Types of Heart Beat

[Extracted from the webpage of www.dilseindia.org]

Slow Heart Beat or Bradycardia

Slow Heart Beat or in medical terms called Bradycardia means that your heart beats very slowly. When the heart beats slower, then the body does not receive the optimum blood and can prove to be fatal for the patient. For most people, a heart rate of 60 to 100 beats a minute, while at rest, is considered normal. If your heart beats less than 60 times a minute, your doctor may diagnose bradycardia. In other people, bradycardia is a sign of a problem with the heart’s electrical system. It means that the heart's natural pacemaker is not working right or that the electrical pathways of the heart are disrupted. In severe forms of bradycardia, the heart beats so slowly that it does not pump enough blood to meet the body's needs. This can be life-threatening. Slow Heart Beat or Bradycardia can be caused by : Changes in the heart that are the result of aging. Diseases that damage the heart's electrical system These include : coronary artery disease heart attack infections such as endocarditis and myocarditis. Conditions that can slow electrical impulses through the heart. Examples include having a low thyroid level (hypothyroidism) or an electrolyte imbalance, such as too much potassium in the blood. Some medicines for treating heart problems or high blood pressure, such as beta-blockers, antiarrhythmics, and digoxin

What are the symptoms ?

A very slow heart rate may cause you to : Feel dizzy or lightheaded. Feel short of breath and find it harder to exercise. Feel tired. Have chest pain or a feeling that your heart is pounding or fluttering (palpitations). Feel confused or have trouble concentrating. Faint, if a slow heart rate causes a drop in blood pressure.

How is bradycardia diagnosed ?

Your doctor may be able to diagnose bradycardia by doing a physical exam, asking questions about your past health, and doing an electrocardiogram (EKG or ECG). An EKG measures the electrical signals that control heart rhythm, so it is the best test for bradycardia. But bradycardia often comes and goes, so a standard EKG done in the doctor’s office may not find it. An EKG can identify bradycardia only if you are actually having it during the test.

How is it treated ?

