Assessment of diastolic filling indexes obtained by radionuclide ventriculography

Assessment of Atypical Cardiovascular Risk Factors Using Single Photon Emission Computed Tomography in Mexican Women

BACKGROUND

Ischemic heart disease (IHD) is a health care problem in women that increases morbimortality, particularly in developing countries. There is limited information regarding atypical risk factors associated with IHD in Mexican women.

AIM

To explore risk factors in women that could contribute to IHD and myocardial dysfunction using the single photon emission computed tomography (SPECT) myocardial perfusion study (MPS).

METHODS

We designed a cross-sectional study in which we evaluated atypical and typical risk factors using a clinical questionnaire. We performed a SPECT-MPS to evaluate the presence of ischemia/infarction, decreased left ventricular ejection fraction, systolic dyssynchrony and diastolic function by peak filling rate and time to peak filling rate.

RESULTS

172 women were included, 64 with IHD. Adverse events during pregnancy (premature birth and miscarriage), rheumatoid arthritis, gynecological conditions (menopause and age of first menstruation) and low educational level, together with previously known typical risk factors were associated with infarction or ischemia and ventricular dysfunction. Potential associated factors for systolic dyssynchrony were rheumatoid arthritis (OR: 2.90, 95% CI: 0.95-8.66, p = 0.054) and history of premature birth (OR: 0.13, 95% CI: 0.01-0.66, p <0.01). Although those women with arterial hypertension and smoking shown an increased risk for dyssynchrony, these factors were not statistically significant. Low-educational level (OR 2.16, 95% CI 1.1-4.18, p = 0.019) was associated with decreased peak filling rate.

CONCLUSION

The presence of atypical risk factors in women could lead to decreased myocardial function, particularly in women at risk of developing IHD.

Diastolic dysfunction without left ventricular hypertrophy is an early finding in children with hypertrophic cardiomyopathy-causing mutations in the beta-myosin heavy chain, alpha-tropomyosin, and myosin-binding protein C genes

OBJECTIVES

We investigated the presence of left ventricular hypertrophy (LVH) and features of diastolic dysfunction in genotype-confirmed children from families with hypertrophic cardiomyopathy (HCM) and healthy control children.

BACKGROUND

In subjects with HCM-causing mutations, LVH usually does not evolve until adolescence. Diastolic dysfunction has not been systematically evaluated in children carrying HCM-causing mutations.

METHODS

All children (aged 1.5-16.7 years) from 14 HCM families with identified disease-causing mutations (the Arg719Trp mutation in the beta-myosin heavy chain gene [MYH7], the Asp175Asn mutation in the alpha-tropomyosin gene [TPM1], the Gln1061X mutation in the myosin-binding protein C gene [MYBPC3], and the IVS5-2A-->C mutation in the MYBPC3 gene) and 53 matched control children were examined with electrocardiography and 2- and 3-dimensional echocardiography (2DE and 3DE). Natriuretic peptides were measured in children from HCM families and 67 control children.

RESULTS

Of 53 children from HCM families, 27 (51%) had a disease-causing mutation (G+). G+ children had slightly thicker septum on 2DE compared with the control children (P = .004), but only 3 (11%) of 27 G+ children exceeded the 95th percentile values of the body surface area-adjusted maximal LV thickness of healthy children (the major echocardiographic criterion for HCM). However, prolonged isovolumetric relaxation time, increased left atrial volume on 3DE, or increased levels of NT-proANP, all features suggestive of diastolic dysfunction, were found in 14 (52%) of 27 G+ children.

CONCLUSIONS

In children with HCM-causing mutations, signs of diastolic dysfunction are found in about half of the cases, as LVH is present only in small percentage of these children.

Does diastolic function evaluated with radionuclide ventriculography predict mortality, hospitalization and the development of new onset heart failure?

Left ventricular systolic dysfunction (LVSD) in asymptomatic patients is associated with the development of heart failure (HF) and the degree of LVSD predicts prognosis. Whether left ventricular diastolic dysfunction (LVDD) predicts the development of HF or mortality is not known. Our objective was to investigate the predictive value of LVDD evaluated by radionuclide ventriculography (RN). All patients referred for RN during a 12 month period were included. Medical records were reviewed to determine characteristics of the patients at the time of RN and events occurring during a 5 year follow-up. Data from 195 patients were analysed. During the follow-up period 49 patients (25.1%) died, 41 (21.0%) were admitted to hospital and 25 (12.3%) developed HF. An ejection fraction (EF) <40% was associated with mortality (relative risk (RR), 2.04; P=0.001) and hospital admissions (RR, 1.33; P=0.002). Patients who developed subsequent HF had, on average, lower EF at baseline. In a multivariate analysis the lower the EF the more likely patients were to develop new onset HF (odds ratio, 0.92; 95% CI 0.88-0.97; P=0.003). LVDD evaluated with peak filling rate and time to peak filling rate was not associated with any of the outcomes. However, a higher proportion of patients with pre-existing HF at the time of the RN had abnormal LVDD than patients with no HF. LVDD evaluated by RN is associated with symptoms of HF at the time of assessment but is not a good predictor of mortality, hospitalization or new onset HF. EF remains a better predictor of outcomes.

