Tachycardia: diltiazem shows a dose-response effect.

Clinical bottom line (level 1b)

  1. Patients with supraventricular tachycardia who are given diltiazem 0.05 mg/kg, have no clear difference in conversion to sinus rhythm than those given placebo.
  2. Patients given diltiazem 0.15 mg/kg are more likely to have conversion to sinus rhythm than those given placebo (NNT = 2 at 17 minutes) .
  3. Patients given 0.25 mg/kg are more likely to have conversion to sinus rhythm (NNT = 1 at 17 minutes) .
  4. Patients given diltiazem 0.45 mg/kg are more likely to have conversion to sinus rhythm (NNT = 2 at 17 minutes) .
Dougherty et al: American Journal of Cardiology 1992; 70: 587-592
Expires October 2004

The study

Single-blinded ?concealed randomised trial with intention-to-treat
Setting: 2 University hospitals, USA

87 patients (aged ?, 52% female) clinical history of paroxysmal supraventricular tachycardia

Excluded if
  • severe congestive heart failure
  • sinus node dysfunction
  • pregnancy
  • myocardial infarction within 2 weeks of study
  • hypotension (systolic pressure <90 mmHg)
  • tachycardia <120 beats per minute
  • tachycardia for <15 minutes


    • Note:
  • 87 patients completed the study, but no indication is made of the number who entered it.


    • Control Group: (n = 24, 24 analysed): placebo
    Experimental Group: (n = 63, 63 analysed): intravenous diltiazem in doses of: 0.05 (14 patients), 0.15 (19), 0.25 (13) and 0.45 (17) mg/kg
    Supraventricular tachycardia was induced and allowed to persist without intervention for 15 minutes to confirm constancy of the arrhythmia prior to randomisation.
    100% followed for 17 minutes

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    conversion to sinus rhythm- 0.05 mg/kg diltiazem 17 minutes 6
    (25.0%)    		 4
    (28.6%)    		 -14.0%
    (-237% to 61.0%)    		 -3.57%
    (-32.9% to 25.8%)    		 28
    (NNT = 3 to infinity;
    NNH = 4 to infinity)
    conversion to sinus rhythm- 0.15 mg/kg diltiazem 17 minutes 6
    (25.0%)    		 16
    (84.2%)    		 -237%
    (-592% to -64.0%)    		 -59.2%
    (-83.1% to -35.4%)    		 2
    (1 to 3)
    conversion to sinus rhythm- 0.25 mg/kg diltiazem 17 minutes 6
    (25.0%)    		 13
    (100%)    		 -300%
    (-700% to -100%)    		 -75.0%
    (-92.3% to -57.7%)    		 1
    (1 to 2)
    conversion to sinus rhythm- 0.45 mg/kg diltiazem 17 minutes 6
    (25.0%)    		 14
    (82.4%)    		 -229%
    (-582% to -59.0%)    		 -57.4%
    (-82.4% to -32.3%)    		 2
    (1 to 3)

  • Hypotension requiring intervention (including Trendelenburg position) occurred in 10 (16%) of patients - all received > 0.05mg/kg diltiazem.

    • Citation

    1. Dougherty AH, Jackman WM, Naccarelli GV, et al: Acute conversion of paroxysmal supraventricular tachycardia with intravenous diltiazem. American Journal of Cardiology 1992; 70: 587-592
    Contributor: Clare Wotton, October 1999
    Reviewer:

    Clinical Question.
    Patient paroxysmal supraventricular tachycardia
    Intervention or Exposure diltiazem
    Comparison control
    Outcome termination of tachycardia