Study objective - The aim of the study was to assess the cardiovascular effects of human calcitonin gene related peptide (CGRP) in patients with congestive heart failure. Design - The effects of CGRP II (or β), 12.5 μg·h−1, given by intravenous infusion for 24 h to digitalised patients with congestive heart failure, were assessed by measurement of cardiac functional indices. Patients - Five patients (four female) were studied. Age was 73-82 years. Three were in New York Heart Association phase III and two in phase IV. Measurements and main results - The pre-ejection period to left ventricular ejection time ratio and the QT distance adjusted for heart rate were lowered by 21% and 4% respectively. The left ventricular shortening index was raised by 43%. The arterial pressure and heart rate did not change consistently. Conclusion - Calcitonin gene related peptide improves myocardial contractility in patients with congestive heart failure. This is the first time this has been show