechanical function, electrophysiology, and metabolism. These methods of assessment vary widely in sensitivity, specificity, relevance, cost, and ease of application. Although occasionally the appropriate choice of diagnostic procedures is clinically difficult, the demonstrated potential of coronary artery bypass surgery to reverse both acute and chronic myocardial ischemia makes the detection of ischemia an important effort in the care of patients with coronary artery disease.

Coronary Angiography↗
PubMed1975

Cardiac features of an unusual X-linked humeroperoneal neuromuscular disease.

To characterize an unusual, sex-linked recessive neuromuscular disease, we studied two families with 37 males who had involvement of distal leg and proximal arm muscle groups. Electromyography and muscle biopsy in five subjects showed features of both neuropathy and myopathy. Bradycardia and syncope in 15 involved subjects were associated with early death (before the age of 50 years). Electrocardiograms in 15 others showed a spectrum of atrial abnormalities that ranged from abnormal P waves to permanent atrial paralysis and from first-degree atrioventricular block to complete heart block. No patient exhibited clinical muscle disease without electrocardiographic atrial disease. Dilated, hypertrophied left ventricles with normal indexes of function were found in three cases with permanent atrial paralysis and chronic junctional bradycardia. Cardiomegaly and cardiac failure were not present in the other cases. We conclude that permanent ventricular pacing (instituted four patients) is indicated in many of these patients to prevent serious sequelae.

Adult↗