Coronary heart disease is the most common cause of sudden cardiac death, known as SCD. Dangerous changes in heart rhythm called arrhythmias can be caused by coronary heart disease. Sometimes these changes cause the heart to beat too fast or too slow. When the rhythm of the heart changes, it can lead to lethal conditions called ventricular tachycardia or ventricular fibrillation. If these abnormal rhythms are not treated immediately, they can lead to death.
CHD can also cause the heart to stop beating altogether. This is called cardiac arrest or asystole. If the heart is not started again quickly, cardiac arrest will cause death.