Heart Rhythm Disorders & Electrophysiology :

• Introduction:
  In order for the heart to do its work of pumping oxygen-rich blood to the body, it needs a trigger or electrical impulse to generate a heart beat. This electrical impulse originates from the sinus node - the heart’s natural pacemaker. The sinus node (SA node) is located in the upper right chamber of the heart called the right atrium. From the sinus node, the impulse travels to the atrioventricular (AV) node causing the atria to contract. The AV node takes the signal from the atria and passes it across the HIS bundle to the ventricles. This causes the ventricles to contract and completes one cardiac cycle.
  
  Problems Related to the Heart's Electrical System :
   

  • Normally, the sinus node delivers electrical impulses at a rate of 60 - 100 beats per minute. This is called “sinus rhythm.” Your heart determines its optimum rhythm depending on your activity. For example, your heart may beat slower when sleeping or faster when exercising.

  • Heart rates below 60 beats per minute are called bradycardia.

  • When your heart rate exceeds 100 beats per minute, it is known as tachycardia.

    • If the tachycardia comes from the upper chambers of the heart it is called supraventriculas tachycardia, or SVT.

    • If it comes from the lower chambers, it is ventricular tachycardia, or VT. Either too slow or too fast a heart beat may cause the following symptoms:

      • Dizziness or light-headedness

      • Fatigue

      • Palpitations (pounding in the chest)

      • Shortness of breath

      • Chest pain or pressure

      • A fainting spel
         

• ElectroPhysiology Studies (EPS):
  Introduction:

  • Electrophysiology (EP) examines the electrical behavior of the heart be recording electrical activity from within the heart chambers.

  • Specially trained cardiologists use catheters inside the heart to evaluate certain symptoms a patient may be experiencing.

  • An EP study looks for explanations for symptoms such as passing out, or to evaluate certain arrhythmias (abnormal heart beats).

  • Patients may need to have an EP study after surviving a cardiac arrest or heart attack. Another reason might be ECG (EKG), or SAECG (Signal-Averaged ECG) findings that may place them in a high risk category.
     

• The EPS Procedure:
  Preparation for the EP Study

  • Your doctor may advise you to stop taking certain medications before your EP study to ensure more accurate results.

  • Prior to the EP test a pre-admission visit will be scheduled so a chest X-ray, electrocardiogram (ECG) and blood work can be obtained.

  • During this visit you will discuss the procedure, and be able to ask questions, or express any concerns you may have.

  • You will need to refrain from eating or drinking for at least six hours prior to EP studies. In most cases you will not be permitted to eat or drink anything after midnight. It’s important to get a good night’s sleep.
     

• The EP Study:

  • Hospital admission usually occurs the same day as your test.

  • During the EPS procedure you will be awake, but you may be given a medication to help you relax.

  • Electrodes will monitor your heart rhythm and rate. This may require that some areas be shaved in preparation.

  • Prior to the test, an intravenous (IV) line will be started. Through it, your physician can administer medications or extra fluids you may need.

  • In preparation for the study, the groin areas are clipped, sterilized and numbed so sheaths can be inserted. Through these sheaths, temporary pacing catheters, about as thin as a piece of spaghetti, are placed in strategic areas of the heart. These catheters record electrical activity inside the heart and allow the physician to artificially “pace” your heart. An X-ray machine will allow the physician to watch the catheters and see that they are properly placed. You will receive only intermittent low doses of X-rays.

  • The physician will artificially create different heart rates and monitor for arrhythmias. During the test you may experience no symptoms whatsoever, or you may feel a rapid heart rate, skipped beats, light-headedness, chest pain or discomfort. If you experience any of these, please let the physician know. You may pass out briefly during the test. It may become necessary to give your heart a mild electric shock to restore your normal rhythm.

  • Usually, complications from EP studies are minimal. Although the procedure may seem somewhat frightening, remember you are being safely monitored in the EP lab by a highly-trained team of doctors, nurses and technicians.

  • At the end of the procedure:

    • If no arrhythmia is found, the catheters are removed, the test is concluded and you will be returned to your hospital room.

    • If your physician is successful in reproducing your arrhythmia, a medication may be administered through your IV. The doctor will then check the drug’s effectiveness. There are several types of medications that your physician may try before finding the right one for you. Everyone responds differently to these medications.

  • EP studies usually last from one to six hours. After the catheters are removed, pressure will be applied to the puncture site just long enough to stop the bleeding. No stitches are required, but a sterile dressing will be applied and can be removed the next day.

  • Some patients may require no further treatment. Others may require any one of the treatment alternatives described below. Your physician will explain his/her findings and recommendations following your study. However, don’t be afraid to ask questions at any time before, during or after the procedure!
     

• After the EP Study:
  After the procedure, when you have returned to your room, you will be given the following instructions:

  • To remain in bed with your leg straight for 2 to 6 hours. Nurses will assist you when it is OK to get up;

  • Keep your head on the pillow;

  • Inform the nurse if you have any warmth, pain or swelling where the catheters were removed.

  • You will be permitted to eat and drink. Your vital signs and catheter insertion site will be checked periodically.

Going Home
The exact length of your hospital stay is determined by your diagnosis and the treatment option prescribed by your physician. A normal EP study usually allows discharge the same day.

ARRHYTHMIA TREATMENT OPTIONS:

• Anti-arrhythmic Therapy
  After a diagnosis is made by the EP study, drugs may be prescribed to prevent arrhythmias from recurring. To determine a drug’s effectiveness, the EP study may be repeated.

• Pacemaker Therapy:
  EP Studies may reveal a conduction disturbance and demonstrate the need for a permanent pacemaker (PPM).
  

• Radio Frequency Ablation
  In the past several years, catheter-based radio frequency ablation (RFA) has become the treatment of choice for specific rhythm disturbances. High frequency radio waves use thermal heat to burn and eliminate the precise location in the heart from which an arrhythmia originates.

• Implantable Cardioverter Defibrillator (AICD)
  An automatic implantable cardioverter defibrillator is a miniature implantable device that monitors the heart rate, and in life threatening arrhythmias administers a shock to the heart to restore normal rhythm.