Good cardiac doctors in yelahanka What is the main cause of cardiac arrest? Cardiac Arrest - What Is Cardiac Arrest? | NHLBI, NIH The main cause of cardiac arrest is ventricular fibrillation or ventricular tachycardia, which are types of arrhythmias. Important risk factors include prior cardiac arrest, coronary heart disease, heart valve disease, congenital heart defects, and arrhythmias caused by faulty genes .