FAQs

Get more information from the following frequently asked questions about:

• Supraventricular Tachycardia (SVT)
• Atrial Fibrillation
• Ventricular Tachycardia
• Devices: Pacemakers
• Devices: Cardioverter-defibrillators

Supraventricular Tachycardia (SVT)

1. What is supraventricular tachycardia?

SVT is an arrhythmia that starts in the upper chambers or atria of the heart.  The heart rate is more than 100 beats per minute.  People who have this type of arrhythmia often say that they can "feel their heart racing."    

2. Are there different types of supraventricular tachycardia?

Yes, there are different types of SVT.  Sometimes there is a single spot in either the right or left atrium (heart's upper chambers) that can independently start this fast heart rhythm.  This is referred to as "atrial tachycardia" (AT). 

In other cases, the fast heart rhythm is caused by an electrical short circuit within the heart's normal conduction system.  This type of SVT can be referred to as "AV node reentry tachycardia" (AVNRT). 

Finally, there is sometimes an extra electrical connection between the atria and ventricles (heart's upper and lower chambers) that allows this fast heart rhythm to occur.  This is referred to as "atrioventricular reentry tachycardia" (AVRT). 

3. What causes supraventricular tachycardia?

People are often born with the extra independent areas, electrical circuits or pathways that start this fast heart rhythm.  In some patients who have had heart surgery, scars that form with normal healing sometimes are associated with development of electrical circuits that can cause SVTs. 

4. What are treatment options for this heart rhythm irregularity?

Medications are often given as the first treatment for this type of arrhythmia.  However, if the medications are not effective, cause side effects, or the patient does not want to take them long-term, catheter ablation is another treatment option for SVT.    

5. What is the success rate of the cardiac catheter ablation procedure when used for supraventricular tachycardias?

The success rate of the catheter ablation procedure when used for SVTs is approximately 90-95%.  This success rate may be lower if the SVT pathway is in a difficult to reach area or near part of the normal electrical conduction system.

Atrial Fibrillation

1. What is atrial fibrillation?

Atrial fibrillation (AF) is an arrhythmia that starts in multiple sites in the upper chambers of the heart.  It is an irregular rhythm that causes the atria to quiver instead of contracting regularly.  The atrial rate can be very rapid but the atrio-ventricular node (a structure in the middle of the heart) helps to limit the number of electrical impulses that can pass to the heart's lower chambers.  Atrial fibrillation makes your pulse irregular and usually fast.

Episodes of AF can occur intermittently.  This type of AF is categorized as "paroxysmal."  If AF occurs more often and episodes last longer, it can be categorized as "persistent."

2. What causes atrial fibrillation?

The exact cause of atrial fibrillation (AF) is not known.  However, there are associated conditions that are seen in conjunction with AF, such as high blood pressure, coronary artery disease, heart failure, heart bypass or valve surgery, chronic lung disease, sleep apnea or hyperthyroidism.  It is known that the risk of developing AF increases with aging.  In some cases, AF occurs without any associated condition or underlying heart disease                    

Some people will notice that there are certain triggers to their AF episodes like alcohol consumption, excessive caffeine intake, lack of sleep or eating a large meal. 

3. Is there a cure for atrial fibrillation? 

Presently there is no absolute cure for atrial fibrillation (AF).  However, there are treatments that can help to control and manage this arrhythmia.

4. Is atrial fibrillation life-threatening?

Atrial fibrillation (AF) is not considered a life-threatening arrhythmia.  However, if episodes of the arrhythmia are prolonged, there is an associated risk of blood clot formation that can lead to a stroke. In most cases, some sort of medication that prevents blood clots from forming, for example Coumadin or aspirin, is highly recommended. 

AF can be a bothersome arrhythmia if it causes symptoms and impacts a person's ability to carry out their activities of daily living. The symptoms that people with AF report (for example, fatigue, lightheadedness, shortness of breath) are most likely caused by the uncoordinated contraction of the heart, which decreases its pumping ability.   There are some people, though, who are not as affected by this.  They are completely unaware that they are in AF, exhibiting no symptoms at all.