How bradycardia is treated depends on what is causing it. Treatment also depends on the symptoms. If bradycardia does not cause symptoms, it usually is not treated. If damage to the heart’s electrical system causes your heart to beat too slowly, you will probably need to have a pacemaker. A pacemaker is a device placed under your skin that helps correct the slow heart rate. People older than 65 are most likely to have a type of bradycardia that requires a pacemaker. If another medical problem, such as hypothyroidism or an electrolyte imbalance, is causing a slow heart rate, treating that problem may cure the bradycardia. If a medicine is causing your heart to beat too slowly, your doctor may adjust the dose or prescribe a different medicine. If you cannot stop taking that medicine, you may need a pacemaker. The goal of treatment is to raise your heart rate so your body gets the blood it needs. If severe bradycardia is not treated, it can lead to serious problems. These may include fainting and injuries from fainting, as well as seizures or even death. **************************************************** Fast Heart Beat or Tachycardia Tachycardia is a fast or irregular heart rhythm, usually more than 100 beats per minute and as many as 400 beats per minute. At these elevated rates, the heart is not able to efficiently pump oxygen-rich blood to your body causing dizziness, lightheadedness, or a fluttering in the chest. It can occur in either the upper heart chambers (atrial tachycardia) or lower heart chambers (ventricular tachycardia). There are many types of tachycardia, but the most common and most severe form of tachycardia is ventricular tachycardia. What causes Tachycardia ? high blood pressure or hypertension poor blood supply to the heart muscle due to coronary artery disease (atherosclerosis) heart valve disease heart failure heart muscle disease (cardiomyopathy) tumors or infections other medical conditions such as thyroid disease certain lung diseases electrolyte imbalance alcohol or drug abuse Emotional stress or drinking large amounts of alcoholic or caffeinated beverages Nervousness Anxiety High Blood Pressure Congestive heart failure Prior heart attack Asthma Anemia Panic attack Panic disorder Potassium deficiency Vitamin B deficiency Excessive dieting What are the symptoms ? Shortness of breath Dzziness and fainting due to the interruption of blood flow to the brain Sudden weakness Fluttering in the chest Lightheadedness Fainting How is Tachycardia diagnosed ? In diagnosing tachycardia, the patient may be asked about the presence of or tested for conditions that may trigger tachycardia, such as heart disease or a thyroid problem. Treatment Treatments for tachycardia may include medication and/or surgical procedures. In some cases, an implanted defibrillator may be inserted in the patient's chest in order to regulate the heart rate. The decision for medical treatment, and the method selected, can be made only after a comprehensive diagnosis. Depending on the cause and severity of the tachycardia, treatment may include : Nonsurgical procedures (catheter radiofrequency ablation) Medical devices — Implanted pacemakers, defibrillators Surgery Medications Intravenous medications, in emergency care Prevention The most effective way to prevent tachycardias is to reduce your risk of developing heart disease. If you already have heart disease, monitor it and follow your treatment plan to lower your tachycardia risk. ******************************************************** Irregular Heart Beat / Arrhythmia An arrhythmia is an abnormality in the heart's rhythm, or heartbeat pattern. The heartbeat can be too slow, too fast, have extra beats, skip a beat, or otherwise beat irregularly. Arrhythmias are deviations from the normal cadence of the heartbeat, which cause the heart to pump improperly. The normal heartbeat starts in the right atrium, where the heart's natural pacemaker (the sinus node) sends an electrical signal to the center of the heart to the atrioventricular node. The atrioventricular node then sends signals into the main pumping chamber to make the ventricle contract. Arrhythmias occur when the heartbeat starts in a part of the heart other than the sinus node, an abnormal rate or rhythm develops in the sinus node, or a heart conduction "block" prevents the electrical signal from traveling down the normal pathway. Middle-aged adults commonly experience arrhythmias but these are harmless. As people age, the probability of experiencing an arrhythmia increases. Arrhythmias often occur in people who do not have heart disease. In people with heart disease, it is usually the heart disease which is dangerous, not the arrhythmia. Arrhythmias often occur during and after heart attacks. Some types of arrhythmias, such as ventricular tachycardia, are serious and even life threatening. Slow heart rates (less than 60 beats per minute) are called bradycardias, while fast heart rates (more than 100 beats per minute) are called tachycardias. Bradycardia can result in poor circulation of blood, and, hence, a lack of oxygen throughout the body, especially the brain. Tachycardias also can compromise the heart's ability to pump effectively because the ventricles do not have enough time to completely fill. Arrhythmias are characterized by their site of origin: the atria or the ventricles. Supraventricular arrhythmias occur in the upper areas of the heart and are less serious than ventricular arrhythmias. Ventricular fibrillation is the most serious arrhythmia and is fatal unless medical help is immediate. Causes and symptoms In many cases, the cause of an arrhythmia is unknown. Known causes of arrhythmias include heart disease, stress, caffeine, tobacco, alcohol, diet pills, and decongestants in cough and cold medicines. Symptoms of an arrhythmia include a fast heartbeat, pounding or fluttering chest sensations, skipping a heartbeat, "flip-flops," dizziness, faintness, shortness of breath, and chest pains. Treatment Many arrhythmias do not require any treatment. For serious arrhythmias, treating the underlying heart disease sometimes controls the arrhythmia. In some cases, the arrhythmia itself is treated with drugs, electrical shock (cardioversion), automatic implantable defibrillators, artificial pacemakers, catheter ablation, or surgery. Supraventricular arrhythmias often can be treated with drug therapy. Ventricular arrhythmias are more complex to treat. Drug therapy can manage many arrhythmias, and the common drugs for suppressing arrhythmias include beta-blockers, calcium channel blockers, quinidine, digitalis preparations, and procainamide. Because of their potential serious side effects, stronger, desensitizing drugs are used only to treat life-threatening arrhythmias. All of the drugs used to treat arrhythmias have possible side effects, ranging from mild complications with beta-blockers and calcium channel blockers to more serious effects of desensitizing drugs that can, paradoxically, cause arrhythmias or make them worse. Response to drugs is usually measured by ECG, Holter monitor, or electrophysiologic study. In emergency situations, cardioversion or defibrillation (the application of an electrical shock to the chest wall) is used. Cardioversion restores the heart to its normal rhythm. It is followed by drug therapy to prevent recurrence of the arrhythmia. Artificial pacemakers that send electrical signals to make the heart beat properly can be implanted under the skin during a simple operation. Leads from the pacemaker are anchored to the right side of the heart. Pacemakers are used to correct bradycardia and are sometimes used after surgical or catheter ablation. Automatic implantable defibrillators correct life-threatening ventricular arrhythmias by recognizing them and then restoring a normal heart rhythm by pacing the heart or giving it an electric shock. They are implanted within the chest wall without major surgery and store information for future evaluation by physicians. Automatic implantable defibrillators have proven to be more effective in saving lives than drugs alone. They often are used in conjunction with drug therapy. Ablation a procedure to alter or remove the heart tissue causing the arrhythmia in order to prevent a recurrence, can be performed through a catheter or surgery. Supraventricular tachycardia can be treated successfully with ablation. Catheter ablation is performed in a catheterization laboratory with the patient under sedation. A catheter equipped with a device that maps the heart's electrical pathways is inserted into a vein and is threaded into the heart. High-frequency radio waves are then used to remove the pathway(s) causing the arrhythmia. Surgical ablation is similar in principle but it is performed in a hospital, using a cold probe instead of radio waves to destroy tissue. Ablation treatments are used when medications fail. Maze surgery treats atrial fibrillation by making multiple incisions through the atrium to allow electrical impulses to move effectively. This is often recommended for patients who have not responded to drugs or cardioversion