Original contribution
Postcountershock pulseless rhythms: Response to CPR, artificial cardiac pacing, and adrenergic agonists

https://doi.org/10.1016/S0196-0644(86)80003-8Get rights and content

Clinically, countershock of ventricular fibrillation (VF) may result in asystole or a pulseless rhythm in more than 50% of attempts. We conducted a study to assess the effects of immediate artificial pacing, CPR, and adrenergic drug therapy in the management of postcountershock pulseless rhythms. Thirty-four episodes of VF followed by countershock were studied in eight anesthetized dogs. Transducer-tipped catheters were positioned in the ascending aorta (Ao) and right atrium (RA). A bipolar pacing catheter was advanced to the apex of the right ventricle and a catheter for measurement of coronary sinus blood flow (CSQ) (continuous thermodilution technique) was positioned in the coronary sinus. VF was induced electrically and a countershock at 400 J was given two minutes later; CPR was not performed during VF episodes. Countershock was followed by asystole or a pulseless rhythm in all animals. Immediate endocardial pacing (0.1 to 5 mA) of bradyarrhythmias produced electrical capture but did not result in arterial pressure pulses in any animal. After pacing, CPR was performed for two minutes or until restoration of spontaneous circulation (ROSC). During CPR, the diastolic coronary perfusion gradient (Ao-RA) was 20 ± 7 mm Hg (mean ± SD) and CSQ was 14 ± 7 mL/min/100 g (53% ± 43% of control). ROSC followed CPR of less than two minutes duration in 24% of VF study episodes. If ROSC did not follow two minutes of CPR, 1 mg epinephrine, or 50 μg or 100 μg isoproterenol was given IV. Epinephrine increased the CPR Ao-RA gradient to 48 ± 25 mm Hg and CSQ to 37 ± 21 mL/min/100 g (130% ± 29% of control) (all values were P < .001 when compared to CPR alone). Isoproterenol decreased the CPR diastolic Ao-RA gradient to 15 ± 5 mm Hg and CSQ to 9 ± 4 mL/min/100 g (P < .01 when compared to CPR alone). The fall in coronary perfusion pressure was due to a decrease in diastolic Ao pressure. ROSC followed isoproterenol administration in only one of 12 study episodes. These findings suggest that early and effective CPR alone may facilitate resuscitation from postcountershock pulseless rhythms; that immediate pacing alone is of no value in the management of postcountershock bradyarrhythmias/asystole; and that epinephrine improves but isoproterenol decreases myocardial blood flow during resuscitation from post-countershock pulseless rhythms. Isoproterenol is of limited value in this setting, and may be contraindicated.

References (28)

  • RalstonSH et al.

    Intrapulmonary epinephrine during prolonged cardiopulmonary resuscitation: Improved regional blood flow and resuscitation in dogs

    Ann Emerg Med

    (1984)
  • WeaverWD et al.

    Ventricular defibrillation — a comparative trial using 175J and 320J shocks

    N Engl J Med

    (1982)
  • WeaverWD et al.

    Amplitude of ventricular fibrillation waveform and outcome after cardiac arrest

    Ann Intern Med

    (1985)
  • Standard and guidelines for cardiopulmonary resuscitation (CPR) and emergency cardiac care (ECC)

    JAMA

    (1980)
  • Cited by (0)

    Presented at the University Association for Emergency Medicine Annual Meeting in Kansas City, Missouri, May 1985.

    This study was supported in part by a Biomedical Research Support Grant from the National Institutes of Health (#S07RR5551) and a grant from the Physio-Control Corporation, Redmond, Washington.

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