The Effect of Pure Right Ventricular Ischemia on Right and Left Ventricular Performance in the Anesthetized Dog

Gattullo, D; Casalucci, D; Gastaldi, Lucia; Morello, Mara; Pagliaro, Pasquale

doi:10.1159/000175949

Cited by 3 publications

(1 citation statement)

References 9 publications

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“…Because the right ventricle differs markedly from the left ventricle in work performed, oxygen extraction and consumption, and transmural pressure, differences in the RC flow-RV function relation might be expected. The canine RC artery does not supply the interventricular septum or at least one-fourth of the RV margin adjacent to posterior longitudinal groove, so it is not surprising that complete occlusion of the RC has been reported to have little effect on RV systolic pressure (13). Clearly, evaluation of the RC flow-RV function relation requires direct assessment of function in the perfusion territory of the RC as was accomplished in the present study.…”

Section: Rc Flow-rv Function Relationmentioning

confidence: 74%

Right coronary autoregulation in conscious, chronically instrumented dogs

Bian

Williams

Gwirtz

et al. 1998

American Journal of Physiology-Heart and Circulatory Physiology

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Right coronary (RC) autoregulation and right ventricular (RV) function were assessed in conscious dogs, chronically instrumented to measure RC flow and RC pressure (RCP) as a hydraulic occluder on the RC was inflated. Dogs were then anesthetized, and RC autoregulation and RV function were again assessed. In the conscious state, moderate RC autoregulation was present with closed loop gains (Gc) of 0.59–0.27 as RCP was reduced from 100 to 40 mmHg. In the anesthetized state, Gc was not significantly less than in the conscious state at RCP >50 mmHg. The range and potency of RV autoregulation were greater in both groups than for previously reported findings in anesthetized dogs with RC perfused by an extracorporeal system. RV contractile function was well maintained in conscious and anesthetized dogs at RCP >45 mmHg. We conclude the following: 1) modest RC autoregulation is present in the conscious dog, 2) anesthesia limits the range but not the degree of RC autoregulation, 3) extracorporeal perfusion systems appear to depress RC autoregulation, and 4) RV contractile function remains constant in both conscious and anesthetized dogs until RCP falls below 50 mmHg.

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Section: Rc Flow-rv Function Relationmentioning

confidence: 74%

Right coronary autoregulation in conscious, chronically instrumented dogs

Bian

Williams

Gwirtz

et al. 1998

American Journal of Physiology-Heart and Circulatory Physiology

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Right Ventricular Dysfunction Secondary to Myocardial Ischemia Provoked by Stress Testing

1998

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We present the cases of two patients, aged 59 and 85 years, who were evaluated with stress echocardiography for chest pain. Both patients developed dramatic echocardiographic findings consisting of severe right ventricular enlargement and hypokinesis, as well as enlargement of the right atrium at relatively low-level exercise. One patient collapsed with severe sinus bradycardia, junctional rhythm, ST elevation in the inferior leads, marked hypotension, and neck vein congestion. The other patient developed staggering and symptoms of hypoperfusion. In both patients, correction of critical proximal right coronary artery stenosis by angioplasty resulted in complete resolution of the right ventricular dysfunction on repeat stress testing. We conclude that in some patients, stress-induced myocardial ischemia may involve primarily the right ventricle with little or no evidence of ischemic changes in the left ventricle. An assessment of right ventricular function should be included in stress echocardiographic studies.

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Mechanisms of Oxygen Demand/Supply Balance in the Right Ventricle

Zong

Tune

Downey

2005

Exp Biol Med (Maywood)

100

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Few studies have investigated factors responsible for the O2 demand/supply balance in the right ventricle. Resting right coronary blood flow is lower than left coronary blood flow, which is consistent with the lesser work of the right ventricle. Because right and left coronary artery perfusion pressures are identical, right coronary conductance is less than left coronary conductance, but the signal relating this conductance to the lower right ventricular O2 demand has not been defined. At rest, the left ventricle extracts approximately 75% of the O2 delivered by coronary blood flow, whereas right ventricular O2 extraction is only ~50%. As a result, resting right coronary venous PO2 is approximately 30 mm Hg, whereas left coronary venous PO2 is approximately 20 mm Hg. Right coronary conductance does not sufficiently restrict flow to force the right ventricle to extract the same percentage of O2 as the left ventricle. Endogenous nitric oxide impacts the right ventricular O2 demand/supply balance by increasing the right coronary blood flow at rest and during acute pulmonary hypertension, systemic hypoxia, norepinephrine infusion, and coronary hypoperfusion. The substantial right ventricular O2 extraction reserve is used preferentially during exercise-induced increases in right ventricular myocardial O2 consumption. An augmented, sympathetic-mediated vasoconstrictor tone blunts metabolically mediated dilator mechanisms during exercise and forces the right ventricle to mobilize its O2 extraction reserve, but this tone does not limit resting right coronary flow. During exercise, right coronary vasodilation does not occur until right coronary venous PO2 decreases to approximately 20 mm Hg. The mechanism responsible for right coronary vasodilation at low PO2 has not been delineated. In the poorly autoregulating right coronary circulation, reduced coronary pressure unloads the coronary hydraulic skeleton and reduces right ventricular systolic stiffness. Thus, normal right ventricular external work and O2 demand/supply balance can be maintained during moderate coronary hypoperfusion.

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The Effect of Pure Right Ventricular Ischemia on Right and Left Ventricular Performance in the Anesthetized Dog

Cited by 3 publications

References 9 publications

Right coronary autoregulation in conscious, chronically instrumented dogs

Right coronary autoregulation in conscious, chronically instrumented dogs

Right Ventricular Dysfunction Secondary to Myocardial Ischemia Provoked by Stress Testing

Mechanisms of Oxygen Demand/Supply Balance in the Right Ventricle

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