What is the electrophysiology(EP) study?
A cardiac ep study is a minimally invasive procedure that is done to study the heart’s electrical system and electrical activity of the heart and to identify the cause, location of origin, possible treatment options, and response to treatment for abnormal rhythms of the heart.
- Electrophysiological study
- Cardiac electrophysiology testing
- Ep test
Is this procedure an elective or an emergency procedure?
A cardiac electrophysiology study is usually performed as an elective procedure.
Indications of electrophysiology
The following are some of the indications for a cardiac electrophysiology study:
- Sustained ventricular tachycardia.
- Sustained ventricular tachycardia with left ventricular dysfunction, and associated with symptoms of hemodynamic compromise.
- Ventricular tachycardia with dilated non-ischemic cardiomyopathy.
- Long QT syndrome
- Brugada’s syndrome
- Symptomatic premature ventricular contractions.
- Symptomatic non-sustained ventricular tachycardia.
- ECG reading of
- Mobitz type I AV block
- Wide QRS complex
- Wide or narrow QRS with mobitz type II block
- Av nodal re-entrant tachycardia(AVNRT)
- Wolff parkinson white syndrome with arrhythmias.
Contraindications and risk factors for EP study
Some contraindications and risk factors for cardiac electrophysiology study include:
- Acute myocardial infarction
- Coronary artery disease
- Pregnant individuals
- Ventricular tachycardia that cannot be mapped
- Polymorphic ventricular tachycardia
- Individuals in whom the outcome will not be positively affected by the study
- Uncooperative individuals
Investigations before the procedure
Some investigations that may be done before a cardiac electrophysiology study may include:
- Laboratory Tests
- CBP & ESR
- Coagulation profile and blood typing
- Liver and Renal Function Tests
- Complete Metabolic Panel
- Imaging tests
Before performing a cardiac ep study the following are done:
- Risks and benefits of the procedure are done
- Medications that are being taken for cardiac conditions may be stopped 1 week before the procedure as they may interfere with the study
- Anticoagulant medications may be stopped 1 week before the procedure
- Nothing by mouth 8-12 hours before the procedure
Intraoperative details of EP study
Duration: A heart EP study may last from 2-4 hours, and it may last longer if additional procedures such as ablation are being done
Anesthesia: A heart electrophysiology study is performed under conscious sedation and a local anesthetic at the site of catheter entry
Description of the procedure:
A cardiac electrophysiology study is done in a cath lab or eps lab. An iv line is put in place to administer a sedative. The sites of catheter entry are cleaned and a local anesthetic is given at these sites. Various monitors are connected to the individual. Depending on the type of arrhythmia that is being investigated or treated a minimum of two and up to 4 catheters may be introduced into the individual via the right groin, left groin, arm, below the clavicle(collar bone), and/or the neck. With the help of fluoroscopic image (x-ray) guidance, the catheters are moved to various locations within the heart. The catheters which have electrodes at their tips can send or receive electrical signals from the heart. Initially, the electrodes are used to receive signals and make baseline measurements of the heart’s electrical activity. Next, the electrodes are used to send signals (pacing) and simulate the arrhythmias that were previously encountered; in addition to the electrical signals from the electrodes, some drugs may also be used to induce these arrhythmias. Based on the response to pacing a treatment plan is decided upon. If the arrhythmia is induced and it is decided that it can be treated with catheter ablation, cardiac mapping is done to mark the sites of the abnormal activity and catheter ablation with radiofrequency is done to destroy the problematic tissues. The catheters used for catheter ablation are slightly larger than the ones used for a cardiac electrophysiology study. After the procedure is completed the catheters are removed and either suturing or pressure bandaging of the catheter entry sites is done.
After a heart EP study is completed the following is done:
- The individual is moved to a recovery room and placed under observation for a few hours
- Cardiovascular functions are monitored
- The individual is advised to lie flat without moving for 3-6 hours; sometimes longer immobility may be required if an artery is used for catheter entry
Common post-procedure occurrences:
- Pain and soreness at the site of catheter entry
- Fatigue and feeling of being unwell
Medications: Antibiotics and pain-relieving medication may be prescribed; additional medications as required by the attending specialist
Discharge: Usually after 12 hours on the same day or the 1st postoperative day.
Review: A review is usually done on the 1st day after discharge and subsequent reviews as required by the attending specialist
Resumption of normal activities: Usually with some restrictions on the 2nd or 3rd after the procedure. A normal diet can be resumed 6 hours after the procedure.
Role of diet/exercise/lifestyle changes
Some measures that need to be taken after a heart EP study include:
- To be watchful of any signs of complications at the site of catheter entry such as swelling, increasing pain, bleeding
- To watch for signs of breathlessness, chest pain, dizziness
- To avoid strenuous activity and exercise until cleared by the attending specialist
- To avoid climbing stairs for a few days or climb very slowly (one step at a time) if the site of catheter entry is in the groin region.
Complications of ep study
Some of the complications that are associated with heart EPS include:
- Bleeding at the site of catheter entry
- Infection at the site of catheter entry
- Numbness or tingling of the extremities
- Pulmonary embolism
- Collapsed lung (depends on the site of catheter entry)
- Cardiac perforations
- Damage to heart valves
- Catheter induced AV block
- Myocardial Infarction
Prognosis of EP study
The prognosis for an electrophysiology study is generally excellent and serious complications are not encountered very often. The outcome of a cardiac electrophysiology study combined with ablation depends on the underlying condition and the general health of the individual.
Indications for hospitalization if required
Hospitalization will be required for an electrophysiology study.
Suggested clinical specialist/department to consult for the procedure
An EP study is performed by specialists from the department of interventional cardiology, cardiac electrophysiology, and cardiology.