title: Diltiazem to treat sinus tachycardia in critically ill patients: a four-year experience.
abstract: OBJECTIVE
  To determine whether an intravenous infusion of the calcium channel blocker diltiazem was effective and safe in treating sinus tachycardia in critically ill adult patients with contraindications to beta-blockers or in whom beta-blockers were ineffective.
  
  
  METHODS
  Retrospective chart review.
  
  
  METHODS
  University medical center.
  
  
  METHODS
  The records of 171 surgical intensive care unit patients with sinus tachycardia treated with intravenous diltiazem were evaluated.
  
  
  METHODS
  In all patients with sinus tachycardia (heart rate >100 beats/min), heart rate control with intravenous diltiazem was attempted after adequate intravascular volume expansion, pain, and anxiety control. In all patients, beta-blockade either was contraindicated or (in 7%) had failed. Intravenous diltiazem was administered as a slow 10-mg bolus dose (0.1-0.2 mg/kg ideal body weight), and then an infusion was started at 5 or 10 mg/hr and increased up to 30 mg/hr, as needed, to decrease heart rate to <100 beats/min. Variables retrospectively collected included demographic data, preinfusion blood pressure, mean arterial pressure, heart rate, and preinfusion pressure-rate quotients (pressure-rate quotient = mean arterial pressure / heart rate). Intravenous bolus dose, when given, and diltiazem infusion rate and time necessary to achieve the target heart rate also were recorded. The lowest heart rate recorded within 24 hrs from the initiation of the infusion and the time necessary to achieve the lowest heart rate after beginning the infusion were recorded.
  
  
  RESULTS
  Of 171 patients studied, 97 (56%) were classified as responders. Multiple linear regression suggested that response could be predicted by age, pressure-rate quotients, baseline mean arterial pressure, and central nervous system failure. In the responders, a heart rate <100 beats/min was achieved in an average of 2 hrs, at a mean diltiazem infusion of 13.3 mg/hr. The lowest rate reached by the responders in a 24-hr period averaged 86 beats/min and was achieved in 4.8 hrs with a mean infusion rate of 14.8 mg/hr. Both target and lowest rate values were statistically different from baseline heart rate.
  
  
  CONCLUSIONS
  Diltiazem was effective in achieving short-term control of heart rate in 56% of the patients, virtually without adverse effects, where beta-blockade was contraindicated or ineffective.
authors.affiliation: Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL, USA.
authors.forename: A
authors.initials: A
authors.lastname: Gabrielli
authors.forename: T J
authors.initials: TJ
authors.lastname: Gallagher
authors.forename: L J
authors.initials: LJ
authors.lastname: Caruso
authors.forename: N T
authors.initials: NT
authors.lastname: Bennett
authors.forename: A J
authors.initials: AJ
authors.lastname: Layon
mesh_terms: D000046:Academic Medical Centers; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D016638:Critical Illness / Q000401:mortality / Q000628:therapy; D004110:Diltiazem / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007262:Infusions, Intravenous; D007362:Intensive Care Units; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D016019:Survival Analysis; D013616:Tachycardia, Sinus / Q000175:diagnosis / Q000188:drug therapy* / Q000401:mortality; D016896:Treatment Outcome
chemical_list: D004110:Diltiazem