Noninvasive evaluation of left ventricular diastolic function by radionuclide angiography: limitations and applications

Left ventricular function in young adults with childhood and adulthood onset growth hormone deficiency

OBJECTIVE

The impairment of heart structure and function in adults with childhood onset GH deficiency has been recently described. However, previous echocardiographic studies have reported no differences in cardiac mass and function between adulthood onset GH deficient patients and healthy subjects.

DESIGN

The aim of this study was to evaluate cardiac performance in adult patients with childhood and adulthood onset GH deficiency, using equilibrium radionuclide angiography, a method more accurate than echocardiography.

PATIENTS

Eleven patients with childhood onset GH deficiency, 9 patients with adulthood onset GH deficiency and 12 age-, gender-, height- and weight-matched healthy subjects entered the study.

MEASUREMENTS

All the study population underwent equilibrium radionuclide angiography at rest and during physical exercise.

RESULTS

Both childhood and adulthood onset GH deficient patients had an impaired left ventricular systolic performance both at rest (ejection fraction was 55 +/- 6%, 55 +/- 10% and 66 +/- 6% in childhood and adulthood onset GH deficient patients and control group, respectively; P < 0.0001) and during physical exercise (ejection fraction was 54 +/- 9% in childhood onset GH deficient patients, 53 +/- 9% in adulthood onset GH deficient patients and 76 +/- 7% in normal subjects; P < 0.0001). Peak ejection rate was 3.2 +/- 0.8 end-diastolic volume/second, 3.0 +/- 0.6 end-diastolic volume/second and 3.9 +/- 0.8 end-diastolic volume/ second in childhood and adulthood onset GH deficient patients and control group, respectively (P < 0.01). Exercise-induced changes in end-systolic volume were increased in both groups of patients compared with healthy subjects. In contrast, exercise-induced end-diastolic volume changes were not different between GH deficient patients and controls. Resting peak filling rate was 2.6 +/- 0.7 end-diastolic volume/second, 2.5 +/- 0.7 end-diastolic volume/ second and 3.1 +/- 0.3 end-diastolic volume/second in the 2 groups of patients and healthy subjects, respectively (P < 0.05). Reduced exercise tolerance in all patients, as shown by the significantly lower values of peak workload (P < 0.0001), peak rate-pressure product (P < 0.01) and exercise duration (P < 0.0001) was observed.

CONCLUSION

Patients affected by GH deficiency have left ventricular systolic dysfunction at rest and during physical exercise, suggesting that GH plays a physiological role in maintaining normal cardiac performance in humans. Furthermore, no difference between childhood and adulthood onset GH deficient patients was found indicating that both group of patients have an impairment of cardiac function.

Improved left ventricular function after growth hormone replacement in patients with hypopituitarism: assessment with radionuclide angiography

Prolonged growth hormone deficiency (GHD) leads to marked cardiac dysfunction; however, whether reversal of this abnormality may be achieved after specific replacement therapy has not yet been completely clarified. Fourteen patients with childhood-onset GHD (nine men and five women, mean age 27+/-4 years) and 12 normal control subjects underwent equilibrium radionuclide angiography under control conditions at rest. Patients with GHD were also studied 6 months after recombinant human (rh) GH treatment (0.05 IU/kg per day). Normal control subjects and patients with GHD did not differ with respect to age, gender and heart rate. In contrast, left ventricular ejection fraction (53%+/-9% vs 66%+/-6%, P <0.001), stroke volume index (41+/-11 vs 51+/-8 ml/m2, P <0.01) and cardiac index (2.8+/-0.6 vs 3.+/-0.5 l/min/m2, P <0.001) were significantly lower in GHD patients than in normal control subjects. None of the GHD patients showed adverse or side-effects during rhGH therapy; thus none required a reduction in GH dose during the treatment period. Heart rate and arterial blood pressure were not significantly modified by rhGH treatment. After 6 months of rhGH therapy a significant improvement in left ventricular ejection fraction (from 53%+/-9% to 59%+/-9%, P <0.01), stroke volume index (from 41+/-11 to 47+/-13 ml/m2, P <0.05) and cardiac index (from 2.8+/-0.6 to 3.3+/-0.8 l/min/m2, P <0.01) was observed in GHD patients. In conclusion, prolonged lack of GH leads to impaired left ventricular function at rest. Reversal of this abnormality may be observed after 6 months of specific replacement therapy in patients with childhood-onset GHD.

Early experience with dobutamine stress testing and cardiac cine-tomographic imaging in the elderly: antianginal effects of nifedipine-GITS

OBJECTIVE

To determine the effects of nifedipine-GITS (GITS = gastrointestinal transport system) on angina and cardiovascular responses to stress-dobutamine infusion, we used ultrafast cine-computed tomography (CT) to assess regional wall motion, myocardial perfusion, and indices of ventricular filling and emptying.

