In deciding on a treatment for a 60 years old patient, Golu, who has chronic hea disease and rheumatoid ahritis, you wish to give him procainamide. He is already taking digoxin, hydrochlohiazide and potassium supplementation. Which of the following is a relevant statement?
(Ref: KDT 6/e p512) Hyperkalemia increases the toxicity of class Ia antiarrhythmics.