Most of us don’t think twice about the steady beating of our hearts. But if the heart misses a beat or takes off racing, the result can be uncomfortable.
An occasional extra beat can be harmless and cause few to no symptoms. A racing heart can cause someone to feel lightheaded and short of breath, or have pain in his or her chest. Some people notice that their heartbeats seem to flutter.
Millions of people have some sort of rhythm disturbance in their heartbeats, known as arrhythmia. The condition occurs most often in people older than 60. The first step for most people is to see a doctor, who can sort out whether the irregular heartbeat is harmless or warrants medical treatment.
“Cardiovascular Disorders Sourcebook” (Omnigraphics, 2010) is an electronic book that provides clear and well-organized information about heart rhythm disorders for the general public. Available at no charge through the Stanford Health Library website, the book describes the causes of heart arrhythmias and whether they pose a risk to heath.
Heartbeats are controlled by the heart’s internal electrical system, which sends electrical signals from the top of the heart to the bottom. Those signals cause the heart to contract and pump blood to the rest of the body.
Disturbances can occur when special nerve cells that produce the electrical impulses don’t work properly, or when electrical signals don’t travel properly through the heart. Smoking, excessive drinking, drugs such as cocaine and amphetamines, or prescription medicine can lead to arrhythmias – as can too much caffeine. Strong emotional anger or stress also can trigger heart changes that lead to arrhythmias.
When the heart’s electrical signals are disrupted, that can cause irregularities in heartbeat. Rhythm disorders usually fall into four types:
• Premature (extra) beats, the most common, which are usually harmless.
• Supraventricular arrhythmias, which can cause the heart to race, and include ventricular arrhythmias, the most common serious arrhythmia.
• Ventricular arrhythmias, the racing beats that can be very dangerous.
• Bradyarrhythmias, which are unusually slow heartbeats that can be serious.
Depending on the cause of the rhythm disturbance, treatment may involve medicine, implanting a pacemaker, removing faulty heart tissue or, in emergencies, shock therapy.
A second book, “Arrhythmias 101” (Jaypee Brothers Medical, 2013), delves into the technical details of the various rhythm disturbances for doctors, nurses and others who want to know more.
You will find these books and many more on the shelves of Stanford Health Library. Electronic books are also available in our collection, accessed through the library website at healthlibrary.stanford.edu/resources/ebooks.html. Using the login and password available on the main screen, click the blue “EBSCO Host” button and enter the login and password.
The main branch of Stanford Health Library is located at Hoover Pavilion, 211 Quarry Road Suite 201, Palo Alto. Hours are 9 a.m. to 5 p.m. weekdays. Other locations include Stanford Cancer Center in Palo Alto, the Ravenswood Family Health Center in East Palo Alto and Stanford Cancer Center South Bay in San Jose.
Donna Alvarado is health library specialist at Stanford Health Library. For more information, call 725-8400 or visit healthlibrary.stanford.edu.