Tachycardia (fast heart rates)

Do you experience Fast heart rates (Tachycardias)?

 

What do the patients complain of?

 

The patients tend to complain of episodes of palpitations due to fast heart rates. Some patients may feel giddy or have  episodes of fainting if the heart rates are too fast.

 

How is this condition diagnosed?

The condition can be diagnosed by a electrocardiogram (ECG) which reveals the fast heart rate. Some patients may need to undergo EP study to diagnose this condition.

What are the causes of Fast heart rates?

These can be due to various causes, however, the common one seen are SVT (supra-ventricular tachycardia), AF (atrial fibrillation) and VT/VF (ventricular tachycardia/ fibrillation).

  • SVT (Supra-Ventricular Tachycardia):  These are caused by the presence of an extra electrical connection between the upper and lower chambers. These patients experience intermittent fast heart rates associated with palpitations and lightheadness. The episodes can be highly distressing and limit one’s activities. They can be easily controlled with medications. However, with the advent of new technology, it has become easier to get rid of them and cure the patient of the fast heart rates. The procedure is called EP (electrophysiology) study and is carried out by inserting small catheters via one’s groin upto the heart. The heart is then stimulated to start the fast heart rate and the location of the extra connection is studied. The pathway can be burnt (ablated) by radiofrequency energy in a controlled manner with the help of catheters. These procedures have a good success rate (> 90%) and take around 2-3 hours. The patient can be mobilized after few hours and discharged the next day.

 

  • Atrial fibrillation: This is a disease of the elderly in which the upper chambers (atria) beat at extremely fast rates (400-750 beats/minute). Thus there is no effective pumping of the upper chamber, causing blood to stagnate and form clots which can cause strokes in high risk individuals. These patients need to be treated with drugs called blood thinners to reduce the risk of stroke. In addition, drug therapy is required to prevent the lower chambers from going fast which can be very distressing to the patient or life threatening. Ablation therapy can be offered in some patients in the early form of the disease. The procedure lasts 4-6 hours and are done through the groin. The chances of recurrence are high (around 30%)

 

  • VT (ventricular tachycardia): These are life threatening and are responsible for sudden cardiac deaths. Most of the patients who suffer from these either have blocks in their blood supply to the heart (have suffered heart attacks before) or have low pumping function of the heart. These patients can be controlled by oral medications. However, devices called Defibrillators are implanted to treat future episodes and to reduce the death rate in patients with heart attacks and poor heart function.  These are implanted just like pacemakers except that they have the additional function to detect and shock these dangerous rhythms. In patients with poor heart functions, an extra wire (lead) is placed on the left side of the heart to improve the heart function.

EP study and Ablation

Cardiac electrophysiology is a medical speciality devoted to the diagnosis and treatment of abnormal heart rhythms.

Electrophysiologists are fully trained cardiologists who have undertaken additional fellowship training in clinical cardiac electrophysiology. Cardiac electrophysiologists have expertise in the invasive diagnosis and treatment of cardiac arrhythmias (abnormal heart rhythms). They perform invasive procedures including diagnostic electrophysiology testing, radiofrequency catheter ablation, and implantation of antiarrhythmic devices such as pacemakers and defibrillators.

What is an EP study?

An electrophysiology (EP) study is a specialized procedure conducted by a highly trained Cardiologist who has gained special expertise in these procedures. In this procedure, 3 thin flexible wires/ catheters are inserted into your veins or arteries from the groin. These catheters are placed in different chambers and locations within your heart to record the electrical activity. With the help of the catheter, the electrical system of your heart is studied and problems diagnosed. These problems may be caused either due to an abnormal extra connection/circuit or abnormal focus. The conduction of the electrical impulses traveling in your heart is studied and extra abnormal ciruits detected and located.

The sources of abnormal extra heart beats or abnormal connections are then burnt off/ blocked by delivering radiofrequency (RF) energy with the help of a fine catheter. This is called Ablation. The procedures usually last 2-3 hours and have been performed safely for many years. Complications are very rare.

What will be done once I get admitted?

You will be told to get admitted one day prior or early morning on the day of the procedure. Once you finish the admission procedure on the ground floor of the Main Hospital building, you will be allotted a bed on one of the floor in the Main Hospital building. You will be examined by one of the nurses and the doctors to see if you have any problems and your medications and reports checked. We are here to make you comfortable and relaxed before the procedure. If you have any doubts or queries do feel free to ask your nurse or doctor. You have nothing to lose by asking queries.

What preparation do I need before the EP procedure?

Your doctor will tell you about the procedure in advance. He will explain to you the procedure in detail before getting admitted and after getting admitted. Your doctor will tell you ahead of time whether to stop taking any of your medications.

