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Biomedical subjects

E J Swanick

Publications and source records attributed to E J Swanick.

5 recordsLinked to original sources
PubMed1977

Improved ECG monitoring during cardiac catheterization using radiotransparent electrodes and chest leads.

Improved electrocardiographic monitoring during cardiac catheterization and angiography is achieved when precordial leads can be used and base line wander and muscle artifact are eliminated or reduced. This can be realized with the use of radiotransparent gold electrodes applied to the chest in C1 and C6 locations. Radiotransparency of the electrodes enables them to be situated on the chest wall throughout the diagnostic procedures without interfering with the radiographic image. The electrical stability of gold helps to eliminate base line drift; the precordial location is less subject to movement and muscle artifact and less restricting for the patient. The electrodes are made from gold film vacuum-deposited on 2 mil mylar with a copper wire five-thousandths of an inch in diameter mounted between two layers of plastic tape. The benefits of this arrangement have been observed in a series of ten patients undergoing cardiac catheterization.

Cardiac Catheterization↗
PubMed1976

Electrocardiographic changes in precordial leads during selective coronary angiography.

Precordial electrocardiographic leads V1, V2, V5, V6, and limb leads I and II were recorded simultaneously utilizing radio transparent electrodes and wire leads during coronary angiography in 35 patients with obstructive coronary disease and in 17 subjects with normal coronary angiograms. The pattern of electrocardiographic changes produced by injection of contrast material into either the right or left coronary artery was similar in both groups of patients. During injections into the left coronary artery a leftward shift of the QRS occurred. Injections into the right coronary artery also produced a leftward shift of depolarization forces but, in addition, the QRS became inferiorly directed more consistently than during left coronary injections. The changes produced by angiography in the pattern of repolarization consisted of a marked increase in T wave amplitude and the transient appearance of large U waves. The changes in T waves were consistently opposite in direction to those of the QRS. The polarity of the U wave coincided with that of the T wave in the majority of cases. No consistent differences in the pattern of electrocardiographic changes were observed in subjects with a dominant right coronary artery from those with a dominant left system nor in subjects with normal coronaries from those with occlusive coronary disease.

Angiography↗
PubMed1976

Effects of exercise on coronary collateralization--angiographic studies of six patients in a supervised exercise program.

The existence of coronary collaterals in man and a positive correlation of their extent with the degree of coronary artery obstruction has been shown. The theory that functional collateralization associated with coronary occlusive disease is a response to local hypoxia is widely advocated. It was theorized here that coronary heart disease patients might enhance coronary collateralization through exercise-induced myocardial hypoxia. This pilot study was carried out to test the specificity of coronary arteriography for measuring changes in collateralization after a period of exercise training. Reports of follow-up examinations 7 years after program termination are also included. Six volunteer, male subjects--3 months to 3 years post-myocardial infarction--completed 10-12 months of medically-supervised exercise. All had an intensive cardiovascular work-up, serial treadmill exercise tests and coronary arteriography before and after training. All demonstrated the expected physical, physiological, metabolic, and psychological benefits. Two showed some definite, increased collateralization, however, in both of these the changes may have been a response to some extension of the occlusive disease and not exclusively an exercise effect. It was evident that minute changes in coronary collaterals are detectable by selective coronary arteriography, but that the specific effect of exercise on the development of collaterals could only be determined by a large-scale, controlled program with randomization of the multiple, uncontrollable variables among exercise and non-exercise populations.

Adult↗