DESIGN

Randomized, double-blind placebo-controlled efficacy study after an open-label dose titration phase.

SETTING

University of California, San Francisco.

PATIENTS

Elderly patients (> 60 years; n = 9:8 male, 1 female) with coronary artery disease by history and diagnostic treadmill or coronary angiography.

INTERVENTION

After a 3-week open-label dose-titration phase, eight subjects were randomized to receive either placebo or nifedipine-GITS at the highest tolerated dose for 2 weeks, followed by a crossover to the alternate therapy for 2 weeks. One declined because of singulus in the open-label period.

MAIN OUTCOME MEASURES

Symptomatic angina relief (frequency and nitroglycerin consumption), dobutamine stress responses (time to ischemia during dobutamine infusions, cardiac output, cardiac ejection fraction, ventricular segmental wall motion, and perfusion as measured by ultrafast cine-CT), and reported adverse effects.

RESULTS

When compared with placebo, nifedipine-GITS administration was associated with less frequent angina and nitroglycerin consumption (NS) and significantly decreased systolic blood pressure. Nifedipine-GITS administration also increased resting supine heart rates. Dobutamine infusions increased heart rate, cardiac output, cardiac ejection fraction, and stroke volume and induced angina symptoms. Neither double product at angina nor systolic indices of cardiac function in response to dobutamine differed between nifedipine-GITS and placebo, although heart rate responses were greater during nifedipine. A trend toward increased peak filling rates was seen during dobutamine stress in the nifedipine-administration period. In most subjects (6/8), perfusion and regional wall motion abnormalities were not visualized on regional wall motion abnormalities were not visualized on either rest or stress cine-CT studies. Edema without congestive heart failure occurred frequently during nifedipine-GITS administration.

CONCLUSIONS

These data suggest that (1) dobutamine stress can be used to induce cardiac ischemia in elderly patients with coronary artery disease, (2) nifedipine-GITS provides symptomatic angina relief in elderly patients, (3) peripheral edema is frequent in elderly patients on nifedipine-GITS, and (4) ultrafast computed cine-tomography testing can be used to assess ventricular performance, but current methodology may not detect perfusion or wall motion abnormalities during angina.

Cross-sectional echocardiography: a window on congestive heart failure in the elderly

The value and limits of ultrasonic cardiac imaging in elderly patients with congestive heart failure (CHF) are not yet fully known. We report the results of an echocardiographic survey on 154 consecutive elderly persons with chronic CHF. The aim of this study was to establish the feasibility and the diagnostic yield of echocardiography in this population, and the relationship, if any, between left ventricular systolic function and main clinical parameters. Satisfactory cardiac imaging was achieved in 118 patients (77%). All patients had abnormal echocardiograms, although no single abnormal finding was present in all the cases. Echocardiography (ECHO) confirmed 147 previously diagnosed CHFs, and further detected a silent coronary artery disease in 26 cases, a valvular disease in 22, and an atrial septal defect in one patient. The most frequent findings were left ventricular (LV) mass increase and dilation (70% and 68%, respectively), and mostly degenerative valvular disease (40%). The LV ejection fraction was within normal limits in 44% of the cases. Although a depressed LV systolic function was more common among patients in III or IV NYHA class, no clinical parameters could identify the 52 patients with normal ejection fraction. Thus, ECHO could play a key role in evaluating CHF in elderly patients. In these patients, due to misleading signs and symptoms, and to multiple CHF etiologies, basic structural and functional features are frequently missed by clinical investigation, chest x-ray and electrocardiography.

Diastolic disease in left ventricular hypertrophy: comparison of M mode and Doppler echocardiography for the assessment of rapid ventricular filling

OBJECTIVE

To investigate possible discrepancies between M mode and Doppler echocardiography in assessing early diastolic filling.

DESIGN

Forty seven patients with left ventricular hypertrophy due to aortic stenosis and 26 healthy controls with a similar age range were studied by M mode, Doppler, apexcardiography, and phonocardiography. The patients also underwent cardiac catheterisation. M mode echograms were digitised by a computer. Early diastolic filling in both groups as assessed by the two techniques was compared.

SETTING

A tertiary cardiac referral centre with facilities for non-invasive and invasive investigations.

SUBJECTS

Patients referred for assessment of aortic stenosis who had left ventricular hypertrophy.

MAIN OUTCOME MEASURES

Filling velocities on Doppler and rates of wall thinning and dimension increase on M mode.

