Final answer:
The correct intervention for decreasing myocardial irritability and automaticity in ventricular arrhythmias is administering an antiarrhythmic medication, including beta blockers and calcium channel blockers.
Step-by-step explanation:
To decrease myocardial irritability and myocardial automaticity, which are often involved in ventricular arrhythmias, the appropriate intervention is c) Administering an antiarrhythmic medication. These medications, such as beta-blockers (e.g., metoprolol and propanolol) and calcium channel blockers, are designed to manage or correct abnormal heart rhythms. Beta-blockers work by blocking the ß-receptors, which are associated with vasoconstriction and cardio acceleration, thus reducing blood pressure and helping to manage arrhythmias and angina. Calcium channel blockers reduce the strength of myocardial contractions and stroke volume. These interventions are vital in managing and treating a variety of cardiovascular conditions.