The hypothesis that neurally mediated coronary vasodilation occurs as part of the carotid baroreceptor reflex was investigated. The left main coronary artery was cannulated and perfused at constant pressure (100 mm Hg) in closed-chest, chloralose-anesthetized dogs. The heart was paced at a constant rate between 60 and 70 beats/min after atrioventricular heart block. Propranolol (1 mg/kg) was gi...

Figure 1 ROI Placement and Flow-Time-Curves. Phase contract MRI images of the CSF for a patient with scleroderma-associated PAH (mPAP 49 mmHg) during rest (top row: A, B) and adenosine-induced stress (bottom row: D, E). The red ROI is drawn around the coronary sinus, the blue ROI is placed in adjacent myocardium to correct for through-plane motion. The flow-time curves (C, F) demonstrate that n...

In patients with atherosclerotic coronary artery disease, cigarette smoking increases myocardial oxygen demand but may cause an inappropriate decrease in coronary blood flow and myocardial oxgyen supply. This study was performed to explore the mechanism of smoking-induced coronary vasoconstriction and, specifically, to determine if smoking causes an ct-adrenergically mediated increase in corona...

The role of the carotid sinus reflex in control of the blood flow in the left circumflex coronary artery was studied in nine open-chest dogs anesthetized with chloralose. Flow was measured with an electromagnetic flowmeter. The effects of bilateral common carotid occlusion were examined in a three-part experiment in each dog. (1) Under vagotomy (control) conditions, occlusion of both common car...

The hemodynamic and myocardial metabolic responses to the cold pressor test were studied in 15 patients with coronary artery disease and stable exertional angina. Every patient had abnormal coronary vasoconstriction during a control cold pressor test, even though 14 were receiving propranolol and 12 were receiving long-acting nitrates. Mean coronary vascular resistance for the group increased 1...

The hemodynamic and myocardial metabolic responses to the cold pressor test were studied in 15 patients with coronary artery disease and stable exertional angina. Every patient had abnormal coronary vasoconstriction during a control cold pressor test, even though 14 were receiving propranolol and 12 were receiving long-acting nitrates. Mean coronary vascular resistance for the group increased 1...

Since the natural history of a coronary artery to left ventricle fistula is not well known, a case of such a fistula in 36-year-old female patient, followed for 20 years is presented. Two-dimensional echocardiography performed as a follow-up examination revealed enlargement of the right coronary artery and the right Valsalva sinus. Two-dimensional color flow mapping showed the jet flow to the a...

An 84-year-old woman with hypertension presented to our medical center with dyspnea and lower extremity edema. Electrocardiography demonstrated atrial fibrillation with a rapid ventricular response. Transthoracic echocardiography color Doppler showed abnormal flow in the region of the interatrial septum (Fig. 1A). Transesophageal echocardiography demonstrated a defect adjacent to the interatria...

Etiology of the negative chronotropic response to coronary artery occlusion was studied in chloralose-anesthetized monkeys. One-minute occlusion of the circumflex (CIRC) coronary artery resulted in marked negative chronotropic responses and consistent alterations in atrial electrograms. These responses were dependent on interruption of flow to a small proximal CIRC branch, and postmortem examin...

In anesthetized dogs with the chest open, supramaximal stimulation of the left cardiac sympathetic nerves at 2 and 4 Hz produced an increase of 40-50% in ventricular contractile force (CF) and of 40-65% in coronary sinus blood flow. At these frequencies of stimulation, norepinephrine (NE) overflow into the coronary sinus was 29.8 +/- 5.1 (SE) and 54.9 +/- 13.2 ng/min, respectively. Concurrent, ...