Archives of Academic Emergency Medicine. 2021; 9(1): e45 OR I G I N A L RE S E A RC H Electrocardiographic Findings and In-Hospital Mortality of COVID-19 Patients; a Retrospective Cohort Study Mohammad Haji Aghajani1,2, Amirmohammad Toloui3, Moazzameh Aghamohammadi1,2, Asma Pourhoseingholi1, Niloufar Taherpour1, Mohammad Sistanizad1,4, Arian Madani Neishaboori3, Ziba Asadpoordezaki5,6,7, Reza Miri1,2∗ 1. Prevention of Cardiovascular Disease Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 2. Department of Cardiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 3. Physiology Research Center, Iran University of Medical Sciences, Tehran, Iran. 4. Department of Clinical Pharmacy, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 5. Department of Psychology, Maynooth University, Kildare, Ireland. 6. Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Kildare, Ireland. 7. Imam-Hussein Medical and Educational Centre, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Received: April 2021; Accepted: May 2021; Published online: 12 June 2021 Abstract: Introduction: Although current evidence points to the possible prognostic value of electrocardiographic (ECG) findings for in-hospital mortality of COVID-19 patients, most of these studies have been performed on a small sample size. In this study, our aim was to investigate the ECG changes as prognostic indicators of in-hospital mortality. Methods: In a retrospective cohort study, the findings of the first and the second ECGs of COVID-19 patients were extracted and changes in the ECGs were examined. Any abnormal finding in the second ECG that wasn’t present in the initial ECG at the time of admission was defined as an ECG change. ECGs were interpreted by a cardiologist and the prognostic value of abnormal ECG findings for in-hospital mortality of COVID-19 pa- tients was evaluated using multivariate analysis and the report of the relative risk (RR). Results: Data of the ECGs recorded at the time of admission were extracted from the files of 893 patients; likewise, the second ECGs could be extracted from the records of 328 patients who had an initial ECG. The presence of sinus tachycardia (RR = 2.342; p <0.001), supraventricular arrhythmia (RR = 1.688; p = 0.001), ventricular arrhythmia (RR = 1.854; p = 0.011), interventricular conduction delays (RR = 1.608; p = 0.009), and abnormal R wave progression (RR = 1.766; p = 0.001) at the time of admission were independent prognostic factors for in-hospital mortality. In the second ECG, sinus tachycardia (RR = 2.222; p <0.001), supraventricular arrhythmia (RR = 1.632; p <0.001), abnormal R wave progression (RR = 2.151; p = 0.009), and abnormal T wave (RR = 1.590; p = 0.001) were also independent prognostic factors of in-hospital mortality. Moreover, by comparing the first and the second ECGs, it was found that the incidence of supraventricular arrhythmia (RR = 1.973; p = 0.005) and ST segment elevation/depression (RR = 2.296; p <0.001) during hospitalization (ECG novel changes) are two independent prognostic factors of in-hospital mortality in COVID-19 patients. Conclusion: Due to the fact that using electrocardiographic data is easy and accessible and it is easy to continuously monitor patients with this tool, ECGs can be useful in identi- fying high-risk COVID-19 patients for mortality. Keywords: Electrocardiography; Prognosis; Hospital mortality; COVID-19 Cite this article as: Haji Aghajani M, Toloui A, Aghamohammadi M, Pourhoseingholi A, Taherpour N, Sistanizad M, Madani Neishaboori A, Asadpoordezaki Z, Miri R. Electrocardiographic Findings and In-Hospital Mortality of COVID-19 Patients; a Retrospective Cohort Study. Arch Acad Emerg Med. 2021; 9(1): e45. https://doi.org/10.22037/aaem.v9i1.1250. ∗Corresponding Author: Reza Miri; Department of Cardiology, Imam Hossein Hospital, Madani St., Tehran, Iran. Phone/Fax: +982173432383/77582733, E- mail: miri.reza@yahoo.com, ORCID: https://orcid.org/0000-0002-8568-9948. