Table 8.

Differential diagnosis of J wave vs intraventricular conduction defect–mediated notch syndromes (IVCD)

	J wave	IVCD-induced end QRS notch
Male predominance	Yes	No
Average age at initial presentation	Young adults	Older adults
Most common morphology	Dome-like smooth appearance	Relatively sharp appearance
Response to change in heart rate	Bradycardia- and pause-dependent augmentation of J wave, which may be accompanied by T-wave inversion	Tachycardia and prematurity-dependent augmentation of the notch
Structural heart diseases	Rare	Common
		History of myocardial infarction and/or cardiomyopathy