Case Report: Diagnosis of Iron-Overload Cardiomyopathy in a Sudden Cardiac Arrest Survivor with known Transfusion-Dependent Beta Thalassemia Major

Description of Clinical Presentation: This is the case of a 25-year-old Filipino female who has been diagnosed with Beta thalassemia major (β-TM) at the age of 2 years, and who had had been receiving regular transfusions since then. A formal diagnosis of hemochromatosis was later made at the age of 16 years due to rising serum ferritin levels. Deferiprone had been started, but dose reductions were made due to nausea. Gonadal hemochromatosis and hepatic hemochromatosis were also diagnosed. There were no recalled heart failure symptoms. No echocardiographic evidence of cardiac iron overload was documented during this period.

At 24 years old (1 year prior to consult), she was hospitalized at another institution for dengue fever. There she suffered three episodes of sudden cardiac arrest (SCA). She was managed accordingly, return of spontaneous circulation was achieved, and she was admitted to the ICU. She then recovered without any reported residual cardiovascular symptoms or neurologic deficits. She was discharged on propranolol for arrhythmia prevention. She was seen at our center and referred for CMR.

Diagnostic Techniques and Their Most Important Findings: There was normal biventricular systolic function but with mild increase in the indexed end diastolic volumes (EDVi) of both the left (85ml/m²) and right (94ml/m²) ventricles on cine imaging. No regional right ventricular wall motion abnormalities were observed.

While septal T2* (26.5ms) and global T2* (20.8ms) values were normal, segmental analysis detected increased iron load in the basal inferior (7.7ms, ~3.76mg/g dry weight) and mid-ventricular inferior (14.13ms, ~1.78mg/g dry weight) segments.

To supplement the analysis, T1 and T2 mapping were performed. T1 values were markedly reduced throughout the myocardium (713-870ms), with the lowest values concentrated in the basal to mid-ventricular inferior segments (713-716ms). T2 values were normal and thus not indicative of active edema.

Learning Points from this Case: Diagnosis of IOC should consider using a segment-level approach to allow increased detection and diagnosis and should go beyond T2*.

The addition of T1 parametric mapping allows better qualification of the extent of iron overload. We demonstrated that while iron load using T2* was “normal” in the septal, anterior, and lateral segments, the T1 mapping values were significantly reduced. While T1 doesn’t allow quantification of grams per dry weight, the bullseye plot provided a more complete picture that the iron load was more severe than if it was assessed by T2* alone.

This case aims to represent the Philippines’ first fully documented case of IOC that used both guideline-recommended and evidence-based CMR sequences – specifically an integration of T2-star (T2*) and T1 mapping – in qualifying the extent and severity of cardiac iron overload and guiding management.

Improving access to CMR and the high cost of chelation in resource-limited nations like the Philippines remains a challenge.

CMR T2* of the basal region, demonstrating abnormal cardiac iron load in the inferior segments of in the basal (7.7ms, ~3.76mg/g dry weight) region.
CMR Parametric mapping bullseye plots according to AHA 16-segment model. Globally reduced T1 relaxation times due to diffuse iron overload (713-870ms).