title: Does QTc interval predict the response to beta-blockers and calcium channel blockers in hypertensives?
abstract: The QT interval corrected for heart rate (QTc) is believed to reflect sympathovagal balance. It has also been established that beta-blockers and dihydropyridine-type calcium channel blockers (DHPCCB) influence the autonomic nervous system. This study tested the hypothesis that QTc interval length is a predictor of the blood pressure reduction induced by beta1-selective beta-blockers or DHPCCB. The predictive values of pretreatment heart rate and of the heart rate change with therapy were also evaluated. The authors conducted an historical reanalysis of 5 clinical trials that looked at the antihypertensive effects of beta-blockers (nebivolol) or DHPCCB (amlodipine, felodipine, isradipine, nifedipine). Correlation and quintile analyses were performed to measure the association between QTc interval, heart rate, or heart rate change and therapeutic blood pressure response. Separate analyses were undertaken for beta-blockers and DHPCCB. Seventy-three and 98 hypertensive subjects respectively were included in the beta-blocker and DHPCCB analyses. QTc interval, pretreatment heart rate, and heart rate change with therapy were not associated with therapeutic blood pressure response. In this study, QTc interval length, pretreatment heart rate, and heart rate change with therapy were not good predictors of the blood pressure response to beta1-selective beta-blockers or DHPCCB in hypertensive subjects.
authors.affiliation: Department of Clinical Pharmacology, Centre hospitalier de l'Université de Montréal-Hôtel-Dieu, Montréal, Qc, Canada. lamarm@ircm.qc.ca
authors.forename: Maxime
authors.initials: M
authors.lastname: Lamarre-Cliche
authors.forename: Yves
authors.initials: Y
authors.lastname: Lacourcière
authors.forename: Jacques
authors.initials: J
authors.lastname: de Champlain
authors.forename: Luc
authors.initials: L
authors.lastname: Poirier
authors.forename: Pierre
authors.initials: P
authors.lastname: Larochelle
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002121:Calcium Channel Blockers / Q000627:therapeutic use*; D004095:Dihydropyridines / Q000627:therapeutic use*; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic; D016896:Treatment Outcome
chemical_list: D000319:Adrenergic beta-Antagonists; D002121:Calcium Channel Blockers; D004095:Dihydropyridines; C038806:1,4-dihydropyridine