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem M. Haji Aghajani et al. 2 1. Introduction COVID-19 is the name of a disease, caused by the novel "Se- vere Acute Respiratory Syndrome Coronavirus 2", which ap- peared in December 2019 in Wuhan, China. Since the an- nouncement of the global pandemic of COVID-19 until De- cember 13, 2020, the number of infected people has ex- ceeded 70 million cases and the death toll has exceeded 1.5 million people worldwide, according to the World Health Or- ganization (1). Overall, COVID-19 can cause a range of symp- toms in different patients, from a mild to a severe and fatal disease (2). There are Studies demonstrating that COVID-19 is a multi- factorial disease, affecting not only the lungs, but also the central nervous system, the cardiovascular system, and even the blood circulation system (3-6). The available clinical ev- idence suggests that current treatments are mostly symp- tomatic, and no definitive cure is yet available. The efficacy of current antiviral and nonsteroidal anti-inflammatory drugs is still questionable (7-9). Since there is no definitive cure available for COVID-19, it may be possible to manage and monitor high-risk patients more accurately, and commence critical care by observing the red flags in patients from the beginning of disease. Sev- eral factors have been proposed for predicting the outcome of COVID-19 patients. Current findings indicate that older age and the presence of comorbidities such as hyperten- sion, diabetes, and cardiovascular diseases are associated with COVID-19 severity, and the highest mortality rates have been observed in these groups of patients (10). Heart failure and cardiac arrest are among the most common causes of death in COVID-19 patients (11). Arrhythmias and electro- cardiographic changes, both due to the administered drugs and as direct effects of the virus, have also been reported (12, 13). In general, ECG is a very useful tool in diagnosing a variety of cardiac disorders. In most cases, electrocardiograms help in diagnosis of myocarditis, arrhythmias and heart failure (14). Due to changes in heart’s electrical activity in most cardio- vascular diseases and its diagnostic value in cardiac damage, and since heart’s damage in the course of COVID-19 is as- sociated with a high mortality rate, the assessment of ECG changes could be used in determining disease prognosis and management of patients (15). Although several studies have been performed to evaluate the prognostic value of electro- cardiographic findings for mortality of COVID-19 patients, most of these studies have a small sample size and they only assess the relationship between electrocardiographic find- ings at the time of admission and patients’ overall mortality (12). Nonetheless, the effect of electrocardiographic changes during hospitalization on patients’ in-hospital mortality is not clear. Given the facts above, our aim in this study was to assess the value of changes in patients’ ECGs as prognos- tic indicators of in-hospital mortality based on a study with large sample size. 2. Methods 2.1. Study design and setting The present retrospective cohort study was performed on the records of patients who were admitted to Imam-Hossein Hospital in Tehran, between 18 February and 10 July 2020. The present study was approved by the ethics committee of Shahid Beheshti University of Medical Sciences (Ethics code: IR.SBMU.RETECH.REC.1399.681) and the researchers adhered to the principles of the Helsinki Convention. 2.2. Subjects All patients with COVID-19 who had at least one ECG dur- ing their hospital stay were included in this study. COVID-19 infection was confirmed by a positive RT-PCR (polymerase chain reaction) test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from a nasopharyngeal speci- men (nasopharynx). Exclusion criteria were patients with- out sufficient information in their hospital records, patients without a recorded discharge status (dead or alive) or pa- tients with known ECG abnormalities. 