Myocarditis does not worsen cardiac arrest outcomes

Prior myocarditis or perimyocarditis does not factor in out-of-hospital cardiac arrest (OHCA) outcomes, but the presence of concomitant heart failure (HF) may contribute to unfavourable outcomes in the short and long term, as suggested in a study.

Researchers used data from the Swedish Cardiopulmonary Resuscitation Registry and identified 54,568 patients (mean age 69.2 years) with OHCA where cardiopulmonary resuscitation was attempted. Of these, 498 patients (0.9 percent, mean age 68 years) had a history of myocarditis or perimyocarditis.

Patients with vs without myocarditis/perimyocarditis were more likely to be male and were more likely to present shockable initial rhythms (28.7 percent vs 23.1 percent). Patients with myocarditis/perimyocarditis also had a higher prevalence of multiple comorbidities, including hypertension (64.3 percent vs 44.6 percent), HF (51.2 percent vs 22.5 percent), and chronic ischaemic heart disease (39 percent vs 20.4 percent).

Analyses showed no association between prior myocarditis/pericarditis and worse short‐term (odds ratio [OR], 0.91, 95 percent confidence interval [CI], 0.61–1.33) or long‐term survival (hazard ratio [HR], 1.01, 95 percent CI, 0.91–1.13).

Of note, the absence of HF was associated with improved short‐term survival (OR, 1.46, 95 percent CI, 1.32–1.62), whereas the presence of HF was a risk factor for worsened long‐term survival (HR, 0.91, 95 percent CI, 0.91–0.95) after OHCA.

The findings underscore the need for innovative treatment approaches and ongoing follow‐up to ensure optimal care for individuals with myocarditis or perimyocarditis.