Helen C. Oxenham

Cardiovascular aging and heart failure.

The aging process is a major factor that contributes to changes seen in the cardiovascular system in older people. Stiffening of the arterial tree alters afterload and left ventricular geometry and although resting left ventricular systolic function is maintained, left ventricular diastolic function changes substantially. Cardiovascular function in older people during exercise is also significantly altered but can be modified by exercise training in older adults or genetic modification in animals. Age‐related changes in cardiovascular structure and function also lower the threshold at which cardiac diseases become apparent. This review describes the changes in cardiovascular structure and function at rest and during exercise in older people and highlights their consequences.

Age-Related Changes in Myocardial Relaxation Using Three-Dimensional Tagged Magnetic Resonance Imaging

PURPOSE Marked changes in left ventricular diastolic filling occur with advancing age, but alterations in myocardial movement accompanying these findings have not been previously documented. We aimed to identify differences in myocardial motion during relaxation and diastole using magnetic resonance imaging (MRI), with tagging, which uniquely allows accurate, noninvasive assessment of myocardial movement in three dimensions. METHODS Tagged MRI images from two groups of normal individuals were analyzed using dedicated computer software to provide values for group comparison of apical rotation, torsion, and circumferential and longitudinal strain throughout the cardiac cycle. RESULTS The mean age of the younger group was 22 years, (n = 15) and that of the older group was 69 years, (n = 16). In the older group, peak apical rotation and torsion were increased during systole and significantly more apical rotation, torsion, circumferential, and longitudinal strain persisted during myocardial relaxation and diastole. In addition, peak normalized reversal of apical rotation was reduced (-5.1 +/- 1.2 degrees s-1 vs. -6.7 +/- 1.2 degrees s-1, p = 0.001), and there were slower peak rates of circumferential lengthening (76.2 +/- 28% s-1 vs. 142.5 +/- 17% s-1, p < 0.001) and longitudinal lengthening (62.7 +/- 21% s-1 vs. 122.5 +/- 20% s-1, p < 0.001). CONCLUSIONS Tagged MRI is a unique, noninvasive imaging method that can identify significant prolongation and reduction of myocardial relaxation in older compared with young normal individuals.

Temporal Evolution of Left Ventricular Strain Late After Repair of Coarctation of the Aorta Using 3D MR Tissue Tagging

PURPOSE Following repair of coarctation of the aorta (CoA), LV mass is increased along with morbidity and mortality. Previous studies have reported increased shortening indices and impaired diastolic function. However, direct measurements of local material motion and temporal evolution of strain have been lacking. METHODS Magnetic resonance (MR) tissue tagging was used to quantify regional three-dimensional myocardial deformation throughout systole and much of diastole in 14 patients (aged 19-23) who had CoA repair 17-23 years previously, and 15 age-, sex- and BSA-matched normal volunteers (NV). RESULTS Mass to end-diastolic volume ratio was increased in the CoA group (1.23 +/- 0.12 g/mL CoA vs. 1.14 +/- 0.10 g/mL NV, p = 0.039), together with ejection fraction (65.3 +/- 4.4 vs. 60.8 +/-1.9%, p = 0.001) and systolic blood pressure (132.5 +/- 14.5 vs. 117.3 +/- 11.6 mmHg, p = 0.004). At end-systole, circumferential shortening was normal, but longitudinal shortening was decreased (14.9 +/- 1.3 vs. 16.8 +/- 1.4%, p < 0.001). Although systolic strain rates were not significantly different, early diastolic strain rate (EDSR) in the CoA group was increased in the circumferential direction (-71 +/- 23 vs. -52 +/- 20%/sec, p = 0.029), but decreased in the longitudinal direction (-27 +/- 12 vs. -39 +/- 11%/sec, p = 0.015). Longitudinal shortening and circumferential EDSR were related to right arm-leg pressure gradient (R2 = 0.20, p = 0.016 and R2 = 0.38, p < 0.001, respectively) and to mass index (R2 = 0.18, p = 0.024 and R2 = 014, p = 0.049, respectively). CONCLUSIONS MR tagging allows quantitative information on the temporal evolution of myocardial deformation. Directionally dependent changes in strain evolution are seen late after CoA repair. These changes are related to both persistent arm-leg pressure gradient and degree of hypertrophy and may be indicators of developing dysfunction.

Angiotensin-converting enzyme inhibitor treatment after myocardial infarction: A selective approach for maximum benefit

Early survival following myocardial infarction (MI) has improved significantly over the past 20 years, due in part to medical treatments including thrombolysis, aspirin and beta-blockade. Now, more MI survivors are at risk from the subsequent development of heart failure [(1)][1]. The clinical