5. Will atrial fibrillation cause any long-term cardiac damage?

Chronic atrial fibrillation can "remodel" or change the structure of the heart's upper chambers over time.  If the heart rate of the ventricles during atrial fibrillation is consistently fast, the heart muscle can weaken, resulting in heart failure.    

6. Am I a candidate for catheter ablation of atrial fibrillation?

Patient factors that are used to determine the appropriateness of proceeding with catheter ablation are:

• Symptoms associated with atrial fibrillation episodes
• Co-existing health problems
• Treatment failures (for example, anti-arrhythmic medications, cardioversions or previous ablations)
• Cardiac structure and function

Generally, patients who are highly symptomatic with their atrial fibrillation and have failed or are intolerant to one or more anti-arrhythmic drugs are candidates. Occasionally, patients who are not interested in taking antiarrhythmic drugs are offered ablation as first-line treatment.

7. How will the ablation procedure help my atrial fibrillation?

The goal of the procedure is to isolate the areas of the heart that are known to start the rapid electrical signals in the upper heart chambers.  Research has shown the electrical signals for atrial fibrillation (AF) usually start around the pulmonary veins in the left atrium.  These four veins bring oxygenated blood from the lungs back into the heart and drain into the left atrium. When electrical isolation of these veins is successful, episodes of AF often stop or decrease in number. 

Within a few months post procedure, some patients can stop the anti-arrhythmic medications that they were taking to control their AF.  If the anti-arrhythmic drugs are continued, the ablation procedure often helps the medications better control AF episodes.  Finally, the ablation procedure can help to decrease symptoms associated with episodes of AF such as palpitations, lightheadedness, fatigue or decreased exercise tolerance, or shortness of breath. 

8. What is the success rate of the cardiac catheter ablation procedure for atrial fibrillation?

The reported success rates vary by institution, with a usual range of 60-70%.  Success rates are influenced by factors such as other co-existing heart and medical conditions, the individual's anatomy, post-procedure follow-up and repeat procedures. 

9. What are the risks of the atrial fibrillation cardiac catheter ablation procedure?

In our center's experience, the risk of any of the below occurring is less than 1%.  The known associated risks of the atrial fibrillation catheter ablation procedure include, but are not limited to:

• Bleeding
• Damage to blood vessels
• Infection
• Atrioesophageal fistula formation (an abnormal connection between the left atrium and esophagus)
• Cardiac perforation (a hole in the heart) that can cause bleeding around the heart
• Pulmonary vein stenosis (narrowing of the pulmonary veins)
• Stroke
• Myocardial infarction (heart attack)
• Death

10.  How effective are medications in controlling or preventing atrial fibrillation?

Research has shown that the most effective anti-arrhythmic medications prevent episodes of atrial fibrillation (AF) in the range of 50-60% of patients.

In many cases, medications that are considered "rate-controlling" agents to prevent AF from getting too fast are also prescribed.  These drugs generally do not prevent AF from occurring, but will lower the heart rate during AF.

Ventricular Tachycardia

1. What is ventricular tachycardia?

Ventricular tachycardia (VT) is an arrhythmia that originates from the lower chambers of the heart.  The normal electrical conduction system begins in the right atrium.  In VT, there is a focus (area) in the ventricles that starts this type of heart rhythm and takes over to drive the heart rate faster.

2. Is this a life-threatening arrhythmia?

Yes, ventricular tachycardia (VT) can be a life-threatening arrhythmia.  The majority of the time it is associated with symptoms like passing out, low blood pressure and dizziness.  However, it can sometimes lead to cardiac arrest.

3. What causes ventricular tachycardia?

The majority of the time, ventricular tachycardia is caused by underlying structural heart problems like coronary artery disease, heart attacks or heart failure.  Some people may have alterations in their electrocardiogram or genetic mutations that alter the signals in the heart and increase the risk of VT.  In some cases, VT can occur in people with normal hearts and no other medical problems.     

