Cardiology Coding Alert

Understanding how biventricular pacing systems work and what the implantation procedure involves should give cardiology coders more thorough knowledge of what to code and why.

Like traditional pacemakers and defibrillators, a biventricular system consists of a generator, leads and electrodes. The generator, which produces the electrical impulses that pace the heart, is a small box about 2 inches in diameter and weighing 3 ounces (some are smaller). They run on lithium batteries that last five to 10 years. When the battery runs out, you replace the entire generator.

The leads, which are silicone-insulated platinum, carry the electrical impulses from the generator. Standard pacemakers have two leads for right atrium and right ventricle stimulation, while biventricular devices have a third lead that stimulates the left ventricle. Each lead has an electrode at its tip, which delivers the electrical impulse to the heart muscle.

During the insertion procedure, the cardiologist makes a small incision in the chest wall, just below the collarbone. The physician places right atrial and right ventricular leads within the subclavian vein to the level of the right atrium, Bailey says.

Next, the physician places a coronary sinus guiding sheath in the vein to the level of the right atrium. Using a deflectable catheter or angiography catheter with a guide wire, the cardiologist places the guiding catheter in the coronary sinus. The physician places a balloon catheter in this vessel, expands the catheter to occlude the blood flow, injects dye and takes multiple angiograms of the venous anatomy.

With this "roadmap," the cardiac physician places the left ventricular pacing lead into the guiding sheath and into the vein, Bailey says.

Following this procedure, the physician attaches the right ventricular lead and, if indicated, the right atrial lead as well. He or she secures the right-sided leads in place using small prongs or tiny screws, which ensure that the electrodes directly touch each heart chamber's inner surface. The cardiologist then wedges the left ventricular lead into a stable position in a branch of the coronary sinus.

Finally, the physician connects the other ends of the wires to the generator, which is inserted in a skin pocket below the collarbone, sutures them in place, and closes the incision.