This herb is regarded as one of the most significant natural remedies for heart disease in Western herbal medicine and is widely used in Europe due to its antihypertensive (blood pressure-lowering) and cardiotonic effects. This herb has been shown to improve blood flow and oxygen supply to the heart, enhance heart muscle contractions to improve cardiac efficiency, and reduce blood pressure and serum cholesterol levels. This herb has also been found to offer significant protection against the development of atherosclerosis. This herb has been used to treat a variety of disorders, including angina pectoris (severe constricting chest pain), arrhythmia (irregular heartbeat), hypertension (high blood pressure), and atherosclerosis (narrowing and hardening of the arteries). What is this herb?