Improvement of the age-related impairment in left ventricular diastolic filling with verapamil in the normal human heart

BACKGROUND

Left ventricular (LV) diastolic function declines with the normal aging process. Because these changes are related to impaired active LV relaxation as well as to structural alterations, we hypothesized that verapamil might improve LV filling in elderly normal subjects compared with young normal subjects.

METHODS AND RESULTS

We studied 27 normal volunteers (between 20 and 71 years old), with normal exercise tests and echocardiograms, by radionuclide angiography before and after 3 to 4 days of oral verapamil therapy. Indexes of global LV function were derived from analysis of background-corrected time-activity curves. Subjects were recruited from three age groups: young (26 +/- 4 years, n = 10), middle-aged (46 +/- 5 years, n = 9), and elderly (66 +/- 3 years, n = 8). Baseline resting heart rate, blood pressure, peak systolic wall stress, and LV ejection fraction did not differ among groups. Baseline peak LV filling rate (expressed in fractional stroke volume per second) was reduced in the middle-aged group (5.8 +/- 1.2, P < .01) and the elderly group (4.3 +/- 1.0, P < .01) compared with the young group (7.8 +/- 1.2). With verapamil, resting heart rate, peak systolic wall stress, LV ejection fraction, and peak ejection rate did not change in any group. Peak filling rate increased in the middle-aged group (to 6.8 +/- 1.5 SV/s, P < .01) and the elderly group (to 5.7 +/- 1.0 SV/s, P < .01) but did not change in the young group (8.0 +/- 1.4 SV/s). Also, time to peak filling rate decreased with verapamil in the elderly group (from 185 +/- 31 to 147 +/- 15 milliseconds, P < .01). The magnitude of change in filling rate was correlated positively with age (r = .55, P < .005).

CONCLUSION

Verapamil selectively enhances LV diastolic filling in middle-aged and elderly subjects, compared with young adults, without affecting systolic function. This observation supports the hypothesis that the impairment of LV filling accompanying the normal aging process is, at least in part, a reversible phenomenon.

Global and regional parameters of left ventricular performance in healthy subjects during rest and exercise assessed by radionuclide ventriculography

The aim of our study was to analyze numerous global and regional parameters of left ventricular (LV) performance during rest and exercise, in the group of 14 healthy subjects, by quantitative gated equilibrium ventriculography in left anterior oblique view (45 degrees). The global LV parameters at rest vs. exercise in our study were: heart rate 68.9 +/- 18.4 vs. 137.5 +/- 38.6; systolic blood pressure (mmHg) 121.8 +/- 18.2 vs. 178.6 +/- 31.2; diastolic blood pressure (mmHg) 82.1 +/- 10.8 vs. 90.7 +/- 12.4; double product 8,368.6 +/- 2,308.8 vs. 24,589.3 +/- 8,357.8; global ejection fraction (%) 61.9 +/- 15.4 vs. 72.8 +/- 12.8, end-diastolic volume index (ml/m2) 82.5 +/- 23.2 vs. 96.9 +/- 27.8; end-systolic volume index (ml/m2) 31.8 +/- 19.8 vs. 26.9 +/- 15.4; stroke volume index (ml/m2) 50.6 +/- 17.6 vs. 70.0 +/- 22.6; peak emptying rate (EDV/s) 3.4 +/- 2.6 vs. 8.3 +/- 3.8 and peak filling rate (EDV/s) 3.6 +/- 2.6 vs. 9.6 +/- 3.8. A significant difference (p < 0.05) between rest and exercise was found for all parameters. The highest values of LV regional ejection fraction were found in anterolateral and posterolateral region, while the lowest values were observed in inferoseptal and inferior regions. During exercise a significant increase of regional ejection fraction was found in all regions. The highest percent of radius shortening during rest was in anterolateral and posterolateral regions, and lowest in inferoseptal and inferior regions. The same sequence was found during exercise, and the difference in percent of radius shortening, between rest and exercise was significant in all regions. The observed normal values of global and regional parameters of LV function during rest may serve as a contribution for referent values. Our results on regional ejection fraction and the percent of radius shortening in rest, and their change during exercise, offer the possibility of additional information in the investigation of cardiac patients by means of radionuclide ventriculography.

