The authors still give a Class I alternative for single lead atrial (AAI) pacing, but only in those with normal AV conduction.

FORBES: Overview of the New HRS/ACCF Pacemaker Guidelines

Single chamber ventricular pacing is considered an acceptable alternative in sedentary patients or those in whom technical issues make atrial lead placement difficult or impossible.

FORBES: Overview of the New HRS/ACCF Pacemaker Guidelines

Dual chamber pacing in SND is also favored over single chamber ventricular pacing (VVI), as it has been shown to reduce the risk of development of atrial fibrillation and the symptoms of pacemaker syndrome.

FORBES: Overview of the New HRS/ACCF Pacemaker Guidelines