2.3. Data collection Baseline and demographic variables of patients were ex- tracted from the hospital’s patient registration system. A total of 893 patients had at least one ECG during hospitalization and more evaluation of these records revealed that 328 pa- tients had also a second ECG. ECGs were interpreted by a car- diologist, and to ensure data accuracy, ECGs were randomly re-examined by a senior cardiology attending. The findings of the first and the second ECGs were reviewed separately and recorded in the statistical program. If an abnormal finding was repeated in at least two leads, it was included in the study as a definite abnormal find- ing. All ECGs were recorded by a 12 standard-lead electro- cardiography tool. Electrocardiographic findings were sinus tachycardia, sinus bradycardia, supraventricular arrhythmia, ventricular arrhythmia, right bundle branch block (RBBB), left bundle branch block (LBBB), incomplete RBBB, incom- plete LBBB, left anterior hemi-block, posterior Interventric- ular conduction delay (IVCD), bifascicular block, abnormal R Wave progression in precordial leads, presence of Q wave, prolonged QT interval, ST segment abnormalities, and ab- normal T wave. To evaluate ECG changes, any abnormal finding in the second ECG that wasn’t present in the initial one at the time of admission was defined as a change in the ECG; accordingly, abnormal findings were defined as any changes in the waves’ shape or differences in length or timing This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem 3 Archives of Academic Emergency Medicine. 2021; 9(1): e45 of the normal components of an ECG. 2.4. Statistical Analysis Continuous variables were described as mean ± standard deviation (SD), and categorical variables were expressed as counts (percentage). We have examined normality assump- tion by checking kurtosis, skewness, box plot and Q-Q plot. T-test and Mann–Whitney U test were used for comparisons of means of variables in alive and dead patients. Besides, for evaluating the association between categorical variables, Chi-square test and fisher’s exact test were used. In addi- tion, a multivariate logistic regression model was performed for investigating the association of electrocardiographic find- ings and in-hospital mortality of COVID-19 patients. To avoid over-fitting in the multivariate model, only factors which had a p-value less than 0.1 in univariate analysis were selected for the multivariate model. Final model was selected according to backward Wald logistic regression. The findings were re- ported as odds ratio (OR) and 95% confidence interval (95% CI). Two-side P-value less than 0.05 was considered statis- tically significant. All analyses were done using Statistical Package for the Social Sciences (SPSS) 24.0. 3. Results 3.1. Baseline characteristics The data of 893 ECGs at the time of admission was docu- mented in patients’ records and could be extracted; Of these, 494 patients were male (55.3%). The mean age of patients was 61.8±17.2 years (range: 10-99 years). The duration of hospitalization varied between 1 and 80 days (mean ± SD: 7.9 ± 6.8 days). 107 patients (12%) were admitted to the ICU and 231 patients (25.9%) finally passed away (Table 1). 3.2. First ECG and in-hospital mortality According to the patients’ records, 893 patients had an in- terpretable ECG at the time of admission. Examination of these ECGs showed that the most common abnormal find- ings in the ECG of COVID-19 patients at the time of ad- mission were Sinus tachycardia (35.5%), abnormal T wave (24.7%), ST segment depression (19.1%), and prolonged QT interval (18.2%), bi-fascicular block (17.2%), and left anterior hemi-block (13.2%). Univariate analyses showed that age (p <0.001), sinus tachycardia (p <0.001), sinus bradycardia (p = 0.022), supraventricular (p <0.001) and ventricular (p = 0.037) arrhythmias, IVCD (p = 0.007), abnormal R wave progression in peri-cordial leads (p = 0.002), ST segment elevation / de- pression (p = 0.002), and abnormal T wave (p = 0.023) had a significant correlation with in-hospital mortality of COVID- 19 patients (Table 1). Multivariate analysis showed that increasing age (RR = 1.036, 95% CI: 1.029, 1.044; p <0.001) is one of the prognostic fac- tors of in-hospital mortality in COVID-19 patients. Addition- ally, sinus tachycardia (RR = 2.342; 95% CI: 1.250, 2.280; p <0.001), supraventricular arrhythmia (RR = 1.688; 95% CI: 1.250, 2.280; p = 0.001), ventricular arrhythmia (RR = 1.854; 95 % CI: 1.154, 2.979; p = 0.011), IVCD (RR = 1.608; 95% CI: 1.129, 2.291; p = 0.009), and abnormal R Wave progression (RR = 1.766; 95% CI: 1.260, 2.474; p = 0.001) in the initial ECG at the time of admission were independent prognostic fac- tors of in-hospital mortality (Table 2). 