Harvest Comprehensive Components of EP Studies


Electrophysiology (EP) is the sub-specialty of cardiology focused on the electrical conduction system of the heart. The EP system is responsible for making the four heart chambers of the heart contract in a sequence to circulate blood. To achieve this, the EP system generates a small electric charge 60 to 80 times each minute which is routed along a conduction pathways network that takes the blood into all four chambers. As the impulse contacts each of the heart’s chambers, it causes them to contract.

Go with the Flow

The electrical activity starts in the top right chamber of the heart, the right atrium. Specialized cells in this chamber generates an electrical impulse that travels throughout the two top chambers of the heart at a rate of approximately 1,000 mm per second. The impulse causes the atria to constrict when it passes through them. As the atria constrict, the accumulated blood from the venous system is squeezed down to the ventricles (the bottom chambers) at a rate of about 800 mm per second.

If the electrical impulse was allowed to travel freely from the atria to the ventricles, it would cause the ventricles to constrict before the blood has a chance to accumulate in the ventricles; this forces blood backward in the circulatory process. Fortunately, the EP system has an electrical speed bump, the atrioventricular node (AV node), slowing the impulse to about 200 mm per second. This electrical speed bump allows blood to accumulate in the ventricles before the electrical impulse makes its way there.

After blood has accumulated in the ventricles, the AV node passes the impulse to the bundle of His. This is a conduction pathway connecting the AV node to the right and left ventricles. As the impulse is delivered to the ventricles’ muscle fibers, they constrict and squeeze blood out of the heart. Ideally, the right and left sides of the heart constrict at the same time, and the top and bottom chambers constrict at altering times: the bottom chambers opening up when the top chambers are squeezing shut.

EP studies involve multiple electrode tipped catheters placed inside the patient’s heart at various points along the conduction pathway. The electrodes allow the physician to measure how the EP system carries electrical impulses (a process called recording). The data obtained from this portion of the study includes heart rate, rhythm, impulse travel speed, and any conduction blocks along the pathway.

Introducing electrical impulses (a process called pacing) allows the doctor to assess how the heart responds to abnormal electrical impulses. In addition to preventing the retrograde conduction of impulses, the AV node filters out abnormal electrical stimuli from the atrium so the bottom chambers can maintain normal rates even when the top chambers are contracting too rapidly. This filtering process is made possible by the refractory period of the AV node.

Refractory Period vs. Flushed Toilet

The concept of the refractory period is best explained with the analogy of flushing a toilet. Immediately following a toilet flush there is a period of time when the toilet will not flush again; a few seconds is needed for the tank to fill up before it can flush. Similarly, there is a period of time after the AV node conducts an electrical charge when it will not respond to another electrical stimulus.

To calculate the refractory period of the AV node, doctors position one electrode in the right atrium, another in the right ventricle. A series of electrical impulses with an equal amount of time between them is delivered to the atrium. The series of impulses is called a pacing train. The pacing train dictates the heart rate, and is equivalent to flushing the toilet for the first time. The electrode positioned in the ventricle confirms each impulse in the pacing train makes its way into the bottom heart chamber (this confirms the toilet has flushed).

The doctor introduces an extra impulse after allowing less time to pass than was allowed between each of the regular impulses in the pacing train. This is equivalent to pushing the lever on the toilet tank while it is still filling up with water. If the extra impulse registers on the ventricular electrode we know that the time between the pacing train and the extra impulse was sufficient for the AV node to recover. The doctor will repeat the process several times, with each attempt allowing less time between the pacing train and the extra impulse until the extra impulse does not register on the ventricular electrode. This pinpoints the antegrade refractory period of the AV node. Pacing in the ventricle and recording in the atrium provides the retrograde refractory period.

EP Components in a Nutshell

According to CPT®, a comprehensive EP study includes five distinct services: recording the atrium, recording the bundle of His, recording the ventricle, pacing the atrium, and pacing the ventricle. When each of these five services are documented, report code 93619 Comprehensive electrophysiologic evaluation with right atrial pacing and recording, right ventricular pacing and recording, His bundle recording, including insertion and repositioning of multiple electrode catheters, without induction or attempted induction of arrhythmia.

When an EP study contains less than the full definition of code 93619, we have five sub-component service codes to choose from:


93600 Bundle of His recording

93602 Intra-atrial recording

93603 Right ventricular recording


93610 Intra-atrial pacing

93612 Intraventricular pacing

Doctors frequently perform EP studies to confirm patients are having abnormal heart rhythms and identify why the heart is allowing the abnormal rhythms to perpetuate. If the patient’s heart has an abnormal rhythm at the procedure’s start, the doctor can map the electrical pathways in the heart to identify a cure. If the patient is in a normal rhythm at the start of the procedure, the doctor frequently induces the arrhythmia.

To induce an arrhythmia, the doctor administers bursts of electrical impulses at various rates. When an underlying arrhythmia is present, these stimulation protocols frequently cause the heart to go into the arrhythmia. Once induced, the nature of the arrhythmia can be studied and the doctor can identify the appropriate therapy. The induction of an arrhythmia can be separately reported with code 93618 Induction of arrhythmia by electrical pacing.

If the arrhythmia induction attempt is made during a comprehensive EP study, CPT® provides a second package code for reporting purposes. The second package code, 93620 Comprehensive electrophysiologic evaluation including insertion and repositioning of multiple electrode catheters with induction or attempted induction of arrhythmia; with right atrial pacing and recording, right ventricular pacing and recording, His bundle recording, includes all five of the services in the first package code, 93619, and the arrhythmia induction service defined by code 93618 and confirms the six distinct services.

