In which case is synchronized cardioversion primarily indicated?

Synchronized cardioversion is primarily indicated in cases of unstable atrial flutter. This procedure is designed to restore normal heart rhythm when a patient experiences tachyarrhythmias that compromise hemodynamics. In situations where atrial flutter causes symptoms such as hypotension, altered mental status, or signs of shock, immediate intervention is crucial due to the potential for serious complications.

In the context of unstable atrial flutter, synchronized cardioversion helps convert the abnormal rhythm effectively while minimizing the risk of causing further complications, such as inducing ventricular fibrillation. This is especially important because unstable conditions can deteriorate quickly, and timely management is required to stabilize the patient.

While stable atrial fibrillation may be treated with medications and does not require immediate electrical intervention, conditions like ventricular fibrillation are managed with unsynchronized defibrillation rather than synchronized cardioversion. First-degree heart block generally does not necessitate such interventions, as it is usually not associated with acute instability or significant symptoms that warrant cardioversion.