Editor’s note: A 70-something relative of mine recently woke feeling so dizzy that she couldn’t walk or even sit up in bed. She phoned her son, a doctor, who told her to get to the ER stat. There she was diagnosed with a dangerously slow heartbeat, a condition called bradycardia.

A pacemaker fixed the problem, and my loved one is fine now—but her scare reminded me how truly vital a steady heartbeat is…and how much can go wrong with the heart’s rhythm. And even though some people think of heart problems as mostly affecting men, the fact remains that heart disease is a leading cause of disability and the number-one killer of women in the US. So I want to share with HealthyWoman readers an article on heart rhythm disorders that recently ran in Bottom Line/Personal, another newsletter in the Bottom Line family (to subscribe, please visit BottomLinePublications.com). Here is that special report…

Has your heart ever “skipped” a beat? Or have you noticed that your heart was racing or fluttering? Occasional irregularities in the heart’s rhythm, known as arrhythmias, generally are harmless for people without underlying heart problems. But some arrhythmias indicate a serious disruption in the heart’s electrical pathways.

Example: More than 325,000 Americans die from sudden cardiac arrest each year. The impulses that regulate the heartbeat become too rapid, too chaotic or both—and the heart simply stops.

What you need to know now about arrhythmia…

TRANSMISSION ERRORS

The heart beats in an on-off rhythm, a cycle that allows the heart to fill with blood and then pump the blood through the body.

How it works: Each heartbeat originates in the sinoatrial node, a cluster of cells in the atria, the top chambers of the heart. Signals from the sinoatrial node cause the atria to contract and pump blood into the ventricles beneath. When the ventricles are full, that electrical signal crosses over a “bridge” to the bottom chambers, causing them to contract and push blood outward into the body.

When you feel as though your heart has “skipped” a beat, what most likely has happened is that either the atria or the ventricles pulsed prematurely. These are premature atrial contractions (PACs) or premature ventricular contractions (PVCs). This type of arrhythmia may not cause symptoms and doesn’t need treatment—although anyone who gets it frequently should undergo testing to make sure that his/her heart is healthy.

Other common arrhythmias that can be more serious…

ATRIAL FIBRILLATION (AF)

This is the most common serious arrhythmia in adults. It is suspected that nearly 50% of patients either have no symptoms or aren’t bothered by the symptoms that they do experience.

What happens: Rather than producing a single, forceful beat, the atria “quiver” for a few minutes to more than an hour and can beat faster than 300 times a minute.

During these episodes, eddies of blood can cause a clot—the trigger of most strokes. Depending on other risk factors, the risk for a stroke in people with AF can be from 5% to 25% higher than in people without this condition.

Symptoms: Sensation of irregular or racing heartbeats…sometimes fatigue and shortness of breath.

Treatment: Anticoagulant therapy to lower the risk for stroke. A daily low-dose aspirin—81 milligrams (mg)—is enough for many patients. Those with a higher risk for stroke will need stronger anticlotting agents, such as warfarin (Coumadin) or dabigatran (Pradaxa). Other treatments…

Medications that slow the heart rate, including beta-blockers, such as propranolol (Inderal), or calcium-channel blockers, such as verapamil (Isoptin). Some patients may need stronger antiarrhythmics.

Cardioversion, an outpatient procedure in which surface electrodes shock the heart back into normal rhythm. This can restore a normal heartbeat for months or even years, especially if combined with antiarrhythmic medication.

Ablation therapy, in which one or more catheters are threaded through blood vessels into the heart. The tips of the catheters are positioned near the areas of the heart that are causing arrhythmias. Heat from the catheter tips destroys (ablates) small patches of heart tissue and blocks irregular electrical signals. Ablation therapy can reduce or eliminate arrhythmias in 70% to 80% of cases. The procedure, usually done under general anesthesia in a hospital, can take four to six hours.

