European Journal of Cardiovascular Medicine

Electrical storm (ES), defined as three or more episodes of ventricular tachyarrhythmia within 24 hours, poses a significant challenge in emergency medicine. Standard interventions such as defibrillation and antiarrhythmic medications are often insufficient, necessitating advanced strategies like dual sequential external defibrillation (DSED) and overdrive pacing.

This case illustrates the successful use of these techniques in managing an electrical storm, with a focus on the prolonged resuscitation efforts that led to a favorable neurological outcome.

A 46-year-old female, morbidly obese presented to the emergency department (ED) of Jaslok Hospital with acute chest pain of about 15-20 minutes. She described the chest pain as diffuse tightness associated with perspiration, one episode of vomiting while she was doing her regular chores.  She had no comorbidities or addictions, except was morbidly obese.

The initial electrocardiogram (ECG), performed within five minutes of arrival, was normal and showed no signs of acute ischemia, with stable hemodynamics. An intravenous line was promptly established, and chest leads were attached. While the examination was underway, the patient retched again and subsequently developed sustained ventricular tachycardia (VT).

Clinical Course: 

Within minutes, the patient experienced repeated episodes of ventricular tachycardia despite defibrillation and antiarrhythmic therapy (amiodarone). She became unresponsive and developed pulseless VT, requiring immediate cardiopulmonary resuscitation (CPR) following the latest Advanced Cardiovascular Life Support (ACLS) guidelines. The diagnosis of electrical storm was established, as the patient had more than three episodes of VT in less than 24 hours, all refractory to conventional defibrillation.

Early Defibrillation and Antiarrhythmic Therapy: 

Defibrillation was initiated promptly with standard doses of amiodarone and lidocaine to control the arrhythmia. Early defibrillation is essential in VT management and significantly increases the chance of terminating life-threatening arrhythmias. However, despite multiple defibrillations, VT recurred, signaling the onset of electrical storm.

Dual Sequential External Defibrillation (DSED): 

With the failure of conventional defibrillation, the medical team employed dual sequential external defibrillation (DSED). This involves administering two near simultaneous shocks from two separate defibrillators, aiming to depolarize a larger portion of the myocardium, which can terminate refractory arrhythmias. While evidence for DSED is still emerging, in this case, it played a pivotal role in breaking the cycle of recurrent VT.

5 Hs and 5 Ts

During ongoing resuscitation, the 5 Hs and 5 Ts are crucial for identifying reversible causes of cardiac arrest. Although the initial ECG was normal and there was no time to repeat the ECG or obtain cardiac markers to confirm cardiac involvement, the patient's clinical presentation and a risk factor of morbid obesity suggested thrombosis as a likely cause of the cardiac arrest. Therefore, intravenous heparin was administered during resuscitation.

Overdrive Pacing: 

Patient achieved ROSC by now but ventricular tachycardia persisted.

Due to the persistence of electrical storm, overdrive pacing was initiated. Overdrive pacing involves using an external pacemaker to pace the heart at a faster rate than its intrinsic rhythm to suppress ventricular tachyarrhythmia. Temporary pacing catheters were placed through venous access, and overdrive pacing, combined with antiarrhythmic medications, successfully stabilized the patient's rhythm.

Prolonged CPR: 

The patient required continuous CPR for 60 minutes, which is considered an extended duration in cardiac arrest.

High quality chest compressions were maintained to ensure adequate perfusion, and defibrillation continued intermittently. Despite the prolonged resuscitation, the team was able to restore a stable heart rhythm.

Post-ROSC Management

The patient, who was already intubated and sedated, had targeted temperature management initiated immediately. A repeat ECG confirmed an anterior wall myocardial infarction. A loading dose of antiplatelet agents was administered, along with vasopressor support.

Coronary Intervention: 

Following rhythm stabilization, the patient was taken for emergency coronary angiography, which revealed an occluded coronary artery hence  A stent was placed 

Outcome: 

Amazingly, the patient regained consciousness within 24 hours of the cardiac arrest, showing no signs of neurological impairment. She was successfully weaned off the ventilator by the second day and was breathing independently. Within 48 hours, she was alert, responsive, and beginning mobilization. The patient was discharged seven days later without any residual deficits, highlighting the success of the advanced resuscitation techniques.

Electrical storm is a critical, yet challenging condition to manage. Early defibrillation remains the primary treatment, but in cases of refractory arrhythmias, advanced methods such as DSED and overdrive pacing are essential. DSED increases the chance of terminating refractory ventricular arrhythmias by delivering higher energy to the myocardium, while overdrive pacing helps control arrhythmias by overriding the heart's own aberrant electrical impulses. This case illustrates the importance of persistent and coordinated resuscitative efforts, which includes a good quality CPR, as well as keeping 5H’S and 5T’s in mind in managing electrical storms and highlights how advanced interventions can improve outcomes, even after prolonged CPR.

The management of this patient’s electrical storm using dual sequential defibrillation and overdrive pacing was instrumental in her survival. This case supports the growing evidence for DSED and overdrive pacing in the management of refractory arrhythmias and electrical storm. The patient's full recovery with no neurological sequelae underscores the effectiveness of these advanced resuscitation strategies in emergency medicine.

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