Alteration of ischemic cardiac function in normal heart by daily exercise

1983 ◽  
Vol 55 (1) ◽  
pp. 52-60 ◽  
Author(s):  
D. R. Knight ◽  
H. L. Stone
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Myocardial Function ◽  
Exercise Program ◽  
Segment Length ◽  
Tissue Blood Flow ◽  
Myocardial Tissue ◽  
Daily Exercise ◽  
Coronary Collateral Blood Flow ◽  
Made In

Myocardial function, tissue blood flow, and heart rate measurements were studied during control and a 2-min occlusion of the left circumflex coronary artery in conscious dogs. These measurements were made in the same dogs before exercise in the untrained state (UT) and after a 4-wk treadmill exercise program in the partially trained condition (PT). Ultrasonic segment length gauges were used to measure myocardial function in the ischemic zone, defined by staining the myocardial tissue. Microspheres (15 microns), labeled with different isotopes, were used to measure the myocardial tissue flow in the normal and ischemic zones. Myocardial function in the ischemic zone of 20 dogs was reduced 71 +/- 6% in the UT condition; however, after PT, the percent reduction in segment length function was only 33 +/- 4% during occlusion. During occlusion, an increase in heart rate of 46 +/- 7% in the UT condition was observed; yet after PT, heart rate increased only 19 +/- 5%. In 5 UT dogs with heart rate held constant (150 beats/min), the decrease from control in tissue blood flow to the ischemic zone in the subendocardium during occlusion was 60 +/- 7%. After PT, the decrease from control in tissue blood flow in the same dogs was 34 +/- 6%. These data indicate that the improved myocardial function during ischemia was a result of the improved coronary collateral blood flow into the ischemic zone after PT.

scholarly journals Left ventricular dysfunction after two hours of polarizing or depolarizing cardioplegic arrest in a porcine model

Perfusion ◽  
2018 ◽  
Vol 34 (1) ◽  
pp. 67-75 ◽  
Author(s):  
Terje Aass ◽  
Lodve Stangeland ◽  
Christian Arvei Moen ◽  
Atle Solholm ◽  
Geir Olav Dahle ◽  
...  
Keyword(s):  
Blood Flow ◽  
Flow Rate ◽  
Myocardial Function ◽  
Blood Flow Rate ◽  
Left Ventricular ◽  
Tissue Blood Flow ◽  
Myocardial Tissue ◽  
Stroke Work ◽  
Cardioplegic Arrest ◽  
Blood Cardioplegia

Introduction: This experimental study compares myocardial function after prolonged arrest by St. Thomas’ Hospital polarizing cardioplegic solution (esmolol, adenosine, Mg2+) with depolarizing (hyperkalaemic) St. Thomas’ Hospital No 2, both administered as cold oxygenated blood cardioplegia. Methods: Twenty anaesthetized pigs on tepid (34°C) cardiopulmonary bypass (CPB) were randomised to cardioplegic arrest for 120 min with antegrade, repeated, cold, oxygenated, polarizing (STH-POL) or depolarizing (STH-2) blood cardioplegia every 20 min. Cardiac function was evaluated at Baseline and 60, 150 and 240 min after weaning from CPB, using a pressure-conductance catheter and epicardial echocardiography. Regional tissue blood flow, cleaved caspase-3 activity and levels of malondialdehyde were evaluated in myocardial tissue samples. Results: Preload recruitable stroke work (PRSW) was increased after polarizing compared to depolarizing cardioplegia 150 min after declamping (73.0±3.2 vs. 64.3±2.4 mmHg, p=0.047). Myocardial tissue blood flow rate was high in both groups compared to the Baseline levels and decreased significantly in the STH-POL group only, from 60 min to 150 min after declamping (p<0.005). Blood flow was significantly reduced in the STH-POL compared to the STH-2 group 240 min after declamping (p<0.05). Left ventricular mechanical efficiency, the ratio between total pressure-volume area and blood flow rate, gradually decreased after STH-2 cardioplegia and was significantly reduced compared to STH-POL cardioplegia after 150 and 240 min (p<0.05 for both). Conclusion: Myocardial protection for two hours of polarizing cardioplegic arrest with STH-POL in oxygenated blood is non-inferior compared to STH-2 blood cardioplegia. STH-POL cardioplegia alleviates the mismatch between myocardial function and perfusion after weaning from CPB

Nocturnal variations in peripheral blood flow, systemic blood pressure, and heart rate in humans

