The importance of avoiding unnecessary right ventricular pacing in clinical practice

Table 1 Summary of the major pacing and implantable cardioverter-defibrillator randomized trials that compared atrial (AAI or DDD) vs ventricular based pacing strategies

Ref.	Patients	Follow-up	Pacing/ICD	Study groups	Endpoints	Results
	(n)	(yr)	indication
Danish study[8] (1997)	225	5.5	SSS	AAI vs VVI	All-cause mortality, CV mortality, AF, stroke, HF, and AV block	Significant reduction in CV mortality, AF, stroke and HF in the AAI group
PASE[11] (1998)	407	1.5	SSS and AVB	DDDR vs VVIR	Quality of life, all-cause mortality1, HF1, and AF1	No overall difference in quality of life albeit moderate improvement in patients with SSS but not AVB in the DDDR group No difference in mortality, HF or AF
CTOPP[9] (2000)	2568	6.4	SSS and AVB	DDD/AAI vs VVI(R)	Stroke, CV mortality, all-cause mortality1, AF1, and HF1	No difference in stroke, CV mortality, all-cause mortality or HF Significant reduction in AF in the DDD/AAI group.
MOST[10] (2002)	2010	2.8	SSS	DDDR vs VVIR	All-cause mortality, stroke, AF1, HF1, QoL1, pacemaker syndrome1	No difference in all-cause mortality, stroke Significant reduction in AF, HF, and QoL in the DDDR group 18.3% cross-over due to pacemaker syndrome in the VVIR group
UK-PACE[14] (2005)	2021	3	AVB	DDD(R) vs VVI(R)	All-cause mortality, AF1, HF1, stroke1	No difference in any of the endpoints
DANPACE[13] (2011)	1415	5.4	SSS	AAIR vs DDDR	All-cause mortality, AF1, HF1, stroke1, need for pacemaker reoperation1	No difference in all-cause mortality, chronic AF, HF or stroke Increased risk of paroxysmal AF and need for pacemaker reoperation (development of AVB) in the AAIR group
DAVID[7] (2002)	506	0.8	Primary and secondary prevention ICD	VVI 40 vs DDDR 70 ICD	Composite of hospitalization for HF and mortality	Prematurely interrupted due to increased occurrences of the composite endpoint in the DDDR 70 group
MADIT II substudy[17] (2005)	1232	1.7	Primary prevention ICD	0%-50% vs 51%-100% VP	Composite of HF and mortality	Nearly two-fold increase in hospitalization for HF in the 51%-100% VP group

¹Secondary endpoints. AF: Atrial fibrillation; AVB: Atrioventricular block; CV: Cardiovascular; HF: Heart failure; ICD: Implantable cardioverter-defibrillator; QoL: Quality of life; SSS: Sick sinus syndrome; VP: Ventricular pacing; VVI: Ventricular.