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M Zabalgoitia

Publications and source records attributed to M Zabalgoitia.

At least 37 records · Page 2Linked to original sources
PubMed1998

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.

Adult↗
PubMed1998

Contractile depression and expression of proinflammatory cytokines and iNOS in viral myocarditis.

We assessed two strains of mice [CD-1 and C3H.HeJ (C3H)] with different responses to coxsackievirus B3 (CVB3) infection at 7, 14, and 21 days after inoculation with 10(5) pfu of CVB3. CD-1 mice developed inflammatory lesions at 7 days that nearly recovered by 21 days; C3H mice demonstrated persistence of infiltrates. Although there were differences in the baseline fractional shortening, it was further reduced at 7 and 14 days in both strains. It recovered in CD-1 mice but remained depressed at 21 days in C3H mice. Interleukin-6 and tumor necrosis factor-alpha transcripts were increased in both strains at 7 days. Levels dropped to near control in CD-1 mice at 21 days but remained elevated in C3H mice. Interleukin-1 beta was minimally elevated in CD-1 mice but increased progressively in C3H mice. mRNA for the inducible form of NO synthase (iNOS) was increased at 7 days in the CD-1 mice, returning to baseline by 14 days; it rose progressively in C3H mice, with a fivefold increase at 21 days. We conclude that mice infected with CVB3 show increased expression of proinflammatory cytokines as well as iNOS associated with reduced contractile performance. In more susceptible mice, contractile depression and cytokine and iNOS expression are more pronounced.

Animals↗
PubMed1998

Hypertension optimal treatment (HOT) study: home blood pressure in treated hypertensive subjects.

The Hypertension Optimal Treatment Study is a prospective trial conducted in 26 countries. The aims are to (1) evaluate the relationship between three levels of target office diastolic blood pressure (BP) (< or = 80, < or = 85, or < or = 90 mm Hg) and cardiovascular morbidity and mortality in hypertensive patients and (2) examine the effects on cardiovascular morbidity and mortality of 75 mg aspirin daily versus placebo. A total of 19,193 patients between 50 and 80 years of age had been randomized by the end of April 1994. Treatment was initiated with felodipine 5 mg daily, and additional therapy was given in accordance with a set protocol. The present substudy of 926 patients performed in nine countries aimed to (1) compare home with office BP in a representative subsample of the HOT population after the titration of treatment was completed and (2) clarify whether the separation into the target groups could be expanded into the out-of-office setting. The differences between office and home measurements in diastolic BP of 0.2 mm Hg (SD, 9; 95% confidence interval, -0.36 to 0.81; P=.40) and systolic BP of 0.5 mm Hg (SD, 15; 95% confidence interval, -0.53 to 1.46; P=.21) were not significant. The group differences in home BP were 1.9 mm Hg (< or = 80 versus < or = 85) and 1.2 mm Hg (< or = 85 versus < or = 90) for diastolic BP (F=11.69; ANOVA, P<.0001) and 2.6 and 2.1 mm Hg for systolic BP (F=8.44, P=.0002). Thus, office and home BPs measured with the same semiautomatic device are comparable in treated hypertensive subjects in the HOT Study, and the separation into the target groups based on office readings prevails at home.

Aged↗
PubMed1997

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.

Aged↗
PubMed1997

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.

Aged↗
PubMed1997

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.

Aged↗
PubMed1997

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.

Adult↗
PubMed1996

Left ventricular mass and function in primary hypertension.

The Hypertension Optimal Treatment study is a prospective, randomized, clinical trial designed to challenge the J curve phenomenon in hypertension. A subpopulation of 665 patients from seven participating centers in the United States were enrolled to evaluate the prevalence of left ventricular mass and its relationship to systolic and diastolic function, as assessed by Doppler echocardiography, and to clinical events during the length of the study. Echocardiographic measurements followed stringent criteria and were rechecked in a core laboratory for accuracy. Baseline data revealed left ventricular hypertrophy in 62% of the patients. Left ventricular hypertrophy was more prevalent in women than in men (72% v 57%, P < .0001). The hypertrophy was further characterized according to left ventricular geometry and found the concentric pattern as the predominant form of hypertrophy (46%). Indices of left ventricular systolic function, including fractional shortening, cardiac index, and ejection fraction, were normal or above-normal. Doppler interrogation of the mitral inflow demonstrated left ventricular diastolic dysfunction in 81% of patients. The constrictive physiology (inversion of the E/A ratio) was the most prevalent mitral flow pattern (79%). Regression of left ventricular hypertrophy, modification of mass index geometry, and alterations in mitral flow characteristics under optimal blood pressure control will be specifically compared with subsequent examinations.

