ABSTRACT
Background and Aim: The safety and efficacy of the antiarrhythmic agents, amiodarone, and digoxin, in patients with pulmonary hypertension (PH), is not described well in the literature, although their use is common practice. Our study aims to investigate the effect of these drugs on pulmonary arteries (PA) which may have implications for their use in patients with PH. Methods: Human PAs were obtained from consenting patients undergoing lobectomies. Arterials rings (n=40 from ten patients) were dissected form the tissue and mounted onto a multiwire myograph. The rings were preconstricted using prostaglandin F2α before the addition of additive dilutions of amiodarone and digoxin. Finally, the reagents were washed out and the arterial rings' viability was confirmed using acetylcholine and potassium chloride. Results: Amiodarone had a slightly vasodilatory effect on the arterial rings, whereas digoxin had a relatively neutral effect. Amiodarone caused the greatest vasodilatory response at 100 µM with an active tension of -0.494 gram force with an EC50 of 9.42 µM. Digoxin produced no significant vasodilatory or vasoconstrictive response. Conclusions: This study demonstrated the ex vivo effects of amiodarone and digoxin on human pulmonary arterial tension. The results of the study showed that neither amiodarone nor digoxin had any vasoconstrictive effects. Amiodarone also exhibited vasodilatory properties and, therefore, may be used preferentially as it could help reduce the impact of PH. However, more studies need to be conducted before we can confirm the safety of these drugs. Relevance for Patients: The ambivalence surrounding treatment of postoperative arrhythmias in patients with PH results is a significant disparity between individual cases. Our study takes the first step in elucidating, in which drugs may be a safer treatment for patients with the aim to resolve the doubts clinicians may have about using these treatments. The principal goal of our work is to ensure that we are providing patients with the most effective and, more importantly, safest treatment.