Myocardial performance and collateral flow after transient coronary occlusion in exercising dogs

Fourteen dogs with prior constriction of the left circumflex (LCf) coronary artery were studied at rest and during treadmill running. Hemodynamics were measured before and after a 1-min LCf occlusion. Coronary and collateral flows were quantitated during occlusion both at rest and during exercise. Group I consisted of 4 dogs with resting collateral flow exceeding one-half (average 78%) of normal flow, and group II consisted of 10 dogs with collateral flows less than one-half (average 30%) of normal. At rest LCf occlusion caused no hemodynamic changes in group I, but stroke volume fell significantly in group II. During running, collateral flow after LCf occlusion doubled in group I, and there was only a small rise in left atrial pressure to 18 mmHg. In group II, collateral flow increased by 50% during running and actually decreased in 4 dogs. Significant cardiac failure developed as stroke volume halved, and left atrial pressure rose to an average 30 mmHg. Therefore exercise-induced depression of left ventricular function in the ischemic heart can be correlated to the amount of coronary collateral flow.

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Restoration of cardiac function and myocardial flow by collateral development in dogs

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1981.240.5.h811 ◽

1981 ◽

Vol 240 (5) ◽

pp. H811-H819 ◽

Cited By ~ 1

Author(s):

M. V. Cohen ◽

T. Yipintsoi

Keyword(s):

Left Ventricular ◽

Balloon Occlusion ◽

Treadmill Running ◽

Left Ventricular Failure ◽

Collateral Flow ◽

Ventricular Failure ◽

Hemodynamic Changes ◽

Group I ◽

Group Ii ◽

Myocardial Flow

Hemodynamics of instrumented beagles with 75-85% stenoses of the left circumflex (LCf) coronary artery were evaluated before and during transient LCf balloon occlusion at rest and during treadmill running. Studies were done after surgery and 3 mo later. Myocardial blood flow was measured with radioactive microspheres during the LCf occlusions. Nine dogs (group I) had patent LCf arteries at the second study, and six (group II) had occluded vessels. Transient LCf occlusion during running in group I at weeks 1 and 12 and in group II at week 1 caused significant left ventricular failure, whereas the same protocol in group II dogs at week 12 produced minimal hemodynamic changes. Left ventricular failure precipitated by coronary occlusion during exercise diminished from week 1-12 in those animals with increasing LCf collateral flow, but actually increased in the animals with diminishing collateral flow. In group II dogs after chronic LCf occlusion total flow to LCf myocardium as well as inner-to-outer layer ratios were normal both at rest and during exercise. Thus coronary collaterals do preserve myocardial function, limit adverse hemodynamic responses to myocardial ischemia, and restore postocclusion tissue flows to normal even during the stress of exercise.

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Effects of exercise and isoproterenol on hemodynamics and myocardial VO2 in lambs with aortopulmonary shunts

Journal of Applied Physiology ◽

10.1152/jappl.1994.76.4.1533 ◽

1994 ◽

Vol 76 (4) ◽

pp. 1533-1539 ◽

Cited By ~ 2

Author(s):

J. W. Gratama ◽

J. J. Meuzelaar ◽

M. Dalinghaus ◽

J. H. Koers ◽

A. M. Gerding ◽

...

Keyword(s):

Stroke Volume ◽

Left Atrial ◽

Systolic Pressure ◽

Random Order ◽

Left Ventricular ◽

Atrial Pressure ◽

Exercise Stress ◽

Left Atrial Pressure ◽

Stress Tests ◽

Isoproterenol Infusion

To compare hemodynamic changes induced by isoproterenol and exercise stress tests in individuals with and without left ventricular volume load, we studied 10 lambs with an aortopulmonary shunt [58 +/- 4% (SE) of left ventricular output] 2 wk after the shunt was created. Two studies, isoproterenol infusion at 0.1 microgram.kg-1.min-1 and treadmill exercise at 76 +/- 4% of predetermined maximal O2 consumption (VO2) were performed in each lamb in random order on different days. Identical experiments were performed in nine lambs without shunts. Isoproterenol and exercise induced similar changes in heart rate (43 +/- 5%); systemic (72 +/- 7%), pulmonary (35 +/- 3%), and shunt blood flows (8 +/- 6%); and stroke volume (NS) in shunt lambs. Aortic systolic pressure increased less during isoproterenol infusion than during exercise (7 +/- 3 vs. 27 +/- 5%), and left atrial pressure decreased during isoproterenol infusion (-23 +/- 4%) but changed in an opposite direction during exercise (7 +/- 6%). These changes were accompanied by a smaller increase in myocardial VO2 during isoproterenol infusion than during exercise (5.0 +/- 0.7 to 5.3 +/- 0.6 and 5.3 +/- 0.8 to 7.3 +/- 0.9 mumol.beat-1 x 100 g-1, respectively). In control lambs, stroke volume decreased during isoproterenol infusion despite an equal decrease in left atrial pressure as in shunt lambs. In conclusion, isoproterenol better stimulates the blood flow changes during exercise in shunt than in control lambs probably because of their higher ventricular filling pressures. In interpreting isoproterenol stress tests it should, however, be kept in mind that these changes are realized at a lower work load for the heart.

