Aging is associated with left ventricular hypertrophy, dilatation, and fibrosis of the heart. The Fischer 344/Brown Norway F1 (F344/BNF1) rat is recommended for age-related studies by the National Institutes on Aging because this hybrid rat lives longer and has a lower rate of pathological conditions than inbred rats. However, little is known about age-associated changes in cardiac and aortic function and structure in this model. This study evaluated age-related cardiac changes in male F344/BNF1 rats using ECHO, gross, and microscopic examinations. Rats aged 6-, 30-, and 36-mo were anesthetized and two-dimensional ECHO measurements, two-dimensional guided M-mode, Doppler M-mode, and other recordings from parasternal long- and short-axis views were obtained using a Phillips 5500 ECHO system with a 12 megahertz transducer. Hearts and aortas from sacrificed rats were evaluated grossly and microscopically. The ECHO studies revealed persistent cardiac arrhythmias (chiefly PVCs) in 72% (13/18) of 36-mo rats, 10% (1/10) of 30-mo rats, and none in 6-mo rats (0/16). Gross and microscopic studies showed left ventricular (LV) dilatation, borderline to mild hypertrophy, and areas of fibrosis that were common in 36-mo rats, less evident in 30-mo rats, and absent in 6-mo rats. Aging was associated with mild to moderate decreases of LV diastolic and systolic function. Thus, male F344/BN F1 rats demonstrated progressive age-related (a) decline in cardiac function (diastolic and systolic indices), (b) LV structural changes (chamber dimensions, volumes, and wall thicknesses), and (c) persistent arrhythmias. These changes are consistent with those in humans. The noninvasive ECHO technique offers a means to monitor serial age-related cardiac failure and therapeutic responses in the same rats over designated time intervals.
Cardiovascular risk factors and carotid atherosclerosis relate to blood flow velocity in the brachial artery during induced hyperaemia. This relation proved to be particularly strong when using the hyperaemic systolic to diastolic blood flow velocity (SDFV) ratio. In this study, we further investigated this ratio in relation to the left ventricular (LV) geometry in a cross-sectional analysis. In the Prospective Investigation of the Vasculature in Uppsala Seniors study, 1016 seventy-year-olds participated. Blood flow velocity during hyperaemia of the brachial artery by Doppler was analysed. Echocardiography was performed, allowing analysis of LV geometry, categorised into four different groups: normal, concentric remodelling, concentric and eccentric hypertrophy. The SDFV ratio increased in subjects with concentric LV-remodelling (P=0.006) or LV-hypertrophy (P=0.001), but not in those with eccentric hypertrophy (P=0.12) when compared with the group with normal LV geometry. These associations remained significant after adjustment for gender, blood pressure, blood glucose, body mass index and antihypertensive treatment. The SDFV ratio in the brachial artery was related to concentric geometry of the LV in an elderly population sample, suggesting this new hemodynamic variable as a marker of increased afterload. Future studies have to determine if the SDFV ratio is a powerful predictor of future CV events, in addition to LV geometry.
Short-axis (SA) magnetic resonance (MR) images are commonly planned parallel to the left atrioventricular valve. This orientation leads to oblique slices of the right ventricle (RV) with subsequent difficulties in separating the RV from the right atrium in the SA images. The insertion points of the tricuspid valve (TV) in the myocardium can be clearly identified in the right ventricle long axis (RVLA) and four-chamber (4CH) views. The purpose of this study was to develop a method that transfers the position of the tricuspid plane, as seen in the RVLA and 4CH views, to the SA images to facilitate the separation of the RV from the atrium. This methodology, termed Dissociating the Right Atrium from the Ventricle Volume (DRAW), was applied in 20 patients for calculations of right ventricular stroke volume (RVSV). The RVSV using DRAW (RVSV(DRAW)) was compared to left ventricular stroke volumes (LVSV) obtained from flow measurements in the ascending aorta. The RVSV was also determined using the conventional method (RVSV(CONV)) where the stack of images from the SA views are summarized, and a visual decision is made of the most basal slice to be included in the RV. The mean difference between RVSV(DRAW) and LVSV was 0·1 ± 12·7 ml, while the mean difference between RVSV(CONV) and LVSV was 0·33 ± 14·3 ml. Both the intra- and interobserver variability were small using the DRAW methodology, 0·6 ± 3·5 and 1·7 ± 2·7 ml, respectively. In conclusion, the DRAW method can be used to facilitate the separation of the RV and the atrium.
