Rhythm Disorders Diagnosis and Manangement
Electrophysiology Study (EP) examines the electrical behavior of the heart by recording electrical activity from within the heart chambers. Specially trained cardiologists use catheters inside the heart to evaluate certain symptoms a patient may be experiencing. An EP Study looks for explanations for symptoms such as passing out and evaluates certain arrhythmias (abnormal heart beats).
Patients may need to have an EP study after surviving a cardiac arrest or heart attack. Another reason might be ECG (EKG), or SAECG (Signal- Averaged ECG) findings that may place them in a high risk category for abnormal heart rhythms.
Preparation for the EP Study:
Your doctor may advise you to stop taking certain medications before your EP study to ensure more accurate results.
Prior to the EP test a pre-admission visit will be scheduled so a chest X-ray, electrocardiogram (ECG) and blood work can be obtained.
During this visit you will discuss the procedure, and be able to ask questions, or express any concerns you may have.
You will need to refrain from eating or drinking for at least six hours prior to the test. In most cases, you will not be permitted to eat or drink anything after midnight. Its important to get a good night sleep.
The EP Study:
Hospital admission usually occurs the same day as your test.
During the EPS procedure you will be awake, but you may be given a medication to help you relax.
Electrodes will monitor your heart rhythm and rate. This may require that some areas be shaved in preparation.
Prior to the test, an intravenous (IV) line will be started. Through it, your physician can administer medications or extra fluids you may need.
In preparation for the study, the groin areas are clipped, sterilized and numbed so sheaths can be inserted. Through these sheaths, temporary pacing catheters, about as thin as a piece of spaghetti, are placed in strategic areas of the heart. These catheters record electrical activity inside the heart and allow the physician to artificially pace your heart. An X-ray machine will allow the physician to watch the catheters and see that they are properly placed. You will receive only intermittent low doses of X-rays.
The physician will artificially create different heart rates and monitor for arrhythmias. During the test you may experience no symptoms whatsoever, or you may feel a rapid heart rate, skipped beats, light-headedness, chest pain or discomfort. If you experience any of these, please let the physician know. You may pass out briefly during the test. It may become necessary to give your heart a mild electric shock to restore your normal rhythm.
Usually, complications from EP studies are minimal. Although the procedure may seem somewhat frightening, remember you are being safely monitored in the EP lab by a highly - trained team of doctors, nurses and technicians.
At the end of the procedure:
If no arrhythmia is found, the catheters are removed, the test is concluded and you will be returned to your hospital room.
If your physician is successful in reproducing your arrhythmia, a medication may be administered through your IV. The doctor will then check the drugs effectiveness. There are several types of medications that your physician may try before finding the right one for you. Everyone responds differently to these medications.
EP studies usually last from one to six hours. After the catheters are removed, pressure will be applied to the puncture site just long enough to stop the bleeding. No stitches are required, but a sterile dressing will be applied and can be removed the next day.
Some patients may require no further treatment. Others may require any one of the treatment alternatives described below. Your physician will explain his/her findings and recommendations following your study. However, dont be afraid to ask questions at any time before, during or after the procedure!
After the EP Study:
After the procedure, when you have returned to your room, you will be given the following instructions:
• Remain in bed with your leg straight for 2 to 6 hours. Nurses will assist you when it is OK to get up
• Keep your head on the pillow • Inform the nurse if you have any warmth, pain or swelling where the
catheters were removed. • You will be permitted to eat and drink. Your vital signs and catheter
insertion site will be checked periodically. Going Home:
The exact length of your hospital stay is determined by your diagnosis and the treatment option prescribed by your physician. A normal EP study usually allows discharge the same day.
Heart Rhythm Disorder:
In order for the heart to do its work of pumping oxygen-rich blood to the body, it needs a trigger or electrical impulse to generate a heart beat. This electrical impulse originates from the sinus node - the hearts natural pacemaker. The sinus node (SA node) is located in the upper right chamber of the heart called the right atrium. From the sinus node, the impulse travels to the atrioventricular (AV) node causing the atria to contract. The AV node takes the signal from the atria and passes it across the HIS bundle to the ventricles. This causes the ventricles to contract and completes one cardiac cycle.
