2018 Korean Heart Rhythm Society Guidelines for Antiarrhythmic Drug Therapy in Non-valvular Atrial Fibrillation

Focused Update of 2016 Korean Society of Heart Failure Guidelines for the Management of Chronic Heart Failure

The incidence of heart failure (HF) is increasing in South Korea and devising the optimal care plan is crucial to promote appropriate and effective treatment of HF. To this end, the first Korean guideline for management of chronic HF was published in 2016 by the HF research group under the Korean Society of Cardiology (KSC). After this publication, considerable data have been accumulated and a new guideline for the management of HF was published in Europe, and an update regarding pharmacological therapy was published in the United States, which made it warrant to update the Korean guideline. Under this premise, The Clinical Practice Guidelines Committee under the Korean Society of Heart Failure (KSHF) founded in 2018 decided to publish a focused update management guideline for chronic HF and selected 15 topics that need an update regarding the diagnosis, definition, diagnostic algorithm, monitoring, novel biomarkers, drug therapy related to non-vitamin K antagonist oral anticoagulants and angiotensin receptor neprilysin inhibitors, and with respect to comorbidities changes in the guidelines of relevant institutions, such as new guidelines for the management of hypertension, a procedure used to treat severe aortic stenosis, information on sodium glucose co-transporter-2 inhibitor, and that about sleep apnea. Among nonpharmacological therapies, changes to the recommendations for implantable cardioverter defibrillator, cardiac resynchronization therapy, and cardiac rehabilitation were updated. Subsequent and continuous updates based on additional clinical research findings, with continual supervision by the KSHF will be needed.

Inhibition of voltage-dependent K+ current in rabbit coronary arterial smooth muscle cells by the class Ic antiarrhythmic drug propafenone

In this study, we demonstrated the inhibitory effect of the Class Ic antiarrhythmic agent propafenone on voltage-dependent K⁺ (Kv) channels using freshly isolated coronary artery smooth muscle cells from rabbits. The Kv current amplitude was progressively inhibited by propafenone in a dose-dependent manner, with an apparent IC₅₀ value of 5.04±1.05 µM and a Hill coefficient of 0.78±0.06. The application of propafenone had no significant effect on the steady-state activation and inactivation curves, indicating that propafenone did not affect the voltage-sensitivity of Kv channels. The application of train pulses at frequencies of 1 or 2 Hz progressively increased the propafenone-induced inhibition of the Kv current. Furthermore, the inactivation recovery time constant was increased after the application of propafenone, suggesting that the inhibitory action of propafenone on Kv current is partially use-dependent. Pretreatment with Kv1.5, Kv2.1 or Kv7 inhibitor did not change the inhibitory effect of propafenone on the Kv current. Together, these results suggest that propafenone inhibits the vascular Kv channels in a dose- and use-dependent manner, regardless of Na⁺ channel inhibition.