Tachyarrhythmia: ventricular: death was common especially with heart disease

Clinical bottom line (level 2b)

  1. 30% of patients with ventricular tachyarrhythmias were dead within 15 months - half died suddenly.
  2. Patients with the following prognostic factors are at increased risk of dying
    • severe heart failure
    • lack of response to anti-arrhythmic therapy at follow-up electrophysiologic study
    • left ventricular aneurysm
    • greater number of cardioversions at electrophysiologic study needed to revert to sinus rhythm
Swederlow et al: New England Journal of Medicine 1983; 308 : 1436-1442
Expires October 2003

The study

Retrospective cohort study with blinded outcomes, adjusted for confounding factors, not validated in an independent set of patients.

Setting: university hospital, USA

239 patients (aged mean 56 +/- 14, 80% male) with spontaneous sustained ventricular tachyarrhythmias (VT or VF) not associated with acute MI, undergoing electrophysiologic study

Factors studied:
  • age, sex
  • cardiac disease (normal clinical examination, normal resting ECG, treadmill, CXR and ECHO and intramyocardial biopsy), clinical arrhythmias, and induced arrhythmias on electrophysiologic study, antiarrhythmic therapy
  • NYHA functional class
  • EP studies (response to therapy was defined as reduced number of arrhythmias during a second EP study on medication



    Multiple regression analysis performed on risk factors

    99% followed for
    Outcomes studied:
  • death
  • cardiac death
  • sudden death

    The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)    		 NNF
    (95% CI)
    death 15 months 74/239 31%
    (25% to 37%)    		 3
    (3 to 4)
    cardiac death 15 months 71/239 30%
    (24% to 36%)    		 3
    (3 to 4)
    sudden death 15 months 44/239 18%
    (14% to 23%)    		 6
    (4 to 7)

    • The following risk factors independently predicted sudden death or cardiac death
      • higher NYHA class
      • lack of response to anti-arrhythmic therapy at follow-up electrophysiologic study
      • left ventricular aneurysm
      • greater number of cardioversions at electrophysiologic study needed to revert to sinus rhythm

    Comments

    1. The population studied was highly selected (a tertiary centre and refered for EP).
    2. EP studies were repeated in only 205 patients (86%) with assessment of drug response in 204 patients
    3. Absence of structural heart disease did not relate to prognosis (but the definition involved an intracardiac biopsy!)
    4. No odds ratios were given for the independent prognostic factors.

    Citation

    1. Swederlow CD, et al: Determinants of survival in patients with ventricular tachyarrhythmias. New England Journal of Medicine 1983; 308 : 1436-1442
    Search Terms:
    Contributor: Bob Phillips, May 1998
    Reviewer: Chris Ball

    Clinical Question.
    Patient VT or VF
    Intervention or Exposure heart failure, left ventricular aneurysm
    Outcome death
    		•