Broadly defined, arrhythmia refers to any abnormal heartbeat. Irregular heart rhythms are not uncommon, and many people experience an occasional "fluttering" or feel that their heart "skips a beat," especially as they get older. However, in some severe cases, arrhythmia can be a dangerous condition requiring medical treatment including surgery and/or medical devices to correct the problem.
The speed and pattern of your heartbeat are both regulated by electrical signals from within your heart. Such signals tell the upper chambers of the heart (atria) to contract to move blood to the lower chambers (ventricles), and tell the ventricles to contract to move blood out to the lungs and to the body. Special electrical cells, called the sinus node, create and send these electrical signals.
If there is a problem with these signals, your heart may beat too quickly (tachycardia), too slowly (bradycardia), or irregularly (arrhythmia). If the electrical signals are not sent or are blocked, a slow heart rhythm (bradycardia) may develop, and blood cannot be pumped and moved throughout the body properly. If too many signals are sent, a fast heart rhythm (tachycardia) may develop. When signals are sent quickly and irregularly, the heart muscle may quiver and fail to beat at all, causing a condition known as fibrillation. Fibrillation can occur in the atria (atrial fibrillation) or in the ventricles (ventricular fibrillation).In extreme cases; fibrillation can cause the formation of blood clots or cardiac arrest.
Forms of tachycardia include:
- Sinus Tachycardia
- Supraventricular Tachycardia
- Atrioventricular Nodal Reentrant Tachycardia
- Bypass Medicated Tachycardia
- Atrial Tachycardia
- Atrial Flutter and Fibrillation
- Ventricular Tachycardia
- Ventricular Fibrillation
When the heart beats slower than it should, less than 60 beats per minute, it is called bradycardia. Less common than tachycardia, these arrhythmias can cause fatigue, dizziness, lightheadedness, fainting or near-fainting spells. In serious cases, bradycardia can even cause cardiac arrest. Forms of bradycardia include:
- Sinus Bradycardia
- AV Nodal Block, including complete heart block
Categories of Arrhythmia
Arrhythmias can be divided into two categories: ventricular and supraventricular. Ventricular arrhythmias originate in the heart's lower chambers, or ventricles. Supraventricular arrhythmias originate in the heart's upper chambers, or atria. Heart block is a type of arrhythmia that prevents electrical signals from traveling from the atria to the ventricles.
Arrhythmias are further defined by the speed of the heartbeats. A very slow heart rate, called bradycardia, is a heart rate less than 60 beats per minute. A very fast heart rate, called tachycardia, is a heart rate faster than 100 beats per minute. Fibrillation, the most serious form of arrhythmia, consists of fast, uncoordinated beats caused by contractions of individual heart muscle fibers.
Causes of Arrhythmia:
Many different factors can cause an irregular heart beat. An arrhythmia can be:
- inborn or congenital
- caused by a medical condition like heart disease or high blood pressure
- environmentally linked to stress, caffeine, smoking, alcohol, and some over-the-counter cough and cold medicines
Arrhythmia symptoms depend on the overall health of the heart, the type, severity, and frequency of the arrhythmia, and the length of the episode. Some arrhythmias do not produce any warning signs. Surprisingly, heart palpitations do not always indicate an arrhythmia.
Symptoms of bradycardia (a slow heart rate) include tiredness, shortness of breath, dizziness, or fainting. Symptoms of tachycardia (a fast heart rate) include a strong pulse in the neck or a fluttering, racing heartbeat in the chest along with chest discomfort, weakness, shortness of breath, fainting, sweating, or dizziness.
Many different diagnostic tools and techniques are used to diagnose arrhythmias, including:
- Electrocardiogram (ECG)
- Holter Monitoring
- Event Monitoring
- Electrophysiology Studies (EPS)
- Exercise Stress Test
- Tilt-table Testing
- Transthoracic Echocardiogram (TTE)
- Transesophageal Echocardiogram (TEE)
Certain arrhythmias may be corrected through a process called cardioversion, in which the chest wall is exposed to a well-controlled and perfectly timed electrical shock. Usually an outpatient procedure, the patient is sedated or given general anesthesia. Patients will likely need to continue antiarrhythmic medication following the procedure.
