Background .– Carcinoid heart disease may occur in patients presenting with carcinoid tumor and carcinoid syndrome. Studies evaluating the echocardiographic follow-up of this specific population remain rare. The aim of this prospective study was to assess the natural history of cardiac involvement in patients presenting with carcinoid tumor and carcinoid syndrome.

Methods .– We studied 100 consecutive patients (48 men, 52 women) presenting with carcinoid tumor and carcinoid syndrome. All patients underwent annual transthoracic echocardiographic studies and biological carcinoid markers.

Results .– Mean age of our population was 60 ± 12 years (range 36 to 83). At baseline, prevalence of carcinoid heart disease was 31%, whereas at the end of follow-up (mean FU: 42 months), this prevalence was 52% ( P = 0.003). Correlations were strong between urinary 5-HIAA and severity score ( r = 0.90, P < 0.0001). A carcinoid heart disease was systematically found in all patients presenting with at least three years of carcinoid syndrome and increased level of urinary 5-HIAA. In patients without carcinoid heart disease, no occurrence of carcinoid heart disease was found after three years of conventional therapeutic strategy.

Conclusion .– Prevalence of carcinoid heart disease increases during follow-up. Carcinoid heart disease may progress over time, leading to perform annual echocardiographic follow-up.