Influence Of β-blocker On Heart Rate In Hypertensives With Different Basic Heart Rate

Objective: To investigate the effect of β-blocker on heart rate in hypertensives withdifferent basic heart rate.Methods:191hypertensives without taking β-blocker were enrolled and divided into3groups according to basic heart rate, group A:70-79beats/min(n=58)，groupB:80-89beats/min(n=90)， group C:≥90beats/min (n=43),taking47.5mg/天ofmetoprolol extended release（ER） for2weeks,23.75mg/天metoprolol ER wasincreased if failed to reach the target heart rate followed up for8weeks. Bloodpressure and heart rate were measured every2weeks.Results:(1)58%of the hypertensives had a basic heart rate≥80beats/min, theaverage dose of metoprolol ER was59.7±17.0mg.(2)After treatment, the heightsequence of mean decrease in heart rate was: group C> group B> groupA(29.3±7.8>18.7±4.9>11.0±4.0beats/min,P<0.05);Decreased heart rate amplitudeincreased about7.9%while heart rate increased of10beats/min.No significantdifferences of decreases in blood pressure were found among3groups（P＞0.05）.(3)The mean decrease in heart rate of the final dose of47.5mg,71.25mg and95mgmetoprolol ER were17.6±8.1,19.5±8.7,22.5±9.2beats/min respectively, an increaseof10.8%,27.8%with1.5,double metoprolol ER.(4)All subjects were only1case ofsinus bradycardia occurred,1case of dizziness.Conclusion: About1/2hypertensive had faster heart rate, Metoprolol ER haddifferent effects on heart rate with different basic heart rate,and basic heart rate faster,heart rate decreased amplitude larger.47.5mg-95mg metoprolol ER was safe andeffective.