PubMed Health⌕ Search

Biomedical subjects

G G Rowe

Publications and source records attributed to G G Rowe.

At least 37 records · Page 2Linked to original sources
PubMed1977

Carpentier ring annuloplasty in severe noncalcific mitral insufficiency.

Sixteen patients have undergone Carpentier ring annuloplasty for severe mitral insufficiency (MI) since 1974. Our criteria were clinical and angiographic evidence of severe noncalcific MI, a dilated mitral anulus, absence of severe subvalvular chordal thickening, and no major loss of leaflet substance. Carpentier annuloplasty has been successful in eliminating MI in every patient except one. There have been no embolic problems and no early or late deaths. From 1971 to 1974, a similar group of 20 patients with the same diagnosis underwent prosthetic valve replacement. Even though all patients were receiving anticoagulant drugs, three had emboli and there were one early and three late deaths. In patients with severe noncalcific MI who meet our criteria, Carpentier ring annuloplasty is preferable to valve replacement, thus eliminating the hazards of a prosthesis and of long-term anticoagulant therapy.

Heart Valve Prosthesis↗
PubMed1977

Asymptomatic left ventricular aneurysm: a sequela of blunt chest trauma.

A routine chest X-ray taken four months after blunt chest trauma revealed a left ventricular aneurysm in a totally asymptomatic patient. At surgery a thin-walled, clot-filled aneurysm was successfully removed. This case demonstrates the need for careful follow-up of all patients sustaining blunt chest trauma even though the initial cardiac evaluation may be negative. Our feeling that all such aneurysms should be treated surgically is further reinforced by our operative findings.

Adult↗
PubMed1977

The acute systemic and coronary hemodynamic effects of acetaldehyde.

Acute coronary and systemic hemodynamic effects of acetaldehyde before and subsequent to beta adrenergic blockade by propranolol were studied in intact anesthetized dogs. Acetaldehyde produces a sympathomimetic effect compatible with catecholamine release as seen by an increase in heart rate, cardiac output, pulmonary and systemic pressures and body oxygen consumption. The marked decrease in coronary vascular resistance and increase in coronary blood flow is blocked to only a minor degree by propranolol, indicating that a major part of its action on the coronary circulation is not due to catecholamine release. Acetaldehyde dilates large coronary vessels and appears to increase collateral blood flow to obstructed arteries, as determined by angiographic study.

Acetaldehyde↗
PubMed1977

The systemic and coronary hemodynamic effects of intracoronary arterial tolazoline (Priscoline).

Intracoronary injection of tolazoline in dogs produces transient coronary vasodilatation with marked reduction in the arteriovenous oxygen difference and little change in myocardial oxygen consumption. At lower doses coronary effects are produced almost exclusively but as the dose increases, systemic cardiovascular changes occur also. No fatalities occurred even with large doses of tolazoline into the coronary arteries of these healthy dogs. Since intraarterial tolazoline is used to improve visualization of vascular beds in other portions of the body, its possible use for coronary arteriography is discussed.

Animals↗
PubMed1977

Hemodynamic effects of controlled degrees of coronary artery stenosis in short-term and long-term studies in dogs.

Coronary and aortic blood flow, aortic and distal coronary blood pressure were measured with electromagnetic flowmeters and pressure gauges in 15 anesthetized dogs with the chest left open. Increasing degrees of known, fixed, partial coronary artery obstruction were applied with concentric plastic cylinders 3 mm. in length and with varying internal diameters. Because these plastic cylinders are radiolucent and can also be permanently implanted, postoperative arteriograms were taken to evaluate the degree of stenosis produced. At necropsy the degree of obstruction was checked by ligating and removing the narrowed vessel and examining a histologic section of a stenosed portion. The reactive hyperemic response to a 20 second complete occlusion was recorded with amounts of obstruction varying from 10 to 90 per cent. The reactive hyperemia began to decrease with an average of 36 +/- 10 per cent stenosis. A pressure gradient of 10 mm. Hg across the obstruction occurred with an average of 57 +/- 8 per cent stenosis. The reactive hyperemic response was abolished with an average of 75 +/- 6 per cent stenosis, and with greater degrees of stenosis the total flow began to decrease below control levels. The phasic coronary flow pattern was also altered with increasing amounts of fixed partial obstruction. As the per cent of stenosis was increased, the ratio of diastolic to systolic coronary flow decreased. When reactive hyperemia was abolished, very little diastolic-to-systolic variation remained.

Animals↗
PubMed1976

Platelet aggregation in partially obstructed vessels and its elimination with aspirin.

In 35 open chest anesthetized dogs coronary and aortic blood flow were measured with electromagnetic flowmeters while aortic and distal coronary blood pressure and an epicardial ECG were recorded. A fixed amount of stenosis (60-80%) was produced in the coronary artery by an externally applied plastic cylinder. In 24 of the 35 dogs the coronary blood flow showed cyclical reductions to near zero, with a sudden spontaneous return to near control levels. During reduced flow the epicardial ECG showed ST-segment depression suggestive of ischemia, and ventricular premature beats were often noted. Six animals died acutely during episodes of reduced flow. After 35 mg/kg of aspirin were given intravenously the cyclical reductions in coronary blood flow were abolished and the in vitro platelet aggregations were reduced from a control of 62.1 +/- 15 units (Born technique) to an average of 23.7 +/- 12 units. Histologic sections of the narrowed coronary artery obtained when coronary flow was reduced show an amorphous mass in the lumen which was thought to be a platelet aggregate. Perhaps a similar process of platelet aggregation occurs in the stenosed coronary arteries in man, producing acute coronary obstruction, ischemia, and sudden death.