1991 ◽  
Vol 261 (4) ◽  
pp. H982-H988
Author(s):  
J. H. Sindrup ◽  
J. Kastrup ◽  
H. Christensen ◽  
B. Jorgensen
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Arterial Blood Pressure ◽  
Flow Rate ◽  
Mean Arterial Blood Pressure ◽  
Blood Flow Rate ◽  
Tissue Blood Flow ◽  
Peripheral Blood Flow ◽  
Arterial Blood

Subcutaneous adipose tissue blood flow rate, together with systemic arterial blood pressure and heart rate under ambulatory conditions, was measured in the lower legs of 15 normal human subjects for 12-20 h. The 133Xe-washout technique, portable CdTe(Cl) detectors, and a portable data storage unit were used for measurement of blood flow rates. An automatic portable blood pressure recorder and processor unit was used for measurement of systolic blood pressure, diastolic blood pressure, and heart rate every 15 min. The change from upright to supine position at the beginning of the night period was associated with a 30-40% increase in blood flow rate and a highly significant decrease in mean arterial blood pressure and heart rate (P less than 0.001 for all). Approximately 100 min after the subjects went to sleep an additional blood flow rate increment (mean 56%) and a simultaneous significant decrease in mean arterial blood pressure (P less than 0.001) were observed. The duration of this hyperemic phase was 116 min. A highly significant reduction of the subcutaneous vascular resistance (50%) was demonstrated during the hyperemic blood flow rate phase compared with the surrounding phases (P less than 0.0001). The synchronism of the nocturnal subcutaneous hyperemia and the decrease in systemic mean arterial blood pressure point to a common, possibly central nervous or humoral, eliciting mechanism.

scholarly journals Blood flow distribution in submerged and surface-swimming ducks

1992 ◽  
Vol 166 (1) ◽  
pp. 285-296
Author(s):  
R. Stephenson ◽  
D. R. Jones
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Water Surface ◽  
Imaging Technique ◽  
Flow Distribution ◽  
Tissue Blood Flow ◽  
Blood Flow Distribution ◽  
Radiological Imaging ◽  
Aythya Americana

Observations that the response of the avian heart rate to submergence varies under different circumstances have led to speculation about variability of blood flow distribution during voluntary dives. We used a radiological imaging technique to examine the patterns of circulating blood flow in captive redhead ducks (Aythya americana) during rest, swimming, escape dives, forced dives and trapped escape dives and have shown that blood flow distribution in escape dives was the same as that in ducks swimming at the water surface. The response during trapped escape dives, however, was highly variable. Blood pressure was unchanged from the resting value during all activities. Predictions made about blood flow distribution during unrestrained dives on the basis of heart rate and other indirect data were confirmed in this study. However, the trapped escape dive responses indicated that heart rate alone is not always a reliable indicator of tissue blood flow in exercising ducks.

Abstract 18497: Hospital-based Exercise Training Program Post Coronary Artery Bypass Graft Surgery: Impact of Once and Twice Daily Exercise Program on Cardiac Autonomic Modulation

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Renata Mendes ◽  
Camila B Pantoni ◽  
Rodrigo P Simões ◽  
Luciana Di Thommazo-Luporini ◽  
Flávia C Caruso ◽  
...  
Keyword(s):  
Heart Rate ◽  
Coronary Artery ◽  
Artery Bypass ◽  
Exercise Program ◽  
Autonomic Modulation ◽  
Discharge Time ◽  
Cardiac Autonomic Modulation ◽  
Daily Exercise ◽  
Cabg Patients ◽  
Dose Dependent

