1. Introduction

Electrical injuries, ranging from low-voltage household accidents to high-voltage industrial accidents, are a major public health problem affecting the whole world and can cause serious morbidity and mortality [1,2]. While the incidence of electric burns in Europe is 4–5%, in the United States of America, approximately 4400 cases of electrical shock are reported annually, 3–8% of which result in death [2–4]. Cardiac complications, especially arrhythmias are one of the most important causes of mortality and morbidity in electrical injuries [3–5].

Trauma caused by electrical injuries can lead to multiple organ damage by affecting the skin, musculoskeletal system, cardiovascular system and nervous system [3–5]. However, electric currents passing through the body tends to follow the least resistance; i.e., the neurovascular structures. Therefore, cardiac involvement is common in electrical injuries and sometimes severe myocardial damage can occur even without significant skin damage [5]. Cardiac effects of electric current are caused by direct thermal damage, electrical simulation and electroporation mechanisms [6,7]. These effects can result in various arrhythmias both in early and late stages [7]. Because of the risk of cardiac injury, both prehospital and hospital emergency room personnel must be trained and alert [8]. For the detection of these arrhythmias, close cardiac monitoring is required in emergency departments, but there is no consensus in the literature regarding which patients require cardiac monitoring following electrical injuries. Various factors affecting the decision for cardiac monitoring in electrical injuries have been identified. These include the voltage level, the path the current takes through the body, the duration of exposure and the patient’s co-morbidities [9]. Although the risk of cardiac complications increases in high-voltage injuries, serious complications can be seen in low-voltage injuries too [10]. Despite these factors, while some authors advise 24-hour cardiac monitoring for all patients with electrical injuries, others consider it necessary for only high risk patients [7,11]. These differences in approach make it difficult to strike a balance between the use of limited hospital resources and patient safety.

In this study, we aimed to investigate the prevalence of cardiac arrhythmias and the factors associated with the development of arrhythmia in patients presenting to the emergency department (ED) after an electric shock, in order to help ED physicians assess these patients and take the necessary precautions. In this way, emergency physicians and pre-hospital medical care providers will be able to identify patients at risk of developing cardiac arrhythmias at an early stage and will be informed about the need for closer and monitored observation.

2. Materials and methods

3. Results

A total of 189 patients who met the criteria were included in the study. The study design is shown in Fig 1. The mean age of patients included in the study was 27.9 ± 15.3 years and 87% were male. 21.2% (40) of the patients developed arrhythmias. The demographic and clinical characteristics and laboratory parameters of the patients according to whether or not they developed an arrhythmia are shown in Table 1. The most common rhythms in patients who developed arrhythmia were sinus tachycardia and non-specific S-T and T changes; rhythm distribution in patients who developed arrhythmia is shown in Fig 2.

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Table 1. Demographic and clinical characteristics of patients with electrical injury.

https://doi.org/10.1371/journal.pone.0337812.t001

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Fig 1. Flow diagram of study population selection.

This flowchart outlines the selection process for the final study population evaluating electrical injuries between 2019 and 2023. From an initial cohort of approximately 3,120,000 emergency department visits and 1,920,000 pre-hospital emergency medical service cases, a total of 384 electrical injury cases were identified. Following exclusion of patients due to age under 18 (n = 52), pregnancy (n = 8), missing medical records (n = 61), absence of routine blood tests or ECG (n = 42), and known rhythm disorders or coronary artery disease (n = 32), the final study population consisted of 189 eligible cases.

https://doi.org/10.1371/journal.pone.0337812.g001

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Fig 2. Distribution of cardiac arrhythmias in patients with electrical injuries.

This pie chart illustrates the distribution of various cardiac arrhythmias observed in patients presenting with electrical injuries. The most common arrhythmia was sinus tachycardia (>100 bpm), observed in 27% of cases, followed by non-specific ST-T changes (17%) and ventricular premature beats (10%). Other identified arrhythmias included sinus bradycardia (<50 bpm), right bundle branch block, supraventricular extrasystoles, atrial fibrillation, ventricular tachycardia, ventricular fibrillation, and electrical activation without pulse. Each category is represented as a percentage of the total arrhythmic events identified during the study.

https://doi.org/10.1371/journal.pone.0337812.g002

Age, CK, troponin, lactate and high voltage were statistically significantly higher in the arrhythmia group than in the non-arrhythmia group (p:0.023, p:0.008, p:0.046, p < 0.001, p = 0.012 respectively). Statistically significant parameters were included in the regression model. In multivariate regression analysis, age (OR: 1.02, 95%CI: 1.01–1.05), CK > 850 U/L (OR: 1.32, 95%CI: 1.17–1.81), troponin >250 ng/ml (OR: 01.23, 95%CI: 1.09–1.72), lactate (OR: 2. 51, 95%CI: 1.67–5.91) and industrial current (OR: 2.03, 95%CI: 1.64–5.39) were identified as independent risk factors (Table 2). We performed ROC analysis to determine the predictive power of cardiac arrhythmia in electrical accidents. We found that high voltage was a predictor of arrhythmia at a cut-off voltage of ≥1000 volts (AUC: 0.804) and was more valuable than lactate (AUC: 0.782) and CK (AUC: 0.792) (Table 3).

