Schematic of the heart showing the minimally invasive approaches to allow access to the surface of the heart (the blue and red areas) during hybrid EP procedure. Image Source: UCLA

High-risk ventricular tachycardia patients can be safely treated through minimally-invasive surgical epicardial access for catheter mapping and ablation, according to a study in the November issue of the Heart Rhythm Journal.

While ablation is usually performed inside the heart, in about 15 to 30 percent of patients with VT, the site responsible for the abnormal rhythm is on the heart's outer surface. Normally, this can be addressed in the electrophysiology (EP) lab by threading a catheter under the ribcage. However, in high-risk patients who have scarring from previous heart surgeries, it is difficult to reach the outside of the heart, according to the researchers.

Yoav Michowitz, MD, and colleagues at the UCLA Cardiac Arrhythmia Center in Los Angeles, and colleagues used one of two minimally-invasive cardiac surgical techniques to open a small window in the chest to view the heart. Depending on the area of the heart the team needed to access, it used either a procedure called a subxiphoid window or one known as a limited anterior thoracotomy.

In the study, they analyzed clinical data of 14 patients (median age, 63 years) with drug-refractory VT who underwent the hybrid surgery in the EP lab.

In 11 patients, physicians gained access to the epicardium through a subxiphoid window procedure, while the other three patients underwent limited anterior thoracotomy.

The indication for surgical access was prior cardiac surgery for 12 patients, a previously failed epicardial access in one patient and ablation in close proximity to the coronary arteries and phrenic nerve in one patient.

Mapping in patients with subxiphoid surgical access was limited to the inferior and diaphragmatic surface of the heart extending posteriorly to the basal lateral wall.

With limited anterior thoracotomy, access to the apex, anterior and mid to apical anterolateral walls was obtained. In these regions, adhesions were more severe and repeat entry into the epicardial region at a different intercostal level was needed in two of three patients.

"These newer, more minimally-invasive procedures offer more treatments for high-risk patients who don't have a lot of options to address a life-threatening arrhythmia, allowing them to avoid potential open heart surgery," said senior author Kalyanam Shivkumar, MD, a professor of medicine and radiological sciences and director of the UCLA Cardiac Arrhythmia Center and Electrophysiology Programs.

The hybrid procedures involved a collaboration among several UCLA departments, including cardiology, cardiac surgery, anesthesiology, radiology and operating-room administration. Pre-procedure imaging was needed, as well as critical care teams for post-surgical care.

The researchers concluded that surgical access with subxiphoid window and limited anterior thoracotomy in the EP lab is feasible and safe. Additionally, the surgical approach can be tailored to the region of interest in the ventricle to be mapped and ablated.