A 40-year-old man presented with palpitations and dizziness that had been ongoing for several days. EMS found that he was in sustained monomorphic ventricular tachycardia and performed cardioversion to restore regular heart rhythm. In conversation with care providers, the patient recalled a prior episode of chest pain that had lasted for several days. He was brought to Temple Health for further care.

Electrocardiogram suggested a history of heart attack, and echocardiogram confirmed a previous anterior myocardial infarction. This had caused damage resulting in poor LV function, LV apical thrombus, and ventricular tachycardia. 

Doctors determined that the patient was a candidate for EV-ICD, a novel type of ICD that involves threading a lead through the substernal space to deliver anti-tachycardia pacing. The device offers several advantages over ICDs with transvenous leads, including lower risk of subsequent infection, notes Edmond Cronin, MD, CCDS, FHRS, a cardiac electrophysiologist at Temple Health.

“In addition, because there’s nothing in the vein, there’s nothing to cause blockage or stenosis, which can be an issue with traditional transvenous ICDs,” he says.

A Complex Ablation

A few days after implantation, the device was activated and delivered ATP, successfully treating an episode of tachycardia. Less than a week later, the patient experienced a ventricular tachycardia storm. The EV-ICD again delivered ATP and also delivered several shocks to stop some of the episodes. He then returned to Temple for further treatment.

The patient received antiarrhythmic drug therapy and neuromodulation, but these approaches did not entirely prevent further VT.

“Often, in this kind of case, we would do an ablation procedure,” Cronin explains. “But in this patient, it was more complicated because of the thrombus in the left ventricle; you can’t do a conventional ablation in that case.”

The team instead accessed the outer surface of the heart to perform an epicardial ablation. This procedure is rarely done on its own and not combined with an epicardial approach.

To access the epicardial space, the team had to navigate around the EV-ICD. They assessed various approaches and reviewed a CT scan to determine which angle would provide the best access.

The procedure was successful, and six months later, the patient has not experienced any more episodes of VT. “He’s doing very well,” Cronin adds.

What Providers Should Know

The main contraindication for EV-ICD is prior sternotomy. Other than these patients, almost anyone eligible for ICD is a candidate. EV-ICD is particularly attractive for younger patients, since it’s thought that the leads may last longer due to reduced risk of fracture. The procedure should also be considered for people who are prone to infections involving the bloodstream, as well as patients who’ve had problems with other defibrillators.

Cronin noted that it’s the first time these advanced procedures have been combined in the U.S.

“Having the expertise to both put in an EV-ICD and also perform the epicardial ablation was key, because it meant we knew exactly what to do, even though that combination had never been done before,” he says.