4. What are the treatment options for ventricular tachycardia?

Medications can be used to help control and prevent ventricular tachycardia (VT).  Additionally, catheter ablation is a recommended treatment for some types of VT.  Implantation of a cardioverter-defibrillator (ICD) can be recommended when VT cannot be eliminated with medication and is associated with symptoms like low blood pressure and passing out.  This device will treat rapid VT by delivering an electric shock to reset the heart's rhythm.

5. What is the success rate for the cardiac catheter ablation procedure for ventricular tachycardia? 

The overall success rate for catheter ablation of ventricular tachycardia (VT) is approximately 70-75%.  Success rates can be higher or lower depending on factors such as the originating location of the VT and the cardiac health of the individual patient.

Devices: Pacemakers

1. What will a pacemaker do for me?

A pacemaker will ensure that your heart rate will not beat too slowly because of its inability to deliver electrical impulses when needed. A minimum heart rate is programmed into the pacemaker by the physician so your pulse will not go below this rate.  It is recommended for people who have slow heart rates accompanied by symptoms such as dizziness, lightheadedness or passing out. Some people have rapid heart rhythms that require medications to control symptoms by reducing the heart rate.  In this case, implantation of a pacemaker might be needed to allow this treatment.

2. What are the restrictions after I have a pacemaker implanted?

For the first two weeks after implantation of the pacemaker, the restrictions are as follows:

• Do not lift the arm on the side that the pacemaker was implanted any higher than your shoulder.  This will reduce the risk of dislodging the leads (wires) that were placed in your heart muscle and attached to your pacemaker.
• No lifting of greater than 10 pounds.
• Avoid sleeping on the same side that the pacemaker is implanted on while the wound is healing.

For a total of eight weeks after implantation:

• No vigorous swinging of the arm on the side that the pacemaker is implanted, such as would occur with activities like golf, tennis, baseball, etc.

Some other things to be avoided after a pacemaker is implanted:

• Magnetic resonance imaging (MRIs)
• Contact with magnetic wands that are used in airports for personal search
• High power magnetic or electrical fields

3. How often do I have to have the pacemaker replaced?

Pacemakers are generally replaced every six-to-eight years.  You will be scheduled for routine follow-up at the Pacemaker Clinic to check for normal functioning and remaining generator life to anticipate when it will need to be replaced. 

Devices: Cardioverter-defibrillators

1. What does a cardioverter-defibrillator do?

An implantable cardioverter-defibrillator (ICD) is able to deliver a shock to the heart when dangerous, life-threatening arrhythmias occur.  All ICDs are also able to provide cardiac pacing if needed for slow heart rates. 

ICDs can be recommended when someone has:

• A severely weakened heart muscle
• Evidence of life-threatening arrhythmias that produce symptoms and cannot be controlled with treatment
• History of cardiac arrest

2. How do pacemakers and ICDs differ?

Pacemakers can only make sure that your heart rate will not go too slow.  ICDs can monitor for life-threatening arrhythmias and deliver a shock if necessary.   Both types of devices can provide pacing if needed.  

3. How often do I have to have the cardioverter-defibrillator replaced? 

ICDs are generally replaced every four-to-six years depending on how much it is used for pacing and how many shocks it delivers. You will be scheduled for routine follow-up at the ICD clinic to check for normal functioning and remaining generator life to anticipate when it will need to be replaced. 

4. Are there any restrictions after I have the ICD implanted?

For the first two weeks after implantation of the ICD, restrictions are as follows:

• Do not lift the arm on the side that the ICD was implanted any higher than your shoulder.  This will reduce the risk of dislodging the leads (wires) that were placed in your heart muscle and attached to your ICD.
• No lifting of greater than 10 pounds.
• Avoid sleeping on the same side that the ICD is implanted while the wound is healing.

For a total of eight weeks after implantation:

• No vigorous swinging of the arm on the side that the ICD is implanted, such as would occur with activities like golf, tennis, baseball, etc.

Some other things to be avoided after an ICD is implanted are:

• Magnetic resonance imaging (MRIs)
• Contact with magnetic wands that are used in airports for personal search
• High power magnetic or electrical fields
• Arc welding