BRADYCARDIA

This is an umbrella term that refers to a slow heartbeat. Anyone whose heart beats less than 60 times a minute has bradycardia, but this doesn’t always mean that he/she has a dangerous condition.

Example: Many healthy adults have a normal heart rhythm of 40 to 60 beats a minute—in athletes, the heart can beat as slowly as 30 times a minute. Bradycardia is a problem only when the heart beats so slowly that it causes symptoms.

Symptoms: Low blood pressure, dizziness, light-headedness, fatigue.

Drug side effects are the main cause of symptomatic bradycardia. This often happens when medications used to lower blood pressure, such as calcium-channel blockers or beta-blockers, slow the heart too much. Bradycardia also can be caused by a number of conditions, including inadequate levels of thyroid hormone, an electrolyte imbalance (such as low levels of calcium or magnesium) or kidney disease.

Treatment: A medication review. In some cases, patients need to stop taking certain medications, or take a lower dose, to see if the heart rate increases—this should be done only under a doctor’s supervision. Or patients may be prescribed medications that don’t have this effect (such as diuretics for hypertension).

Another option: A pacemaker, a device surgically implanted under the skin near the collarbone with electrodes that run to the heart. The pacemaker detects when the heart is beating too slowly and delivers a series of electrical signals that speed up the heart.

In cases where a medical condition is causing brachycardia, treating the underlying problem will correct the heart rate.

VENTRICULAR TACHYCARDIA/FIBRILLATION

These are among the most serious arrhythmias. When you hear that someone “dropped dead” from a heart attack, a ventricular tachycardia/fibrillation most often is the cause.

What happens: Electrical signals in the ventricles are so rapid and chaotic that the heart is unable to pump blood. Result: A rapid drop in blood pressure cuts off circulation to the brain and other organs. Patients will collapse within seconds—most will die without emergency treatment.

Many patients who experience these arrhythmias have underlying heart disease, damage from a previous heart attack or electrical and/or valve abnormalities that have a genetic origin.

Symptoms: Racing heartbeat, loss of consciousness.

Treatment: Call 911 immediately. If an automated external defibrillator (AED) is available, it should be used. This portable device analyzes the heart’s rhythm. If arrhythmias are present, the machine will instruct the operator to press a “shock” button. The heart rhythm will again be analyzed to determine if additional shocks are needed. The machine won’t deliver a shock if the heart rhythm is normal.

Patients with cardiac risk factors, including a previous heart attack, should ask their doctors if they should buy an AED.

If an AED is not available and the heart has stopped, cardiopulmonary resuscitation (CPR) should be done until an ambulance arrives. To learn how to do CPR, go to the American Heart Association Web site, www.Heart.org (put “CPR” in the search box).

Other treatment options: Patients who have survived a heart attack but have a weakened heart muscle may be advised to get an implantable cardioverter defibrillator (ICD), a device that continuously analyzes the heart and administers electrical shocks, as needed, to treat ventricular fibrillation. The procedure takes about an hour and often can be done on an outpatient basis.

In some cases, radiofrequency ablation can be helpful. Your doctor can decide what is right for you.

SUPRAVENTRICULAR TACHYCARDIA (SVT)

These originate in the area above the ventricles, causing a burst of rapid beats that begin suddenly and can last up to an hour. SVTs usually occur in young adults. They’re uncomfortable but rarely dangerous in people without other heart disorders.

Symptoms: Rapid heartbeat that starts and stops suddenly. It may be associated with dizziness, chest pressure and/or shortness of breath. Some people have no symptoms.

Treatment: Patients may be taught how to do a vagal maneuver, such as coughing or holding their breath while bearing down. This stimulates the vagus nerve and slows the electrical impulses that cause rapid beats. If that doesn’t work, radiofrequency ablation can eliminate the problem in most patients. Or patients may be advised to take a beta-blocker or other antiarrhythmic medications that will reduce the frequency of these episodes.