Pericarditis, cardiac tamponade and myocarditis

Essentials

• 1

  Myocarditis is often associated with pericarditis. This has important clinical implications.

• 2

  Pericarditis is diagnosed based on history and findings on both electrocardiography (ECG), and echocardiography. The diagnosis is based on two of the four criteria outlined in Table 5.6.1 .

  Table 5.6.1

  European Society of Cardiology definition of and diagnostic criteria for pericarditis (2015)

  Pericarditis	Definition and diagnostic criteria
  Acute	Inflammatory pericardial syndrome to be diagnosed with at least two of the four following criteria: 1. Pericarditic chest pain 2. Pericardial rub 3. New widespread ST-segment elevation or PR depression in the ECG 4. Pericardial effusion (new or worsening) Additional supporting findings: Elevation of markers of inflammation Evidence of pericardial inflammation by an imaging technique (CT, MRI)
  Incessant	Pericarditis lasting for >4 to 6 weeks but <3 months without remission
  Recurrent	Recurrence of pericarditis after a documented first episode of acute pericarditis and a symptom-free interval of 4 to 6 weeks or longer
  Chronic	Pericarditis lasting for 3 months

  CT , Computed tomography; ECG , electrocardiography; MRI , magnetic resonance imaging.

• 3

  The majority of cases of pericarditis are idiopathic or viral in aetiology and run a benign course.

• 4

  Multimodality imaging for pericardial disease is essential for comprehensive evaluation of the disease condition.

• 5

  The correct identification of pericarditis as opposed to ST-segment elevation myocardial infarction (STEMI) is essential. Administration of fibrinolysis in cases of pericarditis may result in life-threatening complications and delay in reperfusion therapy; it is also deleterious to patient outcome.

• 6

  Longer-term follow up is important, as a sub-acute or chronic course can develop, with complications such as chronic constrictive pericarditis.

History

Chest pain is the most common presentation (>85% to 90% of cases). It tends to be sharp in nature and is usually localized to the precordial/retrosternal area. The pain is classically worse on inspiration and is often positional. Pain may radiate to the trapezius ridge, neck or shoulder due to involvement of the phrenic nerve. It is typically worse when the patient is supine and improves when he or she is sitting up and leaning forwards. The aetiology is often idiopathic, but a focused history should be directed towards the known causative pathologies, such as post–cardiac injury syndromes, rheumatological manifestations of heart disease (e.g. systemic lupus erythematosus) and complications of malignancy. Dyspnoea is not an expected associated feature unless there are secondary complications, such as cardiac tamponade or constrictive pericarditis.

Examination

A careful history and physical examination should be undertaken in any patient with a suspected pericarditis. Temperature above 38°C is uncommon and may indicate purulent (i.e. bacterial) pericarditis. Sinus tachycardia is common. A pericardial friction rub may be audible when the diaphragm of the stethoscope is placed over the lower left sternal edge with the patient leaning forwards in the left lateral decubitus position (<33% of cases). The rub has a superficial scratching or ‘Velcro-like’ quality. Pericardial friction rubs may be difficult to detect, as they can be transient and migratory. A raised jugular venous pressure (JVP), hypotension, and pulsus paradoxus are suggestive of cardiac tamponade. Pericardial tamponade, a potentially lethal complication of pericarditis, complicates up to 15% cases of acute idiopathic pericarditis.

High-risk features

The following high-risk clinical features should raise suspicion of serious underlying pathology, such as tuberculosis (TB) or other bacterial infection, malignancy or autoimmune disease:

• Fever

• True dyspnoea

• A sub-acute course

• Significant effusion or tamponade

• Failure to respond to aspirin or non-steroidal anti-inflammatory drugs (NSAIDs)

• Patients on anticoagulant therapy

• Immunosuppression

• Recent trauma

• Patients with suspected significant associated myocarditis indicated by arrhythmias, significantly elevated ST segments or significantly elevated troponin levels

Blood tests

• Full blood count: leucocytosis is common, but a markedly elevated white cell count should raise suspicion of bacterial infection.

• Serum biochemistry: may identify underlying renal failure.

• Erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) provides confirmatory evidence of an inflammatory process and can be used to follow resolution.

• The troponin level can be minimally elevated in patients with acute pericarditis. Usually the troponin level returns to normal in 1 to 2 weeks. Sustained elevations are suggestive of concomitant myocarditis.

