Diagnosed With a Heart Arrhythmia? Seniors are vulnerable to several abnormal heart rhythms.
What Causes Heart Arrhythmias? Each contraction of your heart is controlled by an electrical signal that originates in a group of cells called the sinus node (see image). The signal spreads through the atria (the upper chambers of the heart), making them contract and pump blood into the ventricles (the lower chambers). The signal then travels through a group of cells called the atrioventricular (AV) node, pausing briefly so the ventricles can fill with blood before continuing and stimulating the ventricles to contract and pump blood from your heart to your body.
This regular heart rhythm is called a normal sinus rhythm. It ensures that your resting heart rate (the number of times per minute your heart beats while you are at rest) stays around 60 to 100 beats per minute (bpm), with each beat the result of a new electrical signal. However, it's possible for your heart's electrical conduction system to be disrupted, and this can cause your heart to beat too fast (tachycardia) or too slow (bradycardia).
Structural problems in the heart are a common cause of disruption. "For example, scarring from a previous heart attack may prevent the electrical signal that controls your heart rate from traveling along the correct pathway," Dr. Darrow explains. "Coronary artery disease, abnormal heart valves, heart disease, and heart failure also make you vulnerable to arrhythmias, as does heart surgery."
Other risk factors include an electrolyte imbalance (electrolytes include potassium, magnesium, and calcium, and a correct balance is vital for controlling your heart rhythm), high blood pressure, diabetes, sleep apnea, thyroid issues, lung diseases, and stress. External factors also increase your risk--for example, smoking, excessive alcohol and/or caffeine intake, and certain medications. "However, sometimes heart arrhythmias can occur without any obvious underlying cause," Dr. Darrow adds. "They also can occur without symptoms."
Tachycardia This is defined as a heart rate of more than 100 bpm. Examples of tachycardia include:
* Sinus tachycardia This is a rapid heart rhythm that stays regular, with no palpitations or skipped beats. Sinus tachycardia is typically a response to overexertion, stress, fever, and/or dehydration, but it also can happen due to heart failure, an overactive thyroid, or chronic obstructive pulmonary disease, among others.
* Atrial fibrillation (Afib) This causes the atria to quiver erratically instead of beating in synchrony with the ventricles. Along with a racing heartbeat, possible symptoms include palpitations, breathlessness, dizziness, and faintness--however, some people have no symptoms. Afib isn't life threatening if properly treated, but uncontrolled (fast) Afib can eventually weaken the heart, and lead to heart failure. "It also can result in blood pooling in the atria and forming clots," says Dr. Darrow. "If a clot travels from the heart to the brain, a stroke can occur--in fact, people with Afib are four to five times more likely to have a stroke."
* Atrial flutter This is closely related to Afib, and can occur alongside Afib. "As with Afib, it can cause a stroke," Dr. Darrow observes. "However, like Afib it isn't life threatening if treated."
* Ventricular tachycardia (Vtach) In Vtach, abnormal electrical impulses occur in the ventricles, preventing them from filling with blood before the heart contracts. This means that not enough blood is pumped out to the body. If symptoms occur, they may include a racing heartbeat and chest pain. "Vtach can be a medical emergency in itself, and can develop into ventricular fibrillation if it isn't treated," Dr. Darrow says.
* Ventricular fibrillation (Vfib) This causes the ventricles to quiver erratically. It is less common and more serious than Afib. "Without immediate treatment to stabilize the heart rate, cardiac arrest and death may occur," Dr. Darrow says.
Bradycardia Bradycardia is defined as a heart rate that is less than 60 bpm, and it can reduce the amount of oxygen-rich blood being pumped to the body. Bradycardia is typically caused by medications or by a heart block (in which the heart's electrical signals are delayed or blocked between the atria and ventricles). The symptoms may include fatigue, weakness, shortness of breath, dizziness, confusion, and loss of consciousness. "If bradycardia is untreated, you may begin to experience excessively high or low blood pressure, chest pain, and/or heart failure," Dr. Darrow says.
Medication to Stabilize the Heart
A heart arrhythmia that is caused by an underlying non-cardiovascular condition should resolve if the underlying condition is treated, while an arrhythmia stemming from a problem in the heart may not need treatment if it isn't causing significant symptoms. "In people who do need treatment, the treatment depends on the specific type of arrhythmia, and how it affects heart function," Dr. Darrow says.
For patients with Afib, atrial flutter, or Vtach, anti-arrhythmia medications are often the first-line option. "The drugs prevent abnormal activity in the sinus node, or slow or block the transmission of electrical impulses through the AV node," Dr. Darrow explains. "They can cause side effects, and you may need to try several before you find the one that works best for you." In the case of Afib or atrial flutter, your doctor also may prescribe a blood thinner to reduce your risk of stroke.
Other Treatment Approaches Afib and atrial flutter that don't respond to drugs may be treated with a procedure called cardioversion, in which the abnormal rhythm is reset using a mild electrical shock delivered via paddles or electrode patches placed on your chest. A more permanent fix, however, is catheter ablation, which also can be used to treat Vtach. In this procedure, a catheter is inserted through a vein in the groin or neck, and threaded through the vein to the area of heart tissue that is disrupting your heart's electrical signal. The catheter emits radio waves that burn (ablate) this area of the heart so the electrical signals can travel along a normal pathway.
Symptomatic bradycardia may lead your doctor to recommend a pacemaker, a small implantable device that generates electical pulses when necessary to help control your heart rate. Vtach and Vfib also may be treated with a pacemaker, or an implantable cardioverter defibrillator (ICD). An ICD is essentially one step up from a pacemaker, and delivers a mild-to-moderate electrical shock to reset the heart if a serious arrhythmia is detected. "All ICDs can function as pacemakers, and in some cases the electrodes are programmed to stimulate the heart in order that the atria and ventricles contract in synchrony," Dr. Darrow says.
Vital to Control Your Risk Factors If you are diagnosed with a heart arrhythmia it's important to follow through on lifestyle modifications that can protect your cardiovascular health. Consume a healthy Mediterranean-style diet that prioritizes fruits, vegetables, whole grains, and lean protein, since this can help protect against risk factors that may contribute to abnormal heart rhythms. Also get plenty of exercise. Don't assume that exercise will aggravate your arrhythmia--most people with arrhythmias benefit from exercise as long as their heart rate doesn't get too fast. "Clarify with your cardiologist how intensely you should exercise, how fast your heart rate should be while engaged in physical activity, and what to do if your heart rate speeds up too much while you're exercising," Dr. Darrow advises.
Caption: Each contraction of your heart is controlled by an electrical signal that starts in the sinus nock and spreads through the atria and ventricles.
Caption: Most people with heart arrhythmias benefit from exercise.
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|Publication:||Focus on Healthy Aging|
|Date:||Jul 1, 2018|
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