ABC | Volume 112, Nº1, January 2019

Original Article Eyuboglu & Akdeniz Prehypertension and fragmented QRS Arq Bras Cardiol. 2019; 112(1):59-64 Methods Patient selection A total of 283 consecutive patients who were defined as newly diagnosed prehypertensive patients after routine cardiac examination at our outpatient clinic between June 2015 and July 2016 were screened for the study. Prehypertension was defined as SBP of 120–139 mmHg and/or a DBP of 80–89 mmHg in accordance with the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC7). 1 Figure 1 demonstrates the flow chart of our study design. Subsequently, all patients underwent 24-hour ambulatory blood pressure monitoring (ABPM) for final blood pressure pattern diagnosis. Of the patients screened, 67 were excluded from the study: 37 who were diagnosed with hypertension after 24-hour ABPM recordings, fourteen with a history of coronary artery disease (CAD), seven with complete or incomplete bundle branch block and QRS duration ≥ 120 ms, three with left ventricular hypertrophy (LVH), three with left ventricular ejection fraction (LVEF) < 50%, two with moderate to severe valvular heart disease, and one with a permanent pacemaker. Consequently, 216 patients were included into the study. Data regarding patients’ medical history were recorded on admission. All biochemical analyses were conducted after an overnight fast. Hypertension was defined as 24-hour mean SBP of ≥ 130 mmhg and/or DBP ≥ 80 mmhg and/or daytime mean SBP ≥ 135 mmhg and/or DBP ≥ 85 mmhg on ABPM recordings. 4,12 Diabetes mellitus was defined as at least two fasting plasma glucose levels of ≥ 126 mg/dL, two-hour plasma glucose levels of ≥200 mg/dL, or treatment with antidiabetic drugs, and smoking was defined as the regular use of cigarettes. All patients underwent a detailed echocardiographic examination, and LVHwas defined based on electrocardiographic modified Sokolow-Lyon index and/or an increased left ventricular mass index of > 95 g/m 2 for women and >115 g/m 2 for men, detected by echocardiography. 12 The study protocol complied with the Declaration of Helsinki and was approved by the local ethics committee. 24-h ABPM recordings Final diagnoses of blood pressure level and pattern were made based on ABPM recordings. All measurements were taken with an oscillometric device. The cuff was placed on the non-dominant arm and automated recordings were obtained every 30 minutes during 24-hours. Recordings were made on working days and patients were encouraged to undertake their normal daily activities. If >20% of the ABPM recordings were invalid, the test was repeated. Sleep durations were evaluated based on the information obtained from the patients, and no patient reported a change in the daily sleeping and waking periods linked to the ABPM device. The 24-h mean and the daytime and nighttime blood pressure values were calculated for each patient from ABPM recordings. Dipper blood pressure pattern was described as more than 10% decline in SBP and DBP at nighttime and non-dipper pattern was defined as less than 10% decline in SBP and DBP at nighttime. 4,12 Electrocardiography A standard 12-lead surface ECG was performed on all patients and blindly analyzed by two independent cardiologists. When there was a disagreement, the final decision on the presence of fQRS was reached by consensus. A narrow fQRS complex was defined as the presence of various RSR’ patterns, or notching in R or S waves in the absence of typical bundle branch block in at least two contiguous leads in one of the major coronary artery territories in the original QRS complex 8 (Figure 2). Statistical analysis Statistical analyses were performed with SPSS (Inc, Chicago, Illinois) version 22.0. Continuous variables were expressed as mean ± standard deviation/median (25-75 percentiles) according to normality and distribution characteristics and were compared using one-way ANOVA, independent samples t-test, or Mann-Whitney U-test, according to group number and distribution characteristics. Categorical variables were expressed as number and percentage (%) and were compared using the χ 2 test or the Fisher exact test. Multinomial logistic regression analysis (using normotensive patients as the reference category) was used to determine the relationship between fQRS and blood pressure pattern in prehypertensive patients. Impact significance was reported as odds ratio (OR) and corresponding 95% confidence interval (CI). P < 0.05 was considered significant in all statistical analyses. Results The patients were divided into three groups based on 24-hour ABPM recordings. According to ABPM recordings, 61 patients had a normotensive blood pressure pattern (SBP < 120 mmHg and DBP < 80 mmHg), and we designated these patients as the control group. Of the remaining 155 prehypertensive patients, 83 had dipper blood pressure pattern and 72 had non-dipper pattern. The mean age of the study population was 50.5 years, with 45.8% being female. The frequency of fQRS was 13.9%. The groups were similar regarding cardiovascular risk factors, laboratory parameters, and clinical characteristics. The baseline characteristics, laboratory parameters, and blood pressure levels of the groups are presented in Table 1. Statistical analysis revealed a statistically significant difference between the groups regarding presence of fQRS (p = 0.028). This difference was mainly due to higher frequency of fQRS in non‑dipper prehypertensives than in normotensives. Despite the higher frequency of fQRS in non-dippers than in dippers, there was no statistically significant difference regarding the presence of fQRS between non-dipper prehypertensives and dipper prehypertensives (p = 0.400). A similar condition was observed between dipper prehypertensives and the control group (p = 0.784). However, non-dipper prehypertensives had a significantly higher frequency of fQRS than normotensives (p = 0.048). Furthermore, multinomial logistic regression analysis revealed that the presence of fQRS on ECG 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), (Table 2). 60