Treatment of Heart Rhythm Problems

Slow Heart Rhythms – Bradycardia

Sometimes a slow heartbeat can be improved by adjusting medications. This may be the situation when the slow heartbeat is due to problems with the sinus node (“sick sinus syndrome”). However, often the slow heartbeat cannot be improved by medication adjustments, in which case a pacemaker is needed. Pacemakers are also needed when there is electrical block of the signals, particularly in “complete heart block” (see Diagnosis of Heart Rhythm Problems insert link here).

How a pacemaker is placed:  Pacing leads (1,2 or 3) are positioned through the collarbone (“subclavian”) vein into the heart chambers and affixed to the heart muscle. These leads are then connected to the pacemaker generator, which is placed under the skin in the front chest region just below the collarbone. Potential complications can occur in up to 2% of patients and include bleeding, infection, lead dislodgement, damage to lungs (“pneumothorax”) or heart (“cardiac tamponade”). There may be other potential complications related to the specific procedure. This procedure is performed in the electrophysiology laboratory and typically takes about 1-2 hours. If  a third lead is needed for what is called “biventricular pacing” for heart failure, the procedure may take up to 3 hours.

What to expect with a pacemaker procedure? The patient arrives (no food that morning) in the cardiac pre-op area. Intake paperwork is completed. ECG electrodes are attached and an i.v. line is placed. The blood pressure, heart rate and blood oxygen values are monitored. The patient is taken to the EP laboratory. Conscious sedation is administered. These medications make the patient very sleepy but it is not the same as anesthesia. The electrophysiologist, assisted by a specially trained nurse or technician, begins the implant procedure. A local anesthetic is injected at the implant site (this may sting and burn a bit similar to injections at the dentist). A small skin incision is made and a pocket is fashioned under the skin for later placement of the pacemaker. Next the pacing leads are inserted into the collarbone vein and, using x-ray, these are advanced and placed inside the heart chambers. These leads have very tiny corkscrews at their tips, which allow them to be fixed in the heart muscle to maintain a stable position. The leads are tested with regard to their ability to pace the heart. The leads are then connected to the pacemaker generator and delivered into the skin pocket. The wound is sutured with absorbable material, taped and dressed and the arm will be placed in a sling. The patient will then be transferred to the recovery area and eventually to a hospital bed. The patient will rest for 4 – 6 hours, and is typically discharged the next day. The arm stays in a sling for 5 days at which time we see the patient back in the pacemaker clinic to review wound healing and once again test evaluate device/lead function – no sutures have to be removed since they are self absorbing. It is important to keep the dressing clean and dry during this 5 day period in order to avoid infection – it is not to get wet or be removed (a hand-held shower or sponge bath works best to avoid getting moisture under the dressing). We will also ask the patient to be careful not to lift the arm above the shoulder for a couple of weeks, depending on the procedure.

Follow up and monitoring: In addition to the 5-day followup appointment, the patient will have future followup appointments in the pacemaker clinic, and can also be followed remotely with a home monitoring unit.

There is very little in the typical environment that interferes with a pacemaker. It is fine to use microwaves and cell phones. We ask that you not place the cell phone directly over the device. A patient with a pacemaker cannot get an MRI, but a CT scan is alright. At the airport, the patient will be hand-patted at security rather than walk through the metal detectors or wanded. At stores with anti-theft devices at the door, we ask that patients simply walk through and not linger by the door.

Prevention of sudden death due to ventricular fibrillation or ventricular tachycardia : An implantable-cardioverter defibrillator (ICD):

Some patients can be identified as being at significant risk for a cardiac arrest, sudden cardiac death due to the life-threatening heart rhythms called ventricular fibrillation or ventricular tachycardia. In most of these situations, the treatment will rely upon implanting a device called an implantable cardioverter-defibrillator, or ICD.

What is an ICD? An ICD is similar to a pacemaker, but is a larger device that is intended to monitor the heart rhythm and if it detects ventricular fibrillation or ventricular tachycardia it can deliver therapy to stop it and restore a  normal rhythm. That therapy may include rapid pacing or a shock. The device itself is implanted in the upper chest below the collarbone in a procedure that is very similar to that described above for pacemakers.

What does a shock feel like? Can someone get hurt if they touch someone who is getting shock? While a shock is intended to save a life, it is painful and not something that we want to occur except on the rare basis. If a patient gets a shock, they should call the pacemaker clinic right away so that we can check by computer what the ICD has seen and why it delivered a shock. Sometimes adjustments are needed to the programming of the device as well. If multiple shocks are received (more than two) or the patient has fainted as a result, they should go to the Emergency Room. You cannot get hurt by touching someone who is shocked by their ICD.

What is biventricular pacing? Biventricular pacing or “cardiac resynchronization therapy” is a special type of device that is usually coupled with an ICD to treat heart failure patients who have severe symptoms related to their heart failure and have evidence of an electrical condition called “left bundle branch block”. In this type of block, the electrical signal travels very slowly from the right side to the left side of the heart, causing the heart muscle to contract in an uncoordinated fashion. A pacing lead can be placed from a vein inside the heart to the left side of the heart to re-coordinate the heart, and to improve symptoms of shortness of breath.

Fast Heart Rhythms – Tachycardia

Some fast heart rhythm problems can be managed by medications, while other fast heart rhythm problems are best treated by a procedure called an “EP study and ablation”.

