Background .– Carcinoid heart disease (CHD) may occur in patients presenting with carcinoid tumor and carcinoid syndrome. Studies evaluating the echocardiographic follow-up of these patients remain rare. The aim of this prospective study was to assess the progression of CHD.

Methods .– We studied 90 consecutive patients presenting with carcinoid tumor and carcinoid syndrome. All patients underwent annual transthoracic echocardiographic studies and biological carcinoid markers. We used a previous validated score of CHD severity.

Results .– At baseline, prevalence of right- and left-sided CHD was 32% and 8%, respectively, whereas at the end of follow-up (mean FU: 38 months), this prevalence was respectively 52% and 20%. Correlations were strong between urinary 5-HIAA and CHD score ( r = 0.86, P < 0.0001). All patients with at least 3 years of carcinoid syndrome and increased level of urinary 5-HIAA presented with echocardiographic evidence of CHD. Interestingly, after 3 years of echocardiographic follow-up of treated patients with carcinoid syndrome but without CHD, no patients developed CHD.

Conclusion .– Prevalence of CHD remains high and increases during follow-up. Carcinoid heart disease progresses over time, highlighting the need for echocardiographic follow-up once the diagnosis of carcinoid syndrome is made.