JAMA：ICD用于心源性猝死一级预防时双腔较单腔ICD无优势

随机对照临床试验中主要使用单腔埋藏式心脏复律除颤器（ICD）作为心源性猝死的初级预防措施。然而在临床实际中，即使并无起搏器的明确适应证，患者植入的多为双腔ICD。双腔ICD与单腔ICD相比，优劣尚不明确。针对这种情况，来自美国科罗拉多大学Denver Health Medical Center的Pamela N. Peterson博士等人进行了一项研究，研究结果在线发表于2013年5月15日的JAMA杂志上。作者发现在无起搏器使用适应证而植入了ICD作为心源性猝死一级预防的患者中，与单腔ICD相比，双腔ICD起搏器相关的并发症风险更高；两者植入后1年死亡率和再住院治疗率效果相似。
研究为回顾性队列研究，得到了National Cardiovascular Data Registry's (NCDR)的许可，采用的资料来自2006-2009年间国家医疗保险、医疗补助计划的相关患者数据。入组的均为无安装起搏器适应证、因心源性猝死一级预防植入ICD的患者。以患者、临床医生、医院相关因素等特征为基础进行匹配，评估1年死亡率、全因再入院率、心力衰竭再入院率，调整危险比以及植入ICD后90天内ICD本身相关的并发症。
研究结果表明在32034名患者中，12246名（38%）植入了单腔ICD，19788名（62%）植入了双腔ICD。在倾向匹配队列研究中，与双腔ICD相比，单腔ICD本身相关的并发症较低(3.51% vs 4.72%; P < .001; 危险比, −1.20 [95% 可信区间, −1.72 to −0.69]。但是两者的1年死亡率(调整比例, 9.85% vs 9.77%; 危险比[HR], 0.99 [95% CI, 0.91 to 1.07]; P =0 .79)、1年所有原因导致的住院率(调整比例, 43.86% vs 44.83%; 危险比[HR], 1.00, 95%可信区间[0.97-1.04]; P = 0.82)或因心力衰竭的住院率并无显著差异(调整比例, 14.73% vs 15.38%;危险比[ HR], 1.05，95% 可信区间[0.99-1.12];P =0 .19)。
该研究发现与单腔ICD相比，在考虑到植入后相关死亡风险、全因再入院率、心力衰竭再入院率方面，双腔ICD并无任何临床获益，甚至有更高比例的并发症风险。因此，在并无明确适应证植入起搏器作为心源性猝死的一级预防时，植入双腔ICD需慎重考虑。

Association of Single- vs Dual-Chamber ICDs With Mortality, Readmissions, and Complications Among Patients Receiving an ICD for Primary Prevention
Importance 
Randomized trials of implantable cardioverter-defibrillators (ICDs) for primary prevention predominantly used single-chamber devices. In clinical practice, patients often receive dual-chamber ICDs, even without clear indications for pacing. The outcomes of dual- vs single-chamber devices are uncertain.
Objective 
To compare outcomes of single- and dual-chamber ICDs for primary prevention of sudden cardiac death.
Design, Setting, and Participants 
Retrospective cohort study of admissions in the National Cardiovascular Data Registry's (NCDR) ICD registry from 2006-2009 that could be linked to Centers for Medicare & Medicaid Services fee-for-service Medicare claims data. Patients were included if they received an ICD for primary prevention and did not have a documented indication for pacing.
Main Outcomes and Measures 
Adjusted risks of 1-year mortality, all-cause readmission, heart failure readmission, and device-related complications within 90 days were estimated with propensity-score matching based on patient, clinician, and hospital factors.
Results 
Among 32 034 patients, 12 246 (38%) received a single-chamber device and 19 788 (62%) received a dual-chamber device. In a propensity-matched cohort, rates of complications were lower for single-chamber devices (3.51% vs 4.72%; P < .001; risk difference, −1.20 [95% CI, −1.72 to −0.69]), but device type was not significantly associated with 1-year mortality (unadjusted rate, 9.85% vs 9.77%; hazard ratio [HR], 0.99 [95% CI, 0.91 to 1.07]; P = .79), 1-year all-cause hospitalization (unadjusted rate, 43.86% vs 44.83%; HR, 1.00 [95% CI, 0.97-1.04]; P = .82), or hospitalization for heart failure (unadjusted rate, 14.73% vs 15.38%; HR, 1.05 [95% CI, 0.99-1.12]; P = .19).
Conclusions and Relevance 
Among patients receiving an ICD for primary prevention without indications for pacing, the use of a dual-chamber device compared with a single-chamber device was associated with a higher risk of device-related complications and similar 1-year mortality and hospitalization outcomes. Reasons for preferentially using dual-chamber ICDs in this setting remains unclear.