p.38 抽出テキスト

............................................................................................................................................................................. 6.5 Pacing in patients with reduced left ventricular ejection fraction and a conventional indication for antibradycardia pacing Three randomized trials proved the superiority of biventricular pacing over RV pacing in patients with moderate to severe systolic dysfunction who required antibradycardia pacing to improve quality of life, NYHA class, and echocardiographic response.190,357,358 In the Biventricular versus RV pacing in patients with AV block (BLOCK HF) trial, 691 patients with AVN disease and an indication for pacemaker with a mildly reduced EF (<50% by inclusion criteria, average 42.9% in the pacemaker group) were randomized to biventricular or RV pacing with or without an ICD, and followed for an average of 37 months.190 The primary endpoint (a composite of >_15% increase in the LV end-systolic volume, HF events, or mortality) was significantly improved in those assigned to CRT. CRT response is high among patients with systolic dysfunction and expected frequent RV pacing. Based on the MOde Selection Trial in Sinus-Node Dysfunction (MOST),183 at least 40% RV pacing is associated with an increased risk of HF hospitalization or AF.

For patients with normal or preserved EF, data on benefit of CRT are conflicting with respect to hospitalization, and no mortality benefit was shown.166,268,323,359 However, adverse remodelling caused by RV pacing was prevented by biventricular pacing, especially during long-term follow up.323,359,360 A single-centre study showed that >20% RV pacing was associated with deleterious LV remodelling in patients with AVB and preserved LVEF.188 Frailty should also be taken into account in deciding on CRT implantation, because of the higher costs and high complication rates of this procedure.

6.6 Benefit of adding implantable

cardioverter defibrillator in patients with indications for cardiac resynchronization therapy The mortality benefit of CRT-D over CRT-P is still unclear, mostly because no head to head RCTs have been designed to compare these two treatments. While CRT-D may further improve survival over CRT-P by reducing arrhythmic death, it does also add ICDspecific risks such as lead failure and inappropriate shocks, as well as costs.

COMPANION is the only trial to randomize patients to CRT-P or CRT-D, but was designed to assess the effects of CRT compared with OMT.260 Crucially, it was not designed to compare CRT-D and CRT-P. CRT-P was associated with a marginally non-significant reduction in the risk of all-cause mortality (HR 0.76, 95% CI 0.58 - 1.01; P = 0.06), whereas CRT-D was associated with a significant, 36% risk reduction (HR 0.64, 95% CI 0.480.86; P = 0.004). Analysis of cause-specific mortality showed that SCD was significantly reduced by CRT-D (HR 0.44, 95% CI 0.23 - 0.86; P = 0.02) but not CRT-P (HR 1.21, 95% CI 0.72.07; P = 0.50).363 Nevertheless, the CARE-HF extension study proved that CRT-P alone reduced the risk of dying suddenly by 5.6%.261 In line with these findings, subgroup analyses from RCTs in mild HF consistently found a reduction in ventricular arrhythmias with CRT.364368 These effects were especially observed among CRT responders, suggesting that the reduction in SCD risk is related to the extent of reverse LV remodelling with CRT. Meta-analyses have drawn different conclusions on the matter. In the study by Al-Majed et al.,369 the survival benefit of CRT was largely driven by a reduction in HF-related mortality, but SCD was not reduced. Lam et al.370 showed that CRT-D significantly reduced mortality compared with medical therapy alone [odds ratio (OR) 0.57, 95% CI 0.400.80], but not when compared with ICD without CRT (OR 0.82, 95% CI 0.571.18) or CRT-P (OR 0.85, 95% CI 0.601.22). However, more recently, a network meta-analysis of 13 randomized trials including >12 000 patients found that CRT-D reduced total mortality by 19% (95% CI 133%, unadjusted) compared with CRT-P.275 Some recent large observational studies highlighted the importance of HF aetiology in the assessment of potential benefits of CRT- D over CRT-P.371373 CRT-D was associated with a significant risk reduction in all-cause mortality compared with CRT-P in patients with ischaemic cardiomyopathy. However, this difference was not found in patients with non-ischaemic cardiomyopathy. These findings are consistent with the results from the DANISH study, which assigned 1116 patients with HF and non-ischaemic cardiomyopathy to receive either a primary prophylactic ICD or usual clinical care alone.374 In both groups, 58% of patients also had CRT. Subgroup analysis showed that CRT-D was not superior to CRT-P in reducing the primary outcome of all-cause mortality (HR 0.91, 95% CI 0.641.29; P = 0.59) after a median follow-up of 67.6 months. However, in a large multicentre registry of >50 000 patients, CRT-D was associated with a significantly lower observed mortality.375 Similar results were found in a recent propensity-matched cohort, where CRT-D was associated with a significantly lower all-cause mortality than CRT-P in patients with ischaemic aetiology and in patients with non-ischaemic HF under 75 years old.376 Furthermore, the CeRtiTuDe Cohort study377 showed better survival in CRT-D vs. CRT-P mainly due to a reduction of non-SCD. In an Italian multicentre CRT registry, the only independent predictor of mortality was the lack of an ICD.378 Whereas these studies are limited by their observational design, important novel information on the issue of CRT-D vs. CRT-P is expected to come from an ongoing randomized trial, Re-evaluation of Optimal Re-synchronisation Therapy in

Recommendation for patients with heart failure and atrioventricular block

Recommendation Classa Levelb

CRT rather than RV pacing is recommended for patients with HFrEF (<40%) regardless of NYHA class who have an indication for ventricular pacing and high-degree AVB in order to reduce morbidity. This includes patients with AF.183,190,196,268,313,323,357359,361,362 I A

AF = atrial fibrillation; AVB = atrioventricular block; CRT = cardiac resynchronization therapy; HF = heart failure; HFrEF = heart failure with reduced ejection fraction (<40%) according to the 2021 ESC HF Guidelines;242 NYHA = New York Heart Association; RV = right ventricular. aClass of recommendation. bLevel of evidence. ESC 2021 Downloaded from academic.oup.com/eurheartj/article/42/35/3427/6358547 by guest on 07 October 2026