RESULTS

Digitised M mode indices of diastolic filling (peak wall thinning rate 6.4 (3.0) v 10.0 (3.0) cm/s and peak rate of dimension increase 9.3 (3.3) v 16 (4.5) cm/s) in the patients and controls were consistently different. In contrast, the Doppler A/E ratio and peak E wave velocity were not; they varied widely among patients with left ventricular hypertrophy. In part, this variability was because the Doppler A/E ratio, but not the digitised M mode indices, was very sensitive to the abnormalities of isovolumic relaxation frequently present in left ventricular hypertrophy. The Doppler A/E ratio varied similarly with age in both normal and hypertrophied hearts; in the patients with ventricular hypertrophy the peak rate of dimension increase depended on age only, whereas the thinning rate was independent of age in both the patients and controls. Neither the A/E ratio nor the M mode indices could be related to the left ventricular end diastolic pressure or the peak aortic pressure difference.

CONCLUSIONS

When Doppler and M mode techniques are used to assess rapid filling in patients with left ventricular hypertrophy the M mode indices are more consistently abnormal. The two methods measure different aspects of left ventricular diastolic function and should be regarded as complementary rather than interchangeable.

Hypertension and left ventricular diastolic function

In recent years, there has been increased recognition of the relative importance of abnormalities of diastolic function in patients with essential hypertension. Indeed, diastolic dysfunction may be the earliest indicator of hypertensive heart disease. In this article, the mechanisms governing normal ventricular relaxation and the factors that may cause diastolic dysfunction are reviewed. Noninvasive clinical methods, particularly Doppler echocardiography and radionuclide angiography, for determination of diastolic function are outlined, and the limited experience in the management of hypertensive patients with abnormalities of diastolic function is discussed. When congestive heart failure develops in a patient with hypertension, it is especially important to determine whether it is due primarily to systolic or to diastolic left ventricular dysfunction.

Diastolic function in patients with aortic stenosis: influence of left ventricular load reduction

Pressure overload hypertrophy of the left ventricle due to aortic stenosis is associated with abnormalities of left ventricular isovolumic relaxation and early diastolic filling. The relative contribution of the hemodynamic load on the left ventricle to the impairment of diastolic function observed in this disorder remains poorly understood. To study this relation, the vasodilator nitroprusside was administered to eight patients with aortic stenosis and normal systolic function. The effect of a short-term reduction in left ventricular preload and afterload on left ventricular isovolumic relaxation and early diastolic filling was assessed by analysis of simultaneous micromanometer left ventricular pressure and radionuclide angiographic volume measurements. At baseline, left ventricular systolic and end-diastolic pressures were markedly elevated, and associated with prolongation of the time constant of left ventricular relaxation and depression of the left ventricular peak filling rate. Infusion of nitroprusside resulted in reduction of left ventricular systolic (204 +/- 31 to 176 +/- 31 mm Hg, p less than 0.05) and end-diastolic (31 +/- 8 to 18 +/- 6 mm Hg, p less than 0.05) pressures, with no associated improvement in time constant of left ventricular pressure decay (T) (68 +/- 25 to 80 +/- 37 ms, p = NS), T 1/2 (34 +/- 8 to 34 +/- 14 ms, p = NS), left ventricular peak filling rate (2.3 +/- 0.5 to 2.3 +/- 0.8 end-diastolic volume/s, p = NS) or time to left ventricular peak filling rate (150 +/- 50 to 144 +/- 37 ms, p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of postural changes, nitroglycerin and verapamil on diastolic ventricular function as determined by radionuclide angiography in normal subjects

Whereas improvement in diastolic function indexes in response to therapeutic interventions has been attributed to a beneficial effect of the intervention, measurements of diastolic function appear to be influenced by changes in loading conditions, heart rate and sympathetic tone. To determine the effect of body position and short-term pharmacologic intervention on radionuclide angiographically determined left ventricular peak filling rate, high temporal resolution time-activity curves and absolute left ventricular volumes obtained by equilibrium-gated blood pool scans were evaluated in 12 normal subjects in the supine position at rest and in response to several postural and pharmacologic manipulations. This study confirmed the reproducibility of the technique and demonstrated that in normal subjects, peak filling rate varies in response to changes in body position and to short-term administration of sublingual nitroglycerin and intravenous verapamil. Peak filling rate ranged from 3.3 to 5.1 end-diastolic volumes (EDV)/s with a variability of 13.7% during five baseline supine measurements in the 12 subjects. Compared with values in the supine position (mean +/- SEM = 4.38 +/- 0.24 EDV/s), peak filling rate increased +16 +/- 6% to 4.75 +/- 0.27 EDV/s in the upright position (p less than 0.05) but did not change significantly with leg elevation. Peak filling rate at baseline and during postural changes correlated significantly with ejection fraction (r = +0.49), with stroke volume (r = +0.26) and inversely with end-systolic volume (r = -0.41), but did not correlate with heart rate or blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of verapamil on left ventricular diastolic filling in children with hypertrophic cardiomyopathy

