QTc interval in young Gujarati hypertensives: Effect of disease, antihypertensive monotherapy, and coexisting risk factors

OBJECTIVES To study the effect of disease duration, treatment and risk factors on QTc interval among young hypertensives. MATERIALS AND METHODS A case-control study was conducted on 142 hypertensives (60 males, 82 females) taking calcium channel blocker (CCB) or angiotensin-converting enzyme inhibitor (ACEI) as monotherapy. After blood pressure measurement, we recorded lead II electrocardiograph with minimum ten waveforms. QTc was derived from average of ten values using Bazett's formula. QTc interval >0.43 s in male and >0.45 s in female was considered abnormal. RESULTS Cases had mean duration of hypertension 5 years, mean age of 40 years, and poor blood pressure control (systolic blood pressure >140 and diastolic blood pressure >90 mm of Hg). Newly diagnosed hypertensives had significantly higher QTc values than the matched known cases (0.44 vs. 0.42 s, P < 0.05). Known hypertensives did not differ significantly in QTc values by the duration of disease. CCB users showed small, insignificant disadvantage for abnormally prolonged QTc values than ACEI users. With coexisting diabetes, smoking, and positive family history of hypertension, there was odds risk of 7.69, 2.75, and 2.54, respectively for prolonged QTc. CONCLUSION Our study showed prolonged QTc in hypertensives more so in newly diagnosed, unaffected by duration or use of ACEI, or CCB but associated with modifiable risk factors. This underscores high risk of repolarization abnormality-induced future events, suggesting early screening of hypertension, strict blood pressure control, optimum use of QTc measurement, and preventive pharmacotherapy to reduce this aftermath.