What is the mortality rate of myocarditis?

Mortality Rate of Myocarditis

The mortality rate of myocarditis varies dramatically by clinical presentation: overall hospital mortality averages 2.4%, but fulminant myocarditis carries a 42-58% short-term mortality, while uncomplicated cases have near 0% in-hospital mortality. 1, 2, 3

Overall Mortality Rates

• General population mortality: Myocarditis affects approximately 4-14 per 100,000 people annually and is associated with an overall mortality rate of 1-7% 2
• Hospital mortality: Among all hospitalized myocarditis patients, the average hospital mortality remained constant at 2.44% over a 16-year period (2007-2022) in Germany 3
• Long-term mortality: In patients with biopsy-proven viral myocarditis followed for over 10 years, all-cause mortality reached 39.3%, cardiac death 27.3%, and sudden cardiac death 10.9% 4

Mortality by Clinical Severity

Uncomplicated Myocarditis

• Approximately 75% of admitted patients have an uncomplicated course with near 0% in-hospital mortality 2
• These patients typically present with chest pain and elevated troponins but maintain hemodynamic stability 2

Complicated Myocarditis with Heart Failure or Arrhythmias

• 12% rate of in-hospital mortality or need for heart transplant when complicated by acute heart failure or ventricular arrhythmias 2
• Patients with sustained arrhythmias have a 5.4-fold increased risk of cardiac arrest, mechanical circulatory support need, or death (OR 5.4,95% CI 3.9-7.4) 1

Fulminant Myocarditis

• Short-term survival rate of only 58% (42% mortality) according to Japanese registry data 1
• However, long-term prognosis is paradoxically favorable: After 11 years, 93% of fulminant myocarditis survivors were alive without heart transplantation, compared to only 45% with non-fulminant forms 1
• This represents a distinct clinical entity with adverse short-term but relatively good long-term prognosis if patients survive the acute phase 1

Cardiogenic Shock

• Approximately 2-9% of patients develop hemodynamic instability requiring inotropes or mechanical circulatory support 2
• These patients have approximately 28% mortality or heart transplant rate at 60 days 2
• Myocarditis-associated cardiogenic shock carries a 9.8% higher adjusted mortality rate compared to other causes of cardiogenic shock 5

Mortality by Specific Subtypes

Giant Cell Myocarditis

• Severe form with dramatic clinical course and particularly adverse prognosis 1
• Frequently affects young patients and requires earlier consideration of device implantation due to poor outcomes 1

COVID-19-Associated Myocarditis

• 12.54% hospital mortality for patients with both myocarditis and COVID-19, compared to 2.26% for myocarditis without COVID-19 3
• Incidence was relatively low at 0.62 per 100,000 inhabitants, but mortality was substantially elevated 3

Pediatric Myocarditis

• Ventricular tachycardia occurred in 76% of 314 children with arrhythmias among 2,148 children with acute myocarditis 1
• Death or transplant occurs in nearly half of pediatric patients within the first 2 years of diagnosis 1

Age-Related Mortality

• 30-day mortality: 4.7% in young adults (20-39 years), 4.8% in mid-life (40-59 years), and 10.0% in older adults (60-79 years) 6
• 10-year all-cause mortality: 25.5% across all hospitalized patients with clinically suspected acute myocarditis 6
• Even young adults with non-complicated phenotypes maintain higher excess mortality compared to the general population for at least 10 years after index hospitalization 6

Sudden Cardiac Death Risk

• Myocarditis accounts for 4-7.5% of sudden cardiac deaths in athletes 1
• Post-mortem data implicate myocarditis in sudden cardiac death of young adults at rates of 8.6-44% 1
• The risk of sudden death does not correlate with severity of myocardial inflammation and can occur even with normal left ventricular function 1

Prognostic Factors

High-Risk Features

• Presence of late gadolinium enhancement (LGE) on cardiac MRI is associated with more than doubled risk of death (HR 2.40), tripled risk of cardiac death (HR 3.00), and 14.79-fold increased risk of sudden cardiac death 4
• Midwall septal LGE is the best independent predictor for sudden cardiac death (HR 4.59) 4
• Troponin levels ≥1.5 ng/mL are associated with 4-fold increased risk of major adverse cardiac events (HR 4.0,95% CI 1.5-10.9) 1

Clinical Warning Signs

• Progressive wall motion abnormalities with deteriorating left ventricular function on echocardiography 1
• Persistent or fluctuating cardiac troponin concentrations 1
• Widening of the QRS complex 1
• Frequent non-sustained ventricular arrhythmias 1

Long-Term Outcomes

• 21% of patients develop dilated cardiomyopathy after acute myocarditis in long-term follow-up studies 1
• Myocarditis is identified as a cause of dilated cardiomyopathy in up to 10% of cases 1
• If patients survive the active phase, prognosis is generally favorable except for chronic latent forms 7