Final answer:
Sodium bicarbonate is used to manage cardiotoxic effects induced by TCA overdose, specifically QRS widening or ventricular arrhythmias. It works by alkalizing the blood to overcome the sodium channel blockade, and is recommended when ECG changes or arrhythmias are present.
Step-by-step explanation:
Sodium bicarbonate is the most effective agent for managing TCA (tricyclic antidepressant) induced cardiotoxic effects, such as QRS widening or ventricular arrhythmias.
The cardiotoxic effects can be severe and may include negative inotropic actions and arrhythmogenesis. These cardiotoxic effects are often a result of inhibition of fast sodium channels by the TCA.
While negative inotropic agents, such as beta blockers and calcium channel blockers, generally decrease the strength of heart muscle contraction and stroke volume (SV), they are not indicated in the case of TCA overdose. In fact, the use of these medications might exacerbate the cardiotoxic effects.
Sodium bicarbonate works by alkalizing the blood, which helps to overcome the sodium channel blockade induced by TCAs, and can mitigate cardiac symptoms by narrowing the QRS complex and suppressing ventricular arrhythmias.
The administration of sodium bicarbonate is typically recommended in symptomatic patients with a noticeably widened QRS complex (>100ms) or ventricular arrhythmias resulting from TCA overdose.