Few things necessary before the procedure:

  1. An informed written consent will be taken from you explaining the procedure, its details and its risks if any.
  2. You will be told not to eat or drink at least 6 hours before the start of the procedure
  3. The catheters are positioned from the groin and sometimes from the neck. These areas will be cleaned and shaved.
  4. An intravenous IV cannula will be inserted in one of you hands/arms before the start of the procedure.
  5. Please let the doctor know if you have any allergies or reactions to any drugs.

Where are these procedures performed?

Electrophysiology (EP) studies are performed on the first floor in the DSA lab situated in the Main Building. The EP laboratory has a moveable procedure table on which the patient lies down and an X-ray machine that is suspended over the table. This X-ray machine guides the doctor in placing the catheters within your heart. In addition, there is a large number of special electronic and computer equipment in the laboratory that is used during the electrophysiology (EP) study. These are EP equipment which transmits electrical signals from the heart onto the monitor, so that the doctor can analyze them.

Patient safety is the first and most important job in the EP laboratory.

Before the Start of the EP procedure:

You will lie flat on the procedure table. The electrocardiogram (ECG) leads will be connected on your chest to record your ECG during the procedure. The nurses will thoroughly cleanse the groin region and/or right neck region with special soap. The procedure is done under local anesthesia with intravenous sedation. You will be given intravenous drugs to make you feel sleepy and relaxed. This will relieve you of your anxiety before the procedure and let your drift to sleep.

Following this, the doctor will inject local anesthesia into your groin at the site where the catheters will be inserted. After the local anesthesia has taken effect, the doctor will introduce 3-4 small tubes (2-2.5 mm wide) into your groin. In some patients, he may opt to put a small tube in the neck on the right side. At all times during your time in the EP laboratory your heart rate, blood pressure, respiration, blood oxygen level, and ECG will be continuously monitored by the nurses and doctors in the room.

The EP procedure:

During an EP procedure, 2-4 temporary electrode catheters/ wires are inserted into multiple heart chambers. The catheters or wires are inserted through the small tubes and positioned in the heart. One does not feel the movement of the catheters when they are moved up to your heart. The catheters are about 50 inches long and 2 mm wide and the electrodes are located near the tip. For some cases, a wire may also be inserted in a vein in the right neck region. The wires are positioned in different locations in the heart by advancing them through the veins under X-ray guidance. Most of them are placed in the upper chamber (atria), the lower chamber (ventricle) and an area called the His bundle and into the coronary sinus vein (which lies behind the heart). The wires permit electrical stimulation of the heart and recording of electrical activity.  The patterns of the electrical conduction through the heart are displayed on a computer monitor. After the completion of the procedure all the catheters are removed.

After insertion of the wires, the diagnostic portion of the electrophysiology study will begin. This involves electrical stimulation of the heart and recording of electrical signals. This may cause the patient to feel their heart beating fast. The physicians analyze these electrical signals to determine the type of tachycardia (fast heart rate), the patient has and the location of the abnormal circuit. The patient should not feel alarmed if they feel their heart beating fast or irregularly during the procedure because this is a normal part of the study.

Radiofrequency (RF) Ablation

Ablation is the burning of the abnormal circuit or focus by delivering a very controlled burn with the radiofrequency energy. Ablation is performed to eliminate the tachycardia/ arrhythmia by getting rid of the abnormal circuit or focus. Not all tachycardias can be ablated. The cure rate for some tachycardias ranges from 90 to 98% while for some other types of tachycardias, it may be lower.

Procedure Time

The entire procedure (diagnostic and therapeutic portions) generally takes 1-3 hours; however, in very rare cases when the abnormal circuit/focus is difficult to find or reach with the ablation catheter, it may take longer, sometimes 5 hours. During the procedure the patient remains sedated and critical vital signs are continuously monitored. At the end of the procedure all the catheters and monitoring equipment are removed and the patient is taken to a regular hospital room where monitoring of vital signs and heart rhythm is continued.

What care should I take after the procedure?

After an ablation procedure the patient must lay in bed for 4-6 hours with the right leg remaining straight to avoid any bleeding from the groin. After that time, the patient can begin moving about, and generally is ready to go home that same day assuming no complications. When an ablation procedure is completed late in the day, the patient is kept overnight and discharged home the following morning.

What are the Benefits and Risks of Electrophysiology Procedures?

Patients need to weigh the small risks of the procedure against the potential benefits with the guidance of their doctor. The risks of the ablation procedure are very small, although it is not a risk-free procedure. The most serious reported complications in the medical literature include death, stroke, heart attack, cardiac perforation requiring emergency surgery, heart valve damage, artery damage, blood clots, bleeding, or infection are rare. Some patients have a risk of complete heart block (electrical block) requiring implantation of a permanent pacemaker although in our experience the risk is still very low. Lot of care is taken during the procedure and these procedures are now extremely safe if carried out by experienced personnel.