Haemochromatosis (cardiac manifestations)

Cardiac involvement in haemochromatosis typically occurs with primary haemochromatosis, as the organ is usually spared in the secondary form of the disease.

For a general discussion, and for links to other system specific manifestations, please refer to the article on haemochromatosis. 

Epidemiology

Cardiac involvement occurs in approximately 15-20% of the patients with haemochromatosis. 

Clinical presentation

Manifestations depend on the extent of iron deposition and include:

• breathlessness
• pedal oedema
• palpitations
• features of congestive heart failure

Pathology

Haemochromatosis can result in an iron overload cardiomyopathy.

Radiographic features 

Echocardiography

Transthoracic echocardiography is a useful screening tool for the presence of cardiac manifestations in patients with known haemochromatosis. Findings are, however, nonspecific, and may be loosely divided into early and late findings ⁷:

• early findings
  • diastolic dysfunction
    • grade II - III dysfunction typical (formerly referred to as the pseudonormal and restrictive filling profiles, respectively)
  • left atrial enlargement
• advanced findings
  • the "dilated" phenotype
    • left and right ventricular chamber enlargement
    • decreased left ventricular systolic function
  • the "restrictive" phenotype
    • grade III diastolic dysfunction
      • formerly referred to as restrictive filling
      • mitral filling velocity profile demonstrates an E/A ratio > 2 with a deceleration time (DT) < 160 ms
    • severe left atrial enlargement
    • right ventricular dysfunction
      • elevated right ventricular systolic pressure (RVSP)
      • elevated systolic pulmonary artery pressure (sPAP)
    • normal to elevated left ventricular ejection fraction

Decreased peak velocities of the left ventricular lateral wall, as measured by speckle tracking echocardiography, may occur before the aforementioned early findings on B-mode/dopper echocardiography ⁶.

MRI

The role of cardiac MRI (CMR) is to identify and quantify the amount of iron deposition. Paramagnetic ferritin and haemosiderin lead to altered relaxation times of adjacent hydrogen nuclei.

T2* imaging is highly sensitive in detecting the amount of iron deposition. T2* mapping in CMR shows decreased myocardial T2* with a cut-off of 20 ms commonly applied at 1.5 T.

Myocardial iron overload also causes a characteristic decrease in myocardial T1 times in T1 mapping, that seems to be more sensitive than T2* mapping ⁸.