Biomedical subjects

C H Hicks

Publications and source records attributed to C H Hicks.

3 recordsLinked to original sources

PubMed1986

Positron imaging of myocardial infarction with rubidium-82.

Positron imaging provides tomographic images of regional myocardial perfusion but has required an on-site cyclotron. Rubidium-82 (82Rb) is a short-lived (T1/2 = 75 sec) positron emitter available from a generator. In order to determine the feasibility for its use to image acute myocardial infarction, 18 patients with transmural infarctions who had coronary arteriography were given 30-40 mCi of 82Rb intravenously and positron tomographic imaging was carried out within 96 hr after onset of symptoms. Nine simultaneous transaxial slices were obtained for each patient with a positron camera. Images were also reconstructed in a long-axis, short-axis, and three-dimensional display. One study could not be interpreted because of excessive lung activity. Fourteen normals were also studied. The infarct related artery determined by angiography was correctly diagnosed by positron imaging in all 17 patients as were all three prior infarcts by readers blinded to the clinical data. No defects were observed in normals or in noninfarcted myocardial regions. This study indicates that 82Rb should be useful for perfusion imaging in patients with acute myocardial infarction. The short half-life of 82Rb should make it ideal for providing serial assessment of perfusion in patients undergoing thrombolytic therapy.

Acute Disease↗

PubMed1984

Congestive heart failure with normal systolic function.

Although there have been isolated reports of congestive heart failure (CHF) with normal systolic function, the prevalence and characteristics of this condition have not previously been described. Accordingly, 188 patients with CHF undergoing radionuclide ventriculography were prospectively evaluated. Sixty-seven (36%) had a normal ejection fraction (EF) of 0.45 or greater, and 121, an abnormal EF of less than 0.45. Of these, 72 (55 with an abnormal EF [group I] and 17 with a normal EF [group II]) were also reviewed for clinical characteristics. There was no demographic difference between groups, except that systemic hypertension appeared to be a contributing factor in 65% of the patients in group II, compared with 23% of the patients in group I (p less than 0.002). Echocardiographic left atrial emptying index, reflecting left ventricular compliance, was determined in 72 patients and 14 normal subjects. Left atrial emptying index in normal control subjects was 0.93 +/- 0.11 (+/- standard deviation), compared with 0.41 +/- 0.18 in group I and 0.44 +/- 0.19 in group II patients (p less than 0.001 vs control in both groups). Thus, normal systolic function is common among patients with CHF. Diastolic dysfunction, consistent with a noncompliant left ventricle, was found in both CHF groups.

Echocardiography↗

PubMed1983

Sustained improvement in left ventricular function and mortality by intracoronary streptokinase administration during evolving myocardial infarction.

One hundred eighty-eight patients with acute myocardial infarction were studied prospectively from August 1980 to September 1982. One hundred thirty-six of these patients were entered into a intracoronary streptokinase study after informed consent was obtained. The remaining 52 patients, who either met exclusion criteria for the study or refused to participate, served as a control group and were treated as those in the study group except that they did not undergo emergency cardiac catheterization. Left ventricular function was determined in both groups by gated radionuclide ejection fraction (EF) on admission to the hospital, at discharge, and 6 months after discharge. With successful reperfusion up to 18 hr after onset of chest pain, mean left ventricular function in the study group improved (EF 39 +/- 13% on admission and 46 +/- 12% at discharge; p less than .001). Mean EF in control patients and those not achieving reperfusion did not change from admission to discharge. Mean EF at 6 month follow-up was not significantly different than at discharge in the study group or the control group. Total cardiac mortality in the control group was 19% compared with 10% in the study group (p = .06, NS). When patients admitted in pulmonary edema or shock (Killip class III or IV) were excluded from both groups, total cardiac mortality in the study group was significantly lower (4%) compared with in the control group (12.5%, p less than .05. The administration of intracoronary streptokinase during evolving myocardial infarction up to 18 hr after onset of chest pain may result in decreased mortality and sustained improvement in left ventricular function.

Aged↗