Hemodynamic Characteristics and Progression to Heart Failure in Regurgitant Lesions

AR and MR are two disorders in which the only similarities are the resultant volume overload of the left ventricle and the potential for irreversible LV systolic dysfunction before the onset of severe symptoms. In the compensated phase of MR, there is increased preload and normal afterload. The left ventricle compensates by undergoing enlargement and very little hypertrophy. These hemodynamic alterations associated with increased preload result in preserved ejection fraction even when contractile dysfunction develops. In contrast, AR results in increased preload and increased afterload, resulting in eccentric and concentric hypertrophy. Patients may remain asymptomatic for years until afterload mismatch results in LV dysfunction that is initially reversible. If left untreated, LV dysfunction in MR and AR may become irreversible [47]. Understanding the adaptive changes that the left ventricle undergoes in these volume-overload conditions has resulted in treatment guidelines to assist clinicians in timing of surgical correction.