Myocardial infarction: selective lidocaine was not clearly better than prophylactic lidocaine.

Clinical bottom line (level 1b-)

  1. Patients with early ventricular arrhythmias of myocardial infarction who were given selective lidocaine, had no clear difference in sustained tachycardia and fibrillation than those given prophylactic lidocaine.
  2. Patients given selective lidocaine were less likely to suffer emergent adverse effects than those given prophylactic lidocaine (NNT = 42 at 24 hours) .
  3. Patients given selective lidocaine had no clear difference in hospital mortality.
Wyse et al: Journal of the American College of Cardiology 1988; 12: 507-513
Expires October 2004

The study

Unblinded ?concealed randomised trial with intention-to-treat
Setting: University hospital, Canada

333 patients (aged mean 57 years, 76% male) proven or suspected acute myocardial infarction (chest pain plus typical Q waves and evolutionary ST-T changes in ECG or a serial increase in serum creatinine kinase (total or MB fraction) or both)

Excluded if
  • >75 years old
  • complex ventricular arrhythmias requiring treatment on arrival
  • in advanced heart failure or shock
  • contraindication to lidocaine, such as persistent sinus bradycardia (<45 beats peer minute)
  • liver disease or allergy
  • received antiarrhythmic drugs in the previous 24 hours
  • refused consent
  • presentation >6 hours after chest pain


    • Control Group: (n = 168, 168 analysed): prophylactic lidocaine -100 mg i.v. loading infusion given over 3-5 minutes, followed by a 3 mg per minute continuous i.v. maintenance infusion. Another 100 mg i.v. infusion was given 30 minutes after the first and the dosage was adjusted on a mg per kg basis for patients <50 or >90 kg.
    Experimental Group: (n = 165, 165 analysed): selective lidocaine -as above
    Initially, patients were randomised to receive either placebo or lidocaine. Following detection of complex ventricular arrhythmias (> or = 5 ventricular premature beats per minute, couplets, runs, ventricular tachycardia, multiform ventricular beats or R on T phenomenon), the protocol required patients receiving placebo to receive lidocaine in an open label fashion (selective strategy), and those patients already receiving lidocaine on unblinding for arrhythmias (prophylactic strategy) therapeutic decisions were individualised by the physician in charge.
    100% followed for 24 hours
    Outcome notes:
    • emergent adverse effects : seizures, loss of consciousness, severe and persistent sinus bradycardia < or = 35 per minute, respiratory arrest or asystole > or = 5 seconds

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    sustained ventricular tachycardia and fibrillation 24 hours 0
    (0.00%)    		 2
    (1.21%)    		 100%
    (% to %)    		 1.21%
    (-0.46% to 2.88%)    		 -83
    (NNT = 219 to infinity;
    NNH = 35 to infinity)
    emergent adverse effects 24 hours 4
    (2.38%)    		 0
    (0.00%)    		 100%
    (% to %)    		 2.38%
    (0.08% to 4.69%)    		 42
    (21 to 132)
    hospital mortality 24 hours 8
    (4.76%)    		 5
    (3.03%)    		 36%
    (-91% to 79%)    		 1.73%
    (-2.42% to 5.88%)    		 58
    (NNT = 17 to infinity;
    NNH = 41 to infinity)

    Comments

    1. Larger trials and systematic reviews with meta-analysis confirm the lack of utility of class IB antiarrhythmics.

    Citation

    1. Wyse G, Kellen J, Rademaker AW: Prophylactic versus selective lidocaine for early ventricular arrhythmias of myocardial infarction. Journal of the American College of Cardiology 1988; 12: 507-513
    Contributor: Clare Wotton and Bob Phillips, October 1999
    Reviewer:

    Clinical Question.
    Patient myocardial infarction
    Intervention or Exposure prophylactic lidocaine
    Comparison selective lidocaine
    Outcome mortality