OBJECTIVE: Arrhythmias can occur because of cardiac involvement in patients with brucellosis. We investigated the effect of Brucella (Brucella melitensis) on cardiac arrhythmias in patients without pre-existing arrhythmogenic heart disease. PATIENTS AND METHODS: 205 patients with sinus rhythm who were diagnosed with brucellosis and 205 healthy controls were enrolled. ECG was performed, and the parameters were recorded for each patient. 24-hour ambulatory ECG (Holter) monitoring was conducted, and the recordings were analyzed. The time-domain heart rate variability (HRV) results were evaluated. RESULTS: The average age of the group with brucellosis was 28.9+/-6.4 years, and 57.1% were male. The ECG parameters, including P dispersion (Pd), QT dispersion (QTd), corrected QTd (QTcd), T-peak to T-end (TpTe), and corrected TpTe (TpTec) were longer and TpTe/QT, TpTe/QTc, TpTec/QT, and TpTec/QTc ratios were higher in the study group compared to the control group (p<0.05). Holter monitoring recorded 33 (16.1%) patients in the study group and 3 (3%) in the control group with abnormal rhythms. In the brucellosis group, low frequency (LF), low/high frequency (LF/HF), and the standard deviation of all R-R intervals (SDNN) values, which are known HRV indicators, were substantially different than in the control group (p<0.001). CONCLUSIONS: We can evaluate the silent involvement of the cardiac conduction system in patients with brucellosis using ECG parameters, which is a non-invasive and simple method in terms of feasibility in clinical follow-up.