Arrhythmias Are Most Common Within Hours After Acute Myocardial Infarction

During the early phase of acute myocardial infarction (AMI), arrhythmias are most frequently observed within the first 24 hours after the onset of symptoms. A wide range of cardiac rhythm disturbances may occur, including ventricular premature contractions, atrial flutter, atrial fibrillation, ventricular tachycardia, and even life-threatening ventricular fibrillation. Coronary artery disease, which is both prevalent and progressive, can lead to severe complications such as myocardial infarction, which in turn can trigger various types of arrhythmias. The primary cause is myocardial ischemia, although heightened sympathetic nervous system activity also plays a significant role.

Reperfusion Therapy and Its Impact on Arrhythmias

Patients with acute myocardial infarction typically undergo reperfusion therapy, which includes intravenous thrombolysis, percutaneous coronary intervention (PCI), or coronary artery bypass grafting (CABG). Following the restoration of blood flow, a specific type of arrhythmia known as reperfusion arrhythmia can occur. These rhythm disturbances often appear during or immediately after procedures such as thrombolytic therapy or stent placement, when circulation is re-established. Reperfusion arrhythmias typically manifest within minutes to several hours after the restoration of myocardial blood flow.

Managing Arrhythmias Based on Risk Level

Low-Risk Arrhythmias

Clinical management of arrhythmias following a heart attack depends largely on the severity and hemodynamic impact. Low-risk arrhythmias generally require only continuous monitoring and do not necessitate immediate intervention unless symptoms worsen.

High-Risk Arrhythmias

In contrast, high-risk arrhythmias such as ventricular tachycardia, ventricular fibrillation, atrial flutter, and atrial fibrillation can significantly compromise blood circulation and require prompt treatment. Antiarrhythmic medications are often administered to stabilize the heart rhythm and prevent further deterioration. In some cases, implantation of a cardiac pacemaker may be necessary to manage bradyarrhythmias like sinus arrest or conduction block. These interventions can greatly improve the prognosis for patients experiencing arrhythmias as a complication of acute myocardial infarction.