Association of electrocardiographic markers with myocardial fibrosis as assessed by cardiac magnetic resonance in different clinical settings

Table 2 Summary of the main findings of all included studies in the systematic review

Ref.	ECG markers studied	Main findings
Bi et al[9], 2020	fQRS, AF, bundle branch block	Quantitative fQRS was an independent predictor for myocardial fibrosis in HCOM
Chen et al[10], 2014	ST and T waves, LVH, Q waves, 1° AV block, 2° and 3° AV block, QRS duration	Abnormal Q waves were related to basal anteroseptal hypertrophy and extensive segmental LGE in HCM
Chen et al[11], 2020	QRS duration, QTc, LVH, RBBB, LAFB, LBBB, Selvester score	Selvester score showed a significant positive correlation with the extent of LGE enhancement in HCM
Riza Demir et al[12], 2019	QRS duration, QTc, TP-e interval, TP-e/QTc	Tp-e interval was an independent predictor of LGE in HCM
Dohy et al[13], 2020	fQRS, Q wave, ST deviation, Sokolow, Cornell, and Romhilt-Estes score	fQRS and ST deviation (strain pattern) predicts myocardial fibrosis in HCM
Fronza et al[14], 2016	Q waves, LBBB, signs of LV hypertrophy, negative T waves, ST depression	Negative T waves were correlated with LGE, whereas Q waves were associated with asymmetric hypertrophy in HCM
Grall et al[15], 2014	AF, QRS duration, ST deviation, negative T wave, Q wave, Sokolow, Cornell, Romhilt-Estes score	Q waves were more prevalent in the presence of LGE but didn´t correlate with LGE location and extent in HCM
Guerrier et al[16], 2016	QRS axis, QTc, PR interval, T wave inversion, ST depression, Q waves, LVH	Low left ventricle precordial voltages in ECG were associated with LGE in pediatric HCM patients
Kawasaki et al[17], 2016	QRS duration and axis, QTc, AF, LVH, Q wave, ST deviation, T wave inversion, notched QRS	Notched QRS was correlated with LGE in HCM without LBBB
Konno et al[18], 2015	Pathological Q waves and fQRS	fQRS was correlated with LGE in HCM, whereas Q waves were not correlated with LGE
Matsuki et al[19], 2020	QT interval, QRS duration, Sum of R-wave amplitude, ventricular late potentials	Ventricular late potentials were not correlated with LGE in HCM
Park et al[20], 2018	QRS, QTc, biphasic T wave, Q waves, sum S V1-3, Sokolow, Cornell, fQRS, AF, giant T wave inversion	The number of fQRS leads was significantly correlated to LGE in HCM
Sakamoto et al[21], 2015	24-hour ECG recordings and Time-domain T-wave alternans and QT dispersion	T-wave alternans and QT dispersion were associated with LGE in HCM
Suwa et al[22], 2014	QRS, QTc, Sokolov, max ST, max T waves, fQRS	fQRS was associated with impaired apical contraction and apical LGE in HCM
Tangwiwat et al[23], 2019	QRS duration, QTc, QRS axis, T-wave inversion, Sokolov, Cornell	fQRS in HCM was found to be associated with myocardial fibrosis in univariate analysis but not in the multivariate analysis
Sakamoto et al[24], 2015	HR, QT, QTc, QTe/RR slope, QTa/RR slope, day/night slope, VT/FV	QTe day/night and QTa day/night ratios were significantly greater in patients with Ventricular Arrhythmias and LGE
Oebel et al[25], 2017	PVC morphologies	RBBB, LBBB morphology and multiple PVC morphologies were associated with LGE in patients undergoing PVC ablation
Piers et al[26], 2016	Prolongation of the paced QRS duration after premature stimulation	QRS duration was associated with ventricular tachycardia but not with LGE in non-ischemic cardiomyopathy
Becker et al[27], 2020	HR, AV delay, 1° AV block, QRS duration, LBBB	QRS-prolongation was not correlated with LGE in non-ischemic dilated cardiomyopathy
Cardona et al[28], 2017	PR, QRS, QT, QTc, Frontal QRS-T angle, LVH Cornell	Surface conduction abnormality was not associated with LGE in myotonic muscular dystrophy type 1
Cho et al[29], 2019	fQRS	f-QRS was correlated with LGE in Duchenne muscular dystrophy with low statistical significance levels
Nadour et al[30], 2014	Q waves	Q waves in ECG have low value to detect a past myocardial infarction in the general population
Chew et al[31], 2018	QRS 120 ms, QRS fragmentation, Axis, AF	fQRS was associated with increased peri-infarct zone LGE and unfavorable left ventricle remodeling
Ferrero et al[33], 2020	fQRS	fQRS was correlated with LGE in patients with myocarditis
Fischer et al[34], 2020	QTc, QRS-T angle, fQRS, BBB, ST deviation, PR depression, low voltage, Q and T wave	fQRS, low voltage and QRS-T angle > 90° were independently correlated with LGE in myocarditis
Inoue et al[35], 2020	QRS duration, QTc, Sokolov and Cornell	QRS Cornell voltage, QRS duration, and QTc were significantly associated with LGE presence, while QRS Sokolow-Lyon voltage was not shown a significant correlation with LGE-CMR
Wieslander et al[36], 2015	LBBB, RBBB, LAFB, RBBB + LAFB and Selvester score	Selvester score was not accurate to detect myocardial scar and LGE in patients with conduction abnormalities and BBB
De Lazzari et al[37], 2018	Depolarization and repolarization abnormalities	Low QRS voltages in limb leads predicted LGE in Arrhythmogenic Cardiomyopathy
Mewton et al[38], 2016	QRS d, QTc, QRS-T angle, QRS score, T wave alternans	A significant association between T-wave alternans value and total scar. Patients with a myocardial ischemic scar had greater QRS duration. QRS-T angle was not associated with total myocardial scar size, core of scar, and gray zone size in grams by LGE-CMR
Sobue et al[39], 2015	QRS duration, atrioventricular block, LAFB, RBBB, Selvester QRS score	Selvester score was correlated with LGE in cardiac sarcoidosis
Wieslander et al[40], 2018	LBBB	Selvester score was not accurate to detect myocardial scar and LGE in patients with LBBB
Ciuffo et al[32], 2020	Inter-atrial block	Advanced IAB is associated with more fibrosis, while longer P-wave duration is also associated with more LA fibrosis.

fQRS: Fragmented QRS; AF: Atrial fibrillation; HCOM: Hypertrophic obstructive cardiomyopathy; HCM: Hypertrophic cardiomyopathy; AV: Atrioventricular; LGE: Late gadolinium enhancement; LVH: Left ventricular hypertrophy; RBBB: Right bundle branch block; LBBB: Left bundle branch block; LAFB: Left anterior fascicular block; PVC: Premature ventricular complexes; IAB: Inter-atrial block.