Aged↗
PubMed1994

Echocardiographic assessment of right and left ventricular function after single-lung transplantation.

To evaluate the impact of single-lung transplantation on right and left ventricular performance and to identify potential preoperative characteristics that could predict postoperative outcome, a large group of patients were retrospectively evaluated by means of serial Doppler echocardiography. Twenty-six of 57 consecutive single-lung transplant patients had satisfactory Doppler echocardiographic studies before and after surgery. A significant reduction in right ventricular diastolic and systolic areas and an increase in right ventricular fractional area were noted after transplantation. The left ventricular contractility remained unchanged. In addition, significant reduction in right atrial area, right ventricular free wall thickness, and tricuspid regurgitation were also seen. Paradoxical septal motion present in eight patients before the procedure resolved in all of them after single-lung transplantation. Transthoracic echocardiography is a useful technique to document improvement in right ventricular function in 63% of patients following single-lung transplantation. Preoperative paradoxical septal motion identifies single-lung transplant recipients who have the largest postoperative right ventricular area reduction and fractional area increase. Alternative imaging modalities should be sought for single-lung transplant candidates in whom conventional transthoracic echocardiography is suboptimal.

Adult↗
PubMed1994

Atrial septal aneurysm as a potential source of neurological ischemic events.

An atrial septal aneurysm (ASA) is a congenital malformation of the atrial septum characterized by bulging of the septum overlying the fossa ovalis region into either atrium. The prevalence of ASA varies according to the diagnostic method used and to the type of population studied. A practical classification of ASA based on the current knowledge of its pathogenesis into Type I, Type II, and Type III is presented. With the widespread use of transesophageal echocardiography in recent years, ASA has become an increasingly recognized entity. Recently, the clinical interest in ASA has been increased by several reports in the literature proposing ASA as a potential source of emboli. The three most plausible mechanisms to link this association are thrombus formation in or around the ASA, paradoxical embolization through an interatrial communication in the form of patent foramen ovale or atrial septal defect, and mitral valve prolapse that has been found to be frequently associated with ASA. Although the echocardiographic detection of ASA is in most cases an incidental finding, the identification of ASA should prompt careful review of the echocardiogram for mitral valve prolapse, atrial septal defect, and patent foramen ovale. Although conclusive evidence of a causal relation between ASA and cerebrovascular emboli has not been shown, the identification of ASA in such patients in the absence of another cause to explain the embolic event may represent an indication for long-term antiplatelet or anticoagulation therapy, or even surgery. Until long-term follow-up results of these patients are available, management should be on an individual basis.

Adult↗
PubMed1993

Biplane transesophageal pacing echocardiography compared with dipyridamole thallium-201 single-photon emission computed tomography in detecting coronary artery disease.

TPE is a new diagnostic technique that uses simultaneous graded transesophageal left atrial pacing and biplane transesophageal echocardiography for the detection of pacing-induced wall motion abnormalities. In a prospective study 30 patients underwent biplane TPE, dipyridamole thallium-201 single-photon emission computed tomography (SPECT), and coronary arteriography. The sensitivity (86% vs 95%, p = not significant [NS]), specificity (89% vs 56%, p = NS), positive predictive value (95% vs 73%, p = NS), and negative predictive value (83% vs 83%, p = NS) of biplane TPE and thallium-201 SPECT in identifying patients with significant coronary artery disease was similar. In the 90 vascular territories analyzed, the agreement between biplane TPE and thallium-201 SPECT for presence or absence of significant disease was 71%. Analysis of the three major vascular territories demonstrated that each imaging modality had a high sensitivity and specificity in the left anterior descending and right coronary artery segments. However, the two techniques demonstrated poorly sensitivity in the segmental distribution of the circumflex coronary artery. In conclusion, biplane TPE compared favorably with thallium-201 SPECT in terms of safety and accuracy for detecting significant coronary artery disease. Accordingly, biplane TPE may be a suitable alternative for those patients with nondiagnostic thallium-201 SPECT studies and in those with contraindications to adenosine or dipyridamole.

Aged↗