Cardiac arrest: defibrillation: apex-anterior chest pads were probably as effective as apex-posterior pads

Clinical bottom line (level 4)

  1. Patients undergoing defibrillation who had electrode pads placed over the apex and anterior chest were not clearly more likely to have successful cardioversion than those who have pads placed over the apex and posterior chest.
  2. There was no clear difference in the impedance for the first shock.
Kerber et al: Journal of the American College of Cardiology 1984; 3 (3): 815-820
Expires October 2003

The study

Case-control study with unblinded, unobjective outcomes, not adjusted for confounding factors, not validated in an independent set of patients.
Setting: acute hospital, USA

80 patients (aged ?, ?% male) undergoing elective cardioversion or emergency defibrillation

Excluded if
  • in ventricular fibrillation and pads not in position


    • Note:
  • Patients received shock strengths ranging from 20 to 400 J depending on the arrhythmia detected.


    • Control Group: (n = 66, 66 analysed): apex-anterior pad position: apex pad placed over the palpable cardiac apex, and the anterior pad place on the right upper sternum under the right clavicle
    Experimental Group: (n = 124, 124 analysed): apex-posterior pad position: apex as above, and the posterior pad placed in the right infrascapular area, one or two interspaces more cephalad than the apex pad.

    100% followed for 2 minutes
    Outcome notes:
    • cardioversion : to sinus rhythm or to AF if in atrial flutter

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    cardioversion unknown 42
    (63.6%)    		 83
    (66.94%)    		 9%
    (-36% to 39%)    		 3.30%
    (-10.96% to 17.56%)    		 30
    (NNT = 6 to infinity;
    NNH = 9 to infinity)

    Outcome Control Group
    (SD)    		 Experimental Group
    (SD)    		 Mean Difference
    (95% CI)
    mean first shock transthoracic impedance 79
    (26)     		73
    (16)     		6
    (0.0 to 12)

    Comments

    1. The numbers in each group refer to the number of shocks given.
    2. The apex-posterior position was used for six months, followed by the apex-anterior position.

    Citation

    1. Kerber RE, Martins JB, Kelly KJ, et al: Self-adhesive preapplied electrode pads for defibrillation and cardioversion. Journal of the American College of Cardiology 1984; 3 (3): 815-820
    Contributor: Chris Ball and Musab Hayatli, October 1999
    Reviewer: Kenneth Ballew

    Clinical Question.
    Patient defibrillation or cardioversion
    Intervention or Exposure electrode pads apex-posterior
    Comparison apex-anterior
    Outcome successful cardioversion