The Role of Thorough Clinical Evaluation in Inherited Arrhythmia Clinic in the Prevention, Diagnosis and Prognosis of Non Ischemic Sudden Cardiac Death

Background: Determining the pathogenesis of sudden cardiac death (SCD) is crucial for management and prognosis. Our aim was to analyze the effectiveness of thorough clinical evaluation in a specialized unit.

Methods: The study included 101 families with at least 1 index case of SCD (resuscitated or not), age 29± 17. Survivors were studied with ECG, 12 lead holter (12LH), exercise testing, cardiac imaging, familial study (FS) and genetic testing (GT). Families with deceased probands were studied using the ECG before, postmortem findings (PM), FS and GT when available.

Results: Channelopathies were the most prevalent diagnosis 43/101 (43%). Cardiomyopathy was in 23 (23%). In 11 patients (11%) the cause of SCD was not genetic. After a thorough clinical evaluation in a specialized clinic, a positive diagnosis was increased from 47% to 88% among the survivors (n=57, 56%). ECG contributed to the diagnosis in 56 patients (55%), 12LH in 48 patients (48%), FS in 31 (31%) and cardiac imaging in 27 (27%). Among the 44 deceased probands the propable diagnosis was given in 29 (66%). This was due to familial evaluation in 14 cases, ECG in 9, GT in 5 and PM finding in 1. GT with NGS was performed in 62 index cases with a positive result in 34 (55%). Of 362 family members (FM) who underwent clinical evaluation, 136 (38%) had an abnormal result. 116 FM (32%) carried a pathogenic mutation. 111 FM are followed in the clinic and medically treated. During 6± 4.8 years, 8 FM experienced appropriate ICD shock, from 19 implanted.

Conclusion: There is a strong likelihood of reaching a diagnosis in SCD after a rigorous protocol in specialized unit. ECG, 12 LH, cardiac imaging and GT are useful tools for the correct diagnosis. Family screening has a major role both in the diagnosis and preventing SCD.