Digoxin toxicity occurs when there is an excessive accumulation of digoxin in the body, often due to impaired renal function or interactions with other medications. It is clinically significant because it can lead to life-threatening arrhythmias, gastrointestinal symptoms, and neurological disturbances, necessitating careful monitoring of digoxin levels, especially in vulnerable populations. A key complication is the development of atrial fibrillation or ventricular tachycardia, which can be fatal if not promptly managed.