| Cardiac effects | ||||||||
|---|---|---|---|---|---|---|---|---|
| Class | Examples | Mechanism | MRD | APD | ERP | AV conduction | Contractility | Uses |
| 1a | Quinidine / Procainamide / Disopyramide | Sodium channel blockade | -- | + | + | -- | - | Atrial and ventricular tachycardias |
| 1b | Lignocaine | Sodium channel blockade (fast dissoc.) | - | - | ++ | 0 | 0 | Post MI dysrythmias |
| 1c | Flecainide | Sodium channel blockade (slow dissoc.) | --- | 0 | 0 | -- | -- | Life-threatening ventricular tachycardias |
| 2 | Propranolol / Metoprolol | β-blockade | 0 | 0 | 0 | 0/- | -- | Stress-induced tachycardias |
| 3 | Amiodarone | Unknown | 0 | +++ | +++ | - | 0 | WPW/AF/VT |
| 4 | Sotalol / Verapamil | Calcium channel blockers | 0 | +++/-- | +++/0 | -/-- | --/--- | Atrial tachyarrythmias |
MRD - Maximum rate of depolarisation
APD - Actionpotential duration
ERP - Effective refractory period