Systo-diastolic ventricular function in patients with hypertension: an echocardiographic tissue doppler imaging evaluation study

The effect of cardiac rehabilitation on blood pressure, and on left atrial and ventricular functions in hypertensive patients

PURPOSE

Hypertension is associated with left ventricular (LV) hypertrophy, impaired LV relaxation, and left atrial (LA) enlargement. Cardiac rehabilitation (CR) improves clinical outcomes in a broad spectrum of cardiac disease. The aim of our study was to determine the effect of CR on blood pressure (BP), and on LA and LV functions in hypertensive patients.

METHODS

Thirty consecutive hypertensive patients who would undergo CR program, and 38 hypertensive patients who refused to undergo CR program were included. All patients underwent ambulatory BP monitoring and transthoracic echocardiography, which were repeated after completion of the CR program, or 12 weeks later in the control group. LA and LV functions were assessed by both speckle tracking and 3-dimensional echocardiography. N-terminal pro-brain natriuretic peptide (NT-proBNP) levels were assessed before and after CR.

RESULTS

Although initial ambulatory BP values and NT-proBNP levels were similar between the groups, daily, day-time, and night-time BP and NT-proBNP were significantly lower in the CR group after rehabilitation. LA reservoir strain and LV global longitudinal strain of the CR group significantly increased after CR while no significant increase was observed in controls.

CONCLUSION

CR improves LA and LV strain while lowering BP and should be encouraged in routine management of hypertensive patients.

Alterations in cardiac structure and function in hypertension

Hypertension is a powerful risk factor for cardiovascular mortality and morbidity, including heart failure with both preserved and reduced ejection fraction. Hypertensive heart disease (HHD) defines the complex and diverse perturbations of cardiac structure and function occurring secondary to hypertension. Left ventricular hypertrophy (LVH) is one of the most recognized features of HHD and is an established risk factor for adverse cardiovascular (CV) outcomes in hypertension. Beyond LVH, LV geometry provides additional information regarding the cardiac response to hypertension. Imaging studies from larger cohorts of hypertensive patients reveal wide variability in the prevalence of LVH and LV geometric patterns, with the prevalence of concentric LVH similar to that of eccentric LVH. Hypertension is also associated with concomitant impairments in LV diastolic and systolic function. It remains uncertain why patients develop different patterns of LVH, although demographics and clinical comorbidities appear to influence that response.

Effects of exercise training on systo-diastolic ventricular dysfunction in patients with hypertension: an echocardiographic study with tissue velocity and strain imaging evaluation

There is a lack of detailed data regarding the effect of exercise training in pharmacologically treated hypertensive patients. Therefore, the aim of this study was to evaluate the effects of exercise training on left and right ventricular morphologic and functional parameters by means of conventional echocardiography and sensitive new echocardiographic techniques including tissue Doppler velocity and strain imaging, that were performed in pharmacologically treated hypertensive patients at baseline and at the end of a specific exercise training protocol for primary prevention of cardiovascular disease. We selected 116 pharmacologically treated hypertensive patients who completed the exercise training protocol. All patients underwent a clinical history and examination; transthoracic echocardiography and exercise testing were performed at baseline and at the end of the exercise training protocol. Conventional echocardiography revealed a mild degree of diastolic dysfunction without significant differences or variations from baseline to the end of the exercise training protocol. In contrast, tissue Doppler velocity and strain imaging measurements demonstrated and highlighted the positive influence of exercise training: for both left and right ventricle myocardial early peak diastolic velocities (Em), the ratio of myocardial early-late peak diastolic velocity (Em/Am), myocardial peak systolic velocities (Sm) and peak strain and strain rate values significantly increased at the end of the exercise training protocol, suggesting a relationship between exercise capacity and both left and right ventricular systo-diastolic function. Our study, by means of newer more sensitive echocardiographic techniques, clearly demonstrated the positive impact of exercise training on both left and right ventricular systo-diastolic function, in terms of adjunctive subclinical improvement, in pharmacologically treated hypertensive patients.

Ultrastructural and cellular basis for the development of abnormal myocardial mechanics during the transition from hypertension to heart failure

Although the development of abnormal myocardial mechanics represents a key step during the transition from hypertension to overt heart failure (HF), the underlying ultrastructural and cellular basis of abnormal myocardial mechanics remains unclear. We therefore investigated how changes in transverse (T)-tubule organization and the resulting altered intracellular Ca(2+) cycling in large cell populations underlie the development of abnormal myocardial mechanics in a model of chronic hypertension. Hearts from spontaneously hypertensive rats (SHRs; n = 72) were studied at different ages and stages of hypertensive heart disease and early HF and were compared with age-matched control (Wistar-Kyoto) rats (n = 34). Echocardiography, including tissue Doppler and speckle-tracking analysis, was performed just before euthanization, after which T-tubule organization and Ca(2+) transients were studied using confocal microscopy. In SHRs, abnormalities in myocardial mechanics occurred early in response to hypertension, before the development of overt systolic dysfunction and HF. Reduced longitudinal, circumferential, and radial strain as well as reduced tissue Doppler early diastolic tissue velocities occurred in concert with T-tubule disorganization and impaired Ca(2+) cycling, all of which preceded the development of cardiac fibrosis. The time to peak of intracellular Ca(2+) transients was slowed due to T-tubule disruption, providing a link between declining cell ultrastructure and abnormal myocardial mechanics. In conclusion, subclinical abnormalities in myocardial mechanics occur early in response to hypertension and coincide with the development of T-tubule disorganization and impaired intracellular Ca(2+) cycling. These changes occur before the development of significant cardiac fibrosis and precede the development of overt cardiac dysfunction and HF.

