Prognostic value of heart rate variability analysis in patients with carcinoid syndrome

Background/Aims: Recently, a decrease in heart rate variability measures wa s found in patients with carcinoid syndrome suffering from carcinoid heart disease compared to those without cardiac involvement of carcinoid syndrome . The prognostic relevance of this finding, however, was not clear. Patients and Methods: Therefore, 35 patients with carcinoid syndrome (21 me n, age 56 +/- 11 years), all of them suffering from metastatic carcinoid tu mors, were followed prospectively at our institution. Digital 24-hour Holte r monitoring, echocardiography, and serum serotonin and urine 5-hydroxyindo le acetic acid (5-HIAA) samplings were performed in all study patients at b aseline. Indices of time domain heart rate variability obtained from Holter recordings included the standard deviation of all normal RR intervals (SDN N) representing overall variability, the square root of the mean of the squ ared differences between adjacent normal RR intervals (rMSSD), and the perc entage of the number of pairs of adjacent normal RR intervals differing by >50 ms (pNN50), both indices reflecting predominantly vagal influences on h eart rate. Results: During a mean follow-up of 18 +/- 7 months, 15 of 35 patients with carcinoid syndrome (43%) died. Patients with cardiac manifestation of the carcinoid syndrome showed a tendency towards an increased mortality in comp arison to patients without cardiac involvement (p = 0.09). Patients with th e combination of decreased heart rate variability (SDNN < 100 ms) a nd pres ence of carcinoid heart disease had a significant worse prognosis (p = 0.04 ) com pa red to patients without carcinoid heart disease and preserved hear t rate variability(SDNN <greater than or equal to> 100 ms). Conclusions:The presence of carcinoid heart disease in combination with dec reased heart rate variability is associated with the most adverse prognosis in the setting of carcinoid syndrome. Copyright (C) 2001 S. Karger AG, Bas el.