Variation of flow propagation velocity with age.

Flow propagation velocity is a new color Doppler M-mode measurement of left ventricular filling characteristics. This study was designed to establish normal values for this measurement in healthy individuals and to compare these findings with pulsed Doppler transmitral velocities. Complete M-mode, two-dimensional, and Doppler echocardiographic studies were performed on 64 volunteers between 21 and 79 years of age. Significant negative correlations (p < 0.001) with age were noted for flow propagation velocity (r = -0.59), peak early diastolic filling velocity (r = -0.65), and peak early diastolic filling/peak atrial filling ratio (r = -0.80). Positive correlations (p < 0.001) with age were observed for peak atrial filling velocity (r = 0.50) and atrial filling velocity integral (r = 0.71). Flow propagation velocity decreased by 44% between the youngest and oldest age groups. We conclude that flow propagation velocity is influenced by age and that it compares favorably with transmitral Doppler indices of left ventricular filling in this regard. These age-related alterations are present in healthy individuals, in the absence of any apparent cardiovascular disease.

Impact of ethnicity on left ventricular mass and relative wall thickness in essential hypertension.

This study was designed to evaluate the impact of ethnicity on left ventricular (LV) mass, and relative wall thickness in 527 patients (57% men, mean age 60 +/- 7 years) with mild to moderate high blood pressure. There were 63% Caucasians, 21% African-Americans, and 16% Hispanics. LV mass was indexed according to body surface area, height, and height to the allometric power of 2.7. Relative wall thickness included the 4 widely recognized patterns: normal, concentric remodeling, eccentric hypertrophy, and concentric hypertrophy. LV mass indexed to body surface area was similar among all 3 ethnic groups (Caucasians 117.1 g/m2, African-Americans 119.2 g/m2, Hispanics 122.7 g/m2); however, when indexed to height and height to the power of 2.7, Hispanics had slightly larger masses than the other 2 groups (Hispanics 168.1 and 73.3 g/m2.7 vs Caucasians 159.8 and 64.4 g/m2.7 [p = NS and p < 0.005]; and vs African-Americans 164.8 and 69.2 g/m2.7 [p = NS for both]). Using body surface area, the concentric remodeling was the predominant form of cardiac adaptation in Caucasians (36%) and African-Americans (42%), whereas the concentric hypertrophy pattern was 38% in Hispanics. Using indexing for both height and height to the power of 2.7, the concentric hypertrophy pattern predominated in all 3 ethnic groups (Caucasians 48% and 51%; African-Americans 68% and 66%; Hispanics 59% and 65%). In conclusion, because of the independent impact of weight on high blood pressure, LV mass adjusted to height or to height at the power of 2.7 should be reported in population studies. The concentric hypertrophy pattern--classic LV response to pressure overload conditions--is better represented when LV mass is indexed to height or to height to the allometric power of 2.7 than to body surface area.

Comparison of exercise and dobutamine stress echocardiography in assessing mitral stenosis.

Dobutamine elicited similar hemodynamic response to exercise in 20 consecutive patients with mitral stenosis, and significantly altered management in 6 of them (30%). Dobutamine stress echocardiography is a safe and feasible alternative to exercise in patients with mitral stenosis of mild-to-moderate severity and ambiguous symptoms.

Role of left ventricular hypertrophy in diastolic dysfunction in aged hypertensive patients.

OBJECTIVE: To evaluate the influence of left ventricular hypertrophy (LVH) on the diastolic dysfunction in older hypertensive patients. METHODS: In total 665 patients (58% men, 61% White, aged 55-80 years) with mild-to-moderate essential hypertension underwent Doppler echocardiography. Data included left ventricular dimensions, left ventricular mass index, body mass index, E- and A-wave mitral flow velocities, E:A ratio, deceleration time > 150 ms), impaired relaxation (E:A ratio < 1.0, prolonged deceleration time according to age), and restrictive physiology (E:A ratio > 2.1, deceleration time < 150 ms)]. Data were distributed according to age (50-59, 60-69, and 70-80 years). RESULTS: The overall prevalence of sex-adjusted LVH in this study was 65%. When we compared hypertensive patients with and without LVH, the E- and A-wave velocities, E:A ratio, and deceleration time were similar. Moreover, the prevalences of normal, impaired relaxation, and restrictive physiology patterns among patients with and without LVH did not differ significantly (20, 79.5, and 0.5 versus 24, 75.5, and 0.5%). When the mitral flow patterns were adjusted according to age, the impaired relaxation pattern increased further with age (to 73% during the fifth decade, 83% during the sixth decade, and 88% during the seventh decade). CONCLUSIONS: LVH is not an independent factor associated with abnormal flow patterns in hypertensive patients aged over 50 years with normal systolic contractility. The impaired relaxation is the predominant pattern of diastolic dysfunction in older hypertensive patients and increases further with aging.

