Canis ISSN: 2398-2942

Heart: myocarditis

Contributor(s): Serena Brownlie, Mark Rishniw

Introduction

  • Myocardial inflammation, infiltrate and necrosis/degeneration of adjacent myocytes.
  • Cause: infectious or non-infectious damage affecting pericardium, myocytes, interstitial or vascular tissue of heart.
  • Signs: variable - arrhythmias to congestive heart failure (CHF).
  • Diagnosis: history and clinical signs (systemic illness), heart auscultation, electrocardiography, echocardiography.
  • Treatment: specific treatment against inciting element plus treatment of arrhythmia/CHF.
  • Prognosis: depends on severity and inciting agent/cause.

Pathogenesis

Predisposing factors

General

  • Immunosuppression.
  • Debility.

Specific

  • Exposure to infectious agent or use of myocardiotoxic substances.

Pathophysiology

  • Inflammation of heart muscle caused by infectious/toxic agent(s) affecting pericardium, myocytes, interstitial or vascular tissue of heart.
  • May be acute or chronic if infectious.
  • Results in cardiac dysfunction.
  • Infection may arise locally or be spread from distant sites, eg dental, prostate, skin, uterus, lung.
  • Infection/toxicity → toxin (local or blood borne)/immune-complex/direct invasion → vasculitis/myocyte damage → myocardial inflammation → cardiac dysfunction = arryhthmias/CHF.
  • Often concurrent signs of systemic infection/toxicity.
  • Severe systemic disease, eg GDV, IMHA - sympathetic 'storm' and release of free radicals - myocardial necrosis - arrhythmias.

Timecourse

  • May have acute (days), or chronic (months) course.
  • Acute disease may progress to a form of cardiomyopathy and eventually heart failure.

Diagnosis

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Treatment

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Prevention

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Outcomes

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Further Reading

Publications

Refereed papers


ADDED