62 2 The Heart in Myxedema 



Comment and Subsequent History 



Although the enormous pericardial effusion disappeared before thyroid ther- 

 apy was begun it seems clear that this effusion, as well as the pleural effusion, 

 ascites, atony of bladder, and constipation ("lazy bowel of myxedema"), were 

 all dtie to hypothyroidism. On two occasions after dismissal myxedematous 

 signs and symptoms returned when this man voluntarily quit taking desic- 

 cated thyroid tablets and disappeared again when thyroid therapy was re- 

 sumed. The changes in the electrocardiograms in relation to the changes in 

 basal metabolic rate can be followed in table 2. Changes in heart size in rela- 

 tion to basal metabolic rate and other pertinent data can be followed in table 3. 

 Selected electrocardiograms are shown in figures 1 to 3. Since thecardiothoracic 

 ratio is quite unreliable, the observed width of the heart shadow is given and 

 also the percentage deviation from the estimated average diameter of the 

 heart as calculated from Ungerleider's table. Since table 3 carries no figures 

 for hearts more than 25 per cent above estimated average size, plus signs have 

 been added to indicate deviations greater than 25 per cent. 



The rapidity of the disappearance of a very large pericardial effusion with 

 the use of Salyrgan, the rapid adjustment of a much dilated pericardial sac 

 to the diminution in bulk of its contents, and the small size of the heart as 

 shown by the X ray on 2-4-35 (^g- 3) '^^^ worthy of comment. On this date 

 (2-4-35), when the pericardial effusion had disappeared and the cardiac shadow 

 was normal in size, the heart sounds were audible though quiet and there 

 were no murmurs. 



Although thyroid therapy was begun on 2-9-35, ^h^ width of the "cardiac" 

 shadow increased steadily until 2-27-35, doubtless due to a return of the effu- 

 sion and not to an increase in heart size. 



The small amount of pitting edema of the face was partly due to increased 

 pressure in the superior vena cava from the obstructive effect of the increased 

 intrapericardial pressure. The dullness at the base of the left lung behind was 

 due to a small pleural effusion and possibly also to compression of the left 

 lung by the increased size of the pericardial contents (Ewart's sign). The acute 

 cardiohepatic angle on the right in the X ray was due to the fixed attachment 

 of the pericardium to the diaphragm inferiorly and the wider displacement 

 of the side walls of the pericardium by the large amount of contained peri- 

 cardial fluid ("water-bottle" heart shadow). The swelling of the feet was due 

 to increased venous pressure in the inferior vena-caval system from the in- 

 creased intrapericardial pressure and to downward displacement of liver and 

 obstruction of the hepatic vein (Elias and Feller^"''^). The underlying disturb- 

 ance of water metabolism characteristic of myxedema was fundamentally re- 

 sponsible for water retention. 



The absence of pulmonary edema was perhaps due to interference by the 

 pericardial effusion with venous filling and the consequent small cardiac out- 

 put. Unfortunately, venous pressure determinations were not made before 



