From the Guidelines
Patients with cardiac sarcoidosis undergoing VT ablation typically require a more extensive approach than standard VT ablation, including both endocardial and epicardial mapping and ablation, due to the patchy and non-contiguous nature of sarcoid granulomas in the heart muscle. This is because sarcoidosis can affect all layers of the heart muscle, making identification and ablation of all potential VT circuits more challenging than with the more discrete scars seen in ischemic heart disease 1.
Key Considerations for VT Ablation in Sarcoidosis Patients
- Success rates for VT ablation in sarcoidosis patients are generally lower than in other VT etiologies, with recurrence rates of 30-50% commonly reported 1.
- Before proceeding with ablation, patients should undergo comprehensive cardiac imaging including cardiac MRI with gadolinium enhancement and PET scanning to identify areas of active inflammation and scarring 1.
- Immunosuppressive therapy with corticosteroids (typically prednisone 30-40mg daily, tapered over months) should be optimized before ablation, as active inflammation can reduce procedural success 1.
- The electrophysiologist performing the ablation should have specific experience with sarcoidosis cases, as the arrhythmogenic substrate differs from typical post-infarction VT 1.
Importance of Early Diagnosis and Intervention
- Early diagnosis and intervention are crucial in sarcoidosis patients, as steroids do not appear to reverse advanced ventricular dysfunction once present 1.
- A systematic combined treatment approach, including medical therapy with steroids and antiarrhythmic medications, followed by radio-frequency catheter ablation if needed, may be effective in managing VT in sarcoidosis patients 1.
- However, the effectiveness of immunosuppressive therapy in reducing VA in patients with cardiac sarcoidosis is still inconsistent, and further studies are needed to determine its role in managing VT in these patients 1.
From the Research
Impact of Sarcoidosis on VT Ablation
- Sarcoidosis is a multisystem granulomatous disease that can affect the heart, leading to ventricular tachycardia (VT) 2.
- The disease has two phases: inflammation and scar, which can both contribute to the development of VT 2.
- VT ablation in patients with cardiac sarcoidosis is technically challenging due to the complex disease substrate, with moderate outcomes and high recurrence rates 2, 3, 4, 5, 6.
Mechanisms of VT in Sarcoidosis
- Macroreentry phenomena around areas of fibrosis is the most frequent mechanism of ventricular arrhythmia in cardiac sarcoidosis 2.
- Inflammation may play a role in initiating reentry with ventricular ectopy in CS patients, or by slowing conduction in diseased tissue 2.
- The ventricular substrate in cardiac sarcoidosis is characterized by confluent right ventricular scarring and patchy left ventricular scarring, capable of sustaining a large number of re-entrant circuits 6.
Outcomes of VT Ablation in Sarcoidosis
- Catheter ablation can be effective in terminating VT storm and eliminating ≥1 inducible VT in the majority of patients with cardiac sarcoidosis 3, 4, 5, 6.
- However, recurrences are common, and multiple procedure VT-free survival is relatively low, ranging from 37% to 60% at 1-2 years 4, 5, 6.
- Preablation left ventricular dysfunction and myocardial inflammation are associated with adverse long-term prognosis 4.
- Ablation in conjunction with antiarrhythmic drugs can help palliate VT in this high-risk population 6.