A Rapid Method to Evaluate Cardiac Repolarization Changes: The Effect of Two Coffee Strengths on the QT Interval

摘要

Objectives: To assess the effect of coffee on ventricular repolarization as measured by an electrocardiogram. Methods: Fifty-four healthy volunteers (34 males and 20 females, age 23 +/- 5 years) received 1 cup of coffee (caffeine content 120 mg) and 11 participants received 2 cups. Blood pressure and heart rate were measured prior to coffee and every hour thereafter for 5 h. A 12-lead digital Holter recorded continuously, and RR, QT, and QTc intervals were obtained every 30 min. Results: Following coffee, RR increased from 802 +/- 102 to 873 +/- 126 ms (p = 0.001), QT increased from 359 +/- 26 to 367 +/- 27 ms at 1.5 h (p = 0.047), and QTc decreased from 387 +/- 21 to 381 +/- 23 ms at 30 min (p = 0.001), with no changes noted at other time points. Caffeine users and caffeine-naive subjects did not differ in QTc effects (p = 0.971). Females had longer QTc at each time point than males (p = 0.037), but neither had QTc prolongation following coffee. The heart rate decreased from 73 +/- 9 to 69 +/- 11 bpm at 1 h (p = 0.018), and no significant changes in blood pressure were noted. The effects of 1 or 2 cups of coffee did not differ in terms of QTc (p = 0.663), heart rate (p = 0.161), diastolic (p = 0.250), or systolic blood pressure (p = 0.168). Conclusion: Neither 1 nor 2 cups of coffee increased ventricular repolarization. (C) 2015 S. Karger AG, Basel