3.3. Second ECG and in-hospital mortality Examination of patients’ records showed that 328 patients underwent a second ECG examination during their hospi- tal stay. The most common abnormal findings on the sec- ond ECGs were abnormal T wave (31.1%), sinus tachycardia (30.5%), ST segment depression (22.6%), prolonged QT in- terval (20.1%), bifascicular block (16.1). %), supraventricular arrhythmia (11.9%), left anterior hemi-block (11.3%), and si- nus bradycardia (10.7%). Univariate analyses illustrated that the presence of sinus tachycardia (p = 0.001), sinus brady- cardia (p = 0.011), supraventricular arrhythmia (p <0.001), ST segment elevation / depression (p = 0.037), and abnormal T wave (p = 0.003) in the second ECG of patients had a signif- icant correlation with their in-hospital mortality. Moreover, the correlation between mortality of patients and the pres- ence of IVCD (p = 0.065) and abnormal R wave progression in peri-cordial leads (p = 0.059) in the second ECG was also close to the significance level (Table 3). Multivariate analysis showed that older age (RR = 1.022, 95% CI: 1.014, 1.031; p <0.001) is still one of the independent prog- nostic factors of in-hospital mortality in COVID-19 patients. Likewise, the presence of sinus tachycardia (RR = 2.222; 95% CI: 1.597, 3.091; p <0.001), supraventricular arrhythmia (RR = 1.632; 95% CI: 1.792, 3.866; p <0.001), abnormal R Wave pro- gression (RR = 2.151) 95% CI: 1.206, 3.834; p = 0.009), and ab- normal T wave (RR = 1.590; 95% CI: 1.221, 2.069; p = 0.001) in the second ECG were independent prognostic factors of in- hospital mortality (Table 4). Electrocardiographic changes during hospitalization and in-hospital mortality Data of 328 patients were analysed in this section. By com- paring the second ECG with the ECG at the time of admis- sion, it was found that the most common changes in elec- trocardiograms during hospitalization were sinus tachycar- dia (11.5%), prolonged QT interval (9.0%), sinus bradycardia (6.7%), ST segment elevation/depression (4.3%), abnormal T wave (4.0%), supraventricular arrhythmia (4.0%), and ven- tricular arrhythmia (3.4%), respectively. Univariate analyses showed that the incidence of supraventricular arrhythmia (p = 0.029) and ST segment elevation/depression (p=0.006) dur- ing hospitalization has a strong correlation with patients’ in- hospital mortality (Table 5). This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem M. Haji Aghajani et al. 4 Moreover, multivariate analysis showed that supraventricu- lar arrhythmia (RR = 1.973; 95% CI: 1.234, 3.154; p = 0.005) and ST segment elevation/depression (RR = 2.296; 95% CI: 1.574, 3.349; p < 0.001) during hospitalization, were two independent prognostic factors of in-hospital mortality in COVID-19 patients (Table 6). 4. Discussion This retrospective cohort is one of the few studies with a large sample size, which investigates the prognostic value of COVID-19 patients’ ECG findings in predicting their in- hospital mortality. The findings of the present study dis- closed that abnormal changes in the ECG, both at the time of admission and during hospital stay can be used for pre- dicting disease prognosis. The analyses were performed in three sections. In the first part, the relationship between elec- trocardiographic findings at the time of admission and in- hospital mortality of COVID-19 patients was studied. In the second part, the relationship between in-hospital mortality and abnormal findings in the second ECG of patients dur- ing hospitalization was investigated. Finally, the relationship between the in-hospital mortality of COVID-19 patients and the changes that occurred between the first and the second ECG was investigated. An interesting point obtained from all three sections of the analysis is the proof of the