Features of vectorcardiograms in patients with hypertension complicated by chronic heart failure with reduced left ventricle ejection fraction

Abstract

Aim. To explore the features of vectorcardiograms (VCG) of patients with essential hypertension complicated by chronic heart failure with reduced left ventricular ejection fraction (CHFrLVEF). Materials and methods. We analyzed VCGs of 70 hypertensive patients with CHFrLVEF and 275 hypertensive patients without clinical signs of CHF and with LVEF50%. We assessed the presence of rhythm and conduction disturbances, and the parameters of the synthesized VCG, i.e., module of the maximum QRS vector, planarity index of the spatial QRS loop (P/S), and spatial angle between the integral QRS and T vectors (sQRS-Ta). Results. In hypertensive patients with CHF, certain conditions were detected more often as compared with hypertensive patients without CHF, i.e., atrial fibrillation (AF) in 52.9% vs 5.1%; p0.0001, and left bundle branch block (LBBB) in 38.6% vs 0.4%; p0.0001. The module of the maximum QRS vector and sQRS-Ta were significantly greater and P/S was significantly less in VCGs of patients with CHF. ROC-analysis showed that the presence of AF and LBBB just as VCG parameters assessed in this study provide clear discrimination between hypertensive patients with or without CHF both in the group as a whole and in the subgroups (1) without LBBB, (2) with sinus rhythm, and (3) with AF. sQRS-Ta was the most informative parameter (threshold 137, sensitivity 91%, specificity 92%). The P/S indicator at the optimal threshold value 0.92 was characterized by lower specificity (68%) with rather high sensitivity (79%). Conclusion. AF, LBBB, increased module of the maximum QRS vector and sQRS-Ta, and decreased P/S index are present in hypertensive patients with CHFrLVEF as compared with patients without CHF.