Great advances have been made in nonsurgical treatments for certain types of arrhythmias. These techniques, including ablation and electrical cardioversion, may restore normal heart rhythms, reduce or elimi- nate symptoms, and reduce or eliminate the need for medications or surgical procedures (such as implantation of a pacemaker or an internal cardioverter-de?brillator).
Catheter Ablation
Catheter ablation is now widely used to treat many types of tachycardia (rapid heartbeat), including atrial ?brillation, atrial ?utter, and atrial tachycardia, as well as some ventricular tachycardias. To perform catheter ablation, a doctor specializing in the treatment of arrhythmias (an electrophysiologist) threads one or more electrode-tipped catheters into the heart chambers and uses some form of energy—usually radiofrequency—to destroy (ablate) abnormal tissue that is generating extra impulses. The area of tissue that is eliminated is very small (about one-?fth of an inch across) and is not signi?cant to overall heart func- tion. A small, harmless scar forms at the site, and normal heart rhythm resumes.
The procedure has a high success rate and a low risk of complications, and requires only mild sedation and local anesthetic. It causes little or no discomfort, and most people can return to their daily activities in a few days. Many people are cured of their tachycardia, so they no longer need to take antiarrhythmic medication.
How Ablation Is Done
If you have ablation done, your doctor will probably tell you to stop taking any antiarrhythmic medications for several days before the
procedure. At the hospital, you will be given a mild sedative and a local anesthetic. The doctor will make one or more small punctures in your groin and in one side of your neck, your elbow, or just under your collarbone. He or she will thread catheters through your veins or arteries and into the heart. The procedure is done with X-ray guidance via ?uo- roscopy in real time, so the doctor can see the progress of the catheter.
Then the doctor often needs to start an episode of tachycardia in order to determine exactly where the arrhythmia is coming from. Using recordings of electrical activity from inside the heart, he or she “maps” the tissue to locate the problem area. Once the site is identi?ed and the ablation catheter is positioned, the radiofrequency energy is turned on and the abnormal tissue is destroyed. To ensure that all abnormal tissue has been eliminated, the doctor may test you with medications or elec- trical stimulation to see if the tachycardia can be induced again. If it can be, he or she repeats the ablation procedure. When the tachycardia can no longer be initiated, the catheters are removed. The entire procedure lasts from 2 to 4 hours.
You will stay in the hospital for at least a few hours, while doctors watch for recurring symptoms, rhythm disturbances, or bleeding from the catheterization sites. You may be able to go home after this obser- vation period, or you may need to stay overnight.
You can probably be moderately active, walking and climbing stairs, almost immediately. Many people go back to work or school in a few days. Your doctor may recommend that you take aspirin for 2 to 4 weeks to thin your blood so that clots do not form at the ablation sites in your heart. You will probably return for a follow-up visit to the electrophys- iologist in a few weeks.
Complications from ablation are rare but can be serious. Depending on the type of arrhythmia treated, and where in your heart the ablation is done, you could develop heart block (requiring a pacemaker) or expe- rience bleeding around the heart. However, the chance of heart attack, stroke, or death from ablation is quite rare.
In people with supraventricular arrhythmia and no other heart dis- ease, a complete cure of tachycardia is achieved by ablation more than
95 percent of the time. In people with ventricular arrhythmia, the cure rate is also high.
In people with other heart problems, such as a previous heart attack resulting in heart muscle damage or in heart muscle problems, an inter- nal defibrillator is almost always implanted as well (see page 275).
Rather than curing the tachycardia entirely, catheter ablation helps reduce the number of times the de?brillator is acti- vated. Sometimes to achieve a cure, though, more than one session of ablation is needed.
Cardioversion
Cardioversion is the medical term for restoration of your heart’s normal rhythm.
Cardioversion can be done either chemi-
cally (with drugs) or electrically (with shock). Atrial fibrillation, ventricular tachycardia, and ventricular ?brillation are the types of arrhythmia most commonly
treated with cardioversion. Ventricular ?brillation, the most serious type of arrhythmia, can only be treated with electrical shock.
If your doctor chooses to treat your atrial ?brillation with antiar- rhythmic drugs, he or she may give you the medications to take at home. But ?rst you take blood thinners for several weeks. Or the doc- tor may admit you to the hospital to give you the antiarrhythmia drugs either intravenously or by mouth, where hospital staff can check to see how you respond to treatment, and equipment can be used to monitor your heart rate and rhythm. Your symptoms, the medication your doc- tor is giving you, and the presence of other heart conditions (if any) will be factors in this decision.
If your doctor recommends electrical cardioversion (sometimes called direct-current or DC cardioversion), the procedure will be done in a hospital. It involves delivering a synchronized electrical current through paddles that touch your chest wall and allow the current to travel to your heart. The shock causes all of your heart cells to contract simultaneously, which stops the abnormal electrical signals without damage to the heart. Then the heart returns to a normal heartbeat.
How Electrical Cardioversion Is Done
Before you have a cardioversion done, your doctor will probably pre- scribe blood thinners such as warfarin for 3 to 4 weeks to reduce your
risk of blood clots. If you take other medications, you should take them as usual unless you are told otherwise. On the day of the procedure, do not eat after midnight. Also, do not use any skin lotions on your back and chest, because they could interfere with the cardioversion apparatus.
In the hospital, you will be given an intravenous sedative, possibly by an anesthesiologist. The doctor will place cardioversion pads (or paddles) on your chest and back, on either side of your heart. The pads are connected to an external de?brillator so that your heart rhythms can be monitored and regulated. Once you are asleep, the doctor will deliver the shock so that the current ?ows across your heart. If the ?rst shock does not restore your normal heart rhythm, the doctor can deliver gradually increased levels of current.
After the procedure, you will probably awaken quickly without any memory of the experience. You may have some minor chest discomfort or skin irritation where the pads were placed. You will probably be able to go home within an hour after the procedure. Have someone else drive you home, and do not drive or try to make any important deci- sions for the rest of the day, until the effects of the sedative are entirely gone. You will need to continue taking warfarin until your physician tells you to stop; periodic blood tests will check your clotting time.
Electrical cardioversion restores normal heart rhythms about 90 per- cent of the time. About half of the people who have the procedure relapse within a year; if so, the procedure can be repeated.