Comparison of left ventricular mass and geometric remodeling in treated and untreated men and women >50 years of age with systemic hypertension.

To investigate the effects of left ventricular (LV) mass and geometry in hypertensive patients >50 years of age, 540 men and women were divided into controlled, uncontrolled, and untreated groups. The high prevalence of concentric LV hypertrophy in postmenopausal women, despite medical therapy, emerged as a potentially important and underrecognized factor of their cardiovascular risk.

Usefulness of dobutamine echocardiography in the hemodynamic assessment of mechanical prostheses in the aortic valve position.

Dobutamine stress echocardiography is a simple, safe, and readily available method to evaluate prosthetic valve hemodynamics under various flow conditions. A normal response of aortic valve prostheses to dobutamine infusion is a 100% increment in transprosthetic pressure gradients with an unchanged valve area.

Use of dobutamine stress echocardiography in assessing mechanical aortic prostheses: comparison with exercise echocardiography.

BACKGROUND AND AIMS OF THE STUDY: Relatively high resting flow velocities are occasionally seen in asymptomatic patients with apparently normal mechanical aortic prostheses. Doppler echocardiography in conjunction with bicycle exercise or dobutamine have been used to 'unmask' symptoms or abnormal hemodynamics in these patients. The aim of this study was to compare the Doppler-derived hemodynamic response to exercise and to dobutamine in patients with normally functioning mechanical aortic prostheses. METHODS: Bicycle ergometry (from 200-400 kg x m/min) and dobutamine (from 5-40 micrograms/kg/min) in conjunction with Doppler echocardiography were performed in 25 asymptomatic patients (21 men, four women; mean age 61 years) with mechanical aortic prostheses (range: 19 mm to 27 mm) who had normal resting hemodynamics and normal left ventricular function. Aortic valve area (continuity equation) and maximal instantaneous and mean gradients were estimated at rest and at peak stress. RESULTS: Target heart rate was achieved in 10/25 (40%) patients with exercise, and in 21/25 (84%) with dobutamine (p < 0.005). At peak stress, exercise induced a 25% increase in peak flow velocity, a 55% increase in valve gradients, and no significant change in valve area. In comparison, dobutamine induced a 48% increase in peak flow velocity, a 105% increase in valve gradients, and also no significant change in valve area. The flow velocity and pressure gradients at peak stress were significantly higher with dobutamine than with exercise. CONCLUSIONS: In normally functioning aortic valve prostheses, the target heart rate can be reached more often with dobutamine than with supine bicycle exercise. Despite significant increase in the transvalvular gradients, the valve area remained unchanged. The clinical significance of exercise or dobutamine in symptomatic patients with mechanical prostheses is yet to be proven.

Disparity between diastolic mitral flow characteristics and left ventricular mass in essential hypertension.

Because left ventricular (LV) hypertrophy and aging have been associated with abnormal LV relaxation, this study evaluated the impact of LV mass on the filling patterns derived by Doppler in a large population aged > or =50 years. Results suggest that in essential hypertension the intrinsic myocardial composition is more important than cardiac hypertrophy in determining LV diastolic properties. This apparent discrepancy between LV mass and diastolic filling patterns highlights the difficulty in establishing the diagnosis of diastolic dysfunction in elderly hypertensives.

Gender dimorphism in cardiac adaptation to hypertension is unveiled by prior treatment and efficacy.

The gender dimorphism in cardiac remodeling, previously recognized in primary hypertension, is unveiled in the group of patients with uncontrolled hypertension despite medical therapy. Prior antihypertensive treatment and its efficacy should be considered in population studies designed to evaluate the impact of left ventricular hypertrophy or its regression.