Histologic findings in a dilated atrium serving as a Fontan pathway for 23 years

We microscopically examined atrial tissues surgically obtained from a 35-year-old woman who had been palliated with the atriopulmonary connection in a Fontan operation 23 years earlier. Apart from mild hypertrophy of myocytes and trivial interstitial fibrosis, no gross abnormalities were identified. Although this finding is somehow surprising, considering the duration of atrial pressure-loading, it seems to be in accordance with the result of her Holter recordings, which demonstrates the absence of any rhythm disturbances other than sporadic premature contractions. Because of the shortage of histologic investigations in this group of patients, we present this case with a review of the literature.