Dual chamber versus single chamber ventricular pacemakers for sick sinus syndrome and atrioventricular block

 

Abstract

Background

Dual chamber pacing or single chamber atrial pacing ('physiologic' pacing) is believed to have an advantage over single chamber ventricular pacing in that it resembles cardiac physiology more closely by maintaining atrioventricular (AV) synchrony and dominance of the sinus node, which in turn may reduce cardiovascular morbidity and mortality thus contributing to patient survival and quality of life. However, a significant proportion of pacemakers currently implanted are single chamber ventricular pacemakers.

Objectives

The objective of this review was to assess the short- and long-term clinical effectiveness of dual chamber pacemakers compared to single chamber ventricular pacemakers in adults with AV block, sick sinus syndrome or both. An additional objective was to assess separately any potential differences in effectiveness between dual chamber pacing and single chamber atrial pacing. The clinical effectiveness of single chamber atrial pacing versus single chamber ventricular pacing was not examined.

Search methods

The Cochrane Controlled Trials Register (The Cochrane Library Issue 3, 2002), MEDLINE (1966 to 2002), EMBASE (1980 to 2002) and the Science Citation Index (1980 to 2002) were searched on 19th August 2002. Citation lists and web sites were checked and researchers in the field contacted.

Selection criteria

Parallel group or crossover randomised controlled trials of at least 48 hours duration comparing dual chamber pacing and single chamber ventricular pacing, and investigating cardiovascular morbidity, mortality, patient related quality of life, exercise capacity and complication rates.

Data collection and analysis

Data was extracted onto pre-piloted data extraction forms. Quality assessment was undertaken using a checklist, with a sub-sample of quality data independently extracted by a second reviewer. Where appropriate data was available, meta-analysis was performed. Where meta-analysis was not possible, the number of studies showing a positive, neutral or negative direction of effect and statistical significance were simply counted.

Main results

Five parallel and 26 crossover randomised controlled trials were identified. The quality of reporting was found to be poor. Pooled data from parallel studies shows a statistically non-significant preference for physiologic pacing (primarily dual chamber pacing) for the prevention of stroke, heart failure and mortality, and a statistically significant beneficial effect regarding the prevention of atrial fibrillation (odds ratio (OR) 0.79, 95% CI 0.68 to 0.93). Both parallel and crossover studies favour dual chamber pacing with regard to pacemaker syndrome (parallel: Peto OR 0.11, 95% CI 0.08 to 0.14; crossover: standardised mean difference (SMD) -0.74, 95% CI - 0.95 to -0.52). Pooled data from crossover studies shows a statistically significant trend towards dual chamber pacing being more favourable in terms of exercise capacity (SMD -0.24, 95% CI -0.03 to -0.45). No individual studies reported a significantly more favourable outcome with single chamber ventricular pacing.

Authors' conclusions

This review shows a trend towards greater effectiveness with dual chamber pacing compared to single chamber ventricular pacing, which supports the current British Pacing and Electrophysiology Group's Guidelines regarding atrioventricular block. Additional randomised controlled trial evidence from ongoing trials in this area will further inform the debate.

 

Plain language summary

Compared to single chamber ventricular pacemakers, dual chamber pacemakers may reduce the incidence of complications in people with sick sinus syndrome and atrioventricular block

Sick sinus syndrome (SSS) and atrioventricular block (AV block) are the two most common reasons people have pacemakers implanted. Both involve the heart beating abnormally slowly. Pacemakers replace or control the heart's own electrical activity. Single chamber pacemakers work on one of the chambers (sections) of the heart, while dual chamber pacemakers, which are more expensive, work on two simultaneously. The review of trials found that dual chamber pacemakers tended to prevent more subsequent heart problems than single chamber ventricular pacemakers. The impact on people's overall quality of life is uncertain. The review did not investigate the relative benefits or risks of surgery to upgrade to a dual chamber pacemaker.

 

摘要

背景

比較雙腔室及單腔室心室節律器在病竇症候群及房室阻隔的治療

雙腔室節律或單腔室心房節律被認為優於單腔室心室節律，因為在維持房室的同步和竇性節律點的支配，它比較相似且接近於心臟生理，也因此可能降低了心血管的病態及死亡率而進一步能改善病人的存活率及生活品質。然而，單腔室心室節律器在目前已植入的節律器中仍佔有重要的比率。

目標

這篇回顧的目的是在於評估比較雙腔室節律器與單腔室心室節律器在成人房室阻斷，病竇症候群或兩者皆有時的短期及長期臨床療效。另一目的是分別評定雙腔室節律器和單腔室心房節律器在效果上任何可能的不同。單腔室心房節律器和單腔室心室節律器的臨床效果並沒有比較。

搜尋策略

2002年8月19日，搜集了考科藍控制試驗紀錄(考科藍資料庫，論題3，2002年)，MEDLINE(1966年至2002年)，EMBASE(1980年至2002年)，和科學引用指標(1980年至2002年)。並檢查引用列表及網站資料，且連繫了在這個領域的研究員。

選擇標準

相似或交叉的隨機控制試驗，比較雙腔室與單腔室心室節律器至少48小時，且研究了心血管的病態，死亡率，病人相關的生活品質，運動的能力，及併發症的比率。

資料收集與分析

將資料擷取到前驅試驗所用的資料擷取表格中。品質評定是由第二個回顧者獨立自主擷取次樣本的品質資料以檢查清單來評定。當取得適合的資料後，則進行統合分析。當統合分析是不可能時，則只計算研究結果呈現正向，中性，或負向效果與具統計意義的試驗的數量。

主要結論

五個平行及二十六個交叉的隨機控制臨床試驗被確定。報告的品質被發現是不好的。從平行研究的資料聚集起來顯示統計學上，使用生理性節律(主要是雙腔室節律器)，對於預防中風，心臟衰竭，及死亡率沒有顯著助益的，而在預防心房顫動上則有顯著的助益(勝算比0.79，95%信賴區間0.68至0.93)。在節律器症候群上，不論是平行或交叉研究，都比較偏向於雙腔室節律器(平行試驗:Peto勝算比0.11，95%信賴區間0.08至0.14；交叉試驗:標準差 −0.74，95%信賴區間 0.95至−0.52)。從交叉試驗的累積資料顯示在運動能力上，雙腔室節律器呈現統計學上顯著的傾向(標準差−0.24，95%信賴區間−0.03至−0.45)。並沒有任何一個研究顯示單腔室心室節律器有較好的預後。

作者結論

這個回顧顯示了雙腔室節律器比單腔室節律器可能有較好的效果，而這個結論支持了目前在房室阻斷的病人，英國節律及電生理團隊的準則。此外，在這個領域，現在正在進行隨機控制的臨床試驗將澄清這項爭辯。

翻譯人

本摘要由臺北榮民總醫院鐘法博翻譯。

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。

總結

相較於單腔室心室節律器，雙腔室節律器可以減少在竇病症候群及房室阻斷的病人，併發症產生的機會。竇病症候群及房室阻斷是兩個最常見植入心律調節器的原因。兩者都包含了心跳速率不正常的變慢。節律器取代或控制心臟的發電活性。單腔室節律器作用在單一心臟的腔室，而較昂貴的雙腔室節律器則同時作用在兩個腔室。這篇試驗的回顧發現，雙腔室節律器較單腔室心室節律器傾向能避免更多隨後發生的心臟問題。在病人生活品質的方面的影響是不確定的。這篇回顧並未探討到在手術升級雙腔室節律器相對性的好處及風險。