Assessment of left ventricular diastolic function in dilated cardiomyopathy with cine magnetic resonance imaging: effect of an angiotensin converting enzyme inhibitor, benazepril

The effects of angiotensin converting-enzyme inhibitor, benazepril, on diastolic function in patients with dilated cardiomyopathy, with (n = 4) or without (n = 11) mitral regurgitation, were examined with the time-volume curve of the left ventricle derived from cine magnetic resonance images. Peak filling rate/end-systolic volume and ejection fraction were increased in the group without regurgitation (p < 0.01) but not in the group with regurgitation after treatment. There was a strong correlation between peak filling rate/end-systolic volume and ejection fraction (r = 0.89) and between the change in peak filling rate/end-systolic volume and that in ejection fraction after treatment (r = 0.74) in the group without regurgitation. These findings suggest that in some patients with dilated cardiomyopathy benazepril has favorable effects on diastolic function, which seem to be related to improvement in systolic function. This drug may not be as beneficial in patients with dilated cardiomyopathy complicated by mitral regurgitation.

Evidence for or against efficacy of beta-blockers and aspirin for management of feline cardiomyopathies

Feline myocardial diseases today are largely represented by disorders involving LV hypertrophy. They may be attended by arrhythmias, congestive heart failure, systemic hypertension, thromboembolic complications, and sudden death. These structural myocardial disorders and their hemodynamic and electrocardiographic derangements may cause or result in variable degrees of diastolic dysfunction. Propranolol and aspirin represent two agents commonly employed to treat feline cardiomyopathies for more than 15 years. Nevertheless, clinical data describing their effect on morbidity and mortality are lacking. It is likely that propranolol administered at moderate to high doses effects favorable responses in some cats with clinical signs attributable to severe hypertrophy, outflow obstruction, or tachyarrhythmias. It is unknown whether clinical improvements are due to direct myocardial effects or (more likely) secondary responses to a beta-adrenergic blockade reduction in heart rate or contractility. Personal experience also indicates that high numbers of cats have received the drug for many years in combination with other therapies (especially furosemide) and remain in a compensated state of heart failure without untoward drug effects. On the other hand, many cardiomyopathic cats experience heart failure, arrhythmias, and death despite treatment with beta-blocking agents. Feline thromboembolism is a devastating complication of cardiomyopathic disorders. Until or unless the primary cause(s) of current diseases is elucidated to promote disease reversal, factors responsible for thrombus formation will accompany the heart diseases, protected from effective management. It appears unlikely that aspirin as currently recommended produces any obvious benefit in treating or preventing thromboembolism. Modifications of therapeutic protocols prescribing these frequently used drugs await well-constructed clinical trials evaluating their efficacy with respect to cardiovascular morbidity and mortality.

Effects of acute alterations in left ventricular loading conditions on peak filling rate in the denervated (transplanted) ventricle

Peak filling rate is an indicator of left ventricular (LV) diastolic function. It is influenced by heart rate, loading conditions, sympathetic nervous system activity, ejection fraction and other factors. To determine the effect of altered loading conditions on peak filling rate, independent of heart rate and sympathetic nervous system activity, 12 patients were studied 3 weeks after orthotopic heart transplantation. Plasma catecholamine level, heart rate and ejection fraction were not changed by any maneuver. Nitroglycerin caused a decrease in pulmonary artery wedge pressure (9 +/- 2 to 6 +/- 1 mm Hg, p less than 0.001) and in absolute peak filling rate (46.0 +/- 3.0 to 42.8 +/- 2.5 kcts/s, p less than 0.01), but no change in normalized peak filling rate. Volume infusion increased pulmonary artery wedge pressure (9 +/- 2 to 12 +/- 2 mm Hg, p less than 0.001) and absolute peak filling rate (46.0 +/- 3.0 to 51.5 +/- 5.3 kcts/s, p less than 0.01), but peak filling rate normalized to stroke volume was unchanged. During nitroglycerin and volume infusions, there was a high correlation between changes in pulmonary artery wedge pressure and absolute peak filling rate (r = 0.82, p less than 0.001). With normalization of peak filling rate, these variables correlated less well. With methoxamine, 4 patients demonstrating systolic dysfunction had a decrease in absolute and normalized peak filling rate despite a large increase in pulmonary artery wedge pressure. The other 8 patients without systolic dysfunction had an increase in pulmonary artery wedge pressure with increased absolute but unchanged normalized peak filling rate.(ABSTRACT TRUNCATED AT 250 WORDS)