Cardiac performance during exercise in hypertensive patients without ventricular hypertrophy

BACKGROUND

Reduced systolic reserve on effort may be present in subjects with hypertension but no evidence of hypertensive cardiomyopathy. We assessed the determinants of abnormal cardiac performance during exercise in hypertensive patients without left ventricular hypertrophy.

MATERIALS AND METHODS

Thirty-five newly diagnosed, never-treated-earlier hypertensive patients without definite indication for left ventricular hypertrophy at echocardiography underwent radionuclide ambulatory monitoring of left ventricular function at rest and during upright bicycle exercise testing.

RESULTS

The patients were classified into two groups according to their ejection fraction response to exercise. In 21 patients (group 1), the ejection fraction increased > or = 5% with exercise and in 14 patients (group 2), the ejection fraction either increased < 5% or decreased with exercise. Patients of group 1 had lower peak filling rate at rest and less augmentation in end-diastolic volume during exercise (both P < 0.01) when compared with patients of group 2. A significant relationship between the magnitude of change in ejection fraction with exercise and both peak filling rate at rest (r = 0.58, P < 0.01) and exercise-induced change in end-diastolic volume (r = 0.45, P < 0.01) was found.

CONCLUSIONS

In newly diagnosed, never-treated-earlier hypertensive subjects with no evidence of hypertensive cardiomyopathy, the cardiac response to exercise is dependent on adequate diastolic filling volume to maintain systolic performance.

Early diastolic peak velocity of left ventricular wall segment lying in isovolumic relaxation period as determined by tissue Doppler imaging

BACKGROUND

The early diastolic peak velocity of left ventricular (LV) wall segment has always been regarded as appearing in the rapid filling phase. However, we find some segments of which early diastolic peak velocities appear in the isovolumic relaxation period (PVIVR segments). The present study aimed to investigate the characteristics of PVIVR segments.

METHODS

Tissue Doppler imaging was performed in each of the 16 segments of LV wall in 99 patients with known or suspected coronary heart disease and 50 normal subjects. Early diastolic velocity pattern was classified as PVIVR, post-systolic shortening (PSS) and normal pattern.

RESULTS

The multivariate logistic regression analyses showed that the significant echocardiographic predictors of the presence of PVIVR in a patient were transmitral E/A ratio and isovolumic relaxation time. Segmental early diastolic velocity pattern was significantly associated with actual coronary stenosis, relative coronary stenosis and wall motion score. PVIVR segments had a lower early diastolic peak velocity than other segments.

CONCLUSION

PVIVR segments more frequently appear in the territory with the relatively mildest coronary stenosis, whereas PSS segments more frequently appear in the territory with the relatively most severe coronary stenosis. Patients with PVIVR have lower global LV diastolic function. A decreased early diastolic peak velocity of PVIVR segments does not necessarily mean impaired myocardial relaxation.

Cardiac Function as Assessed by Echocardiography in the Oldest Old .GEQ. 90 Years of Age

Although several studies have demonstrated that cardiac diastolic function is impaired but cardiac systolic function is preserved with aging, no large-scale analysis of cardiac function by echocardiography in subjects aged > or = 90 years exists. The purpose of the present study was to elucidate the cardiac structure and function in the oldest old in order to assess the effect of aging on cardiac function. Echocardiographic examination was performed in 1793 subjects who were in their fifties, sixties, seventies, eighties, and nineties. Left ventricular (LV) wall thickness and dimension were measured by M-mode echocardiography. LV ejection fraction (LVEF) was calculated and used as the parameter representing LV systolic function. LV diastolic function was assessed using the peak velocity of early rapid filling (E velocity) and the peak velocity of atrial contraction (A velocity), and the ratio of E to A (E/A) by the transmitral flow. The Tei index, which reflects both LV diastolic and systolic function, was also calculated. The E/A decreased progressively with aging, and demonstrated the closest correlation with age among all the indexes of cardiac function (r = -0.44, P < 0.001). In contrast, LVEF and the Tei index demonstrated a very weak correlation with age (r = -0.13, P < 0.001 and r = 0.16, P < 0.001, respectively). The mean value for LVEF remained normal with aging in all age strata (50s: 71 +/- 8%, 60s: 71 +/- 8%, 70s: 70 +/- 9%, and 80s: 71 +/- 10%), but decreased significantly in subjects in their 90s (66 +/- 10%, P < 0.001). In addition, the mean value for the Tei index also remained normal with aging in subjects in their 50s (0.35 +/- 0.10), 60s (0.38 +/- 0.14), 70s (0.38 +/- 0.12), and 80s (0.39 +/- 0.15), but showed an abnormal value in subjects in their 90s (0.45 +/- 0.12, P < 0.001). In conclusion, both diastolic dysfunction and systolic dysfunction with advancing age were observed in the oldest old aged > or = 90 years. The age-related impairment of systolic function as well as diastolic function should be considered when echocardiography is used to evaluate the causes of heart failure in the oldest old.