Involves normal or decreased volume of both ventricles with bi-atrial enlargement, normal wall thickness, normal cardiac valves and impaired ventricular filling with restrictive physiology but near-normal systolic function
Aetiology
Infiltration of the myocardium by an invasive substance e.g. sarcoidosis, amyloid, tumours
Fibrotic myocardium without an external invasive substance e.g. as a result of radiation exposure
Pathophysiology
The walls of the ventricles become stiff, but not necessarily thickened
Compliance of the ventricular walls during diastolic filling is reduced, resulting in the clinical features of heart failure
Clinical presentation
As heart failure - dyspnoea, fatigue, elevated JVP, oedema
AF develops in 75% of patients
Investigations
ECG - reduced QRS, ST-segment and T wave changes
Echocardiography
Management
Manage heart failure
Management of underlying cause if possible e.g. amyloidosis