Myocardial remodeling in hypertension

Left ventricular (LV) hypertrophy and remodeling are frequently seen in hypertensive subjects and result from a complex interaction of several hemodynamic and non-hemodynamic variables. Although increased blood pressure is considered the major determinant of LV structural alterations, ethnicity, gender, environmental factors, such as salt intake, obesity and diabetes mellitus, as well as neurohumoral and genetic factors might influence LV mass and geometry. The conventional concept of hypertensive LV remodeling has been that hypertension leads to concentric hypertrophy, as an adaptive response to normalize wall stress, which is then followed by chamber dilation and heart failure. However, several lines of evidence have challenged this dogma. Concentric hypertrophy is not the most frequent geometric pattern and is less usually seen than eccentric hypertrophy in hypertensive subjects. In addition, data from recent studies suggested that transition from LV concentric hypertrophy to dilation and systolic dysfunction is not a common finding, especially in the absence of coronary heart disease. LV hypertrophy is also consistently associated with increased cardiovascular morbidity and mortality, raising doubts whether this phenotype is an adaptive response. Experimental evidence exists that a blunting of load-induced cardiomyocyte hypertrophy does not necessarily result in LV dysfunction or failure. Furthermore, the hypertrophic myocardium shows fibrosis, alterations in the coronary circulation and cardiomyocyte apoptosis, which may result in heart failure, myocardial ischemia and arrhythmias. Overall, this body of evidence suggests that LV hypertrophy is a complex phenotype that predicts adverse cardiovascular outcomes and may not be necessarily considered as an adaptive response to systemic hypertension.