Immediate cardiac responses to exercise were investigated in five normal male volunteer subjects by measuring heart rate and systolic intervals from rest through the onset of exertion at three different work loads. Recordings were continued for fifty beats and again at one minute with measurements plotted on a beat-to-beat basis and grouped for statistical analysis. During exercise, heart rate and corrected ejection time increased, pre-ejection period and PEP/LVET decreased, and pulse transmission time remained stable. The heart rate acceleration was sudden, occurring in the first few beats of exercise, a phenomenon also demonstrated by previous investigators. A significant new finding was the equally abrupt major change in each of the other parameters. The immediacy of all responses was independent of load and was consistent with experimental studies showing that changes in both neural activity and venous return at the onset of exercise are virtually instantaneous.

Adult↗

PubMed1975

Effects of age on responses to isometric exercise. Isometric handgrip in noninvasive screening for cardiovascular disease.

Isometric handgrip (IHG) imposes an acutely increased afterload on the left ventricle. Utilizing systolic time intervals, we studied various responses to IHG, measured as changes from resting values with near-maximum IHG, in old normal (ON) subjects, young normal (YN) subjects, and old patients with hypertensive heart disease (HHD) and patients with coronary artery disease (CAD). There were no differences in responses to IHG between ON and patients with HHD or patients with CAD. However, there were clear differences between the responses of ON and YN subjects. Increase in heart rate (HR) was much more prominent in YN (ON vs. YN = +11.6 +/- 2.6 vs. +15.6 +/- 5.7 beats per minute p less than 0.001). Pre-ejection period (PEP) end isovolumic contraction time (IVCT) increased in ON but decreased in YN (PEP + 6.2 +/- 1.7 vs. -11.0 +/- 3.7 msec., p less than 0.001; IVCT +8.1 +/- 2.2 vs. -13.8 +/- 3.4 msec., p less than 0.001. Shortening of LVET was much more marked in YN (-6.5 +/- 4.1 VS. -63.3 +/- 9.9 msec. p less than 0.001), but this was entirely due to the HR differences since there was no difference in ejection time index (+ 5.1 +/- 3.4 vs. -0.4 +/- 7.3 msec. p greater than 0.5). IHG produced no significant differences between ON and YN in the timing of the "mitral" component of the first heart sound (q-Im), in the ratio PEP/LVET, or in pulse transmission time (PTT). By contrast, resting control PTT was markedly short in ON, especially those with CAD. Resting PTT in ON was 27.1 +/- 2.6 msec.; in YN 43.7 +/- 1.4 msec.; in CAD patients 20.7 +/- 1.3 msec. We conclude that even near-maximal IHG does not seem to be an adequate noninvasive screening test for cardiovascular disease in that age alone seems to have the most significant influence on the responses.

Adult↗

PubMed1975

Pericardial rub. Prospective, Multiple observer investigation of pericardial friction in 100 patients.

A prospective, multiple observer ausculatory and phonocardiographic study of 100 patients with pericardial friction confirmed the dominant prevalence of triphasic pericardial rubs (56 percent of patients with sinus rhythm). In 9 of 33 patients with various biphasic rub patterns there was summation of the ventricular diastolic rub with the atrial systolic rub, concealing an additional 10 percent of potential triphasic friction. Fourteen of 15 monophasic rubs were audible or recordable only during ventricular systole. Rubs were best heard along the left sternal border in 84 percent of cases and tended to be louder during inspiration than during expiration; in 35 cases there was no respiratory predilection. Twenty-three rubs were palpable. Ten rubs occurred in patients with pericardial effusion, five of whom had tamponade. Extension of the neck did not have a dependable effect on rub intensity.

Cardiac Tamponade↗

PubMed1975

Constant-load versus heart rate-targeted exercise: responses of systolic intervals.

Eight normal male volunteers were studied during bicycle ergometry at constant work loads of 50, 100, and 150 W for 4 min each and heart rate-targeted exercise to rates which matched those during the end of the 4th min at each constant work load. Systolic intervals measured prior to and during exercise included: Q-IM, isovolumic contraction time (IVCT), preejection period (PEP), left ventricular ejection time (LVET), ejection time index (ETI), PEP/LVET, and pulse transmission time (PTT). Directional changes during both exercise methods were consistent with previously reported results. Comparable control values indicated equivalent starting points for each bout and confirmed recovery from preceding exercise. There was striking similarities within each matched exercise set for Q-IM, IVCT, PEP, and PEP/LVET. LVET was significantly shorter for rate targeted exercise. We conclude that either constant-load or rate-targeted bicycle ergometry may be employed with choice of method determined by the purpose of the protocol and that systoloc intervals (except LVET) should not be importantly altered owing to the method chosen.

Adult↗

PubMed1975

Letter: First and second versus second and third exercise tests.

Explore the source record for details and available documents.

Coronary Artery Bypass↗

PubMed1975

Editorial: Clinical consequences of acute pericarditis.

Explore the source record for details and available documents.

Acute Disease↗

PubMed1975

Atrial diastolic friction.

A typical triphasic pericardial rub was heard in a patient with acute myocardial infarction. Phonocardiograms during atrioventricular block demonstrated a fourth rub component in atrial diastole following every sufficiently isolated P wave.

Aged↗

PubMed1975