Right ventricular systolic function and cardiac resynchronization therapy

AIMS: The effect of cardiac resynchronization therapy (CRT) on right ventricular ejection fraction (RVEF) has not been well studied. Furthermore, it is unclear whether baseline RVEF influences response to CRT. To evaluate the acute and chronic effects of CRT on right ventricular systolic function, and to investigate whether baseline RVEF impacts response to CRT. METHODS AND RESULTS: Forty-four patients with a standard indication for CRT underwent radionuclide angiography at baseline and after at least 6 months' follow-up for measuring RVEF, right ventricular synchrony (using phase analysis), and left ventricular ejection fraction (LVEF). In addition, NYHA functional class and 6-min walking distance (6MWD) were evaluated. There were no significant acute changes in RVEF with CRT. After a mean follow-up of 9 +/- 5 months, RVEF was slightly improved (by 1.9 +/- 5.0% in absolute terms, P = 0.016), and to a lesser extent than LVEF (5.1 +/- 9.0%, P = 0.009 compared with RVEF). Right ventricular dyssynchrony was significantly improved at follow-up (P = 0.016). Patients with a baseline RVEF < or = 0.35 (n = 19) were less likely to improve in NYHA class (P = 0.016), and also tended to improve less in 6MWD and LVEF (P < 0.06). CONCLUSION: Cardiac resynchronization therapy has no acute effect on RVEF, and only slightly improves RVEF at follow-up. Patients with reduced RVEF at baseline were less likely to respond to CRT, indicating that right ventricular systolic dysfunction may play a role in patient selection.

Assessment of right ventricular systolic function: Comparison between cardiac magnetic resonance derived ejection fraction and pulsed-wave tissue Doppler imaging of the tricuspid annulus

Systolic right ventricular (RV) function is an important predictor in the course of various congenital and acquired heart diseases. Its practical determination by echocardiography remains challenging. We compared routine assessment of lateral tricuspid annular systolic motion velocity (TV(lat), cm/s) using pulsed-wave tissue Doppler imaging from the apical 4-chamber view with cardiac magnetic resonance (CMR) as reference method.

Right ventricular systolic function assessment: rank of echocardiographic methods vs. cardiac magnetic resonance imaging

Right ventricular (RV) systolic function is prognostically important, but its assessment by echocardiography remains challenging, in part because of the multitude of available measurement methods. The purpose of this prospective study was to rank these methods against the reference of RV ejection fraction (EF) as obtained in a broad clinical population by magnetic resonance imaging (MRI).

Echocardiogram versus cardiac magnetic resonance imaging for assessing systolic function of subaortic right ventricle in adults with complete transposition of great arteries and previous atrial switch operation

In adults with congenital heart disease and a systemic right ventricle, subaortic ventricular systolic dysfunction is common. Echocardiographic assessment of systolic right ventricular (RV) function in these patients is important but challenging. The aim of the present study was to assess the reliability of conventional echocardiographic RV functional parameters to quantify the systolic performance of a subaortic right ventricle. We compared 56 contemporary echocardiograms and cardiac magnetic resonance studies in 37 adults, aged 26.9 ± 7.4 years, with complete transposition and a subaortic right ventricle. The fractional area change (FAC), lateral tricuspid annular plane systolic excursion, lateral RV systolic motion velocities by tissue Doppler, RV myocardial performance index, and the rate of systolic RV pressure increase (dp/dt) measured across the tricuspid regurgitant jet were assessed by echocardiography and correlated with the cardiac magnetic resonance-derived RV ejection fraction (EF). The mean RVEF was 48.0 ± 7.8%. FAC (r(2) = 0.206, p = 0.001) and dp/dt (r(2) = 0.173, p = 0.009) significantly correlated with RVEF, and the other nongeometric echocardiographic parameters failed to show a significant correlation with RVEF by linear regression analysis. FAC <33% and dp/dt <1,000 mm Hg/s identified a RVEF of <50% with a sensitivity of 77% and 69% and a specificity of 58% and 87%, respectively. In conclusion, in patients with a systemic right ventricle, routine nongeometric echocardiographic parameters of RV function correlated weakly with cardiac magnetic resonance-derived EF. RV FAC and the measurement of the rate of systolic RV pressure increase (dp/dt) should be preferentially used to assess systemic systolic function in adult patients with a subaortic right ventricle.