Problems Related to the Heart's Electrical System :
Normally, the sinus node delivers electrical impulses at a rate of 60 - 100 beats per minute. This is called sinus rhythm. Your heart determines its optimum rhythm depending on your activity. For example, your heart may beat slower when sleeping or faster when exercising.
Heart rates below 60 beats per minute are called bradycardia.
When your heart rate exceeds 100 beats per minute, it is known as tachycardia.
• If the tachycardia comes from the upper chambers of the heart it is called supraventriculas tachycardia, or SVT.
• If it comes from the lower chambers, it is ventricular tachycardia, or VT. Either too slow or too fast a heart beat may cause the following
o Dizziness or light-headedness o Fatigue
o Palpitations (pounding in the chest)
o Shortness of breath
o Chest pain or pressure
o A fainting spel
Arrhythmia Treatment Options:
After a diagnosis is made by the EP study, medication may be prescribed to prevent arrhythmias from reocurring. To determine a drugs effectiveness, the EP study may be repeated.
EP Studies may reveal a conduction disturbance and demonstrate the need for a permanent pacemaker (PPM).
Radio Frequency Ablation:
In the past several years, catheter-based radio frequency ablation (RFA) has become the treatment of choice for specific rhythm disturbances. High frequency radio waves use thermal heat to burn and eliminate the precise location in the heart from which an arrhythmia originates.
Implantable Cardioverter Defibrillator (ICD):
An automatic implantable cardioverter defibrillator is a miniature implantable device that monitors the heart rate, and in life threatening arrhythmias administers a shock to the heart to restore normal rhythm.
Atrial fibrillation is an irregular and often rapid heart rate that commonly causes poor blood flow to the body. During atrial fibrillation, the heart's two upper chambers (the atria) beat chaotically and irregularly — out of coordination with the two lower chambers (the ventricles) of the heart. Atrial fibrillation symptoms include heart palpitations, shortness of breath and weakness.
Episodes of atrial fibrillation can come and go, or you may have chronic atrial fibrillation. Although atrial fibrillation itself usually isn't life threatening, it is a serious medical condition that sometimes requires emergency treatment. It can lead to complications. Treatments for atrial fibrillation may include medications and other interventions to try to alter the heart's electrical system.
Possible causes of atrial fibrillation Abnormalities or damage to the heart's structure are the most common cause of atrial fibrillation. Possible causes of atrial fibrillation include: High blood pressure, heart attacks, abnormal heart valves, heart defects you're born with (congenital), an overactive thyroid gland or other metabolic imbalance, and exposure to stimulants such as medications, caffeine or tobacco, or to alcohol.
Other causes are: Sick sinus syndrome — improper functioning of the heart's natural pacemaker, emphysema or other lung diseases Previous heart surgery, Viral infections, and sleep apnea.
However, some people who have atrial fibrillation don't have any heart defects or damage, a condition called lone atrial fibrillation. In lone atrial fibrillation, the cause is often unclear, and serious complications are rare.
Risk factors for atrial fibrillation include:
* Age. The older you are, the greater your risk of developing atrial fibrillation.
* Heart disease. Anyone with heart disease, including valve problems and a history of heart attack and heart surgery, has an increased risk of atrial fibrillation.
* High blood pressure. Having high blood pressure, especially if it's not well controlled with lifestyle changes or medications, can increase your risk of atrial fibrillation.
* Other chronic conditions. People with thyroid problems, sleep apnea and other medical problems have an increased risk of atrial fibrillation.
* Drinking alcohol. For some people, drinking alcohol can trigger an episode of atrial fibrillation. Binge drinking — having five drinks in two hours for men, or four drinks for women — may put you at higher risk.
* Family history. An increased risk of atrial fibrillation runs in some families.
Some people with atrial fibrillation have no symptoms and are unaware of their condition until it's discovered during a physical examination.
Those who do have atrial fibrillation symptoms may experience:
Palpitations, which are sensations of a racing, uncomfortable, irregular heartbeat or a flopping in your chest.
Decreased blood pressure Weakness Lightheadedness Confusion, shortness of breath, chest pain
Atrial fibrillation may be Occasional. In this case it's called paroxysmal atrial fibrillation. You may have symptoms that come and go, lasting for a few minutes to hours and then stopping on their own.
Or Chronic: With chronic atrial fibrillation, your heart rhythm is always abnormal.
