Haemodynamic effects of encainide, flecainide, lorcainide and tocainide.
The haemodynamic effects of encainide, flecainide, lorcainide and tocainide in man are reviewed. Most of the investigations discussed are acute intervention studies after intravenous administration of the drugs. With all four drugs, haemodynamic changes, when present, were moderate. In most studies a decrease in left ventricular maximal dp/dt is demonstrated, suggesting a negative inotropic action. Left ventricular filling pressures are unchanged or slightly increased. A small decrease in cardiac performance, as determined by measurements of cardiac output and left ventricular ejection fraction, is usually observed, while systemic vascular resistance is increased or remains unchanged. Haemodynamic deterioration and/or hypotensive reactions after intravenous administration of any of the above drugs are uncommon in patients without severe cardiac dysfunction. Conclusions relative to drug safety in frank congestive failure are not warranted, in view of the small number of patients studied. While comparative studies between the drugs discussed have not been performed, the data presented here indicate that, on the basis of haemodynamic action, no one drug can be preferred above the other.