Page created on April 9, 2022. Last updated on April 20, 2022 at 08:54

Non-infective endocarditis is very rare and therefore not covered. Infective endocarditis is covered in topic 18.

Pericarditis

Introduction and epidemiology

Pericarditis refers to inflammation of the pericardium. It can be acute, recurrent, or chronic. It often leads to formation of a pericardial effusion.

Etiology

There are many possible causes of pericarditis, but the most common are viral and autoimmune.

• Infectious
  • Viral (coxsackie, others)
  • Bacterial
• Non-infectious
  • Autoimmune (SLE, Sjögren, RA, +++)
  • Metastasis
  • Metabolic disorder

Classification

• Exudative pericarditis – causes pleural effusion
• Fibrinous pericarditis – does not cause effusion

Clinical features

There’s a typical form of chest pain in acute pericarditis, described as a sharp pain in the retrosternum which worsens on inspiration. The pain improves when leaning forward. Other symptoms include fever and dyspnoea.

A pericardial friction rub on auscultation is typical, which sounds like high-pitched scratching. It’s best heard over the left sternal border. If there’s a large pericardial effusion, heart sounds may be distant.

Diagnosis and evaluation

The diagnosis is based on typical clinical features and findings on ECG, echo, and imaging.

• X-ray – enlarged cardiac silhouette due to pericardial effusion
• ECG – widespread ST elevation or PR depression
• Echocardiography – pericardial effusion and thickened pericardium
• Inflammatory markers may be elevated
• Inflammation of the pericardium can be visualised on CT or MRI

Treatment

First-line treatment are NSAIDs + colchicine + exercise reduction. Second line are glucocorticoids and other immunosuppressants. In case of chronic pericarditis, pericardiectomy is an option.

Complications

• Constrictive pericarditis – diastolic heart failure due to thickened, rigid, fibrous pericarditis following acute pericarditis. Jugular vein distention which worsens on inspiration (Kussmaul sign), pericardial knock, and pulsus paradoxus are typical findings.
• Cardiac tamponade (see below)

Myocarditis

Introduction and epidemiology

Myocarditis refers to inflammation of the myocardium. It has a wide range of presentations, anywhere from acute and fulminant to chronic.

As the cardiac conduction system is in the myocardium, myocarditis predisposes to arrhythmias. It also affects the myocardium’s ability to contract. It may mimic ACS.

Myocarditis is mostly a disorder of younger adults.

Etiology

• Viral (coxsackie) (most common)
• Bacterial (rheumatic fever)
• Autoimmune disorders
• COVID-19
• COVID-19 vaccines (rare)

Clinical features

Many are asymptomatic, and symptoms are highly variable. Some have preceding symptoms of viral infection.

• New onset or worsening heart failure
• Acute coronary syndrome-like symptoms (chest pain, dyspnoea)
• Arrhythmias

Diagnosis and evaluation

Troponins are elevated, as are inflammatory markers. ECG is often abnormal, but no findings are specific for myocarditis. ST-elevations and heart blocks are probably the most common. Echocardiography is important to determine the myocardial contractility and to exclude differential diagnoses.

MRI is usually sufficient to diagnose myocarditis. In doubtful cases, and endomyocardial biopsy can be performed, which may also provide information on the etiology.

Treatment

There is no specific treatment, except if there’s a treatable underlying cause. Most cases are self-limiting. Patients should be continuously monitored for arrhythmias by telemetry. The patient may require antiarrhythmics or treatment for heart failure. Unlike in pericarditis, NSAIDs cannot be used as they are not helpful and might even worsen outcomes.

Complications

• Cardiogenic shock
• Sudden cardiac death
• Secondary dilated cardiomyopathy

Cardiac tamponade

Introduction and epidemiology

Cardiac tamponade is a condition where a pericardial effusion compresses the heart, leading to life-threatening acute heart failure. This occurs if the pericardial effusion develops rapidly or is large. It’s an emergency which should be treated empirically even before a proper diagnosis is made.

Etiology

• Acute pericarditis
• Cardiac wall rupture (trauma, MI)
• Cardiac surgery

Clinical features

Cardiac tamponade has a distinct clinical presentation:

• Hypotension
• Tachycardia
• Jugular venous congestion
• Pulsus paradoxus

Diagnosis and evaluation

• ECG – low voltage, electrical alternans
• X-ray – enlarged cardiac silhouette
• Echocardiography – large effusion, collapse of chambers, swinging of the heart

Treatment

Treatment should not be delayed due to diagnostic evaluations. Treatment is by pericardiocentesis, under ultrasound or fluoroscopic guidance. If unsuccessful, surgery may be necessary.