1Universitätsklinikum Mannheim I. Medizinische Klinik Mannheim, Deutschland; 2Universitätsklinikum Mannheim Med. Klinik IV Mannheim, Deutschland
Background:
Ajmaline testing is used to unmask Brugada syndrome (BrS) in case of clinical suspicion. While specificity and sensitivity are considered high, there is no long-term data on the clinical outcome of ajmaline-negative patients who are considered to have no BrS.
Objective:
To assess diagnostic reliability of negative ajmaline test result in patients with suspected BrS
Methods:
279 patients underwent standardized intravenous ajmaline challenge between 2014 and 2022. In 191 patients (68%) the test was considered negative with a fractionated maximal dose up to 1mg/kg body weight. Of those, 27 patients with documented ventricular fibrillation and history of survived cardiac arrest were excluded from analysis.
In total 164 patients were interviewed using a standardized questionnaire, which included questions regarding occurrence of syncope, unexpected hospitalizations and palpitations. Further, electronic patient files were screened for individual clinical symptoms, e.g., palpitations, syncope, documentation of ventricular tachyarrhythmias and sudden death.
Results:
69 patients (42%) underwent ajmaline testing due to family history of Brugada syndrome or unexplained cardiac arrest, 57 patients (35%) reported at least one unexplained syncope and had ECG abnormalities suggestive of possible Brugada syndrome (e.g. type 2 Brugada pattern), and the remaining 38 patients (23%) had other indications for an ajmaline challenge. Mean age was 42±11 yrs, 109 patients (66%) were male.
80 (49%) patients self-reported outcome data. Recurrent syncope occurred in 11 (14%) patients, during a median follow-up of 75 (IQR 46-88) months. Among those patients 27% had family history of BrS and 73% history of unexplained syncope. 1 patient reported fever-related syncope accompanied by enuresis and seizure. 9 (82%) syncopes occurred at rest and 2 (18%) during or after exercise. Palpitations were reported by 7/11 (64%) patients with syncope and 22/69 (32%) without syncope.
In the cohort of patients with negative ajmaline test, two deaths occurred during follow-up. One male patient with recurrent syncope died age 78 due to complications of subdural hematoma. One female patient with family history of BrS died due to sudden cardiac arrest during daily activity at age 52. No autopsy was available.
Conclusion:
Syncope remains a clinical challenge and frequent symptom in patients with negative ajmaline challenge. Arrhythmic complications could eventually explain the increased rate of cardiac events in this group of patients. Systematic and large-scale follow-up is therefore necessary to assess the reliability of negative ajmaline testing, especially in asymptomatic patients and/or family history of BrS.