The physician may opt to induce an arrhythmia after he infuses a drug to pharmacologically stress the patient’s heart. This approach enhancing the doctor’s ability to induce an underlying arrhythmia can’t be induced by routine electrical stimulation. The appropriate code for this service is 93623 Programmed stimulation and pacing after intravenous drug infusion (List separately in addition to code for primary procedure).

Once an arrhythmia is present (either spontaneously, after electrical stimulation, or after pharmacologic stimulation), the doctor will assess where the arrhythmia originates and why it is perpetuated. To do this, the doctor must obtain a “map” of the electrical impulses travel path. A specialized mapping catheter to obtain data from a broad intra-cardiac surface swath is employed for this task. EPs can perform two kinds of mapping: two-dimensional, 93609 Intraventricular and/or intra-atrial mapping of tachycardia site(s) with catheter manipulation to record from multiple sites to identify origin of tachycardia (List separately in addition to code for primary procedure) and three-dimensional, 93613 Intracardiac electrophysiologic 3-dimensional mapping (List separately in addition to code for primary procedure). The results of the mapping procedure dictate future therapeutic efforts which may include ablative therapy (93650–93652), cardiac rhythm management device implantation (33202–33249), or anti-arrhythmic drug prescription.

EP Study Reimbursement Doesn’t Add up

Accurate coding for EP studies is fairly straightforward after you become acquainted with the anatomy, physiology, and code structure; however, obtaining accurate reimbursement for these procedures is much more of a challenge. While CPR is the common abbreviation for cardio-pulmonary resuscitation, it is also an acronym describing the three illogical forces currently hindering accurate electrophysiology reimbursement: Correct Coding Initiative (CCI) edits, parenthetical notes in the CPT® book, and reimbursement rates. Accurately coded electrophysiology procedures will continue to be denied until the CPR challenges are remedied.

The first illogical force involves a set of CCI edits cannot be bypassed with any modifiers. The current listing of component code combinations includes edits that bundle codes 93600, 93602, and 93603 into the 2-D mapping service code, 93609. This is problematic because 2-D mapping is frequently performed at the same time as a less than comprehensive EP study that could be reported with many combinations of the six sub component services, including codes 93600, 93602, and 93603.

The current version of CCI also bundles code 93610 into code 93623 Programmed stimulation and pacing after intravenous drug infusion (List separately in addition to code for primary procedure). Similar to the mapping procedure described above, stimulation and pacing after intravenous drug infusion is frequently performed with a less than comprehensive EP study. The EP study portion of these tests would be reported with a collection of the sub-component codes (frequently including 93610).

The second illogical force is specific to parenthetical notes in the CPT® book. The notes following codes 93609 (2-D mapping) and 93603 (3-D mapping) suggest that these add-on codes are only appropriately reported in addition to one of the following primary procedure codes: 93620 (comprehensive EP study with attempted arrhythmia induction), 93651 Intracardiac catheter ablation of arrhythmogenic focus; for treatment of supraventricular tachycardia by ablation of fast or slow atrioventricular pathways, accessory atrioventricular connections or other atrial foci, singly or in combination, or 93652 Intracardiac catheter ablation of arrhythmogenic focus; for treatment of ventricular tachycardia.

If the patient is in the arrhythmia at the start of the procedure, it is not necessary to induce the arrhythmia and the diagnostic portion of the study would more appropriately be reported with code 93619 (comprehensive EP study without attempted arrhythmia induction). Similarly, mapping could be performed at the time of a “less than comprehensive” electrophysiology study that could be reported with several combinations of the six sub-component codes described above: 93600, 93602, 93603, 93610, 93612, and 93618.  The absence of these seven CPT® codes in the parenthetical notes following codes 93609 and 93613 frequently cause denials of accurately coded EP claims.

The third illogical force involves Medicare payment rates; we get paid more money for doing less work in the EP lab. The Medicare fee schedule currently reimburses code 93620 (the six-component comprehensive EP study) at a national unadjusted rate of about $700; however, the reimbursement rates for the six sub-components included in this code definition add up to approximately $1,000. When one of the comprehensive EP study sub-components is not performed we will see an increase in reimbursement of between $120 and $170. When two of the sub-components are not performed we will see approximately the same compensation as if we performed all six of the sub-components.

The reimbursement variance is compounded when Medicare applied the multiple procedure reduction status to the comprehensive EP study codes (93619 and 93620) but not to the six sub-component services (93600, 93602, 93603, 93610, 93612, or 93618). As a result, physicians will receive the full fee schedule amount for each of the reported sub-component services when performed at the time of another procedure impacted by the multiple procedure reduction such as: 93651 (supra-ventricular tachycardia ablation), 93652 (ventricular tachycardia ablation), or 33249 (defibrillator implantation). If the physician performed a comprehensive EP Study (93619 or 93620) he will only receive 50 percent of the Medicare fee schedule amount for the EP study.

While the first two illogical forces described above will frequently result in accurately coded services being denied, the third illogical force will trigger higher physician reimbursement for less extensive procedures. Until these forces can be resolved, we are left hoping that the premium reimbursement amounts generated by less than comprehensive EP studies will offset the inappropriately denied sub-component services. Coders are responsible for reporting services accurately without regard to the reimbursement amounts generated by claims.


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