By Samantha Bartlett
Boxer cardiomyopathy, also known as arrhythmogenic right ventricular cardiomyopathy (ARVC), is an inherited heart disease in boxers. The disease is caused by a mutation in the striatin gene which codes for normal cardiomyocyte function. Boxers with this disease have ventricular arrythmias, episodes of collapse, intermittent lethargy and sudden death. Disease severity ranges from asymptomatic to congestive heart failure.
Traditionally, ARVC has been treated with various anti-arrhythmic drugs and require monitoring several times a year with a Holter monitor to ensure the medications are adequate. Even with treatment, these dogs are at risk of sudden death.
Recently, a 9-year-old Boxer named Sophie was presented at Penn’s School of Veterinary Medicine with a new diagnosis of AVRC. Dr. Anna Gelzer, a cardiologist at Penn’s School of Veterinary Medicine reached out to her human medical counterparts to see if something more could be done. In humans with ARVC, a procedure called cardiac ablation targets damaged heart tissue and burns it so that it no longer has a part in driving heart rhythms. Many of these patients can go forward without medication or risk of sudden death.
Dr. Gelzer collaborated with Dr. Cory Tschabrunn at Penn’s School of Medicine Translational Cardiac Electrophysiology Laboratory. Together they decided that cardiac ablation was possible for Sophie. Together, the two medical teams mapped out a plan for Sophie’s procedure.
Before the procedure, a Reveal LINQ device was placed just under the skin. This device is a continuous ECG loop recorder that maps the arrhythmias in Sophie’s heart. This allows the clinicians to target the area of the heart for the ablation. On the day of the procedure, the team used GPS technology, known as CARTO, to map the voltages in Sophie’s heart and find the exact problem areas within the heart. Areas of low voltage are the target tissues for the ablation. With the information gleaned from CARTO, Tschabrunn directed radiofrequency to burn tiny, millimeter-sized portions of tissue in the right ventricle.
Sophie’s pilot case has led to a study with grant funding that will provide more support for cardiac ablation as an option in dogs. Hopefully, in the future it will be much more accessible to dog owners as a result of this research.