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Left ventricular function and the relationship between left atrial pressure and peak early diastolic filling velocity in dog

Cardiovascular Research ◽

10.1093/cvr/26.2.109 ◽

1992 ◽

Vol 26 (2) ◽

pp. 109-114 ◽

Cited By ~ 12

Author(s):

S. Nakatani ◽

S. Beppu ◽

K. Miyatake ◽

Y. Nimura

Keyword(s):

Left Ventricular Function ◽

Ventricular Function ◽

Left Atrial ◽

Left Ventricular ◽

Atrial Pressure ◽

Left Atrial Pressure ◽

Diastolic Filling ◽

The Relationship

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THE EFFECTS OF BETA-ADRENERGIC STIMULATION WITH ISOPROTERENOL AND THE CONTRIBUTION OF LEFT VENTRICULAR DIASTOLIC FUNCTION ON LEFT ATRIAL PRESSURE IN PATIENTS WITH ATRIAL FIBRILLATION: A COMPARISON TO ATRIAL PACING

Journal of the American College of Cardiology ◽

10.1016/s0735-1097(15)60431-4 ◽

2015 ◽

Vol 65 (10) ◽

pp. A431

Author(s):

Tae-Hoon Kim ◽

Junbeom Park ◽

Jin-Kyu Park ◽

Jae-Sun Uhm ◽

Boyoung Joung ◽

...

Keyword(s):

Atrial Fibrillation ◽

Diastolic Function ◽

Left Atrial ◽

Left Ventricular Diastolic Function ◽

Left Ventricular ◽

Atrial Pressure ◽

Left Atrial Pressure ◽

Atrial Pacing ◽

Adrenergic Stimulation ◽

Ventricular Diastolic Function

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Blunted rate-dependent left atrial pressure response during isoproterenol infusion in atrial fibrillation patients with impaired left ventricular diastolic function: a comparison to pacing

EP Europace ◽

10.1093/europace/euv239 ◽

2015 ◽

Vol 17 (suppl 2) ◽

pp. ii89-ii96 ◽

Cited By ~ 1

Author(s):

Tae-Hoon Kim ◽

Jihei Sara Lee ◽

Junbeom Park ◽

Jin-Kyu Park ◽

Jae-Sun Uhm ◽

...

Keyword(s):

Atrial Fibrillation ◽

Diastolic Function ◽

Left Atrial ◽

Left Ventricular Diastolic Function ◽

Left Ventricular ◽

Atrial Pressure ◽

Left Atrial Pressure ◽

Ventricular Diastolic Function ◽

Rate Dependent ◽

Isoproterenol Infusion

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Desflurane, Sevoflurane, and Isoflurane Affect Left Atrial Active and Passive Mechanical Properties and Impair Left Atrial–Left Ventricular Coupling In Vivo

Anesthesiology ◽

10.1097/00000542-200109000-00023 ◽

2001 ◽

Vol 95 (3) ◽

pp. 689-698 ◽

Cited By ~ 23

Author(s):

Meir Gare ◽

David A. Schwabe ◽

Douglas A. Hettrick ◽

Judy R. Kersten ◽

David C. Warltier ◽

...

Keyword(s):

Left Atrial ◽

Minimum Alveolar Concentration ◽

Left Ventricular ◽

Atrial Function ◽

Left Atrial Function ◽

Atrial Pressure ◽

Left Atrial Pressure ◽

Stroke Work ◽

Ventricular Elastance

Background The effects of volatile anesthetics on left atrial function in vivo have not been described. The authors tested the hypothesis that desflurane, sevoflurane, and isoflurane alter left atrial mechanics evaluated with invasively derived pressure-volume relations. Methods Barbiturate-anesthetized dogs (n = 24) were instrumented for measurement of aortic, left atrial, and left ventricular pressures (micromanometers) and left atrial volume (orthogonal sonomicrometers). Left atrial contractility and chamber stiffness were assessed with end-systolic and end-reservoir pressure-volume relations, respectively, obtained from differentially loaded diagrams. Relaxation was determined from the slope of left atrial pressure decline after contraction. Stroke work and reservoir function were assessed by A and V loop areas, respectively. Left atrial-left ventricular coupling was determined by the ratio of left atrial contractility and left ventricular elastance. Dogs received 0.6, 0.9, and 1.2 minimum alveolar concentration desflurane, sevoflurane, or isoflurane in a random manner, and left atrial function was determined after 20-min equilibration at each dose. Results Desflurane, sevoflurane, and isoflurane decreased heart rate, mean arterial pressure, and maximal rate of increase of left ventricular pressure and increased left atrial end-diastolic, end-systolic, and maximum volumes. All three anesthetics caused dose-related reductions in left atrial contractility, relaxation, chamber stiffness, and stroke work. Administration of 0.6 and 0.9 minimum alveolar concentration desflurane, sevoflurane, and isoflurane increased V loop area. All three anesthetics decreased the ratio of stroke work to total left atrial pressure-volume diagram area, increased the ratio of conduit to reservoir volume, and reduced left atrial contractility-left ventricular elastance to equivalent degrees. Conclusions The results indicate that desflurane, sevoflurane, and isoflurane depress left atrial contractility, delay relaxation, reduce chamber stiffness, preserve reservoir and conduit function, and impair left atrial-left ventricular coupling in vivo.

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