Relationship between Fragmented QRS and Microvascular Dysfunction in Masked Hypertension

Abstract

Aim: The aim of this study was to investigate the presence of fQRS and its association with subclinical systolic and microvascular dysfunction in patients with masked hypertension (MH).

Methods: The study population consisted of 95 (mean age 48.9 ± 11.3, 61% males) subjects with MH and 80 age- and gender-matched healthy individuals who served as a control group. Coronary flow reserve (CFR) using transthoracic echocardiography and for left ventricular global longitudinal strain (LVGLS) using speckle-tracking strain imaging were performed. Patients with MH were stratified into two groups according to the presence of fQRS on surface electrocardiogram.

Results: Fragmented QRS was more common among MH patients compared with controls (38.9% vs. 6.25%, p < 0.003). CFR was significantly lower in patients with fQRS compared with those without fQRS and controls (p < 0.001). Likewise, LVGLS values were lower in MH patients with fQRS (p < 0.001) compared with subjects without fQRS and controls. Fragmented fQRS was significantly correlated with systolic blood pressure, CFR, and LVGLS. Multivariate analysis showed that the presence of fQRS, number of leads, and CFR were independent predictors of subclinical systolic dysfunction. With ROC cure analysis, number of leads with fQRS ≥4 was the optimal value for predicting the presence of subclinical systolic dysfunction in subjects with MH.

Conclusions: Fragmented QRS is more frequent among subjects with MH compared with controls. The presence of fQRS is related with pronounced subclinical left ventricular systolic dysfunction. Furthermore, CFR was significantly reduced in subjects with MH, a finding supposed that microvascular dysfunction to be a mechanistic link.

Keywords: Fragmented QRS; Masked hypertension; Myocardial and microvascular dysfunction.