Related Experiment Video
Updated: Feb 7, 2026

Visualizing the Beating Heart in Drosophila
Published on: September 28, 2009
The Beat Goes On: The Story of Five Ageless Cardiac Drugs
1Department of Medicine, Upstate Medical University, State University of New York, Syracuse, New York.
Abstract:
This article traces the history of 5 cardiac drugs-Aspirin, Atropine, Digitalis, Nitroglycerine, and Quinidine-that have been in continuous use for centuries and some for longer. Four of the 5 started life as botanicals and 4 have as also served widely varied functions far removed from their current purposes. Collectively, they have played a role in the history of royalty, religious leaders, assassinations and military campaigns in addition to their place in medical therapy. Their present clinical status has evolved from long-term clinical observation without the need for controlled clinical trials, detailed statistical analyses or FDA approvals. This review of their background illustrates the varied means by which markedly different substances from widely separated sources can come together to participate in the management of circulatory disorders.
Related Concept Videos
Beats
Cardiac Output II: Effect of Stroke Volume on Cardiac Output
Preload
Preload refers to the initial elongation of the cardiac myocytes before contraction and is related to the volume of blood filling the heart at the end of diastole, or end-diastolic volume. The...
Cardiac Output I:Effect of Heart Rate on Cardiac Output
Cardiac output (CO) refers to the total amount of blood ejected by one of the ventricles in liters per minute (L/min). In a resting adult, CO ranges from 5 to 6 L/min, adjusting according to the body's metabolic requirements.
Effect of Heart Rate on Cardiac Output
Cardiac output adapts to metabolic demands during stress, physical activity, or illness. The autonomic nervous system regulates heart rate via the sinoatrial node. The parasympathetic nervous system decreases heart...
The Cardiac Cycle
The Process
Electrical signals—sent from the sinoatrial (SA) node in the right atrial wall to the atrioventricular (AV) node between the right atrium and right ventricle—cause both atria to simultaneously contract. When the signal reaches the AV node, it pauses for approximately a tenth of a second, allowing the atria to contract and...
Cardiac Cycle
During the cardiac cycle, blood flow through the heart is regulated entirely by changing pressure gradients. This sequence of events begins with the heart in a state of total relaxation, known as mid-to-late diastole, during which blood passively flows from...
Exercise and Cardiac Output
Sustained exercise increases the muscles' oxygen demand, which can be...

