Table 2.

Summary of studies of rhythm control in patients with atrial fibrillation and cardiac resynchronization therapy

Study (year)	Study design	Inclusion criteria	Comparator groups	N	F/U (mo)	Baseline characteristics		Outcome
Non-ablation strategies
Turco et al (2012)	Multicenter prospective observational	Permanent AF CRT for -NYHA III–IV -QRSd ≥120 ms -LBBB -LVEF ≤35%	Rhythm control (group A)∗ Standard care (group B)	28 27	12	Age Sex (% M) LVEF (%) QRSd (ms) NYHA class (% IV)	70.5 (10.0) 80 24 (5.5) 132 (16.3) 5.5	No difference in mortality between groups (P = .469)
			∗DCCV via ICD + amiodarone					Lower mortality for patients in SR at follow-up vs those in AF (P = .048)
			NB groups from different centers					Improvement in LVEF seen in both groups, but LVESV reduction only seen in group A (P = .018 vs baseline)
Schwartzman et al (2015)	Single-center RCT	Persistent AF NYHA class III Mean HR >85 LVEF ≤35% LVEDD >55 mm LBBB QRSd >130 ms	Rhythm control∗ Standard care$	26 26	12	Age Sex (% M) LVEF (%) QRSd (ms) NYHA class	70.0 (8.0) 71.2 28 (7.6) 143.5 (12.6) 3.3 (0.5)	No significant difference between groups for incidence of CRT response or change in: NYHA class, MLWHF score, 6MWT, LVEF, LVEDD
			∗DCCV ± AAD $DCCV + reinduction of AF					Higher hospital encounters in rhythm control group (11.7% vs 3.2%; P = .002)
								NB 4 patients with failed rhythm control excluded from analysis
PilotCRAfT (2021)∗	Single-center RCT	CRT Perm AF or pers AF lasting >6 months BiVp% <95%	Rhythm control∗ Rate control$	22 21	12	Age Sex (% M) LVEF (%) QRSd (ms) NYHA class	68.4 (8.3) 97.7 30 (8) NA NA	No difference between groups in improvement in BiVp%, VO2max, QOL / clinical endpoints
∗Abstract			∗DCCV $Drugs ± AVNA					In per-protocol analysis, higher LVEF in rhythm control group at follow-up (36.8% vs 29.9%; P = .039)
			NB both groups received amiodarone
AF Ablation
Fink et al (2019)	Single-center retrospective observational	AF and CRT nonresponse∗ who underwent AF ablation	No control group	38	12	Age Sex (% M) LVEF (%) QRSd (ms) NYHA class	67.8 (9.8) 78.9 30.4 (7.2) NA 3.0	68% in sinus rhythm at follow-up Significant improvements from baseline in:∗ BiVp% (Δ7.5%; P < .001) LVEF (Δ2.2; P = .0225) NYHA class (P < .0001)
		∗at least 1 of: -BiVp% <95% -ΔNYHA <1 -ΔLVEF <5%						∗6 patients underwent AVNA during follow-up and were excluded in analysis
CASTLE-AF (2018)	Multicenter RCT (subgroup analysis)	Symptomatic pers AF or pAF LVEF ≤35% Failed AAD Biotronik ICD / CRT-D	AF ablation Medical therapy	48 52	37.6	Not reported for subgroup of patients with CRT-D		No significant difference in primary endpoint of death or HFH (HR 0.65; 95% CI 0.43–0.98)
			Subgroup of total cohort who had CRT-D					NB No significant interaction between presence of CRT-D vs ICD on primary endpoint on Cox logistic regression analysis (P = .6)

Continuous baseline characteristics expressed as mean (standard deviation).

6MWT = 6-minute walk test; AAD = antiarrhythmic drug; AF = atrial fibrillation; AVNA = atrioventricular node ablation; BiVp% = biventricular pacing percentage; CI = confidence interval; CRT = cardiac resynchronization therapy; DCCV = DC cardioversion; F/U = mean follow-up; HFH = heart failure hospitalization; HR = hazard ratio; ICD = implantable cardioverter-defibrillator; LBBB = left bundle branch block; LVEDD = left ventricular end-diastolic diameter; LVEF = left ventricular ejection fraction; LVESV = left ventricular end-systolic volume; MLWHF = Minnesota Living with Heart Failure Questionnaire; NA = not available; NYHA = New York Heart Association; pAF = paroxysmal AF; pers AF = persistent atrial fibrillation; QOL= quality of life; QRSd = QRS duration; RCT = randomized controlled trial SR = sinus rhythm.