Study objectives: Congenital malformations of
the right atrium (RA) and the coronary sinus (CS) are rare, and only
sporadic cases have been reported. Little is known about the clinical
relevance of this disorder. We report on two patients, one with a giant
RA diverticulum, the other with a diverticulum of the CS, and review
103 cases of such malformations that have been reported
Design: A MEDLINE search was performed to
collect all cases of congenital malformations of the RA and the CS
reported in the literature between 1955 and 1998. Cases were classified
into the following categories: (1) congenital enlargement of the RA;
(2) single diverticulum of the RA; (3) multiple diverticula of the RA;
and (4) diverticulum of the CS. Clinical presentation and outcome of
the different types of malformations were analyzed.
Results: The patients most frequently presenting with
symptoms were those with diverticula of the CS (n = 28) followed by
those with single diverticula of the RA (n = 13), multiple
diverticula (n = 4), and congenital enlargements of the RA
(n = 60). The percentages of symptomatic patients were 93, 84, 75,
and 53%, respectively. Symptoms were frequently caused by arrhythmias.
Supraventricular tachycardia (SVT) was found in 42 of the patients
(40%) and was most common in patients with diverticula of the CS (24
of 28 patients) and multiple atrial diverticula (3 of 4 patients).
Sudden cardiac death was reported more frequently in patients with
diverticula of the CS (18%) compared to those with congenital
enlargement of the RA (5%) or single or multiple diverticula of the RA
(6%). All seven patients with diverticula of the CS who were not
treated with catheter or surgical ablation eventually died.
Conclusion: Congenital malformations of the RA and the CS
frequently are associated with arrhythmias. SVT and sudden cardiac
death have been reported in a significant percentage of patients with
diverticula of the CS.