ABC | Volume 111, Nº5, November 2018

Short Editorial Can We Consider PR Interval to Screen Patients for Cardiac Resynchronization Therapy? Martino Martinelli Filho Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (InCor – HCFMUSP), São Paulo, SP – Brazil Short Editortial related to the article: Baseline Prolonged PR Interval and Outcome of Cardiac Resynchronization Therapy: A Systematic Review and Meta-analysis Mailing Address: Martino Martinelli Filho • Rua Peixoto Gomide, 1638 Apt. 51. Postal Code 01409-002, Cerqueira Cesar, São Paulo, SP – Brazil E-mail: martino.martinelli@incor.usp.br Keywords Electrocardiology/methods; Heart Failure/complications; Cardiac Resynchronization Therapy; Review. DOI: 10.5935/abc.20180224 This is an open-access article distributed under the terms of the Creative Commons Attribution License The search for responsemarkers toCardiac Resynchronization Therapy (CRT) remains intensive. Currently, the main criteria for CRT indication are the QRS morphology and the absence of myocardial fibrosis. 1 The electrocardiogram remains an important tool for selecting CRT candidates, and new parameters, such as the PR interval, are interesting to discriminate the prognosis in this population. On this issue, we have a meta-analysis study 2 concluding that the presence of prolonged PR interval is a marker of poor prognosis at baseline. In clinical practice, these data may surprise clinicians. The common sense is that it is much easier to make adjustments of the atrioventricular interval to obtain the best hemodynamic response, 3 as well as to ensure a higher rate of effective atriobiventricular resynchronization. 4 The pathophysiological hypotheses that could justify this worse prognosis remain a challenge for medicine. However, a critical viewof these data is needed. The question of strong clinical interest is “Can the PR interval be used as a selection criterion for CRT indication?” This doubt cannot be clarified yet, focusing on findings of this systematic review and meta-analysis. The reason is very clear: the analysis did not include a control group with prolonged PR interval in patients not undergoing CRT, to assess its actual benefit. Therefore, this meta-analysis adds scientific collaboration, but we still have much more to study! 1. Ponikowski P, Voors AA, Anker SD, BuenoH, Cleland JG, Coats AJ, et al. 2016 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure: the Task Force for the diagnosis and treatment of acute and chronic heart failureoftheEuropeanSocietyofCardiology (ESC).Developedwiththe special contribution of the Heart Failure Association (HFA) of the ESC. Eur J Heart Fail. 2016;18(8):891-975. 2. Rattanawong P, Prasitlumkum N, Riangwiwat T, Kanjanahattakij N, Vutthikraivit W, Chongsathidkiet P, et al. Baseline prolonged PR interval and outcome of cardiac resynchronization therapy: a systematic review and meta-analysis. Arq Bras Cardiol. 2018; 111(5):710-719 3. Kosmala W, Marwick TH. Meta-analysis of effects of optimization of cardiac resynchronization therapy on left ventricular function, exercise capacity, and qualityof life inpatientswithheartfailure.AmJCardiol.2014;113(6):988-94. 4. Upadhyay GA, Choudhry NK, Auricchio A, Ruskin J, Singh JP. Cardiac resynchronization in patients with atrial fibrillation: a meta-analysis of prospective cohort studies. J Am Coll Cardiol 2008;52(15):1239-46. References 720