Background: Known to influence the cardiovascular system, hyperthyroidism has gained much interest in the recent decades in describing cardiac abnormalities brought about by the disease with the advent of echocardiogram, particularly in subclinical cases. With recent findings of cardiac abnormalities and long-term cardiac complications related even to subclinical cases, treatment may well be indicated for all cases.
This is a retrospective descriptive study conducted to describe cardiac morphology and function of Filipino hyperthyroid patients through 2-dimensional echocardiogram, admitted at De La Salle University Medical Center for a period of 5 ½ years. Patients were divided into 2 groups: overt and subclinical hyperthyroidism. Cardiac morphology, systolic and diastolic functions were determined as a population, and compared between the two groups of hyperthyroidism.
Subgroup data comparison for subclinical hyperthyroidism was done at the cut off level of treatment threshold (complete and partial thyroid stimulating hormone suppression subgroups). Seventy-five hyperthyroid patients were studied, 56% with overt hyperthyroidism. Cardiac morphology was slightly compromised with hyperthyroidism due to slight thickening of interventricular septal and left ventricular posterior wall thickness at diastole, thereby mildly increasing left ventricular mass, more pronounced in overt hyperthyrodism.
Systolic function parameters fractional shortening and ejection fraction were normal. Impaired left ventricular myocardial relaxation manifested as low early mitral peak E wave velocity, low E/A ratio and prolonged isovolumetric relaxation time was observed for most hyperthyroid patients, particularly in overt hyperthyroidism.
Abnormalities noted were comparable between the two groups of hyperthyroidism. Less affectation of cardiac morphology and function was observed in subclinical hyperthyroidism with partial TSH suppression. But interventricular septal thickness at diastole was comparable with overt hyperthyroidism. Hence, early treatment might be necessary for all subclinical cases.