Introduction: Coronary artery bypass surgery (CABG) patients with postoperative decreased cardiac autonomic modulation (CAM) have a higher mortality rate and although cardiovascular rehabilitation and exercises have substantial benefits in CAM, there is a paucity of information about its effects considering a possible "dose-dependent” autonomic adaptation in a hospital-based exercise program. The aim was to evaluate the impact of once daily versus twice daily dosing regimens of hospital-based exercise training on CAM in post CABG patients. Hypothesis: We hypothesized that there is a dose-dependent exercise adaptation on CAM and greater benefit to twice daily exercise group. Methods: Thirty-seven patients post-CABG were divided into: GEX1 (n = 12) and GEX2 (n = 11), composed of patients who underwent exercises one and two daily sessions, respectively; and of a control group (CG, n = 14) who received usual care (respiratory therapy). GEX patients initiated the exercises on post-operative day 1 (PO1), following a whole progressive program until discharge. CAM was assessed by indices of heart rate variability (HRV) analyzed from heart rate and R-R intervals signals recording at rest during 10 minutes on PO1 (baseline) and discharge time. Results: At the time of discharge after the hospital rehabilitation conclusion, GEX2 presented higher values of rMSSD index, representative of parasympathetic modulation, and also higher values of RRtri, TINN and STDRR indices, representative of overall variability of RRi compared to GC, respectively (rMSSD: 7.5±1.9 vs 5.2±1.8 ms; RRtri: 3.2±1.4 vs 2.0±0.7ms; TINN: 46.0±30.5 vs 25.7±11.0 ms and STDRR: 10.0±6.3 vs 5.4±3.3 ms), while GEX1 presented only higher values of rMSSD compared to CG (rMSSD: 7.8±2.5 vs 5.2±1.8 ms). However, no differences were observed between groups on HRV baseline and at discharge time between groups GEX1 and GEX2. Conclusion: Our results suggested that twice daily hospital-based exercise program stimulated more favorably the cardiac autonomic nervous system adaptations in patients post-CABG. Although a daily exercise session promotes beneficial adaptations, two sessions should be encouraged to additional benefits in the cardiac autonomic modulation FAPESP 2015/2015 / 16730-3.

Myocardial function in sepsis and endotoxin shock

1989 ◽  
Vol 257 (6) ◽  
pp. R1265-R1281 ◽  
Author(s):  
F. L. Abel
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Calcium Transport ◽  
Myocardial Function ◽  
Endotoxin Shock ◽  
Low Doses ◽  
Myocardial Performance ◽  
Myocardial Depression ◽  
Sympathetic Nerve Stimulation ◽  
Overwhelming Evidence

Myocardial function in sepsis and endotoxin shock is reviewed. Clinical, whole animal, and isolated tissue studies are compared to answer the question whether sepsis and/or endotoxin directly damage the myocardium. Myocardial performance is considered relative to control of preload, afterload, and heart rate. Despite the fact that these vary widely in different studies, there is overwhelming evidence that myocardial performance is depressed in both sepsis and endotoxin shock. The depression is dose related, occurs early after large doses of endotoxin but may follow a hyperdynamic phase in sepsis or after low doses of endotoxin. Endotoxin itself does not appear to be the depressant factor; the final depressant substance(s) is unknown. Calcium transport by the sarcoplasmic reticulum is depressed. This defect is more prominent in the endocardium than in the epicardium. Myocardial adenosinetriphosphatase (ATPase) and norepinephrine stores may be depleted. The septic myocardium has an increased dependence on sympathetic nerve stimulation. There is little evidence that the cause of the myocardial depression is an inadequate coronary blood flow.

Cardiovascular and metabolic responses to low dose adrenaline infusion: an invasive study in humans

1986 ◽  
Vol 70 (2) ◽  
pp. 199-206 ◽  
Author(s):  
U. Freyschuss ◽  
P. Hjemdahl ◽  
A. Juhlin-Dannfelt ◽  
B. Linde
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Adipose Tissue ◽  
Cardiac Output ◽  
Cyclic Amp ◽  
Plasma Concentrations ◽  
Metabolic Responses ◽  
Tissue Blood Flow ◽  
Arterial Plasma

1. Cardiovascular and metabolic responses to intravenous infusions of adrenaline (ADR), which raised arterial plasma ADR in a stepwise fashion from 0.3 to 1.3, 2.3 and 6.0 nmol/l, were studied in 11 healthy volunteers. 2. ADR evoked marked and concentration-dependent increases in stroke volume and cardiac output (thermodilution), as well as decreases in the vascular resistances of the systemic circulation, calf and adipose tissue. These changes were significant from 1.3 nmol/l ADR. Less marked effects were found on blood pressure and heart rate. 3. Significant arterial ADR concentration-effect relationships were found for cyclic AMP, glycerol, glucose, lactate and noradrenaline, but not for insulin. Cyclic AMP and glycerol were significantly elevated at 1.3, glucose at 2.3, but lactate not below 6.0 nmol/l ADR. Increases in adipose tissue blood flow and arterial glycerol levels were correlated (P < 0.001), suggesting a metabolic component in the blood flow response of adipose tissue. 4. Invasive haemodynamic measurements revealed that ADR at arterial concentrations within the lower physiological range had considerable effects on cardiac output and vascular resistances, despite moderate changes in the conventional non-invasive haemodynamic variables blood pressure and heart rate. 5. ADR elicited clear-cut responses at arterial plasma concentrations attained during various kinds of mild to moderate stress.

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