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Table 2. Univariate and multivariate analysis of predictive factors for arrhythmia in electric shocks.

https://doi.org/10.1371/journal.pone.0337812.t002

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Table 3. Analysis of the area under the ROC curve for arrhythmia in electrical accidents.

https://doi.org/10.1371/journal.pone.0337812.t003

4. Discussion

Electrical shocks are a major cause of morbidity and mortality worldwide [11,13,14]. Although it affects all systems in the body, its effect on the cardiovascular system is the most lethal one [11,15]. Cardiovascular effects can include myocardial damage, arrhythmias and even cardiac arrest [13,15]. It has been suggested that electric currents may cause permanent damage to the cardiac conduction tissue and thus cause predisposition to early and late stage arrhythmias [11]. Cardiac arrhythmia, which can occur in the early stages after an electrical shock and be life-threatening [2,4], is a major concern for emergency physicians. Therefore, we planned to evaluate the risk of cardiac arrhythmia in patients following an electrical shock and to investigate the associated factors. In our study, we found that cardiac arrhythmia was not detected in 21.2% of patients following an electrical shock, and the risk of developing arrhythmia was increased significantly in patients with high voltage exposure (especially work related injuries), advanced age, high CK, troponin and lactate levels.

In our study, we found that sinus tachycardia and non-specific ST-T changes were the most common rhythm disorders in patients who developed arrhythmia. Waldmann et al. reported that tachycardia due to the activation of the sympathetic nervous system was common in electrical injuries [16]. A detailed study by Jensen et al. showed that electric current increases the risk of arrhythmia by causing direct myocardial damage and repolarisation abnormalities [2]. Our study highlighted that ventricular arrhythmias were more common with high voltage electrical injuries. In their study analysing the natural course of electrical injuries, Solem et al. reported that ST-T changes and tachyarrhythmias were predominant in the early stages [17].

CK and troponin levels are important markers used to assess myocardial damage after an electrical shock [18]. Electric currents can cause damage to skeletal muscles and myocardium, leading to increased CK levels [16]. While it has been emphasised that especially CK-MB results should be interpreted with caution because of peripheral muscle damage [18], troponin is a marker specific to myocardial damage, and the damage and necrosis in myocardial cells caused by electrical shock may lead to elevated troponin levels [19]. The study by Douillet et al. shows that troponin levels are used to predict myocardial damage due to electrical shock [20]. Purdue et al. reported that elevated cardiac enzymes are an important risk factor for developing arrhythmia in electrical injuries [18]. In our study, a significant relationship has been found between elevated troponin and CK-MB levels and the development of arrhythmia. The risk of arrhythmia was significantly increased in patients with troponin >250 ng/mL (OR: 1.23, 95% CI: 1.09–1.72).

We also found lactate levels to be an important predictor of arrhythmia development after electrical shock (OR: 2.51, 95% CI: 1.67–5.91). The risk of arrhythmia was significantly increased in patients with lactate >2.1 mmol/L. Dahl et al. reported in their experimental study that electric currents caused direct myocardial damage and that this damage could be detected by biochemical markers [7]. In light of these findings, it can be said that elevated lactate levels are an important risk factor that requires close cardiac monitoring, especially in high-voltage electrical injuries.

The relationship between the level of voltage and the development of arrhythmia is one of the most important findings of our study. The rate of arrhythmia development was found to be significantly higher in the high voltage group (≥1000V) (AUC: 0.804). In a series of 65 cases, DiVincenti et al. emphasised that cardiac complications were more frequent in patients with high voltage exposure and that these patients required close follow-up [21]. Wilbourn et al. also reported that voltage level was one of the most important factors in determining the clinical course of electrical injuries [22].

There was no association between whether patients came from urban or rural areas and the development of arrhythmias. In addition, there was no delay in the transport times of pre-hospital medical services, and this factor was also not related to the occurrence of arrhythmias (p-values > 0.05). In the study by Drahap et al., no significant association was found between pre-hospital time and the mortality of trauma patients [23].

Our study has several limitations. Firstly, there were difficulties in accessing some data due to its retrospective design. This limited the assessment of late stage follow-up outcomes in particular. In addition, our study population consists of patients presenting to a single centre and therefore the generalisability of our findings may be limited. However, our study also has its strengths. Few studies in the literature have analysed the risk factors associated with developing arrhythmia following electrical shocks in such a comprehensive manner. Both the sufficient number of patients and the availability of detailed cardiac monitoring data increase the reliability of our study.

5. Conclusions

In conclusion, determining the factors that predict the development of arrhythmias following electrical shocks is important in terms of efficient use of resources and patient safety. As found in our study, closer follow-up of patients with high-voltage exposure, CK > 850 U/L, troponin >250 ng/mL, lactate >2.1 mmol/L may allow early diagnosis and treatment of possible cardiac complications. This approach will ensure that high-risk patients are not overlooked. However, future studies could look more closely at the factors associated with the development of arrhythmias after electrical shocks by analysing larger groups of patients and different types of electrical shocks. In addition, strategies and treatments to prevent the development of arrhythmias following electrical shocks can be explored.

Supporting information

Acknowledgments

There is no person, instution or company to acknowledgement.

Animal and Human Rights Statement: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. No animal studies were carried out by the authors for this article.

Scientific Responsibility Statement: All authors declare that they are responsible for the scientific content of this article. This responsibility covers all aspects of the manuscript including the study design, data collection, analysis and interpretation, writing, preparation, scientific review, and approval of the final version of the article.