Biomedical subjects

A T Marmor

Publications and source records attributed to A T Marmor.

8 recordsLinked to original sources

PubMed1991

Comparative evaluation of the effect of afterload- and preload-reducing drugs on diastolic cardiac function in hypertensive patients.

The effects of cilazapril, isosorbide-5-mononitrate (ISMN), hydrochlorothiazide and placebo on systolic and diastolic cardiac function were studied to evaluate the relative importance of afterload and preload reduction on cardiac function in hypertensive patients. In 86 patients with essential hypertension, radionuclide studies were performed before and after a single oral dose of placebo (18 patients), cilazapril 2.5 mg (35 patients), ISMN 20 mg (18 patients) or hydrochlorothiazide 25 mg (15 patients). The effects on blood pressure, heart rate, left ventricular ejection fraction, peak filling rate and time to peak filling rate were measured. Placebo had no significant effect. A comparable blood-pressure-lowering effect was achieved with cilazapril and hydrochlorothiazide. Cilazapril improved diastolic function by increasing the normalized peak filling rate from 2.3 +/- 0.7 to 2.7 +/- 0.7 vol/s (p less than 0.05) and reducing the time to PFR from 174.5 +/- 33.6 to 152.4 +/- 30.8 ms (p less than 0.005). Hydrochlorothiazide and ISMN, however, impaired left ventricular diastolic function: hydrochlorothiazide decreased the normalized peak flow rate from 2.2 +/- 0.6 to 1.9 +/- 0.6 vol/s (p less than 0.05). ISMN prolonged the time to peak flow rate from 176 +/- 36 to 195 +/- 29 ms and increased the percentage of diastole to peak flow rate from 46 to 53% (p less than 0.05), whereas the normalized peak flow rate was unaltered. In conclusion, predominant afterload reduction by cilazapril improves left ventricular diastolic function in hypertensive patients, while preload reduction by diuretics and nitrates impairs it.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1991

Anti-ischemic effects of cilazapril in patients with both hypertension and angina pectoris. Preliminary report of a pilot study.

We report the preliminary findings in the first 12 patients enrolled in a double-blind randomized placebo-controlled study of the antianginal effect of the new angiotensin-converting enzyme inhibitor, cilazapril (2.5 mg once daily) in patients with both hypertension and angina pectoris. After 3 weeks of treatment, placebo had no effect whereas cilazapril significantly prolonged exercise duration. In 2 of the patients on cilazapril, exercise duration was markedly prolonged from 387 to 534 and 352 to 556 s. The maximal ST segment depression was unaltered. It is suggested that in selected patients with both hypertension and angina pectoris cilazapril may have an antianginal effect. A larger study is now underway.

Angina Pectoris↗

PubMed1988

Elevated CK-MB isoenzyme after exercise stress test and atrial pacing in patients with ischemic heart disease.

Using a highly sensitive monoclonal antibody kit for CK-MB, significant release of small amounts of CK-MB isoenzyme after exercise stress test was detected 4 to 6 h after induction of ischemia. This occurred in ten out of 15 patients with ischemic heart disease (66 percent) and in only one of the 18 healthy subjects (5.6 percent) serving as a control group. In five patients with coronary artery disease in whom atrial pacing was performed with simultaneous blood sampling from coronary sinus, a drastic elevation in CK-MB isoenzyme (from 2.04 +/- 2.06 ng/L to 10.88 +/- 6.9 ng/L; p less than 0.001) was detected within 10 to 30 min after induction of acute ischemia. A small but significant increase in total CK also was detected (from 21 +/- 12 IU/L to 52 +/- 14IU/L; p less than 0.01). These preliminary observations have to be further investigated in a larger group of patients before a definitive conclusion can be reached about the clinical significance of CK-MB release during exercise.

Adult↗

PubMed1987

Method for noninvasive measurement of central aortic systolic pressure.

A method for noninvasive generation of central aortic systolic pressure curves is presented. The method is based on plotting the occlusive pressure values applied at the brachial artery level against the time intervals needed for the aortic pressure wave to equalize and break through the occlusive pressure at the brachial artery level. These time intervals were obtained by measuring the time from the beginning of depolarization (the QRS complex) to the detection of the pressure wave at the temporarily occluded brachial artery. The validity of the method was documented by 3 different approaches. The pressure values measured by a device developed by us were superimposed on the simultaneously measured central intra-aortic pressure waves and all values were within one standard deviation from the central aortic recordings in 8 of the 10 patients studied. At the same time, the noninvasively recorded pressure waves were completely different from the peripheral artery pressure recorded simultaneously at the femoral artery site. The DP/DT values derived from the central aortic recordings and the noninvasive device correlated (r = 0.83). These results indicate that the noninvasive device measures the central aortic pressure or a close approximation of it. By combining noninvasive pressure measurements with volume measurements obtained by radionuclide angiography, noninvasive pressure-volume curves were generated in 10 subjects. Possible clinical application of the systolic noninvasive pressure-volume curves is suggested.

Aorta↗

PubMed1987

The value of right atrial emptying rate in predicting reduction in pulmonary artery pressure in patients with chronic obstructive pulmonary disease.