The effects of oral verapamil on resting left ventricular (LV) diastolic filling were examined in 10 children and adolescents with hypertrophic cardiomyopathy. Measurements of diastolic filling were made from gated technetium-99m radionuclide angiograms with postbeat rejection of data outside a 5% RR-interval window. LV time-activity curves were generated and the rapid-filling phase fit with a 3 degrees polynomial to calculate the peak filling rate and the time from end-systole to the point of peak filling. All patients had a radionuclide angiogram performed before and after 0.25 to 3 years of oral verapamil therapy. Verapamil did not change the LV ejection fraction but increased the peak filling rate (3.24 +/- 0.15 to 4.62 +/- 1.05 end-diastolic volume/s,p less than 0.01) and reduced the time to peak filling (217 +/- 57 to 168 +/- 63 ms, p less than 0.01). An increase in exercise endurance as measured by exercise treadmill test and subjective symptomatic improvement were also seen after verapamil therapy. Thus, in children with hypertrophic cardiomyopathy, symptomatic improvement and LV diastolic filling parameters improved with long-term oral verapamil.

Radionuclide assessment of left ventricular diastolic filling in diabetes mellitus with and without cardiac autonomic neuropathy

Indexes of left ventricular diastolic filling were measured by radionuclide ventriculography in 28 patients with insulin-dependent diabetes mellitus without evidence of ischemic heart disease. Six patients (21%) had abnormal diastolic filling and differed from diabetic patients with normal filling in their greater severity of cardiac autonomic neuropathy, assessed by noninvasive means, and their lower plasma norepinephrine levels in the supine (131.1 +/- 24.7 versus 356.2 +/- 58.4 pg/ml, p less than 0.01) and upright (224.9 +/- 47.8 versus 673.3 +/- 122.3 pg/ml, p less than 0.005) positions. The diabetic patients determined as having cardiac autonomic neuropathy (n = 15) had depressed left ventricular diastolic filling compared with subjects free of autonomic neuropathy, whether measured as the time to peak filling rate (154.2 +/- 12.0 versus 119.1 +/- 10.6 ms, p less than 0.05) or the time to peak filling rate normalized to the cardiac cycle length (24.3 +/- 2.2 versus 16.2 +/- 1.5%, p less than 0.01). Of the various tests of autonomic nervous system function, the strongest correlate of impaired diastolic filling was orthostasis, measured as the decrease in systolic blood pressure with standing (r = 0.584, p less than 0.001). Thus, in patients with diabetes mellitus, alterations in sympathetic nervous system activity are associated with abnormalities of left ventricular diastolic filling.

Improvement in indexes of diastolic performance in patients with congestive heart failure treated with milrinone

To elucidate the mechanisms by which the new bipyridine inotropic agent milrinone improves cardiac function, we examined multiple indexes of left ventricular diastolic function before and after administration of milrinone to patients with advanced (NYHA class III or IV) congestive heart failure. In 13 patients left ventricular pressure measurements were made with a micromanometer to permit assessment of peak negative dP/dt and the time constant of left ventricular isovolumic relaxation, T, before and after milrinone. In nine patients radionuclide ventriculographic studies were performed during left heart catheterization, allowing calculation of left ventricular peak filling rate, volumes, and the diastolic pressure-volume relationship before and after milrinone. After intravenous administration of milrinone, peak negative dP/dt increased (+ 18%; p less than .01) and T decreased (-30%; p less than .01), while heart rate increased by only 8% (87 +/- 12 to 94 +/- 15 beats/min; p less than .01), left ventricular systolic pressure did not change, and mean aortic pressure fell by 11% (p less than .01). Left ventricular peak filling rate increased (1.2 +/- 0.6 to 1.7 +/- 0.7 end-diastolic volumes/sec; p less than or equal to .02) despite a decrease in left ventricular filling pressure (mean pulmonary wedge pressure 27 +/- 7 to 18 +/- 9 mm Hg; p less than .01). There was a fall in left ventricular end-diastolic pressure (28.6 +/- 6 to 19 +/- 7 mm Hg; p less than or equal to .01), with no significant change in left ventricular end-diastolic volume. This was associated with a downward shift in the left ventricular diastolic pressure-volume relationship in most cases.(ABSTRACT TRUNCATED AT 250 WORDS)