prognostic role of supraventricular arrhythmia in predicting in-hospital mortality of COVID-19 patients. It was also found that the presence of sinus tachycardia and abnormal R Wave progres- sion in precordial leads, both in the first and the second ECG of patients has a significant independent relationship with in-hospital mortality in COVID-19 patients. Finally, the pres- ence of abnormal T wave in the second ECG or ST segment elevation/depression during hospitalization is a prognostic factor for mortality of COVID-19 patients. In the present study, supraventricular arrhythmia consisted of atrial fibrillation, atrial flutter, premature atrial contrac- tion, atrial tachycardia, and multifocal atrial tachycardia. In all three parts of analysis, it was found that supraventricular arrhythmia has a significant and independent relationship with mortality in patients with COVID-19. Numerous stud- ies have shown that the occurrence of supraventricular ar- rhythmias, especially atrial fibrillation, increases the risk of stroke, heart attack, heart failure, and sudden cardiac death by increasing the risk of thrombosis. To be further illustrated, sudden cardiac death is the most common cause of cardiac death in patients with atrial fibrillation (16). In a situation with increased pressure on the cardiovascular system, due to hyperactivity of the immune system or infection, the oc- currence of atrial arrhythmias with a risk of thrombosis, in- creases the risk of fatal cardiovascular events; and It must be taken into consideration that COVID-19 itself, especially in its severe forms, also rigorously increases the risk of throm- bosis (17). Moreover, the risk of complications from atrial fibrillation such as stroke and thrombosis increase in the set- ting of other underlying diseases such as dyslipidaemia and diabetes, which have also been shown to be associated with more severe COVID-19 (18). There are other studies that show the association of other types of supraventricular ar- rhythmias, such as premature atrial contraction, with patient mortality (19). The occurrence of abnormal R Wave progression in the pre- cordial leads can point to 4 different causes: anterior myocar- dial infarction, left ventricular hypertrophy, right ventricular hypertrophy, and a natural variant in people whose anterior cardiac forces are weaker than others. Abnormal R Wave pro- gression is expected to be more frequently detected in severe COVID-19; since in most cases, more severe COVID-19 usu- ally occurs in the presence of other comorbidities such as di- abetes and coronary heart disease, and these underlying dis- eases themselves could cause abnormal R Wave progression (20, 21). Considering the fact that abnormal R Wave progres- sion is an independent prognostic factor in predicting pa- tients’ in-hospital mortality, the emergence of this finding in patients’ ECGs could warn physicians of the need for more accurate patient management. Sinus tachycardia is common in patients with severe medi- cal conditions and is significantly associated with COVID-19 patients’ mortality. A patient with severe COVID-19 may de- velop sinus tachycardia due to fever, systemic inflammation, shortness of breath, hypoxia, and dehydration. The presence of untreated sinus tachycardia can lead to ischemia of the heart, decreased cardiac output, cardiomyopathy, cardiac ar- rest, and death (22, 23). Therefore, sinus tachycardia seems to be a warning sign that the patient’s condition could be get- ting worse and the patient is developing a more severe form of COVID-19; accordingly, sinus tachycardia can be used as an indicator in management of COVID-19 patients. Abnormal T wave was another finding that was directly re- lated to in-hospital mortality of COVID-19 patients. T wave inversion has been reported in 27% of patients with my- ocarditis and this T-wave was associated with cardiac edema in the corresponding position on cardiac MRI (24). Nonethe- less, in delayed contrast enhancement imaging, performed to examine cardiac fibrosis, no correlation with T wave inver- sion was observed, which suggests its emergence in the acute phase of myocarditis and cardiac edema (25). Therefore, it seems that the presence of abnormal T wave in patients with COVID-19 may be due to acute myocardial injury as a result of the virus directly attacking the heart tissue, which could seriously affect the outcome of disease. More comprehen- sive studies are needed to prove this hypothesis. The analyses of the present study showed that the occurrence of ST segment elevation/depression during hospital stay in This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem 5 Archives of Academic Emergency Medicine. 