Felodipine in ventricular dysfunction

The systemic and coronary haemodynamic effects of felodipinewere evaluated at rest and during stress induced atrial pacingin fourteen patients with chronic cardiac failure, secondaryto coronary heart disease. Felodipine was an effective arteriolarvasodilator producing increases in cardiac index from 2.6 ±0.l to 3.5 ± 0.2 l min^–1 m^–2 (P<0.001)and stroke volume 35.3 ± 2.7 to 41.4 ± 2.4 mlbeat^–1 m^–2 (P<0.002). Coronary venous flow also increased significantly (126 ±8 to 168 ± 13 ml min^–1) (P<0.005) and this didnot appear to be accompanied by an increase in myocardial oxygenusage, as myocardial oxygen consumption was essentially unchanged.When the myocardium was stressed by atrial pacing the increasein cardiac output and stroke volume was maintained—25%and 23%, respectively (P<0.01). These results suggest thatfelodipine may well have a significant role in the managementof patients with congestive cardiac failure.     

The systemic and coronary haemodynamic effects of felodipine in patients with coronary heart disease

The cardiovascular effects of felodipine, a new arteriolar vasodilator,were studied in 22 patients with coronary heart disease. Therewere significant falls in blood pressure and systemic vascularresistance of 16 and 38% respectively (P = 0.001), thus affectingafter-load. Cardiac index and stroke index increased by 35 and12% respectively. There was reflex tachycardia-from 75 ±3to 85 ±3 b.p.m. (P =0.005). Coronary sinus blood /lowincreased from 134±9 to 191 ±17 ml/min (P<0.005)and myocardial arterio- venous oxygen difference narrowed from12.l±0.5 to 9.0±0.4 vols% (P<0.001) indicatingless oxygen usage. With the heart rate held constant by atrialpacing, cardiac index and stroke index increased by 30 and 26%(P<0.001), whilst systolic blood pressure and systemic vascularresistance fell by 20 and 29% (P<0.001). This would suggestthat the improved haemodynamics were largely secondary to after-loadreduction.     

The influence of arm position and cardiac output on bolus clearance from the arm

The importance of arm position and cardiac output on the clearance of a bolus injection from the arm was assessed in 63 patients using technetium-99m. Injections were made in the left arm which was either adducted, abducted or adducted with the forearm flexed over the lower chest. The clearance of isotope was assessed by measuring the amount of radioactivity remaining in the arm at 10 s intervals and calculating it as a fraction of the injected dose. The clearance of Tc-99m was significantly faster and more complete from the abducted arm than from the adducted arm. There was no correlation between clearance and cardiac output.