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D H Spodick

Publications and source records attributed to D H Spodick.

At least 397 records · Page 22Linked to original sources
PubMed1977

Systolic time intervals utilizing ear densitography. Advantages and reliability for stress testing.

Systolic time intervals were determined in 10 volunteer subjects at rest and during a variety of cardiocirculatory stresses to further evaluate the ear densitogram derivative as a replacement for the carotid pulse curve. There was close tracking of the two methods not only for left ventricular ejection time (r = +0.98), but also for pre-ejection period (r = +0.98). The results confirmed that this technically simple and remarkably stable wave form permits reliable measurement of the systolic time intervals both at rest and during the actual performance of stress.

Adult↗
PubMed1977

Physiological responses to prompt and sustained squatting. Measurement by systolic time intervals.

Ten healthy men, ages 22 to 35, were studied non-invasively standing (control), at the onset of squatting ('prompt squat'), and at two minutes of squatting. Squatting produced decreases in heart rate, isovolumic contraction time, pre-ejection period, and pulse transmission time from onset of depolarisation to the first heart sound, left ventricular ejection time, and the ejection time index. These results of systolic time intervals are consistent with the bradycardia and increased ventricular filling induced by squatting. Major changes from control measurements were found at the onset of squatting, showing the impact of prompt squat of left ventricular performance.

Adult↗
PubMed1977

Left axis deviation as a single screening criterion in acquired nonvalvulvar heart disease. Association with abnormal systolic time intervals in hypertensive subjects.

The value of left axis deviation (LAD) as a single discriminator of clinical cardiac abnormality and its association with reduced left ventricular function was investigated in 100 consecutive ambulatory subjects with LAD, and 100 age and sex-matched subjects without LAD from the patient population of a voluntary screening clinic. Analysis of clinical data and measurement of QRS frontal plane axis as well as systolic time intervals (STI) were each done separately by different investigators in a blind manner. The only large groups in the study population were those with coronary heart disease and those with hypertension. The high prevalence of definite and probable coronary artery disease among subjects with LAD (32/100) contrasted with its paucity in the control group (8/100). Hypertensive and borderline hypertensive subjects occurred in sufficient numbers.

Aged↗
PubMed1977

Postural effects on the noninvasive baselines of ventricular performance.

The effects of posture on time-based noninvasive measurements were determined utilizing the sequence supine-sitting-standing in a formal protocol in which observer biases were eliminated by blinding the measurement and calculation phases. Compared to the supine posture, the sitting and standing postures produced significant increases in heart rate, isovolumic contraction time, pre-ejection period and pre-ejection periog/left-ventricular ejection time and significant decreases in ejection time and ejection time index. The response patterns are consistent with their hemodynamic correlates cited in the literature which show increased adrenergic activity and decreased venous return in the sitting and standing postures, the effect on venous return being dominant.

Adult↗
PubMed1977

Exercise testing.

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Electrocardiography↗
PubMed1977

Comparative orthostatic responses: standing vs. head-up tilt.

In both physiologic and clinical studies, standing is often loosely equated with head-up tilt(HUT) although the cardiovascular effects of these variants of orthostasis have not been formally compared, except for heart rate. The effects of HUT and standing were measured noninvasively in male volunteers satisfying identical criteria for age and normal status. In both postures, there were significant increases in heart rate, pre-ejection period, isovolumic contraction time, and the ratio of pre-ejection to ejection period, and significant decreases in ejection period and ejection time index. All of these changes were greater for standing than for tilt. Pulse transmission time changed significantly (-14%) only with tilt. We conclude that head-up tilt and standing are rather comparable but not physiologically identical forms of orthostasis.

Adult↗