2021; 9(1): e45 a patient who had a normal ST segment at the time of ad- mission, could be an alarm sign of their poor prognosis. The occurrence of ST segment elevation/depression during hos- pitalization can be due to virus’ direct attack to myocardial tissue, side effects of therapeutic agents used for patients, or an indicator of myocardial ischemia (26). This study, like other retrospective studies, had its limita- tions. First, due to the recent pandemic, access to patients’ previous ECGs taken before the onset of COVID-19 was not possible and they were not included in this study. Second, other diagnostic tools such as echocardiography and labo- ratory tests were not used along with the ECG, as a result, the prognostic value of ECG may be over or underestimated. Moreover, due to the short follow-up period of patients (only during hospitalization), some of the changes that occurred after the second ECG were not included in this study. 5. Conclusion The findings of the present study showed that abnormal changes in ECG, both at the time of admission and dur- ing hospitalization, can be very useful in predicting the prognosis of COVID-19. Supraventricular arrhythmia, sinus tachycardia, and abnormal R wave progression in precor- dial leads, in both of patients’ ECGs had a significant inde- pendent relationship with in-hospital mortality. Abnormal T wave in the second ECG or the presence of ST-segment el- evation/depression during hospitalization can have a good prognostic role in predicting the mortality of COVID-19 pa- tients. Therefore, considering the fact that measuring the electrical activity of heart is a cheap and accessible method and it is easy to continuously monitor patients with this tool, ECGs can be useful in identifying high-risk COVID-19 pa- tients and giving them more medical care. 6. Declarations 6.1. Acknowledgments The authors would like to thank the ICU and CCU medical and nursing personnel of Imam Hossein Hospital, Shahid Be- heshti University of Medical Sciences; Dr. Ainaz Samadi, Dr. Amir Heydari, Dr. Fatemeh Nasiri, Dr. Mahboubeh Ghaz- anfarabadi, Faezeh Nesaei, Faezeh Fakour, Ghazaleh Aman- Abadi, Ghodsi Najjari, Golnoush Mortezaei, Maedeh Sayyad, and Vida Torabi who participated in this project and helped us in performing this project. 6.2. Funding and Support This research has been supported and funded by Shahid Be- heshti university of medical sciences. 6.3. Author contribution Study design: RM, MHA Data gathering: MHA, MA, AP, NT, MS, ZA Data analysis: RM, AP Interpreting the findings: All authors Manuscript writing: All authors 6.4. Conflict of interest The authors declare no conflict of interests. References 1. World Health O. WHO Coronavirus Disease (COVID-19) Dashboard: World Health, Organization; 2020 [Available from: https://covid19.who.int/table. 2. 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Downloaded from: http://journals.sbmu.ac.ir/aaem 7 Archives of Academic Emergency Medicine. 