Do women have impaired regional systolic function in hypertensive heart disease? A 3-dimensional echocardiography study

AIMS: In pressure overload left ventricular (LV) hypertrophy, gender-related differences in global LV systolic function have been previously reported. The goal of this study was to determine regional systolic function of the left ventricle in male and female patients with hypertensive heart disease. METHODS AND RESULTS: Regional LV function was analyzed from multiplane transesophageal echocardiography with three-dimensional (3D) reconstruction of the left ventricle. In 24 patients (13 males and 11 females), four parallel (2 basal and 2 apical) equidistant short axis cross-sections from base to apex were obtained from the reconstructed LV. In each short axis 24 wall-thickness measurements were carried out at 15 degrees intervals at end-diastole and end-systole. Thus, a total of 192 measurements were obtained in each patient. Wall thickening was calculated as difference of end-diastolic and end-systolic wall thickness, and fractional thickening as thickening divided by end-diastolic thickness. Fractional thickening and wall stress were inversely related to end-diastolic wall thickness in both, males and females. Females showed less LV systolic function when compared to males (p<0.001). However, when corrected for wall stress, which was higher in females, there was no gender difference in systolic function. CONCLUSION: There are regional differences in LV systolic function in females and males which are directly related to differences in wall stress. Thus, gender-related differences in LV regional function are load-dependent and not due to structural differences.

Pretransplant pulmonary hypertension and long-term allograft right ventricular function

Graft right ventricular (RV) function is compromised directly posttransplant, especially in heart transplantation (HTx) recipients with pretransplant pulmonary hypertension (PH). Graft RV size and systolic function, and the effect of the recipient's pulmonary haemodynamics on the graft extracellular matrix are not well characterised in the patients long-term after HTx.

Early repolarization, left ventricular diastolic function, and left atrial size in professional soccer players

Recent data have suggested a relation among long-term endurance sport practice, left atrial remodeling, and atrial fibrillation. We investigated the influence of an increased vagal tone, represented by the early repolarization (ER) pattern, on diastolic function and left atrial size in professional soccer players. Fifty-four consecutive athletes underwent electrocardiography, echocardiography, and exercise testing as part of their preparticipation screening. Athletes were divided into 2 groups according to presence or absence of an ER pattern, defined as a ST-segment elevation at the J-point (STE) > or =0.1 mm in 2 leads. For linear comparisons average STE was calculated. Mean age was 24 +/- 4 years. Twenty-five athletes (46%) showed an ER pattern. Athletes with an ER pattern had a significant lower heart rate (54 +/- 9 vs 62 +/- 11 beats/min, p = 0.024), an increased E/e' ratio (6.1 +/- 1.2 vs 5.1 +/- 1.0, p = 0.002), and larger volumes of the left atrium (25.6 +/- 7.3 vs 21.8 +/- 5.0 ml/m(2), p = 0.031) compared to athletes without an ER pattern. There were no significant differences concerning maximum workload, left ventricular dimensions, and systolic function. Univariate regression analysis revealed significant correlations among age, STE, and left atrial volume. In a stepwise multivariate regression analysis age, STE and e' contributed independently to left atrial size (r = 0.659, p <0.001). In conclusion, athletes with an ER pattern had an increased E/e' ratio, reflecting a higher left atrial filling pressure, contributing to left atrial remodeling over time.

