Hemodynamic correlates of myocardial oxygen consumption during upright exercise.

Kitamura, K; Jorgensen, Charles R.; Gobel, Fredarick L.; Taylor, Henry L.; Wang, Y

doi:10.1152/jappl.1972.32.4.516

Cited by 509 publications

(218 citation statements)

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“…Myocardial oxygen consumption per minute is affected by left ventricular afterload (SBP) and contractile frequency (HR) (11). Neither the absolute nor the increased values of HR during exercise were significantly affected by age in this study.…”

Section: Fig 5 Relationships Between Systemic Arterial Compliance (contrasting

confidence: 65%

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Age-Related Reduction of Systemic Arterial Compliance Induces Excessive Myocardial Oxygen Consumption during Sub-Maximal Exercise

Otsuki

Maeda

Kesen³

et al. 2006

Hypertens Res

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Reduction of systemic arterial compliance (SAC) with aging increases left ventricular afterload. The present study was designed to examine whether age-related reduction of SAC is related to excessive myocardial oxygen consumption during sub-maximal aerobic exercise. We studied elderly (60-69 years; n =25) and senior (70-82 years; n =25) subjects. We measured SAC immediately before the start of the ramp-fashion exercise (i.e., at the end of the 20 W warm-up exercise) and the double product (DP: systolic blood pressure heart rate) during the ramp-fashion exercise (20-50 W). SAC was significantly lower in senior subjects

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Section: Fig 5 Relationships Between Systemic Arterial Compliance (contrasting

confidence: 65%

“…The body surface area was calculated from height and weight as ( DP was highly correlated with the myocardial oxygen consumption measured using catheters during exercise (r= 0.90) (11).…”

Section: Discussionmentioning

confidence: 99%

Age-Related Reduction of Systemic Arterial Compliance Induces Excessive Myocardial Oxygen Consumption during Sub-Maximal Exercise

Otsuki

Maeda

Kesen³

et al. 2006

Hypertens Res

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“…Heart rate was derived from the arterial blood pressure signal and an index of myocardial oxygen demand, the double product, was calculated as systolic blood pressureϫheart rate. 19 At each measurement period, data from several heartbeats were measured and averaged. The LV WTh was calculated from the regional wall motion data according to the formula WThϭ100ϫ[(ESDϪEDD)/EDD], where ESDϭend-systolic dimension, calculated from the end of the T wave or 20 ms before peak negative dP/dt; and EDDϭend-diastolic dimension, calculated from the peak of the R wave or the onset of positive dP/dt.…”

Section: Discussionmentioning

confidence: 99%

Reversal of Reflex-Induced Myocardial Ischemia by Median Nerve Stimulation

et al. 1998

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Background-Acupuncture is reported to reduce myocardial ischemia, arrhythmias, and hypertension. To investigate the physiological mechanisms underlying these observations, a model of reflex-induced, reversible myocardial ischemia was developed to test the effects of median nerve stimulation as a surrogate for electroacupuncture. Methods and Results-Chloralose-anesthetized cats were instrumented to measure arterial blood pressure, left ventricular pressure, left ventricular dP/dt, heart rate, left anterior descending (LAD) coronary blood velocity, and regional wall motion. The LAD artery either was partially occluded or a small diagonal branch was ligated. Subsequently, transient reflex activation of the cardiovascular system was evoked by application of bradykinin (typically 1 g/mL) to the gallbladder, which significantly increased myocardial oxygen demand (double product), left ventricular dP/dt, and coronary blood velocity and caused ischemia-induced regional dysfunction, evidenced by significant (PϽ.05) reduction in normalized wall thickening (10.7Ϯ4.2% versus Ϫ23.6Ϯ2.9%; control versus ischemia; nϭ7). However, when median nerves were stimulated with low frequency (5 Hz) to mimic electroacupuncture, bradykinin-induced change in normalized wall thickening was significantly improved (Ϫ23.6Ϯ2.9% versus 9.8Ϯ4.9%; ischemia versus median nerve stimulation, PϽ.05) and remained augmented Ն1 hour. Results were similar in partial and complete occlusion groups. Significant improvement in wall thickening was associated with unchanged increment of coronary blood velocity and significantly diminished increments of double product and diastolic blood pressure. Conclusions-These results suggest that stimulation of the median nerve to mimic electroacupuncture diminishes regional myocardial ischemia triggered by a sympathetically mediated increase in cardiac oxygen demand. The mechanism of this effect is related to reduction in cardiac oxygen demand, secondary to a diminished pressor response. These data provide the first documentation of the physiological mechanisms underlying the possible beneficial effect of electroacupuncture in the context of restricted coronary blood flow and augmented myocardial oxygen demand.