2021; 9(1): e45 Table 1: Baseline characteristics and first electrocardiographic (ECG) findings of COVID-19 patients Variable Alive (n=662) Dead (n=231) Total (n=893) P Age (year; mean ± SD) 58.4±16.9 71.4±13.9 61.8±17.2 <0.001 Sex Women 307 (46.4) 92 (39.8) 399 (44.7) 0.85 Men 355 (53.6) 139 (60.2) 494 (55.3) ECG findings Sinus tachycar- dia No 449 (67.8) 127 (55.0) 576 (64.5) <0.001 Yes 213 (32.2) 104 (45.0) 317 (35.5) Sinus bradycardia No 614 (92.7) 224 (97.0) 838 (93.8) 0.022 Yes 48 (7.3) 7 (3.0) 55 (6.2) Supraventricular arrhythmia* No 616 (93.1) 189 (81.8) 805 (90.1) <0.001 Yes 46 (6.9) 42 (18.2) 88 (9.9) Ventricular arrhythmia# No 646 (97.6) 219 (94.8) 865 (96.9) 0.037 Yes 16 (2.4) 12 (5.2) 28 (3.1) RBBB No 633 (95.6) 219 (94.8) 852 (95.4) 0.611 Yes 29 (4.4) 12 (5.2) 41 (4.6) LBBB No 644 (97.3) 223 (96.5) 867 (97.1) 0.562 Yes 18 (2.7) 8 (3.5) 26 (2.9) Incomplete RBBB No 643 (97.1) 225 (97.4) 868 (97.2) 0.829 Yes 19 (2.9) 6 (2.6) 25 (2.8) Incomplete LBBB No 656 (99.1) 226 (97.8) 882 (98.8) 0.306 Yes 6 (0.9) 5 (2.2) 11 (1.2) Left anterior hemi-block No 570 (86.1) 205 (88.7) 775 (86.8) 0.307 Yes 92 (13.9) 26 (11.3) 118 (13.2) Left posterior hemi-block No 662 (100.0) 229 (99.1) 891 (99.8) 0.067 Yes 0 (0.0) 2 (0.9) 2 (0.2) IVCD No 648 (97.9) 218 (94.4)7 866 (97.0) 0.007 Yes 14 (2.1) 13 (5.6) 27 (3.0) Bifascicular block No 546 (82.5) 193 (83.5) 739 (82.8) 0.710 Yes 116 (17.5) 38 (16.5) 154 (17.2) Abnormal R wave progression No 639 (96.5) 211 (91.3) 850 (95.2) 0.002 Yes 23 (3.5) 20 (8.7) 43 (4.8) Q wave in inferior leads No 624 (94.3) 219 (94.8) 843 (94.4) 0.756 Yes 38 (5.7) 12 (5.2) 50 (5.6) Q wave in lateral leads No 659 (99.5) 231 (100.0) 890 (99.7) 0.573 Yes 3 (0.5) 0 (0.0) 3 (0.3) Q wave in precordial leads No 642 (97.0) 224 (97.0) 866 (97.0) 0.994 Yes 20 (3.0) 7 (3.0) 27 (3.0) Prolonged QT interval No 548 (82.9) 181 (78.7) 729 (81.8) 0.154 Yes 113 (17.1) 49 (21.3) 162 (18.2) This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem M. Haji Aghajani et al. 8 Table 1: Baseline characteristics and first electrocardiographic (ECG) findings of COVID-19 patients Variable Alive (n=662) Dead (n=231) Total (n=893) P Age (year; mean ± SD) 58.4±16.9 71.4±13.9 61.8±17.2 <0.001 ST segment Normal 527 (79.6) 159 (68.8) 686 (76.8) 0.002 Elevation 21 (3.2) 15 (6.5) 36 (4.0) Depression 114 (17.2) 57 (24.7) 171 (19.1) Abnormal T wave No 511 (77.2) 161 (69.7) 672 (75.3) 0.023 Yes 151 (22.8) 31.7 (30.3) 221 (24.7) Abnormal T wave No 511 (77.2) 161 (69.7) 672 (75.3) 0.023 Yes 151 (22.8) 31.7 (30.3) 221 (24.7) IVCD: Interventricular conduction delay; LBBB: Left bundle branch block; RBBB: Right bundle branch block; SD: Standard deviation. *, Supraventricular arrhythmia includes atrial fibrillation, atrial flutter, premature atrial contraction, atrial tachycardia, and multifocal atrial tachycardia. #, Ventricular arrhythmia includes premature ventricular contraction, and ventricular tachycardia. Table 2: Multivariate analysis of abnormal finding in first electrocardiography and in-hospital mortality of COVID-19 patients Variable Relative risk 95% CI P Male sex 1.110 0.913-1.350 0.292 Increase in age 1.036 1.029-1.044 <0.001 Sinus tachycardia 2.342 1.84-2.982 <0.001 Supraventricular arrhythmia* 1.688 1.250-2.280 0.001 Ventricular arrhythmia# 1.854 1.154-2.979 0.011 IVCD 1.608 1.129-2.291 0.009 Abnormal R wave progression 1.766 1.260-2.474 0.001 Abnormal T wave 1.108 0.909-1.350 0.308 CI: Confidence interval; IVCD: Interventricular conduction delay. *, Supraventricular arrhythmia includes atrial fibrillation, atrial flutter, premature atrial contraction, atrial tachycardia, and multifocal atrial tachycardia. #, Ventricular arrhythmia includes premature ventricular contraction and ventricular tachycardia. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem 9 Archives of Academic Emergency Medicine. 2021; 9(1): e45 Table 3: Second electrocardiographic findings of COVID-19 patients Variable Alive (n=218) Dead (n=110) Total (n=328) P Sinus tachycardia No 165 (75.7) 63 (57.3) 228 (69.5) 0.001 Yes 53 (24.3) 47 (42.7) 100 (30.5) Sinus bradycardia No 188 (86.2) 105 (95.5) 293 (89.3) 0.011 Yes 30 (13.8) 5 (4.5) 35 (10.7) Supraventricular arrhythmia* No 203 (93.1) 86 (78.2) 289 (88.1) <0.001 Yes 15 (6.9) 24 (21.8) 39 (11.9) Ventricular arrhythmia# No 213 (97.7) 104 (94.5) 317 (96.6) 0.191 Yes 5 (2.3) 6 (5.5) 11 (3.4) RBBB No 208 (95.4) 103 (93.6) 311 (94.8) 0.493 Yes 10 (4.6) 7 (6.4) 17 (5.2) LBBB No 209 (95.9) 102 (92.7) 311 (94.8) 0.225 Yes 9 (4.1) 8 (7.3) 17 (5.2) Incomplete RBBB No 215 (98.6) 109 (99.1) 324 (98.8) 0.716 Yes 3 (1.4) 1 (0.9) 4 (1.2) Incomplete LBBB No 214 (98.2) 108 (98.2) 322 (98.2) >0.999 Yes 4 (1.8) 2 (1.8) 6 (1.8) Left anterior hemi-block No 194 (89.0) 97 (88.2) 291 (88.7) 0.827 Yes 24 (11.0) 