ABC | Volume 112, Nº1, January 2019

Original Article Association Between Non-Dipping and Fragmented QRS Complexes in Prehypertensive Patients Mehmet Eyuboglu 1 and Bahri Akdeniz 2 Department of Cardiology - Medical Park Izmir Hospital, 1 Karsiyaka, Izmir – Turkey Department of Cardiology - Dokuz Eylul University Hospital, 2 Izmir – Turkey Mailing Address: Mehmet Eyuboglu • Department of Cardiology, Medical Park Izmir Hospital - Yeni Girne Bulvari, 1825 Sok. N°:12 Karsiyaka,Izmir -Turkey E-mail: mhmtybgl@gmail.com Manuscript received February 22, 2018, revised manuscript June 20,2018, accepted July 02, 2018. DOI: 10.5935/abc.20180242 Abstract Background: Fragmented QRS (fQRS) is a sign of adverse cardiovascular events in various cardiovascular diseases. It is also associated with increased blood pressure and non-dipping in hypertensive patients. However, no study has investigated the importance of fQRS in prehypertensive patients. Objectives: The aim of our study is to investigate the relationship between fQRS and non-dipper status in prehypertensive patients. Methods: Two hundred and sixteen eligible, newly diagnosed prehypertensive patients who underwent 24-hour ambulatory blood pressure monitoring (ABPM) for further evaluation of blood pressure between June 2015 and July 2016 were included into the study. Patients were divided into three groups according to ABPM results: normotensives, dipper prehypertensives, and non-dipper prehypertensives. Groups were compared regarding presence of fQRS on electrocardiography. Additionally, multinomial logistic regression analysis was used to determine the relationship between fQRS and blood pressure pattern in prehypertensive patients. Results: According to ABPM recordings, 61 patients had normotensive blood pressure pattern (systolic blood pressure < 120 mmHg and diastolic blood pressure < 80 mmHg). Of the remaining 155 prehypertensive patients, 83 were dippers and 72 were non-dippers. Non‑dipper prehypertensives had a significantly higher frequency of fQRS compared to normotensives (p = 0.048). Furthermore, multinomial logistic regression analysis revealed that fQRS is an independent predictor of non-dipping blood pressure pattern in prehypertensive patients (p = 0.017, OR: 4.071, 95% CI: 1.281-12.936). Conclusions: We found that fQRS is a predictor of non-dipping in prehypertensives. As a marker of fibrosis and higher fibrotic burden within myocardium, fQRS may be useful in identifying high-risk prehypertensive patients before the development of hypertension. (Arq Bras Cardiol. 2019; 112(1):59-64) Keywords: Prehypertension; Hypertension; Electrocardiography; FragmentedQRS; Ambulatory Blood PressureMonitoring; Non-dipping. Introduction Increased blood pressure is one of the leading causes of cardiovascular morbidity and mortality around the globe. Because of the difficulties involved in diagnosing prehypertension, the definition of prehypertension remains controversial. Prehypertension is not a benign condition; it indicates future hypertension and adverse cardiovascular events and is generally defined as systolic blood pressure (SBP) of 120–139 mmHg and/or diastolic blood pressure (DBP) of 80–89 mmHg. 1,2 Normal blood pressure has a circadian variability with a morning surge and reduction during the rest of the day with a 10% to 20% decline at nighttime, and this phenomenon is known as dipping. Non-dipping pattern, which is defined as less than 10% decrease in blood pressure levels at nighttime, is associated with worse adverse cardiovascular events compared to dipping blood pressure pattern. 3,4 A narrow fragmented QRS complex (fQRS) on electrocardiography (ECG) is a sign of inhomogeneous and delayed ventricular conduction and is associated with myocardial scarring, fibrosis, and adverse cardiovascular events in various cardiovascular diseases. 5-7 It is defined by the presence of notches in the R or S wave in two contiguous leads in one of the major coronary artery territories without a typical bundle branch block and with a QRS duration of < 120 milliseconds. 8 Importantly, increased blood pressure is associated with presence of fQRS on ECG. 9 Furthermore, non-dipper hypertensive patients have higher frequency of fQRS on ECG compared to dippers, thus indicating myocardial fibrosis and higher fibrotic burden in non‑dippers. 10,11 However, the importance and usefulness of fQRS in prehypertensive patients is not clear. The present study aimed to investigate the relationship between prehypertensive blood pressure patterns and the presence of fQRS on ECG to identify the myocardial fibrotic burden and risk assessment of prehypertensive subjects before the development of hypertension. 59