Sometimes atrial fibrillation can lead to the following complications:
Stroke: In atrial fibrillation, the chaotic rhythm may cause blood to pool in your heart's upper chambers (atria) and form clots. If a blood clot forms, it could dislodge from your heart and travel to your brain. There it might block blood flow, causing a stroke. The risk of stroke in atrial fibrillation depends on your age (you have a higher risk as you age) and on whether you have high blood pressure, diabetes, or a history of heart failure or previous stroke, and other factors. Medications such as blood thinners can greatly lower your risk of stroke or damage to other organs caused by blood clots.
Heart failure. Atrial fibrillation, especially if not controlled, may weaken the heart, leading to heart failure — a condition in which your heart can't circulate enough blood to meet your body's needs.
To diagnose atrial fibrillation, your doctor may do tests that involve the following:
Electrocardiogram (ECG). In this noninvasive test, patches with wires (electrodes) are attached to your skin to measure electrical impulses given off by your heart. Impulses are recorded as waves displayed on a monitor or printed.
Holter monitor: This is a portable machine that records all of your heartbeats. You wear the monitor under your clothing. It records information about the electrical activity of your heart as you go about your normal activities for a day or two. You can press a button if you feel symptoms, so your doctor can know what heart rhythm was present at that moment.
Event recorder: This device is similar to a Holter monitor except that not all of your heartbeats are recorded. There are two recorder types: One uses a phone to transmit signals from the recorder while you're experiencing symptoms. The other type is worn all the time (except while showering) for as long as a month. Event recorders are especially useful in diagnosing rhythm disturbances that occur at unpredictable times.
Echocardiogram: In this noninvasive test, sound waves are used to produce a video image of your heart. Sound waves are directed at your heart from a wand-like device (transducer) that's held on your chest. The sound waves that bounce off your heart are reflected through your chest wall and processed electronically to provide video images of your heart in motion, to detect underlying structural heart disease.
Blood tests. These help your doctor rule out thyroid problems or other substances in your blood that may lead to atrial fibrillation.
Chest X-ray. X-ray images help your doctor see the condition of your lungs and heart. Your doctor can also use an X-ray to diagnose conditions other than atrial fibrillation that may explain your signs and symptoms.
The treatment option best for you will depend on how long you've had atrial fibrillation. Generally, the goals of treating atrial fibrillation are:
Reset the rhythm or control the rate
Prevent blood clots
The strategy you and your doctor choose depends on many factors, including whether you have other problems with your heart and if you're able to take medications that can control your heart rhythm. In some cases, you may need a more invasive treatment, such as surgery or medical procedures using catheters.
Resetting your heart's rhythm Ideally, to treat atrial fibrillation, the heart rate and rhythm are reset to normal. To correct your condition, doctors may be able to reset your heart to its regular rhythm (sinus rhythm) using a procedure called cardioversion, depending on the underlying cause of atrial fibrillation and how long you've had it. Cardioversion can be done in two ways:
Cardioversion with drugs. This form of cardioversion uses medications called anti-arrhythmics to help restore normal sinus rhythm. Depending on your heart condition, your doctor may recommend trying intravenous or oral medications to return your heart to normal rhythm. This is often done in the hospital with continuous monitoring of your heart rate. If your heart rhythm returns to normal, your doctor often will prescribe the same anti- arrhythmic or a similar one to try to prevent more spells of atrial fibrillation.
Electrical cardioversion: In this brief procedure, an electrical shock is delivered to your heart through paddles or patches placed on your chest. The shock stops your heart's electrical activity momentarily. When your heart begins again, the hope is that it resumes its normal rhythm. The procedure is performed with sedation, so you shouldn't feel the electric shock.
Before cardioversion, you may be given a blood-thinning medication, such as warfarin (Coumadin), for several weeks to reduce the risk of blood clots and stroke. Unless the episode of atrial fibrillation lasted less than 24 hours, you'll need to take warfarin for at least four to six weeks after cardioversion to prevent a blood clot from forming even after your heart is back in normal rhythm.
Or, instead of taking warfarin, you may have a test called transesophageal echocardiography — which can tell your doctor if you have any heart blood clots — just before cardioversion. In transesophageal echocardiography, a tube is passed down your esophagus and detailed ultrasound images are made of your heart. You'll be sedated during the test.