13 (11.8) 37 (11.3) Left posterior hemi-block No 218 (100.0) 108 (98.2) 326 (99.4) 0.112 Yes 0 (0.0) 2 (1.8) 2 (0.6) IVCD No 215 (98.6) 104 (94.5) 319 (97.3) 0.065 Yes 3 (1.4) 6 (5.5) 9 (2.7) Bifascicular block No 186 (84.9) 90 (81.8) 276 (83.9) 0.469 Yes 33 (15.1) 20 (18.2) 53 (16.1) Abnormal R wave progression No 208 (95.4) 99 (90.0) 307 (93.6) 0.059 Yes 10 (4.6) 11 (10.0) 21 (6.4) Q wave in precordial leads No 206 (94.5) 106 (96.4) 312 (95.1) 0.458 Yes 12 (5.5) 4 (3.6) 16 (4.9) Prolonged QT interval No 171 (79.2) 87 (81.3) 258 (79.9) 0.651 Yes 45 (20.8) 20 (18.7) 65 (20.1) ST segment Normal 163 (74.8) 70 (63.6) 233 (71.0) 0.037 Elevation 15 (6.9) 6 (5.5) 21 (6.4) Depression 40 (18.3) 34 (30.9) 74 (22.6) Abnormal T wave No 162 (74.3) 64 (58.2) 226 (68.9) 0.003 Yes 56 (25.7) 46 (41.8) 102 (31.1) IVCD: Interventricular conduction delay; LBBB: Left bundle branch block; RBBB: Right bundle branch block; SD: Standard deviation. *, Supraventricular arrhythmia includes atrial fibrillation, atrial flutter, premature atrial contraction, atrial tachycardia, and multifocal atrial tachycardia. #, Ventricular arrhythmia includes premature ventricular contraction, and ventricular tachycardia. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem M. Haji Aghajani et al. 10 Table 4: Multivariate analysis of abnormal finding in second electrocardiography and in-hospital mortality of COVID-19 patients Variable Relative risk 95% CI P Increase in age 1.022 1.014-1.031 <0.001 Sinus tachycardia 2.222 1.597-3.0915 <0.001 Supraventricular arrhythmia* 1.632 1.792-3.866 <0.001 Ventricular arrhythmia# 1.510* 0.754 -3.022 0.244 Abnormal R wave progression 2.151 1.206-3.834 0.009 Abnormal T wave 1.590 1.221-2.069 0.001 CI: Confidence interval *, Supraventricular arrhythmia includes atrial fibrillation, atrial flutter, premature atrial contraction, atrial tachycardia, and multifocal atrial tachycardia. #, Ventricular arrhythmia includes premature ventricular contraction, and ventricular tachycardia. Table 5: Changes in clectrocardiographic findings during hospitalization in COVID-19 patients Variable Alive (n=218) Dead (n=110) Total (n=328) P Sinus tachycardia No 193 (88.5) 99 (90.0) 292 (89.0) 0.688 Yes 25 (11.5) 11 (10.0) 36 (11.5) Sinus bradycardia No 200 (91.7) 106 (96.4) 306 (93.3) 0.114 Yes 18 (8.3) 4 (3.6) 22 (6.7) Supraventricular arrhythmia* No 213 (97.7) 102 (92.7) 315 (96.0) 0.029 Yes 5 (2.3) 8 (7.3) 13 (4.0) Ventricular arrhythmia# No 213 (97.7) 106 (96.4) 319 (97.3) 0.483 Yes 5 (2.3) 4 (3.6) 11 (3.4) LBBB No 215 (98.6) 106 (96.4) 321 (97.9) 0.174 Yes 3 (1.4) 4 (3.6) 7 (2.1) Left anterior hemi-block No 215 (98.6) 106 (96.4) 321 (97.9) 0.174 Yes 3 (1.4) 4 (3.6) 7 (2.1) Bifascicular block No 212 (97.2) 105 (95.5) 317 (96.6) 0.394 Yes 6 (2.8) 5 (4.5) 11 (3.4) Prolong QT interval No 197 (91.2) 97 (90.7) 294 (91.0) 0.871 Yes 19 (8.8) 10 (9.3) 29 (9.0) Abnormal R wave progression No 214 (98.2) 106 (96.4) 320 (97.6) 0.449 Yes 4 (1.8) 4 (3.6) 8 (2.4) ST segment No 214 (98.2) 100 (90.9) 314 (95.7) 0.006 Yes 4 (1.8) 10 (91) 14 (4.3) Abnormal T wave No 212 (97.2) 103 (93.6) 315 (96.0) 0.137 Yes 6 (2.8) 7 (6.4) 13 (4.0) LBBB: Left bundle branch block. *, Supraventricular arrhythmia includes atrial fibrillation, atrial flutter, premature atrial contraction, atrial tachycardia, and multifocal atrial tachycardia. #, Ventricular arrhythmia includes premature ventricular contraction, and ventricular tachycardia This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem 11 Archives of Academic Emergency Medicine. 2021; 9(1): e45 Table 6: Multivariate analysis of changes in electrocardiographic findings during hospitalization and in-hospital mortality of COVID-19 pa- tients Variable Relative risk 95% CI P Supraventricular arrhythmia 1.973 1.234-3.154 0.005 ST elevation/depression 2.296 1.574-3.349 <0.001 CI: Confidence interval. *, Supraventricular arrhythmia includes atrial fibrillation, atrial flutter, premature atrial contraction, atrial tachycardia, and multifocal atrial tachycardia. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem Introduction Methods Results Discussion Conclusion Declarations References