Table 1: Recommendations for Permanent Pacing in Adults with Complex CHD.

Class	Clinical Indication	Level of Evidence
Class I	Symptomatic SND, including documented sinus bradycardia or chronotropic incompetence that is intrinsic or secondary to required drug therapy	C
	Symptomatic bradycardia in conjunction with any degree of AV block or with ventricular arrhythmias presumed to be because of AV block	B
	Postoperative high-grade second- or third-degree AV block that is not expected to resolve	C
Class IIa	Impaired haemodynamics, as assessed by non-invasive or invasive means, due to sinus bradycardia or loss of AV synchrony	C
	Sinus or junctional bradycardia for the prevention of recurrent IART	C
	Adults with complex CHD and an awake resting heart rate (sinus or junctional) <40 bpm or ventricular pauses >3 seconds	C
Class IIb	Adults with CHD of moderate complexity and an awake resting heart rate (sinus or junctional) <40 bpm or ventricular pauses >3 seconds	C
	History of transient postoperative complete AV block, and residual bifascicular block	C
Class III	Pacing is not indicated in asymptomatic adults with CHD and bifascicular block with or without first-degree AV block in the absence of a history of transient complete AV block	C
	Endocardial leads are generally avoided in adults with CHD and intracardiac shunts	B

AV = atrioventricular; CHD = congenital heart disease; IART = intra-atrial re-entrant tachycardia; SND = sinus node dysfunction. Adapted from Khairy, et al., 2014.²