Left Ventricular Strain in Heart Failure with Preserved Ejection Fraction

Abstract

Heart failure with preserved ejection fraction (HFpEF) is a heterogeneous clinical syndrome of effort intolerance based on structural and functional abnormalities of the cardiovascular system (CVS). Its prevalence is increasing progressively in comparison to that of heart failure with reduced ejection fraction due to aging, obesity, metabolic stress, and hypertension. Multiple domains of the CVS and peripheral organs have reduced reserve capacity and increased stiffness in patients with HFpEF. This high-gain CVS exhibits increased filling pressures and reduced filling volumes under stress despite the left ventricular ejection fraction, commonly estimated parameter of contractile performance, being normal, i.e., >50%. The cost of increasing cardiac output in terms of left ventricular filling pressures is increased and their relationship shows an upward and more left-directed slope due to reduced ventricular and arterial compliance. At the tissue level, there is myocytic hypertrophy and increased extracellular matrix with capillary rarefaction. There are many phenogroups of HFpEF based on the heart’s ability to secrete natriuretic peptides, degree of dysmetabolism, age, renal function, body fat, rhythm, underlying etiology, and subclinical systolic dysfunction. The left ventricle may be pressure-loaded, volume-loaded, or have equipoise with regard to remodeling. Myocardial performance estimated by parameters other than those based on distance or volume displacement may be abnormal in more than half of the patients underlying the presence of subtle systolic dysfunction. This review looks at myocardial performance and characteristics in HFpEF by deformation imaging using acoustic speckle tracking and its diagnostic and prognostic significance. Research points toward the utility of global longitudinal strain in early detection, biological characterization, and risk stratification of HFpEF. Echocardiographic speckle-tracking-based longitudinal strain analysis represents a method of relatively high value and for sensitive phenotyping of HFpEF which is yet to be utilized optimally. Other dimensions of strain, although extensively studied in HFpEF, do not add much value. The focus is on systolic deformation since there is limited utility of diastolic strain and its rate.