What is an EP study and ablation? This is a procedure in which a fast heart rhythm problem can be treated by directly cauterizing, or heating, the muscle tissue that causes the problem. We advance catheters (small spaghetti-sized electrodes) from the veins (and sometimes artery) in the groins (thighs) of both legs. These catheters are then positioned inside the heart in specific locations that allow us to record the electrical signals. We then induce the tachycardia, and analyze how the heart is electrically activated to determine the areas of the heart that are responsible for starting or perpetuating the abnormal rhythm. Energy (typically radiofrequency) is then applied at that spot to cauterize the muscle tissue that is responsible for the abnormal rhythm. The success rate depends on the type of heart rhythm problem being treated and is greater than 90% for most heart rhythm problems. For ablation of atrial fibrillation (see below) the success rate depends on the nature of the atrial fibrillation but is usually between 60 and 80%. Potential complications are rare and occur in less than one percent of patients: Bleeding and infection at the groin sites, damage to the heart (“cardiac tamponade”), damage to the electrical system of the heart (AV block, requiring a pacemaker). There may be other potential complications related to the specific type of ablation being performed.

How do we see inside the heart? It is amazing how one can see inside the heart! We do so using a variety of methods. We use x-rays to guide where to place the catheters, and we can reconstruct an image of the heart just from the electrical signals themselves. Sometimes we also use sound waves – echocardiography from inside the heart.

What to expect in an EP study and ablation? These procedures are done in the EP laboratory and typically require an overnight stay. The procedure takes about 2 – 4 hours, more complex cases up to 6 hrs. The patient arrives (no food that morning) in the cardiac pre-op area. Intake paperwork is being completed. ECG electrodes are attached and an i.v. line is placed. The blood pressure, heart rate and blood oxygen values are monitored. The patient is taken to the EP laboratory. Both groins are prepped with disinfectant and the patient ‘s whole body is draped with a sterile drape lifted up at the head area for patient comfort.   Conscious sedation is administered. These medications make the patient very sleepy but are not the same as anesthesia. The electrophysiologist injects a local anesthetic in both groin sites (this may sting and burn a bit similar to injections at the dentist). At the end of the procedure the patient will then be transferred to recovery area and eventually to a hospital bed. The patient rests for 6 hrs, and typically will be able to be up the same evening.  The next morning we will see the patient, assess the groin sites and review overnight ECG strips. After review of the discharge instructions the patient can go home. Over the next 48 hours we advise light activity (up and around in the house), then back to normal activities. The patient will typically see his referring physician, often medications needed to control the heart rhythm before the ablation procedure can be stopped or modified. The risk of the fast heart rhythm returning is usually less than 5%, but depends on the type of heart rhythm problem.

Treatment of Atrial Fibrillation

Atriral fibrillation is such a common heart rhythm problem, particularly in people over the age of 70, that its treatment deserves special mention. As with all heart rhythm problems, medications may be sufficient to control symptoms. If medications are insufficient, then an ablation may be recommended. Two different types of ablations are performed for atrial fibrillation:

Pulmonary vein isolation and left atrial ablation is a procedure intended to either cure or control the frequency of episodes. In this procedure patients are first asked to undergo either a CT scan or MRI scan of their heart to show us the anatomy of the left atrium and the pulmonary veins, which drain into this chamber. This helps us to plan the procedure. The day before the procedure, the patient will undergo a transesophageal echocardiogram (TEE) using a probe that is swallowed into the stomach. This is performed to make sure there are no preexisting clots in the heart. If there is a clot, then the procedure cannot be performed as there would be too high a risk of causing a stroke. The next day, the ablation procedure is performed.

The procedure is similar to what is described above for other ablation procedures. In addition, a catheter is placed through the nose into the esophagus so we can see where the esophagus lies in relation to the left atrium. We create a three dimensional geometry of the heart using the electrical signals from our catheters and we cauterize muscle tissue in the left atrium to electrically isolate the pulmonary veins from the left atrium, and also to target certain other areas of muscle tissue in the left atrium that are electrically  complex and likely to contribute to the perpetuation of atrial fibrillation. Complications are rare, but can occur. In addition to the complications mentioned above, there is also a small risk of narrowing a pulmonary vein, a risk of causing a stroke, a risk of damaging the nerve to the diaphragm, and a very remote risk of damaging the esophagus.

In the first 2-3 months after the ablation for atrial fibrillation, one can absolutely expect atrial fibrillation to occur! During this time the left atrium is healing and inflamed, and that is why atrial fibrillation usually comes back during this early period. Medications can be helpful during this period of time. After two to three months, the patient should notice a clear improvement in their symptoms. About 20% of the time, however, atrial fibrillation may continue to recur and some patients may need a second ablation procedure.

AV node ablation: This type of procedure is intended to alleviate the symptoms of rapid heartbeat with atrial fibrillation. In this procedure, a pacemaker is implanted first. The AV node is then cauterized, inducing a state of complete heart block. The pacemaker then takes over, generating the heartbeat. Atrial fibrillation still is ongoing in the upper chambers (the atrium), but the ventricles will now be entirely under the control of the pacemaker. This is a relatively simple procedure that is very useful for older people wishing to get off the heartrate-slowing medications that they need to take to keep their pulse under control. This procedure, however, does not prevent the risk of stroke, and warfarin may still be needed.

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