Animals↗
PubMed1975

Systemic and coronary haemodynamic effects of ketamine in intact anaesthetized and unanaesthetized dogs.

Ten intact anaesthetized dogs breathing room air spontaneously (Group A) were compared with ten artificially ventilated dogs (Group B). All were given a bolus of ketamine 2 mg/kg followed by a 20-min infusion of ketamine 0.1 mg/kg/min. In Group A, coronary sinus blood flow, measured with a thermodilution flowmeter, increased by 90% while coronary vascular resistance decreased by 28% and coronary sinus oxygen content decreased by 27%. Heart rate increased by 47%, and arterial pressure by 9%. Cardiac output, calculated by the dye dilution method, increased by 29%, while the left ventricular work index decreased by 50%. Minute ventilation rate decreased by 55%. The Group B dogs were studied as described above, except that they were artificially ventilated. The haemodynamic ahanges were less in Group B, possibly because of improved arterial oxygenation. Heart rate increased by 24%, cardiac output by 21% and arterial pressure by 2%. The coronary sinus blood flow increased by 12% while coronary vascular resistance decreased by 11%. Coronary sinus oxygen concentration decreased by 15%. Five unanaesthetized dogs with electromagnetic flowmeter probes chronically implanted on the aorta and circumflex coronary artery, and an indwelling arterial catheter were studied before, during and after the intravenous administration of ketamine 2, 4, and 8 mg/kg. A dose of 8 mg/kg produced increases in cardiac output, heart rate and arterial pressure of 21%, 44% and 24%, respectively, while coronary blood flow increased 47%. We conclude that, in healthy dogs, ketamine produces an increase in heart rate and cardiac work. A significant increase in coronary blood flow appears to be insufficient to meet the metabolic demands of the myocardium, as the coronary sinus oxygen content decreased.

Anesthesia, General↗
PubMed1975

Congenital diverticulum of the right and left ventricles.

An asymptomatic congenital cardiac diverticulum was seen on a routine chest film in a 45-year-old man. Right atrial and left ventricular cineangiography showed that the diverticulum communicated independently with both ventricles. There was no evidence of heart failure, arrhythmia, or mural thrombus, and surgery was not deemed necessary.

Diverticulum↗
PubMed1975

A technique for measurement of retrograde coronary blood flow in intact anesthetized dogs.

A technique for measurement of retrograde coronary blood flow in intact anesthetized dogs is described. Occlusion of the coronary artery is produced by the inflation of a small rubber balloon at the tip of a no. 9 cardiac catheter placed under fluorescopy in a branch of the left coronary artery. Blood which bleeds back from the occluded coronary artery through the no. 9 catheter is diverted into a small reservoir of 1-ml capacity. The time to fill this reservoir is recorded electrically. Retrograde coronary blood flow is calculated from the time required to fill this reservoir. Results indicate good repeatability of meadurements. The technique seems to be a simple, adequate, and convenient means for assessing agents for possible vasodilator action on the collateral circulation in intact animals.

Animals↗
PubMed1975

Effects of partial obstruction on phasic flow in aortocoronary grafts.

Phasic blood flow recorded in five unobstructed dog aortocoronary bypass grafts to the left coronary artery was similar to that of normal coronary arteries, with a high diastolic-to-systolic flow ratio which averaged 2.7 +/- 0.4. With an average of 52 +/- 7% and 72 +/- 6% stenosis in the coronary artery distal to the graft, the phasic graft-flow pattern was altered, with a decrease in the diastolic-to-systolic flow ratio to 1.9 +/- 0.4 and 1.2 +/- 0.4, respectively. Phasic patterns recorded in 42 human saphenous vein grafts to branches of the left coronary artery subsequently shown to be patent by postoperative coronary arteriography were similar to those of a normal coronary artery, with an average diastolic-to-systolic flow ratio of 2.3 +/- 0.83 and an average flow of 76 +/- 48 ml/min. Phasic flow measured in 20 grafts shown to be occulded at restudy had an average diastolic-to-systolic flow of 1.3 +/- 0.45, with an average flow of 72 +/- 33 ml/min and a phasic graft flow which was similar to that obtained from partially obstructed coronary arteries. We conclude that partial obstruction of the graft or the distal coronary artery alters the flow pattern, and this partial obstruction may lead to closure of the graft.

Animals↗
PubMed1974

Indomethacin and the prostaglandin hypothesis of coronary blood flow regulation.

1. Recent experimental data support the view that prostaglandins might be involved in autoregulation of coronary blood flow. Since indomethacin blocks prostaglandin synthesis, the present study was performed to determine whether indomethacin also inhibits coronary vasodilatation induced by hypoxia.2. Coronary and systemic haemodynamic and metabolic effects of hypoxia (5% and 8% oxygen in nitrogen) were studied in intact, anaesthetized and vagotomized dogs before and after indomethacin.3. 30 and 60 min after administration of indomethacin coronary blood flow increases produced by hypoxia were considerably lower than those before indomethacin.4. These results are held to lend support to the hypothesis that prostaglandins are involved in the autoregulation of coronary blood flow.

Animals↗