The rhythmoinotropic dependence of the papillary muscles was studied in rats with postinfarction cardiosclerosis after blocking of beta(1)-adrenoreceptors by concor (7 mg/kg daily). The development of postinfarction cardiosclerosis led to a reduction of the postextrasystolic potentiation and of potentiation induced by periods of rest. Preliminary blocking of beta(1)-adrenoreceptors stimulated the postextrasystolic contractions and contractions after periods of rest in the myocardium of rats with postinfarction cardiosclerosis. These results suggest that blocking of beta(1)-adrenoreceptors promotes an improvement of calcium-accumulating function of the cardiomyocyte sarcoplasmatic reticulum in the myocardium of rats with postinfarction cardiosclerosis.
While echocardiography (ECHO)-measured left ventricular mass (LVM) predicts adverse cardiovascular events that are common in hemodialysis (HD) recipients, cardiac magnetic resonance imaging (CMR) is now considered the reference standard for determination of LVM. This study aimed to evaluate concordance between LVM measurements across ECHO and CMR among chronic HD recipients and matched controls.
A single-centre, cross-sectional study of 41 chronic HD patients and 41 matched controls with normal kidney function was performed to compare LVM measurements and left ventricular hypertrophy (LVH) designation by ECHO and CMR.
In both groups, ECHO, compared with CMR, overestimated LVM. Bland-Altman analysis demonstrated wider agreement limits in LVM measurements by ECHO and CMR in the chronic HD group (mean difference, 60.8 g; limits -23 g to 144.6 g) than in the group with normal renal function (mean difference, 51.4 g; limits -10.5 g to 113.3 g). LVH prevalence by ECHO and CMR in the chronic HD group was 37.5% and 22.5%, respectively, while 17.5% and 12.5% had LVH by ECHO and CMR, respectively, in the normal kidney function group. Intermodality agreement in the designation of LVH was modest in the chronic HD patients (? = 0.42, P = 0.005) but strong (? = 0.81, P
An early and accurate diagnosis of chronic heart failure is a big challenge for a general practitioner. Assessment of left ventricular function is essential for the diagnosis of heart failure and the prognosis. A gold standard for identifying left ventricular function is echocardiography. Echocardiography requires input from specialized care and has a limited access in Swedish primary health care. Impedance cardiography (ICG) is a noninvasive and low-cost method of examination. The survey technique is simple and ICG measurement can be performed by a general practitioner. ICG has been suggested for assessment of left ventricular function in patients with heart failure. We aimed to study the association between hemodynamic parameters measured by ICG and the value of ejection fraction as a determinant of reduced left ventricular systolic function in echocardiography.
A non-interventional, observational study conducted in the outpatients heart failure unit. Thirty-six patients with the diagnosis of chronic heart failure were simultaneously examined by echocardiography and ICG. Distribution of categorical variables was presented as numbers. Distribution of continuous variables was presented as a mean and 95% Confidence Interval. Kruskal-Wallis test was used to compare variables and show differences between the groups. A p-value of
The purpose of the study was to compare the accuracy and evaluation time of quantifying left ventricular (LV), left atrial (LA) volume and LV mass using short axis (SAX) and long axis (LAX) methods when using cardiovascular magnetic resonance (CMR).
We studied 12 explanted canine hearts and 46 patients referred for CMR (29 male, age 47 ± 18 years) in a clinical 1.5 T CMR system, using standard cine sequences. In standard short axis stacks of various slice thickness values in dogs and 8 mm slice thickness (gap 2 mm) in patients, we measured LV volumes using reference slices in a perpendicular, long axis orientation using certified software. Volumes and mass were also measured in six radial long axis (LAX) views.LV parameters were also assessed for intra- and inter-observer variability. In 24 patients, we also analyzed reproducibility and evaluation time of two very experienced (> 10 years of CMR reading) readers for SAX and LAX.
In the explanted dog hearts, there was excellent agreement between ex vivo data and LV mass and volume data as measured by all methods for both, LAX (r² = 0.98) and SAX (r² = 0.88 to 0.98). LA volumes, however, were underestimated by 13% using the LAX views. In patients, there was a good correlation between all three assessed methods (r² = 0.95 for all). In experienced clinical readers, left-ventricular volumes and ejection fraction as measured in LAX views showed a better inter-observer reproducibility and a 27% shorter evaluation time.
When compared to an ex vivo standard, both, short axis and long axis techniques are highly accurate for the quantification of left ventricular volumes and mass. In clinical settings, however, the long axis approach may be more reproducible and more time-efficient. Therefore, the rotational long axis approach is a viable alternative for the clinical assessment of cardiac volumes, function and mass.