The Sound of Evolution
Quinidine
Mechanism of action:
Quinidine is an epimer of quinine. Quinidine blocks fast voltage-gated sodium channels, suppressing the phase 0 depolarization rate in cardiac myocytes and slowing conduction velocity, particularly in the atria, ventricles, and Purkinje fibers. Quinidine also inhibits potassium channels, reduces potassium efflux, and thereby prolongs action potential duration and the effective refractory period.
Reference(s):
1. Yang F et al. (2009). Quinidine revisited. Am J Med.
2. Vitali Serdoz L et al. (2019). Quinidine-A legacy within the modern era of antiarrhythmic therapy. Pharmacol Res.
3. Priori SG et al. (2013). HRS/EHRA/APHRS expert consensus statement on the diagnosis and management of patients with inherited primary arrhythmia syndromes: document endorsed by HRS, EHRA, and APHRS in May 2013 and by ACCF, AHA, PACES, and AEPC in June 2013. Heart Rhythm.