Hemodynamics of pericardial tamponade and constriction.

Published in early 2000s, titled "Pericardial effusion: haemodynamic spectrum".

Key Hemodynamic Concepts from the Article

The article explains the distinct hemodynamic features of both conditions, highlighting how they affect cardiac function:

Pericardial Tamponade

• Pressure-Volume Relationship: The article emphasizes that the physiological effect of an effusion depends more on the pressure of the fluid than its total volume. The pericardial sac is relatively non-compliant, so even a small, rapid accumulation of fluid can cause a dramatic rise in pressure, leading to severe tamponade.
• Equalization of Pressures: A key hemodynamic hallmark of tamponade is the equalization of diastolic pressures in all four heart chambers. The rising pericardial pressure compresses the heart, causing the right and left ventricular diastolic pressures, and right and left atrial pressures, to rise to a level equal to the pressure in the pericardium.
• Ventricular Interdependence: The increased pressure within the pericardial sac exaggerates the normal ventricular interdependence. During inspiration, increased venous return to the right ventricle causes it to expand, but the rigid pericardial sac limits its ability to do so. This pushes the interventricular septum to the left, which in turn reduces the space available for the left ventricle, impairing its filling and decreasing cardiac output.

Pericardial Constriction

• Impaired Diastolic Filling: Pericardial constriction is caused by a scarred, thickened, and often calcified pericardium that impairs the heart's ability to fill properly during diastole. This is the primary mechanism leading to heart failure.
• Early Diastolic Filling: Initial ventricular filling in early diastole is rapid because the ventricles can still expand into the available space within the pericardial sac. However, once the rigid pericardium is reached, further filling is abruptly halted. This creates a characteristic "dip and plateau" or "square root sign" in the ventricular pressure tracings.
• Respiratory Variation: Unlike tamponade, the stiff pericardium in constriction isolates the cardiac chambers from normal respiratory pressure changes. This can lead to Kussmaul's sign, an abnormal rise in jugular venous pressure during inspiration, as the increased venous return cannot be accommodated by the restricted right ventricle.

Consensus statement on the diagnosis and management of pericarditis.

The American College of Cardiology (ACC). Concise Clinical Guidance (CCG).

The document focuses on closing educational gaps for clinicians, with a primary goal of improving patient outcomes.

Key Takeaways from the CCG

Diagnostic Criteria

The guidance provides new diagnostic criteria for pericarditis, which include a pleuritic chest pain presentation plus at least one of the following clinical findings:

• Pericardial friction rub
• Specific electrocardiogram (ECG) changes
• Elevated inflammatory biomarkers
• New or worsening pericardial effusion

Multimodality Imaging

The document emphasizes a multimodality imaging-guided therapeutic approach.

• Echocardiography: Remains the first-line imaging modality for evaluating pericarditis, as well as complications like pericardial effusion, cardiac tamponade, and constrictive pericarditis.
• Cardiac magnetic resonance (CMR): Recommended when indicated to assess and grade pericardial thickness, inflammation, effusion, and constrictive physiology.
• Cardiac computed tomography (CT): Also recommended, when indicated, for assessing pericardial thickness, calcification, constrictive physiology, and for aiding in pre-operative planning.

Management

The CCG provides recommendations for managing pericarditis and its complications.

• First-line treatment: For acute and first-recurrence pericarditis is a combination of colchicine and NSAIDs (or aspirin), along with exercise restriction.
• For medically refractory pericarditis or constrictive pericarditis: The document recommends radical pericardiectomy.
• The guidance also highlights the importance of treating the underlying etiology and referring complicated cases to a specialized pericardial diseases center.