Pulmonary artery pressure and cardiac function in children and adolescents after rapid ascent to 3,450 m

High-altitude destinations are visited by increasing numbers of children and adolescents. High-altitude hypoxia triggers pulmonary hypertension that in turn may have adverse effects on cardiac function and may induce life-threatening high-altitude pulmonary edema (HAPE), but there are limited data in this young population. We, therefore, assessed in 118 nonacclimatized healthy children and adolescents (mean ± SD; age: 11 ± 2 yr) the effects of rapid ascent to high altitude on pulmonary artery pressure and right and left ventricular function by echocardiography. Pulmonary artery pressure was estimated by measuring the systolic right ventricular to right atrial pressure gradient. The echocardiography was performed at low altitude and 40 h after rapid ascent to 3,450 m. Pulmonary artery pressure was more than twofold higher at high than at low altitude (35 ± 11 vs. 16 ± 3 mmHg; P < 0.0001), and there existed a wide variability of pulmonary artery pressure at high altitude with an estimated upper 95% limit of 52 mmHg. Moreover, pulmonary artery pressure and its altitude-induced increase were inversely related to age, resulting in an almost twofold larger increase in the 6- to 9- than in the 14- to 16-yr-old participants (24 ± 12 vs. 13 ± 8 mmHg; P = 0.004). Even in children with the most severe altitude-induced pulmonary hypertension, right ventricular systolic function did not decrease, but increased, and none of the children developed HAPE. HAPE appears to be a rare event in this young population after rapid ascent to this altitude at which major tourist destinations are located.

MR findings of endocardial fibroelastosis in children

BACKGROUND: Endocardial fibroelastosis (EFE) is characterized by a diffuse white fibrous tissue lining the endocardium. The diagnosis is difficult to establish because clinical symptoms and electrocardiographic findings are nonspecific. Surgical resection of EFE requires the establishment of the diagnosis and delineation of the extent of the fibrotic changes. OBJECTIVE: To describe the use of MRI in the assessment of EFE in children. MATERIALS AND METHODS: Three children after surgery for aortic stenosis who were suspected of having EFE were evaluated by echocardiography and MRI. The MR evaluation consisted of black-blood, triple IR, bright-blood, perfusion and myocardial delayed-enhancement sequences. EFE was confirmed at surgery in all patients. RESULTS: Echocardiograms demonstrated vigorous systolic function but substantial diastolic dysfunction of the left ventricle in all. Mild endocardial brightening of the anterior septum, anterior wall, or papillary muscles was present in two. No study was thought to be diagnostic of endocardial fibrosis. On MRI EFE manifested at the endocardial surface as a rim of hypointense signal in the perfusion sequences and as a rim of hyperintense signal in the myocardial delayed-enhancement sequences. The black-blood, triple IR, and bright-blood sequences were not diagnostic. CONCLUSION: The diagnosis of EFE is difficult to establish by echocardiography. MRI using perfusion and myocardial delayed enhancement can be useful in establishing the diagnosis.

Persistent diastolic dysfunction late after valve replacement in severe aortic regurgitation

BACKGROUND: Regression of left ventricular (LV) hypertrophy with normalization of diastolic function has been reported in patients with aortic stenosis late after aortic valve replacement (AVR). The purpose of the present study was to evaluate the effect of AVR on LV function and structure in chronic aortic regurgitation early and late after AVR. METHODS AND RESULTS: Twenty-six patients were included in the present analysis. Eleven patients with severe aortic regurgitation were studied before, early (21 months) and late (89 months) after AVR through the use of LV biplane angiograms, high-fidelity pressure measurements, and LV endomyocardial biopsies. Fifteen healthy subjects were used as controls. LV systolic function was determined from biplane ejection fraction and midwall fractional shortening. LV diastolic function was calculated from the time constant of LV relaxation, peak filling rates, and myocardial stiffness constant. LV structure was assessed from muscle fiber diameter, interstitial fibrosis, and fibrous content. LV muscle mass decreased significantly by 38% early and 55% late after surgery. Ejection fraction was significantly reduced preoperatively and did not change after AVR (P=NS). LV relaxation was significantly prolonged before surgery (89+/-28 ms) but was normalized late after AVR (42+/-14 ms). Early and late peak filling rates were increased preoperatively but normalized postoperatively. Diastolic stiffness constant was increased before surgery (22+/-6 versus 9+/-3 in control subjects; P=0.0003) and remained elevated early and late after AVR (23+/-4; P=0.002). Muscle fiber diameter decreased significantly after AVR but remained increased at late follow-up. Interstitial fibrosis was increased preoperatively and increased even further early but decreased late after AVR. Fibrosis was positively linearly correlated to myocardial stiffness and inversely correlated to LV ejection fraction. CONCLUSIONS: Patients with aortic regurgitation show normalization of macroscopic LV hypertrophy late after AVR, although fiber hypertrophy persists. These changes in LV myocardial structure late after AVR are accompanied by a change in passive elastic properties with persistent diastolic dysfunction.