• Other blood tests will be dictated by the clinical assessment and the degree of clinical suspicion for any given causative pathology.

Chest x-ray

The chest x-ray is usually normal in acute pericarditis unless there is a large pericardial effusion. This investigation has a class 1 indication in the European Society of Cardiology (ESC) guidelines for pericardial disease.

European Society of Cardiology guidelines

The ECG is a critical investigative tool and will show abnormalities in 90% of patients with acute pericarditis. ECG changes are the result of the associated epimyocarditis. The pericardium is electrically neutral and does not produce ECG changes. Therefore, in the occasional ‘pure’ case of pericarditis, the ECG will be normal.

The typical ECG pattern of pericarditis follows four stages:

• Stage 1: hours to days

• Widespread concave upwards ST elevation (60% of cases). This may occur in all leads apart from AVR and VI ( Fig. 5.6.1 ).

  • PR depression.

  • ‘Spodick’ sign (down-sloping TP segments) seen in 80% of patients with acute pericarditis. It is not usually observed in patients with acute coronary syndrome or early repolarization.

  

• Stage 2: the PR and ST segments normalize, which can lead to a transiently normal ECG.

• Stage 3: days to weeks: T-wave inversion occurs.

• Stage 4: normalization of the ECG: over a period of up to 3 months; however, in some cases the T-wave changes may be permanent.

Atypical ECG findings may include the following:

• A normal ECG in cases of pure pericarditis (remembering that during stage 2 the ECG may also be transiently normal during a typical evolution).

• The PR-segment depression may occur in isolation, without any ST-segment elevation.

• Stages 1 and 2 without progression to stage 3.

• Localized as opposed to diffuse ECG changes.

Echocardiography

As per ESC guidelines for pericardial diseases, routine transthoracic echocardiography (TTE) is recommended in all patients with acute pericarditis (class 1, level C). It is a crucial imaging technique for detecting pericardial fluid and its haemodynamic effects on the heart if cardiac tamponade or constrictive physiology is suspected. It is also helpful to differentiate from acute myocardial ischaemia by excluding wall motion abnormality. A normal echocardiogram does not rule out a diagnosis of pericarditis. Transoesophageal echocardiography (TOE) is better at measuring thickness of the pericardium than TTE.

Computed tomography scan/magnetic resonance imaging

Computed tomography (CT) and magnetic resonance imaging (MRI) should be considered as further imaging modalities in patients with underlying aetiologies such as malignancy, TB or systemic inflammatory conditions. In most patients, they provide excellent images of the pericardium, including thickness, the presence of effusion and any pericardial lesions. In patients with myopericarditis, MRI shows late gadolinium enhancement in the pericardium. Pericardial uptake of F-fluorodeoxyglucose (FDG) tracer is found in patients with solid cancers and lymphoma and is indicative of malignant pericardial involvement. Positron emission tomography (PET)/CT is also of value in identifying the nature of inflammatory pericarditis. In particular, TB pericarditis yields a higher FDG uptake than idiopathic forms.

Pericardiocentesis and biopsy

Rarely required, pericardiocentesis and biopsy may be indicated in suspected bacterial, tuberculous or neoplastic pericarditis, when cardiac tamponade is present or in chronic or recurrent cases for diagnostic purposes.

Classification of pericarditis

The ESC Task Force has classified pericarditis into three broad categories based on clinical behaviour. The term ‘acute’ should be adopted for new-onset pericarditis. The term ‘incessant’ refers to cases with persistent symptoms without a clear-cut remission after the acute episode. The term ‘chronic’ refers to disease processes lasting more than 3 months. Incessant refers to pericarditis with symptoms persisting for more than 4 to 6 weeks (that is generally the approximate length of conventional anti-inflammatory therapy and its tapering). Finally, ‘chronic’ refers to pericarditis lasting longer than 3 months.

Colchicine

Colchicine is an important component of therapy and has been shown to be effective not only in reducing symptoms but also leading to a 50% reduction in recurrence. It should be given with aspirin and NSAIDs. The ESC 2015 guidelines suggest 0.5 mg once daily for patients weighing <70 kg or 0.5 mg twice a day for those weighing more than 70 kg for 3 months. The initial dose should be maintained until resolution of symptoms and normalization of biomarkers when tapering should be considered.