Soňa Kiňová, Michal Koreň
Neuroendocrine tumours are among the tumours with low incidence but with relatively high prevalence due to long
term survival of patients with well-differentiated tumours. They occur most often in the gastrointestinal tract, and
about 25% of these tumours are localized in the respiratory tract. They may exceptionally be localized in virtually all
organs. The clinical presentation is modified by local manifestations of the tumour, however typical symptomatology
is that arising from hormonal overproduction such as a carcinoid syndrome. An excess in hormones may also influence
the cardiovascular system. These influence the heart frequency, myocardial contractility, vascular tonus, intravascular
volume, and thus also blood pressure. They also affect the balance of minerals, and especially changes in plasmatic levels
of potassium, calcium and magnesium can contribute to severe cardiac arrhythmias. A long-term overproduction
of serotonin leads to fibrotic changes in the endocardium and the development of damage to valves predominantly in
the right heart. This leads to the carcinoid heart disease. Therefore, when examining patients with cardiac disease we
have to apply differential diagnosis and take into consideration also a possible endocrine disease, which causes acute
cardiovascular problems or leads to the worsening of the pre-existing problems. The treatment is complex and includes
surgical resection of the tumour and metastases. In serotonin overproduction treatment we administer somatostatin
analogues. Their suppressive effect on the production of hormone-active substances decelerates the development of
damage to the endocardium and the heart valves. In case of severe damage to the valves we indicate their replacement.