Heart rate response determines long term exercise capacity after heart transplantation

BACKGROUND: Exercise capacity after heart transplantation (HTx) remains limited despite normal left ventricular systolic function of the allograft. Various clinical and haemodynamic parameters are predictive of exercise capacity following HTx. However, the predictive significance of chronotropic competence has not been demonstrated unequivocally despite its immediate relevance for cardiac output. AIMS: This study assesses the predictive value of various clinical and haemodynamic parameters for exercise capacity in HTx recipients with complete chronotropic competence evolving within the first 6 postoperative months. METHODS: 51 patients were enrolled in this exercise study. Patients were included when at least >6 months after HTx and without negative chronotropic medication or factors limiting exercise capacity such as significant transplant vasculopathy or allograft rejection. Clinical parameters were obtained by chart review, haemodynamic parameters from current cardiac catheterisation, and exercise capacity was assessed by treadmill stress testing. A stepwise multiple regression model analysed the proportion of the variance explained by the predictive parameters. RESULTS: The mean age of these 51 HTx recipients was 55.4 +/- 13.2 yrs on inclusion, 42 pts were male and the mean time interval after cardiac transplantation was 5.1 +/- 2.8 yrs. Five independent predictors explained 47.5% of the variance observed for peak exercise capacity (adjusted R2 = 0.475). In detail, heart rate response explained 31.6%, male gender 5.2%, age 4.1%, pulmonary vascular resistance 3.7%, and body-mass index 2.9%. CONCLUSION: Heart rate response is one of the most important predictors of exercise capacity in HTx recipients with complete chronotropic competence and without relevant transplant vasculopathy or acute allograft rejection.

Masked hypertension and cardiac remodeling in middle-aged endurance athletes

OBJECTIVES: Extensive endurance training and arterial hypertension are established risk factors for atrial fibrillation. We aimed to assess the proportion of masked hypertension in endurance athletes and the impact on cardiac remodeling, mechanics, and supraventricular tachycardias (SVT). METHODS: Male participants of a 10-mile race were recruited and included if office blood pressure was normal (<140/90 mmHg). Athletes were stratified into a masked hypertension and normotension group by ambulatory blood pressure. Primary endpoint was diastolic function, expressed as peak early diastolic mitral annulus velocity (E'). Left ventricular global strain, left ventricular mass/volume ratio, left atrial volume index, signal-averaged P-wave duration (SAPWD), and SVT during 24-h Holter monitoring were recorded. RESULTS: From 108 runners recruited, 87 were included in the final analysis. Thirty-three (38%) had masked hypertension. The mean age was 42 +/- 8 years. Groups did not differ with respect to age, body composition, cumulative training hours, and 10-mile race time. Athletes with masked hypertension had a lower E' and a higher left ventricular mass/volume ratio. Left ventricular global strain, left atrial volume index, SAPWD, and SVT showed no significant differences between the groups. In multiple linear regression analysis, masked hypertension was independently associated with E' (beta = -0.270, P = 0.004) and left ventricular mass/volume ratio (beta = 0.206, P = 0.049). Cumulative training hours was the only independent predictor for left atrial volume index (beta = 0.474, P < 0.001) and SAPWD (beta = 0.481, P < 0.001). CONCLUSION: In our study, a relevant proportion of middle-aged athletes had masked hypertension, associated with a lower diastolic function and a higher left ventricular mass/volume ratio, but unrelated to left ventricular systolic function, atrial remodeling, or SVT.