We used an improved noninvasive radionuclide method, recently developed by us, to evaluate changes in pulmonary artery pressure induced by sublingual nifedipine in patients with chronic obstructive pulmonary disease and pulmonary hypertension. The new method enhances the predictive power of right ventricular ejection fraction by using the right atrial emptying rate as an index of reduced right ventricular compliance. The results were compared to those of invasively measured pulmonary arterial pressure. In the 21 patients studied 20 mg of nifedipine sublingually reduced pulmonary arterial pressure by 13.35% from 36.95 +/- 13.95/12.71 +/- 6.24 (mean 20.79 +/- 8.19) mmHg to 32.67 +/- 12.17/10.9 +/- 6.2 (mean 18.16 +/- 7.3) mmHg (p less than 0.05 for all pressures). Cardiac index increased and the pulmonary and systemic resistances decreased. The percent changes in right atrial emptying rate showed an excellent correlation with the percent change in pulmonary pressure. An increase of 12% or more in right atrial emptying rate predicted in all patients a reduction in pulmonary arterial pressure of at least 8%, the specificity and positive predictive accuracy being 100%. The sensitivity and the predictive accuracy of a negative test were 93% and 80%, respectively. The new method is useful for long-term evaluation of drug therapy in patients with pulmonary hypertension.

Blood Pressure↗

PubMed1986

Decrease in global ejection fraction after volume challenge in long-standing hypertension.

An easy noninvasive volume challenge method which takes advantage of the diastolic filling differences existing between patients with recent onset and long-standing hypertension is presented. By passively elevating the patients' legs at 45 degrees for 5 minutes, a sudden increase in venous return was induced in 14 healthy and in 42 hypertensive subjects. The global ejection fraction measured by radionuclide ventriculography increased markedly in both 14 normal subjects and in 18 patients with recent onset hypertension (67 +/- 9% to 75 +/- 6%, p less than 0.001 and 64 +/- 10% to 71 +/- 11%, p less than 0.001, respectively). In contrast, a decrease in global ejection fraction was found in all patients with long-standing hypertension (66 +/- 4% to 58 +/- 10%, p less than 0.001). Similar results were obtained when echocardiographic measurements were made after the legs-up procedure in 24 patients. The correlation with the radionuclide measurements done in the same patients was excellent, r = 0.89. In 20 patients with long-standing hypertension in whom exercise radionuclide ventriculography was done, a marked elevation in global left (LVEF) and right ventricular ejection fraction (RVEF) was found (65 +/- 5% to 71.5 +/- 11% LVEF, and 42 +/- 5% to 45 +/- 7% RVEF, p less than 0.01), whereas the legs-up procedure induced a significant reduction in both global LVEF and RVEF (65 +/- 5% to 57 +/- 6% LVEF, and 44 +/- 7% to 37 +/- 5% RVEF, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1986

Improved radionuclide method for assessment of pulmonary artery pressure in COPD.

An improved method of noninvasive assessment of pulmonary arterial pressure is presented. The already existing radionuclide method for assessment of pulmonary arterial pressure based on right ventricular ejection fraction, although having a relatively good positive predictive accuracy (75 percent), lacks in specificity and correlates only weakly with pulmonary arterial pressure, r = .66. In the present study a diastolic index of the ventricular performance (right atrial early diastolic emptying rate) was used to improve the predictive value of the right ventricular ejection fraction. Phase image analysis was used to differentiate the right atrium from the rest of the cardiac structures, and right atrial emptying rate was calculated after time activity curves were generated. A reasonably good correlation was found between right atrial emptying rate and pulmonary arterial pressure, r = .75. This diastolic index, however, was limited in its ability to detect patients with COPD and normal pulmonary arterial pressure (negative predictive value 62 percent). In order to improve the predictive value of right ventricular ejection fraction, having low specificity (33 percent) but high sensitivity (93 percent), a score index was constructed, combining right ventricular ejection fraction with right atrial emptying rate (having high specificity 100 percent, but modest sensitivity 78 percent). Score index proved to be an excellent indicator of pulmonary arterial hypertension (positive predictive value 93 percent, negative predictive value 100 percent.

Adult↗

PubMed1985

Early detection of diastolic impairment in long-standing hypertension by a noninvasive volume challenge method.

A simple, easily reproducible, noninvasive, provocative test for the assessment of early diastolic impairment in long-standing hypertension is presented. Volume challenge of the heart was produced by elevating the subject's legs to 45 degrees for 5 minutes, thus increasing the venous return to the right heart. Using gated radionuclide ventriculography and Fourier analysis, the atrial structures were delineated and time-activity curves were generated. Early diastolic emptying slope of the left atrium was used to assess left ventricular compliance changes in hypertensives. The left atrial early diastolic emptying rate was markedly reduced in 38 hypertensive patients (45.5 +/- 15.4 counts/s) when compared with 14 healthy subjects (78 +/- 16 counts/s). The legs-up procedure induced subsequent decrease in left atrial emptying rate in patients with long-standing hypertension and left ventricular hypertrophy (-27.4 +/- 11%). In patients with recent onset hypertension there was a depressed early diastolic emptying rate (55.79 +/- 10 counts/s), but a "normal" response to the legs-up procedure (an increase in left atrial emptying rate: 12.84 +/- 7%). Global ejection fraction was normal in all subjects studied, decreasing after induction of augmented venous return in long-standing hypertension. Reduction in left atrial early diastolic emptying rate, caused by the legs-up manoeuvre appears to be an early and sensitive indicator of the left ventricular diastolic impairment in essential hypertension.

Blood Volume↗