Maintaining a normal heart rhythm After electrical cardioversion, anti- arrhythmic medications often are prescribed to help prevent future episodes of atrial fibrillation. Commonly used medications include:
* Amiodarone (Cordarone, Pacerone)
* Dronedarone (Maltaq) Propafenone (Rythmol) Sotalol (Betapace) Dofetilide (Tikosyn) Flecainide (Tambocor)
Although these drugs can help maintain a normal heart rhythm in many people, they can cause side effects, including:
Nausea Dizziness Fatigue
Heart rate control Sometimes atrial fibrillation can't be converted to a normal heart rhythm. Then the goal is to slow the heart rate to between 60 and 100 beats a minute (rate control). Heart rate control can be achieved two ways:
Medications: Doctors have prescribed the medication digoxin (Lanoxin). It can control heart rate at rest, but not as well during activity. Most people require additional or alternative medications, such as calcium channel blockers or beta blockers. Other blood pressure lowering medications, such as angiotensin-converting enzyme (ACE) inhibitors, also are sometimes used to lower blood pressure and reduce the risk of atrial fibrillation complications.
Atrioventricular (AV) node ablation. If medications don't work, or you have side effects, AV node ablation may be another option. The procedure involves applying radiofrequency energy to the pathway connecting the upper and lower chambers of your heart (AV node) through a long, thin tube (catheter) to destroy this small area of tissue. The procedure prevents the atria from sending electrical impulses to the ventricles. The atria continue to fibrillate, though, and anticoagulant medication is still required. A pacemaker is then implanted to establish a normal rhythm. After AV node ablation, you'll need to continue to take blood-thinning medications to reduce the risk of stroke, because your heart rhythm is still atrial fibrillation.
Other surgical and catheter procedures Sometimes medications or cardioversion to control atrial fibrillation doesn't work. In those cases, your doctor may recommend a procedure to destroy the area of heart tissue that's causing the erratic electrical signals and restore your heart to a normal rhythm. These options can include:
Radiofrequency catheter ablation. In many people who have atrial fibrillation and an otherwise normal heart, atrial fibrillation is caused by rapidly discharging triggers, or "hot spots." These hot spots are like abnormal pacemaker cells that fire so rapidly that the upper chambers of your heart quiver instead of beating efficiently. Radiofrequency energy is directed to these hot spots through a catheter inserted in an artery near your groin and threaded up to your heart. This catheter is used to destroy these hot spots, scarring the tissue so the erratic electrical signals are normalized. This corrects the arrhythmia without the need for medications or implantable devices. In some cases, other types of catheters that can freeze the heart tissue (cryotherapy) are used.
Surgical maze procedure. The maze procedure is done during an open- heart surgery. Using a scalpel, doctors create several precise incisions in the upper chambers of your heart to create a pattern of scar tissue. Because scar tissue doesn't carry electricity, it interferes with stray electrical impulses that cause atrial fibrillation. Radiofrequency or cryotherapy also can be used to create the scars, and there are several variations of the surgical maze technique. The procedure has a high success rate, but because it usually requires open-heart surgery, it's generally reserved for people who don't respond to other treatments or when it can be done during other necessary heart surgery, such as coronary artery bypass surgery or heart valve repair. Some people need a pacemaker implanted after the procedure.
Preventing blood clots Most people who have atrial fibrillation or who are undergoing certain treatments for atrial fibrillation are at especially high risk of blood clots that can lead to stroke. The risk is even higher if other heart disease is present along with atrial fibrillation. Your doctor may prescribe blood-thinning medications (anticoagulants) such as:
Warfarin (Coumadin). If you're prescribed warfarin, carefully follow your doctor's instructions on taking it. Warfarin is a powerful medication that can have dangerous side effects. You'll need to have regular blood tests to monitor warfarin's effects.
Dabigatran (Pradaxa). Another option for preventing blood clots is dabigatran. Dabigatran is as effective as warfarin at preventing blood clots that can lead to strokes, and doesn't require blood tests to make sure you're getting the proper dose. Talk to your doctor about taking dabigatran as an alternative to warfarin if you're concerned about your risk of stroke.
You may need to take medications to prevent blood clots in addition to medications designed to treat your irregular heartbeat. Many people have spells of atrial fibrillation and don't even know it — so you may need lifelong anticoagulants even after your rhythm has been restored to normal.