Use of echocardiography reveals reestablishment of ventricular pumping efficiency and partial ventricular wall motion recovery upon ventricular cryoinjury in the zebrafish

AIMS While zebrafish embryos are amenable to in vivo imaging, allowing the study of morphogenetic processes during development, intravital imaging of adults is hampered by their small size and loss of transparency. The use of adult zebrafish as a vertebrate model of cardiac disease and regeneration is increasing at high speed. It is therefore of great importance to establish appropriate and robust methods to measure cardiac function parameters. METHODS AND RESULTS Here we describe the use of 2D-echocardiography to study the fractional volume shortening and segmental wall motion of the ventricle. Our data show that 2D-echocardiography can be used to evaluate cardiac injury and also to study recovery of cardiac function. Interestingly, our results show that while global systolic function recovered following cardiac cryoinjury, ventricular wall motion was only partially restored. CONCLUSION Cryoinjury leads to long-lasting impairment of cardiac contraction, partially mimicking the consequences of myocardial infarction in humans. Functional assessment of heart regeneration by echocardiography allows a deeper understanding of the mechanisms of cardiac regeneration and has the advantage of being easily transferable to other cardiovascular zebrafish disease models.

Hydrogel-based engineered skeletal muscle grafts normalize heart function early after myocardial infarction

Tissue engineering represents an attractive approach for the treatment of congestive heart failure. The influence of the differentiation of myogenic graft for functional recovery is not defined. We engineered a biodegradable skeletal muscle graft (ESMG) tissue and investigated its functional effect after implantation on the epicardium of an infarcted heart segment. ESMGs were synthesized by mixing collagen (2 mg/mL), Matrigel (2 mg/mL), and rat skeletal muscle cells (10(6)). Qualitative and quantitative aspects of ESMGs were optimized. Two weeks following coronary ligation, the animals were randomized in three groups: ESMG glued to the epicardial surface with fibrin (ESMG, n = 7), fibrin alone (fibrin, n = 5), or sham operation (sham, n = 4). Echocardiography, histology, and immunostaining were performed 4 weeks later. A cohesive three-dimensional tissular structure formed in vitro within 1 week. Myoblasts differentiated into randomly oriented myotubes. Four weeks postimplantation, ESMGs were vascularized and invaded by granulation tissue. Mean fractional shortening (FS) was, however, significantly increased in the ESMG group as compared with preimplantation values (42 +/- 6 vs. 33 +/- 5%, P < 0.05) and reached the values of controlled noninfarcted animals (control, n = 5; 45 +/- 3%; not significant). Pre- and postimplantation FS did not change over these 4 weeks in the sham group and the fibrin-treated animals. This study showed that it is possible to improve systolic heart function following myocardial infarction through implantation of differentiated muscle fibers seeded on a gel-type scaffold despite a low rate of survival.

Age-related normal structural and functional ventricular values in cardiac function assessed by magnetic resonance

BACKGROUND The heart is subject to structural and functional changes with advancing age. However, the magnitude of cardiac age-dependent transformation has not been conclusively elucidated. METHODS This retrospective cardiac magnetic resonance (CMR) study included 183 subjects with normal structural and functional ventricular values. End systolic volume (ESV), end diastolic volume (EDV), and ejection fraction (EF) were obtained from the left and the right ventricle in breath-hold cine CMR. Patients were classified into four age groups (20-29, 30-49, 50-69, and ≥70 years) and cardiac measurements were compared using Pearson's rank correlation over the four different groups. RESULTS With advanced age a slight but significant decrease in ESV (r=-0.41 for both ventricles, P<0.001) and EDV (r=-0.39 for left ventricle, r=-0.35 for right ventricle, P<0.001) were observed associated with a significant increase in left (r=0.28, P<0.001) and right (r=0.27, P<0.01) ventricular EF reaching a maximal increase in EF of +8.4% (P<0.001) for the left and +6.1% (P<0.01) for the right ventricle in the oldest compared to the youngest patient group. Left ventricular myocardial mass significantly decreased over the four different age groups (P<0.05). CONCLUSIONS The aging process is associated with significant changes in left and right ventricular EF, ESV and EDV in subjects with no cardiac functional and structural abnormalities. These findings underline the importance of using age adapted values as standard of reference when evaluating CMR studies.