ELECTRICAL INJURY - INDUCED ATRIAL FIBRILLATION: A CASE REPORT

Introduction: Electrical injury can cause various cardiac dysrhythmias such as asystole, ventricular fibrillation, sinus tachycardia, and heart blocks. However, it rarely causes atrial fibrillation. Case report: Patient S.M, born in Nis in 1973, was admitted to the emergency department after receiving an electric shock (<600 V). He subsequently lost consciousness, fell down, and sustained back and head injuries. During the examination heart rate was irregular but with no heart murmurs. There was an entry wound on the front of the left thigh and an exit wound on the front of the neck. An electrocardiogram showed newly appearing atrial fibrillation. The laboratory tests showed no pathological deviation and focus cardiac ultrasound showed that contractile force was preserved with no wall-motion abnormalities and normal left atrium dimensions. The patient was administered low-molecular-weight heparin subcutaneously and propafenone (600 mg) orally. At follow up after 24 hours, an electrocardiogram showed normal sinus rhythm. Conclusion: We report a rare case of an electrical injury-induced atrial fibrillation, which was converted to sinus rhythm by pocket therapy. Although most cases of an electrical injury-induced AF represent benign conditions which are self-limited, cardiac monitoring as a routine measure should be considered.


Abstract
Introduction: Electrical injury can cause various cardiac dysrhythmias such as asystole, ventricular fibrillation, sinus tachycardia, and heart blocks. However, it rarely causes atrial fibrillation. Case report: Patient S.M, born in Nis in 1973, was admitted to the emergency department after receiving an electric shock (<600 V). He subsequently lost consciousness, fell down, and sustained back and head injuries. During the examination heart rate was irregular but with no heart murmurs. There was an entry wound on the front of the left thigh and an exit wound on the front of the neck. An electrocardiogram showed newly appearing atrial fibrillation. The laboratory tests showed no pathological deviation and focus cardiac ultrasound showed that contractile force was preserved with no wall-motion abnormalities and normal left atrium dimensions. The patient was administered lowmolecular-weight heparin subcutaneously and propafenone (600 mg) orally. At follow up after 24 hours, an electrocardiogram showed normal sinus rhythm. Conclusion: We report a rare case of an electrical injury-induced atrial fibrillation, which was converted to sinus rhythm by pocket therapy. Although most cases of an electrical injury-induced AF represent benign conditions which are self-limited, cardiac monitoring as a routine measure should be considered. Iako većina ovako nastalih epizoda AF predstavlja tranzitorni poremećaj ritma sa spontanom konverzijom, rutinsko praćenje ovih bolesnika je neophodno.

INTRODUCTION
Atrial fibrillation (AF) is the most common sustained arrhythmia at discharge from hospital (1). The etiopathogenesis of AF is rather complex and usually multifactorial (2).
Arterial hypertension, valvular heart disease and heart failure are listed as the most common causes of AF. Electrical injury can cause various cardiac dysrhythmias such as asystole, ventricular fibrillation, sinus tachycardia, and heart blocks. However, it rarely causes atrial fibrillation (3).
We will present a case of a patient with electrical injury-induced AF as a consequence of an occupational accident.

CASE REPORT
Patient S.M., born in Nis in 1973, was admitted to the emergency department of the Institute for Treatment and Rehabilitation Niska Banja due to feeling palpitations, dizziness, and instability when standing and walking. The patient stated that he had come into direct contact with an exposed wire while using a pool cleaning machine, thus receiving an electric shock (<600 V). He subsequently lost consciousness, fell down, and sustained back and head injuries. He was unaware of how long he had been unconscious but he felt irregular heart rate, dizziness, and exhaustion immediately after regaining consciousness. He confirmed that he was not suffering from any disease and that he had not been hospitalized or clinically examined before. In addition, he denied the consumption of alcohol and the intake of medications and psychoactive substances.
During the examination, the patient was conscious, oriented, eupnoeic, and had normal skin colour. There was an entry wound on the front of the left thigh and an exit wound on the front of the neck (Figure 1). There were no pathological findings in the lungs. Heart rate was irregular but with no heart murmurs. Vital parameters: blood pressure 120/80 mm Hg, heart rate 80 bpm, SaO2 98%, body temperature 36.6 °C, respiration rate 12 per minute.  The patient was administered low-molecular-weight heparin (enoxaparin) subcutaneously and propafenone (600 mg) orally (pocket therapy). Wounds were treated and an antibiotic was administered. At follow up after 24 hours, an electrocardiogram showed normal sinus rhythm (Figure 3). Once again, laboratory tests confirmed normal values. The patient was discharged in a stable state. A decision was made not to administer antiarrhythmic and anticoagulant therapy (CHA2DS2VASc score 0, HAS-BLED score 0).

Figure 3. ECG 24h after the electrical injury
Three months later, a 24-hour ECG Holter monitoring showed normal sinus rhythm.
Moreover, a follow-up cardiac ultrasound showed preserved ejection fraction, with neither valvular heart disease nor segmental wall-motion abnormalities, left atrium 36 mm. A submaximal exercise stress test did not show signs of myocardial ischaemia nor arrhythmias.

DISCUSSION
An electric shock can lead to myocardial necrosis, left ventricular dysfunction, arrhythmia and conduction disorders (4). The most common arrhythmias are sinus tachycardia, sinus bradycardia, ventricular fibrillation, and asystole, whereas the most prevalent conduction disorders are branch blocks, AV blocks of different degrees, and the QT interval prolongation. On the other hand, it is quite rare for an electric shock to cause AF (5).

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The mechanism of AF occurrence as a consequence of an electric shock is complex and only briefly examined. Blood is an excellent conductor of electricity and the heart is one of the most vulnerable organs when it comes to impact of electric current. An electrical injury can lead to myocardial necrosis with subsequent fibrosis that may become a chronic arrhythmogenic focus (6). Furthermore, an electric shock can disrupt the sodium-potassium pump with a subsequent increase in the concentration of potassium, which can potentially lead to a change in the permeability of cardiomyocytes and, therefore, to myocardial depolarization (7).
The other pathogenic mechanisms such as coronary spasm, catecholamine release, and coronary hypoperfusion due to arrhythmia-induced hypotension are uncommon in the basis of the pathogenesis of electric shock-induced AF (8).
Exactly which arrhythmia or conduction disorder occurs as a consequence of an electric shock depends on the intensity of electric current and its type (direct and alternating), the surface area of the body coming into contact with electric current, the duration of the contact, and the state of the patient (9). The changes caused by high voltage current are usually complex and pronounced, whereas those caused by low voltage current (<600 V) are likely to be benign and transitory and it was the case with our patient as well.
Most atrial fibrillations after electric shocks are self-limiting (10), especially when caused by low voltage current (3). Moreover, no AF relapse has been reported so far.
However, Boggild et al. reported a case of electric shock-caused AF with a duration of over 20 years, supporting the notion of chronic damage to left atrium (6). This makes cardiac monitoring a necessary routine measure.
Various treatment methods have been developed to deal with electrical shockinduced AF but with lack of proper guidance and protocols. These include DC cardioversion, pharmacological reversion, or even simple waiting for spontaneous resolution.

CONCLUSION
We report a rare case of an electrical injury-induced atrial fibrillation, which was converted to sinus rhythm by pocket therapy. Although most cases of an electrical injuryinduced AF represent benign conditions which are self-limited, cardiac monitoring as a routine measure should be considered.