Cardiac Sarcoidosis Diagnosis: IHJ, 2025 North Indian Study Identifies Diagnostic Hurdles and Clinical Profiles
A recent observational study highlights significant difficulties in diagnosing Cardiac Sarcoidosis (CS), particularly when the disease presents with primary cardiac symptoms but lacks evidence in other organs. Researchers found that ventricular tachycardia (VT) was the most common clinical manifestation, yet a definitive histological diagnosis remained elusive for the majority of patients.
These findings are published in August 2025 in the Indian Heart Journal (IHJ).
The Clinical Burden of Granulomatous Inflammation
CS is a multisystem disorder of unknown cause defined by chronic, non-necrotizing granulomatous inflammation. This condition is associated with high rates of illness and death and is often suspected when patients present with new-onset conduction disturbances, such as Complete Heart Block (CHB), or unexplained Heart Failure (HF). Traditionally, diagnosis relies on international guidelines like those from the Heart Rhythm Society (HRS) or the Japanese Circulation Society, which require evidence of the disease outside the heart. However, many patients exhibit isolated cardiac involvement, creating a substantial diagnostic gap and leaving many cases classified as uncertain.
Study Overview
The retrospective, hospital-based study was conducted at a tertiary care facility in North India, analyzing 42 patients who presented with clinical features suggestive of cardiac sarcoidosis and imaging evidence of patchy myocardial inflammation. The study cohort was predominantly male (average age of 40.7 years) and underwent extensive evaluation, including positron emission tomography (PET), contrast-enhanced cardiac magnetic resonance imaging (MRI), and various biopsy procedures. Researchers applied existing diagnostic criteria to evaluate the effectiveness of current protocols in a real-world clinical setting.
The key findings from the study include:
• Among the 42 patients, VT was the most frequent cardiac manifestation (47.6%), followed by HF (28.5%) and CHB (23.8%).
• The diagnostic yield of Endomyocardial Biopsy (EMB)—the supposed gold standard—was remarkably low; only one out of 11 patients (9%) who underwent the procedure showed histological proof of the disease.
• While imaging via PET and MRI showed a high concordance rate of 79%, only 28% of the total population had any biopsy-proven evidence of sarcoidosis from either cardiac or extracardiac sources.
• Notably, 71.4% of patients remained in the "uncertain" diagnostic category according to the Heart Rhythm Society 2014 criteria because they lacked the required extracardiac clinical or histological evidence.
Clinical Relevance and Targeted Prevention
For practicing physicians, this study underscores that isolated cardiac sarcoidosis is a frequent but difficult-to-confirm presentation that often bypasses established diagnostic criteria. The poor yield of heart biopsies (9%) and the absence of extracardiac findings in many patients suggest that clinicians should maintain a high index of suspicion even when standard tests are inconclusive. Furthermore, in regions where tuberculosis (TB) is endemic, the fact that nearly 10% of the cohort had evidence of tubercular infection—which closely mimics sarcoidosis—adds a significant layer of diagnostic complexity. Overall, there is an urgent need for updated diagnostic classifications to better capture isolated cardiac presentations and ensure that these high-risk patients receive timely and appropriate treatment.
Reference
Panda A, Kumar S, Naik N. Challenges in diagnosis of cardiac sarcoidosis-an observational study from tertiary care center in north India. Indian Heart Journal. 2025 Aug;77:459–461. doi:10.1016/j.ihj.2025.08.003.
