Table 2.

Left Ventricular Scars in the Septal Region With Specific Disease Characteristics

LV Scar	Distribution	Phenotype	Red Flags		Etiologies	Further Investigation
Septal region	Mid-wall/transmural	NDLVC/DCM	CLINICAL:	•Family history of DCM or SCD •Evaluation of serum creatine kinase	Familial DCM	Genetic testing
			ECG:	•Early AV blocks •QS in V1-V2 •Fragmented QRS
			ECHO:	•Mechanical dispersion by strain (irrespective of GLS and LVEF)
		RCM	CLINICAL:	•Pulmonary or gastrointestinal or skin disease	Systemic Sclerosis	Antinuclear antibody testing
			ECG:	•Prolongation of QT interval and dispersion
			ECHO:	•Early impaired diastolic function •Pulmonary hypertension
				•Pericardial effusion
		HCM	CLINICAL:	•Family history of HCM or SCD	Sarcomeric HCM	Genetic testing
			ECG:	•“Pseudo STEMI” pattern •Q waves
			ECHO:	•Mitral valve abnormalities: elongated anterior leaflet/SAM
				•Apical or asymmetric LVH
	Subepicardial/mid-wall	NDLVC/DCM/ARVC	CLINICAL:	•Family history of SCD	Arrhythmogenic cardiomyopathy	Genetic testing
			ECG:	•Low limb voltage •Fragmented QRS
				•Ventricular arrhythmias with a RBBB morphology of the ectopic QRS
			ECHO:	•Systolic LV dysfunction related to the global extent of LGE
		NDLVC	CLINICAL:	•Gait disturbance •Myotonia/Muscle weakness •Visual impairment	Neuromuscular disorders	Genetic testing Muscle biopsya
			ECG:	•AV nodal and infra-nodal disease
			ECHO:	•Regional wall motion abnormalities •Regional wall thinning or thickening
		NDLVC/DCM	CLINICAL:	•Peripartum period	Peripartum Cardiomyopathy
			ECG:	•Sinus tachycardia •Nonspecific ST-segment alterations
			ECHO:	•Global hypokinesia
		NDLVC/DCM	CLINICAL:	•Recent influenza-like illness	SARS-CoV-2 myocarditis	Molecular viral test
			ECG:	•Sinus tachycardia •Nonspecific ST-segment alterations •RBBB
			ECHO:	•a “reverse tako-tsubo” pattern of GLS
	Subepicardial/transmural	DCM/HCM	CLINICAL:	•Pulmonary disease •Unexplained brady or tachyarrhythmia	Sarcoidosis	Thoracic FDG-PET imaging
			ECG:	•PR prolongation •Advanced AV blocks •RBBB/LBBB
			ECHO:	•Basal septum thinning •Regional LV thickening
				•RV dysfunction in absence of PH
				•Regional wall motion abnormalities (without coronary distribution)

ARVC = arrhythmogenic right ventricular cardiomyopathy; AV = atrioventricular; DCM = dilated cardiomyopathy; FDG-PET = fluorodeoxyglucose positron emission tomography; HCM = hypertrophic cardiomyopathy; GLS = global longitudinal strain; LBBB = left bundle branch block; LGE = late gadolinium enhancement; LVEF = left ventricular ejection fraction; LVH = left ventricular hypertrophy; NDLVC = nondilated left ventricular cardiomyopathy; PH = pulmonary hypertension; RBBB = right bundle branch block; RCM = restrictive cardiomyopathy; RV = right ventricular; SAM = systolic anterior motion; SARS-CoV-2 = severe acute respiratory syndrome-coronavirus-2; SCD = sudden cardiac death; STEMI = ST-segment elevation myocardial infarction.

^aIndicated when genetic testing is negative and clinical suspicion remains high.