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Biomedical subjects

P F Cohn

Publications and source records attributed to P F Cohn.

At least 163 records · Page 9Linked to original sources
PubMed1975

Right ventricular performance in patients with coronary artery disease.

While left ventricular (LV) performance in patients with coronary artery disease (CAD) has been extensively investigated, little attention has been given to right ventricular (RV) function in this disease. For this purpose, a new geometric model for RV volume has been developed and RV end-diastolic volume index (EDVI), end-systolic volume index (ESVI), stroke volume index (SVI) and ejection fraction (EF) have been determined from biplane RV cineangiograms in 26 patients. Eight patients served as normal (control) subjects (group I). Eighteen patients with obstructive CAD comprised two other groups: six who had no significant disease of the right coronary artery (RCA) (group II) and 12 who had a high grade RCA lesion (group III). The mean values for EDVI, SVI and EF in group I were 76 +/- 11 ml/m2, 50 +/- 6 ml/m2, and 66 +/- 6%. The only significant difference between groups I and II was that SVI was lower in group II than in group I (P less than 0.01). No measurements in groups II and III were statistically different from each other. However, markedly subnormal values were found in group III (EDVI: 61 +/- 16 ml/m2, SVI: 33 +/- ml/m2 and ef: 52 +/- 7%); all values being significantly lower (SVI and EF: P less than 0.001; EDVI: P less than 0.05) than in group I. RV end-diastolic pressure was normal in all patients. These findings may related to 1) reduced RV compliance, 2) distorted LV geometry, 31 possible RV ischemia or 4) reduced Frank-Starling effect.

Adult↗
PubMed1975

Detection of latent function in acutely ischemic myocardium in the dog: comparison of pharmacologic inotropic stimulation and postextrasystolic potentiation.

In poorly perfused myocardium with resultant ischemic dysfunction, augmentation of contractility can, under certain conditions, be used to detect viable but ordinarily noncontracting muscle. Two methods of inotropic augmentation, pharmacologic inotropic stimulation and postextrasystolic potentiation (PESP), were studied in acutely ischemic canine myocardium with controlled coronary blood flow. A caliper length gauge to record segmental shortening and left ventricle pressure was used to construct pressure-length loops. Acute regional ischemia depressed segmental function: early segmental shortening decreased (-20 plus or minus 0.02% [SE]) and frequent dyskinesia occurred. Restoring coronary blood flow corrected segmental shortening to control levels. During acute regional ischemia, PESP consistently augmented segmental function (+49 plus or minus 0.03%) and abolished dyskinesia. Pharmacologic inotropic stimulation with isoproterenol or calcium administered into the coronary arteries did not produce a comparable improvement in segmental function (+9 plus or minus 0.05%). Although early shortening markedly increased with pharmacologic stimulation, there was no consistent change in total shortening, and the area of the pressure-length loop decreased. Due to late dyskinesia, there was a decrease in injection shortening. Systemically administered pharmacologic agents accentuated early dyskinesia but caused no consistent change in total shortening. Unlike PESP, pharmacologic agents either worsened segmental function or caused responses that were minimum and inconsistent; such responses clearly cannot be used to identify viable ischemic myocardium.

Acute Disease↗
PubMed1974

Hemoglobin affinity for oxygen in the anginal syndrome with normal coronary arteriograms.

Oxyhemoglobin dissociation (OHD) curves were performed on whole blood (WB) from 20 patients with anginal pain, normal hemodynamics, and normal coronary arteries, as demonstrated by selective coronary cinearteriography. OHD curves in 19 of 20 patients, from zero to full saturation, were nearly identical to those in normal control subjects with values for P(50) (Po(2) at 50% saturation and pH 7.4) of 26.7+/-1.5 (mean+/-SD of the mean) torr (mm Hg) and red blood cell (RBC) levels of 2,3-diphosphoglyceric acid (2, 3-DPG) of 0.72+/-0.10 (mean+/-SD of the mean) M/M hemoglobin (Hb). Normal values for nonsmoking adults were: P(50), 26.6+/-1.4 (mean+/-SD of the mean) torr: and RBC 2,3-DPG, 0.81+/-0.09 (mean+/-SD of the mean) M/M Hb. Mean levels of carbon monoxide were normal at 0.14+/-0.01 (mean+/-SEM) ml/100 ml WB in 10 patients who were nonsmokers and 0.45+/-0.15 (mean+/-SEM) ml/100 ml WB in 10 smokers. In one patient, a heavy smoker with markedly elevated blood carbon monoxide levels, an abnormal leftward shift of the OHD curve was observed. This was corrected after discontinuation of smoking. In utilizing these methods, we could not detect consistent abnormalities of Hb affinity for oxygen at rest in the patients studied, which suggests that a defect in oxygen transport at rest is an unlikely explanation for the symptoms of chest pain in patients with the anginal syndrome and normal coronary arteriograms.

Adult↗