Relationship Between Fragmented QRS Complex and Left Ventricular Fibrosis and Function in Patients With Danon Disease.

Jiajun Xie,Yining Wang,Yucheng Chen,Zekun Tan,Lei Zhao,Yang Liu,Minjie Lu,Zelan Ma,Xiaoyu Wei,Guanyu Lu,Weitao Ye,Xiaohu Li,Hui Liu,Tingyu Li

doi:10.3389/fcvm.2022.790917

Abstract

BackgroundFragmented QRS (f-QRS) complex on the surface ECG is a cardiac conduction abnormality that indicates myocardial scarring. The relationship between the f-QRS complex and cardiac status in patients with Danon disease (DD) remains unclear and will be explored in this study.MethodsPatients with genetically confirmed DD and cardiac magnetic resonance imaging (CMR) examinations were recruited from multiple centers. The number of leads, pattern, score, and segmental distribution of the f-QRS complex were assessed by surface 12-lead ECG. Cardiac status, such as left ventricular (LV) volume, function, and extent of late gadolinium enhancement (LGE), was demonstrated by CMR. The segmental distribution of LGE was also assessed. Correlations between the f-QRS and cardiac status were assessed.ResultsFifteen patients (14 men) with DD who underwent 12-lead ECG and CMR imaging were included. The f-QRS complex was documented in all patients (n = 15, 100%). Three patterns of f-QRS were found, with the notched R/S pattern (74%) being the most common, followed by fragmented QRS (16%) and various RSR' (11%). The fragmented QRS pattern showed an association with a higher level of myocardial fibrosis (LGE > 35%). The burden of f-QRS in each patient was assessed by the number of leads with f-QRS (median 7, range 2–12) and the f-QRS score (median 9, range 2–33). In the correlation analysis, the f-QRS score was positively correlated with LGE% (r = 0.726, p = 0.002), negatively correlated with LV ejection function (LVEF; r = −0.617, p = 0.014) as evaluated by CMR. In the local distribution, f-QRS score and LGE% were both predominant in the LV free wall but did not correlate well among the anterior, lateral, and inferior segments.ConclusionIn this DD cohort, the quantitative f-QRS was correlated well with myocardial fibrosis burden and LV dysfunction in general. This finding suggests that f-QRS can be used as a simple screening tool to assess cardiac status in patients with DD.

Highlights

Danon disease (DD) is a rare X-chromosome-linked genetic disorder caused by a lysosome-associated membrane protein2 (LAMP2) gene mutation [1]
The fragmented QRS pattern showed an association with a higher level of myocardial fibrosis (LGE >35%)
The high prevalence of Fragmented QRS (f-QRS) in DD subjects raised our interest in investigating its importance to the cardiac status of this unique disease

Summary

Introduction

Danon disease (DD) is a rare X-chromosome-linked genetic disorder caused by a lysosome-associated membrane protein (LAMP2) gene mutation [1]. Due to the accumulation of intracytoplasmic autophagic vacuoles in the myocardium, many patients with DD cardiomyopathy usually develop in their childhood or young adulthood severe conditions, such as fatal cardiac hypertrophy, progressive heart failure, and often ventricular arrhythmias [2, 3]. Late gadolinium enhancement (LGE) at CMR usually reflects irreversible myocardial fibrosis or scarring [6, 7]. The typical pattern of LGE in DD cardiomyopathy is generally characterized by an extensive distribution in the left ventricular (LV) free wall and usually sparing or relatively less involved in the interventricular septum [8,9,10,11]. The relationship between the f-QRS complex and cardiac status in patients with Danon disease (DD) remains unclear and will be explored in this study

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