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“…The rate-pressure-product (RPP) was calculated as the product of the systolic blood pressure and the heart rate. 22 Measurement of blood glucose, insulin and hematocrit The animals were anesthetized with an intraperitoneal injection of sodium pentobarbital (50 mgakg). After reaching a plane of surgical anesthesia (15 min later), the chest of the animal was opened, exposing the contracting heart.…”

Section: Experimental Designmentioning

confidence: 99%

Mechanism for obesity-induced increase in myocardial lipid peroxidation

et al. 2001

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OBJECTIVE:To determine the mechanisms underlying the obesity-induced increase in myocardial lipid peroxidation in the faafa rat. We hypothesized that elevated heart work (ie rate-pressure product), an increased rate of superoxide (O 2 À ) production, total myocardial lipid content, andaor insuf®cient antioxidant defenses are potential contributors to myocardial lipid peroxidation in obesity. DESIGN: Comparative, experimental study of myocardial tissue in 16-week-old lean control (Faa?, normal diet), obese high-fat fed (Faa?, 45% dietary fat), and obese fatty (faafa, normal diet) Zucker rats. MEASUREMENTS: Myocardial work (heart rate Â systolic blood pressure), myocardial lipid content, oxidative and antioxidant enzyme activities (citrate synthase (CS), catalase (CAT), glutathione peroxidase (GPX), superoxide dismutase (SOD)), the rate of papillary muscle superoxide radical production in vitro, thiol content, basal and post-oxidative challenge myocardial lipid peroxidation levels using thiobarbituric reactive acid substances (TBARS) and lipid hydroperoxides (PEROX) as indices of lipid peroxidation. RESULTS: Compared to lean controls, the high-fat fed and fatty animals had similar elevations (P`0.05) in myocardial TBARS and PEROX (23%, 25% and 29% 45%, respectively; P`0.05), and elevated susceptibilities to oxidative stress in vitro following exposure to oxidizing agents (P`0.05). Resting heart work was slightly higher (P`0.05) in both the high-fat fed and fatty animals compared to controls. Myocardial lipid content, SOD activities and non-protein thiol (glutathione) levels were elevated (P`0.05) in high-fat fed and fatty animals compared to controls. The rate of superoxide formation by isolated papillary muscles in vitro did not differ among groups (P`0.05). Regression analysis revealed that the myocardial lipid content contributed most to myocardial lipid peroxidation (R 2 0.76, P`0.05). CONCLUSIONS: Myocardial oxidative injury is closely associated with myocardial lipid content, but is not closely correlated with heart work, insuf®cient antioxidant defenses or a greater rate of superoxide production.

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Hemodynamic correlates of myocardial oxygen consumption during upright exercise.

Cited by 509 publications

References 0 publications

Age-Related Reduction of Systemic Arterial Compliance Induces Excessive Myocardial Oxygen Consumption during Sub-Maximal Exercise

Age-Related Reduction of Systemic Arterial Compliance Induces Excessive Myocardial Oxygen Consumption during Sub-Maximal Exercise

Reversal of Reflex-Induced Myocardial Ischemia by Median Nerve Stimulation

Mechanism for obesity-induced increase in myocardial lipid peroxidation

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