A 40-year old female was admitted with complaints of general
fatigue and dyspnoea brought on by effort. There were
edema on the face, a diffuse and slightly hard
goiter on the neck and non-pitting
edema in the lower legs. Laboratory findings showed low levels of serum T3 (0.37 ng/ml) and T4 (2.0 micrograms/dl), a very high level of serum TSH (549.8 microU/l), positive thyroid test (x 400) and positive microsome test (x 102,400). The chest roentgenogram showed an enlargement (CTR 62%) of the cardiac silhouette in the shape an
ice bag, and the electrocardiogram revealed low QRS voltage with T-wave flattening in all leads. Remarkable
pericardial effusion was shown on the two-dimensional echocardiogram. Judging from the indications of
hypothyroidism, positive antithyroid antibody and
pericardial effusion. This patient was diagnosed as having
myxedema heart due to
chronic thyroiditis. The levels of plasma
alpha-hANP did not elevate so much as the levels in normal controls after right atrial (RA) pacing, although mean right atrial pressure was higher than in normal controls after RA pacing. The levels of plasma
alpha-hANP after RA pacing in euthyroid state were higher than those in hypothyroid state. The levels of plasma
alpha-hANP after RA pacing became higher after the administration of
ATP or db-cAMP both in euthyroid and hypothyroid states. These results indicate that the impaired
alpha-hANP secretion in
myxedema heart is improved by the administration of
thyroxine,
ATP or db-cAMP.