Background: Echocardiography is widely used for evaluating cardiovascular symptoms, but its application in routine and non-cardiac evaluations has led to an increased detection of incidental structural heart anomalies. Understanding the prevalence and types of these findings in adults is essential for informed clinical decision-making and risk stratification.

Methods: Methods: A systematic review with descriptive quantitative synthesis was conducted following PRISMA guidelines to identify observational studies and large case series reporting incidental structural heart disease findings in adults via transthoracic or transesophageal echocardiography. Databases searched included PubMed, Embase, Scopus, Web of Science, and Cochrane Library (2000–2024). Eligible studies involved adults (≥18 years) undergoing echocardiography for reasons unrelated to structural heart disease, with documented incidental findings. Data were extracted on prevalence, types of abnormalities, and clinical significance.

Results: Out of 320 identified records, 7 studies met all inclusion criteria. These included a total sample size of 5,693 adult human subjects and 1 veterinary case. The most frequently reported incidental findings were localized septal hypertrophy (0.47%, n=26/5,582), membranous ventricular septal aneurysms (single case), doubled interatrial septum (single case), and coronary artery-to-pulmonary artery fistulas (1.0%, n=101/10,100 pediatric echoes; noted for comparative relevance). Some anomalies, such as right atrial membrane or double atrial septum, influenced surgical decisions or carried embolic risks. Despite being asymptomatic, most findings warranted further imaging or follow-up to rule out complications or mimicry of pathologic conditions like hypertrophic cardiomyopathy.

Conclusion: Incidental structural heart abnormalities detected via echocardiography are uncommon but clinically significant in specific contexts. Their recognition is essential to avoid misdiagnosis, inform patient counseling, and guide appropriate follow-up. Future large-scale population studies are needed to better estimate prevalence and determine clinical implications of these findings.