A pacemaker is designed to treat an abnormally slow heart rhythm. It consists of a small, lightweight electronic device that is surgically placed in your chest for long-term management. The pacemaker continuously monitors your heart rhythm to detect abnormalities. When necessary, it generates an electrical signal, similar to the heart's natural signals, to regulate your heartbeat at the correct speed.
Pacemakers may have one lead (wire) ending in either the right atrium or right ventricle, or two leads with one ending in the right atrium and one ending in the right ventricle. Some pacemakers are rate-adaptive, meaning they can help adjust your heart rate to your activity level.
Implantable Cardioverter Defibrillator (ICD)
An ICD is a small electronic device that is surgically implanted in your body to continuously monitor your heart rhythm. However, unlike a pacemaker, the ICD is designed to slow down a heart that is beating too fast. It can pace your heart to slow the rhythm down, and, if necessary, send electrical shocks to restore the heart's normal rhythm. An ICD can also be implanted alongside a pacemaker, and some ICDs contain a pacemaker that can be activated.
In severe cases of atrial fibrillation, when other treatments (such as medication, cardioversion and catheter ablation) have failed to correct the problem, your doctor may recommend a maze procedure. This open-heart surgery takes about three hours to complete, and recovery time may last six to eight weeks. This innovative procedure creates a "maze" of new pathways for electrical impulses to travel from the top to the bottom of the heart. It restores a regular coordinated, heartbeat, abolishes atrial fibrillation, and restores coordinated pumping to the upper chambers of the heart.
What Takes Place during Surgery?
Implanting a pacemaker or ICD is a relatively simple and safe procedure, often taking about two hours. The patient may remain awake during the procedure and be given local anesthesia. Typically, an incision is made in the skin below the collarbone to create a small pocket. The lead is threaded into a vein and guided into the heart. The generator is then attached to the lead(s) and placed in the pocket under the skin. Finally, the device is programmed to regulate your heartbeat and the incision is closed.
A maze procedure is much more complicated, because the surgeon must actually work on the heart muscle. An incision is made down the center of the chest and the breastbone is split so that the surgeon can access the heart. After being attached to a heart-lung machine, your heart will be stopped and cooled so that the surgeon can make a number of incisions in the upper chambers of the heart. When the procedure is done, the heart is restarted and the patient is removed from the heart-lung machine. The incision is closed.
Your doctor will monitor your pacemaker or ICD regularly to make sure it is working correctly, and will make adjustments as necessary. Most electronic devices do not interfere with modern pacemakers, so you may return to normal activities within a few weeks. Batteries in the device do wear down and will need to be replaced occasionally.
Patients recovering from a maze procedure should expect a much longer and more difficult recovery period. Expect to spend about one 5 to 7 days in the hospital, including one or two days in the Intensive Care Unit (ICU). Full recovery may take two to three months.
Robotic-assisted Maze procedure and epicardial lead implantation: less invasive options
The robotic-assisted Maze procedure and robotic-assisted lead implantation are minimally invasive alternatives to traditional approaches. When performed robotically with the da Vinci Surgical System, the Maze procedure and lead implantation is done with unparalleled precision and control through a few small incisions along the side of the chest. In addition to avoiding the pain and trauma of sternotomy and rib spreading, this may provide patient benefits such as:
- Less risk of infection
- Less blood loss and need for blood transfusions
- Shorter hospital stay
- Significantly less pain and scarring
- Faster recovery
- Quicker return to normal activities
As with any surgery, these benefits cannot be guaranteed, as surgery is both patient- and procedure-specific. While the robotic-assisted Maze procedure and robotic-assisted lead implantation are considered safe and effective, they may not be appropriate for every individual. Always ask your doctor about all treatment options, as well as their risks and benefits.