Background and aim: The aim of this study was to evaluate the relationship between ECG findings and blood parameters indicative of inflammation and myocardial injury in COVID-19 patients. Methods: The study included 159 females and 194 males. Demographics, ECG findings (axis, rhythm, branch block, ST- and T-wave changes, premature ventricular contractions, early repolarization, S1Q3T3, fragmented QRS [fQRS], rate, PR, QRS, QT interval, QTc, P-wave dispersion) and albumin, D-dimer, ferritin, pro-BNP, procalcitonin, protein, troponin T, neutrophil-to-lymphocyte ratio (NLR), C-reactive protein/albumin ratio (CAR) were recorded. Results: In the study, 45% of the cases were female and 55% were male. The mean age of the included patients was 45.7 ± 24.4 years. The most frequent comorbidities were chronic obstructive pulmonary disease (COPD) and hypertension (HT) in both groups. The incidence of fQRS on the 1st day was significantly higher in patients with negative COVID- 19 test (23% for positive RT-PCR versus 35.6% for negative RT-PCR, p = 0.016). QTc values on the 3rd and 5th day were significantly higher in patients with negative RT-PCR (p = 0.045 and p = 0.042, respectively). Albumin and procalcitonin were significantly higher in patients with positive COVID-19 test results (p = 0.018 and p <0.001, respectively). Patients with fragmented QRS presented significantly lower serum albumin (40.62 ± 4.73 g/L vs. 42.92 ± 3.72 g/L, p = 0.01), and protein levels (p = 0.02), as well as lower lymphocyte count, and significantly higher levels of C-reactive protein (47.01 ± 65.01 mg/L vs. 24.55 ± 44.17 mg/L, p = 0.001), D-dimer (p = 0.009), neutrophil count, pro-BNP (p = 0.004), troponin T (p <0.001), NRL and CAR (1.28 ± 1.83 versus 0.6 ± 1.11, p <0.001). Conclusion: Patients with COVID-19 infection presented significantly higher levels of C-reactive protein, D-dimer, neutrophil, pro-BNP, procalcitonin, troponin T, NLR, and CAR, and significantly lower levels of albumin, lymphocyte count, and serum proteins, indicating the level of inflammation and its relationship with myocardial injury. Further follow-up studies are required, on larger patient sets, for the development of risk prediction tools in COVID-19 patients.