PT - JOURNAL ARTICLE AU - Chun Shing Kwok AU - Muhammad Rashid AU - Rhys Beynon AU - Diane Barker AU - Ashish Patwala AU - Adrian Morley-Davies AU - Duwarakan Satchithananda AU - James Nolan AU - Phyo K Myint AU - Iain Buchan AU - Yoon K Loke AU - Mamas A Mamas TI - Prolonged PR interval, first-degree heart block and adverse cardiovascular outcomes: a systematic review and meta-analysis AID - 10.1136/heartjnl-2015-308956 DP - 2016 May 01 TA - Heart PG - 672--680 VI - 102 IP - 9 4099 - http://heart.bmj.com/content/102/9/672.short 4100 - http://heart.bmj.com/content/102/9/672.full SO - Heart2016 May 01; 102 AB - Objective First-degree atrioventricular block is frequently encountered in clinical practice and is generally considered a benign process. However, there is emerging evidence that prolonged PR interval may be associated with adverse outcomes. This study aims to determine if prolonged PR interval is associated with adverse cardiovascular outcomes and mortality.Methods We searched MEDLINE and EMBASE for studies that evaluated clinical outcomes associated with prolonged and normal PR intervals. Relevant studies were pooled using random effects meta-analysis for risk of mortality, cardiovascular mortality, heart failure, coronary heart disease, atrial fibrillation and stroke or transient ischaemic attack (TIA). Sensitivity analyses were performed considering the population type and the use of adjustments.Results Our search yielded 14 studies that were undertaken between 1972 and 2011 with 400 750 participants. Among the studies that adjusted for potential confounders, the pooled results suggest an increased risk of mortality with prolonged PR interval risk ratio (RR) 1.24 95% CI 1.02 to 1.51, five studies. Prolonged PR interval was associated with significant risk of heart failure or left ventricular dysfunction (RR 1.39 95% CI 1.18 to 1.65, three studies) and atrial fibrillation (RR 1.45 95% CI 1.23 to 1.71, eight studies) but not cardiovascular mortality, coronary heart disease or myocardial infarction or stroke or TIA. Similar observations were recorded when limited to studies of first-degree heart block.Conclusions Data from observational studies suggests a possible association between prolonged PR interval and significant increases in atrial fibrillation, heart failure and mortality. Future prospective studies are needed to confirm the relationships reported, consider possible mechanisms and define the optimal monitoring strategy for such patients.