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Biomedical subjects

R Gunnar

Publications and source records attributed to R Gunnar.

6 recordsLinked to original sources
PubMed1983

Effects of low-dose dobutamine on coronary hemodynamics, myocardial metabolism, and anginal threshold in patients with coronary artery disease.

Fourteen patients with coronary artery disease and normal or near-normal left ventricular function were studied at rest and during atrial pacing until the occurrence of angina (12 patients) before and during infusion of dobutamine (3.80 +/- 0.45 micrograms/kg/min). At rest, during the infusion, three patients developed chest pain, mean ST segment depression increased from 0.02 to 0.08 mV (p less than .001), and myocardial lactate extraction fell from +17.5% to -1.4% (p less than .05). These ischemic changes were associated with significant increases in arterial systolic pressure (134 to 149 mm Hg), heart rate (79 to 91 beats/min), coronary sinus flow (89 to 113 ml/min), and myocardial oxygen consumption (10.8 to 13.5 cc/min). In contrast, during atrial pacing, dobutamine did not reduce the pacing threshold or further increase myocardial oxygen consumption or ST segment changes; however, arterial mean and diastolic pressures were significantly lower with pacing during dobutamine infusion compared with control pacing. In the absence of heart failure, dobutamine in low doses can cause myocardial ischemia in patients with coronary artery disease. The absence of increased ischemia from dobutamine during pacing may reflect reversal of pacing-induced ventricular dysfunction.

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PubMed1977

Reversal of advanced left ventricular dysfunction following aortic valve replacement for aortic stenosis.

A series of 12 consecutive patients who underwent aortic valve replacement (AVR) for aortic stenosis complicated by severe left ventricular dysfunction was reviewed. Ventricular dysfunction was reflected by pulmonary congestion, edema, renal and hepatic dysfunction, and by severely depressed ejection fractions (mean, 13%; range equal to 0-20%). Aortic valve replacement was accompanied by mitral commissurotomy in 1 patient and aortocoronary bypass in 5. Three of 5 patients with greater than 50% coronary obstruction died without reversal of heart failure, and 1 of the 5 died after a stroke. The 1 survivor of this group has done well. All 7 patients with minimal or no coronary disease survived operation and are now in New York Heart Association Class I or II. Postoperative catheterization (2 to 12 months) in 6 patients showed improved cardiac index and filling pressures. Left ventricular diastolic volume fell from 159 to 82 ml/m2, and ejection fraction rose from 13 to 45%. We conclude that left ventricular dysfunction owing to aortic stenosis alone is reversible and that AVR results in great clinical improvement. When coronary disease is present, survival may be accompanied by great improvement but the operative mortality is much higher.

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PubMed1976

Balloon counterpulsation following surgery for ischemic heart disease.

Intraaortic balloon counterpulsation (IABC) was used in 40 patients who developed left ventricular pump failure following surgery for ischemic heart disease. The IABC was inserted in the operating room in 32 patients, and within 36 hours of surgery in eight patients. Four patients could not be weaned from cardiopulmonary bypass and died in the operating room. Of the other 36 patients, eight died while on IABC. Twenty-eight patients (70%) were successfully weaned from IABC, although six died later in hospital. Twenty-two patients (55%) survived hospitalization. No late deaths have occurred at 5-33 months of follow-up (mean 16-4 months). Twenty (91%) of 22 survivors are Class I or II at time of this report. Postoperative pump failure occurs because of perioperative acute myocardial infarction and/or major preoperative left ventricular dysfunction. Patients with perioperative infarction who have no prior left ventricular dysfunction have a significantly lower mortality (14%) than do those patients with preoperative left ventricular dysfunction who have subsequent acute perioperative infarction (mortality 67%) P less than 0.05.

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