Diagnosis of cardiac electrical storm before and after implantable cardioverter defibrillator device therapy: a case report

¹Cardiocare Multi-speciality Hospital, Garki Area 11, Abuja, Nigeria, ²Primecare Hospital, Garki Area 8, Abuja, Nigeria, ³Sensei Ag Aldergrove, British Columbia, Canada, ⁴Vinnytsia National Pirogov Medical University, Vinnytsia Oblast, Ukraine, ⁵Medstar Union Memorial Hospital, Baltimore, USA, ⁶Chukwuemeka Odumegwu Ojukwu University, Awka, Anambra State, Nigeria, ⁷Alex Ekwueme Federal University Teaching Hospital, Abakaliki, Ebonyi State, Nigeria, ⁸Yanqul Health Center, Ad Dhahirah Governorate, Oman, ⁹Ebonyi State University College of Health Sciences, Abakaliki, Ebonyi State, Nigeria, ¹⁰King Khalid General Hospital, Hafar Al Batin, Kingdom of Saudi Arabia

^&Corresponding author
Okorie Chinedum Anya, Primecare Hospital, Garki Area 8, Abuja, Nigeria

Introduction    

An Electrical Storm (ES) is a life-threatening condition in which there is cardiac electrical instability presenting with three or more ventricular arrhythmia episodes separated by at least 5 minutes within a 24-hour period, the common rhythms are monomorphic ventricular tachycardia, polymorphic ventricular tachycardia and ventricular fibrillation [1]. The Implantable Cardioverter-defibrillator (ICD) is a battery-powered device that detects life-threatening heart rhythms, such as polymorphic ventricular tachycardia and ventricular fibrillation, and responds with electric shocks or pacemaker activity, and it can be employed in the management of CES in individuals without an ICD, with the sole purpose of aborting the lethal arrhythmias and preventing sudden death, without addressing the underlying cause of the repeated arrhythmias [2]. A certain study carried out by Emkanjoo et al. [3] involving 227 participants who had an ICD in situ reported that 30 of the patients had a CES 6.1 ± 6.7 months after ICD implantation. We report a case of a 56-year-old female with background hypertensive heart disease who was diagnosed with a CES, and had an ICD implanted, which was able to abort lethal arrhythmias and prevent sudden death. However, she presented to the clinic six months after discharge with frequent device electrical shocks which qualified for a diagnosis of CES.

Patient and observation     

Patient information: a 56-year-old woman referred on account of sudden-onset palpitations, chest discomfort, and a history of a transient loss of consciousness. Past medical history of essential hypertension, type 2 diabetes mellitus, and hyperlipidemia. A recent electrocardiography tracing reported as ventricular tachycardia.

Clinical findings: conscious and well-oriented, no abnormal breathing patterns or current complaints. Blood pressure 132/76 mmHg, pulse rate was 86 beats per minute, with skipped beats. Body temperature of 36.7°C.

Timeline of current episode: April 4, 2023: referred to our centre; April 7, 2023: diagnosed with CES and ICD implanted; April 13, 2023: first device interrogation and reprogramming; April 21, 2023: first post-discharge visit; May 5, 2023: second post-discharge visit; October 14, 2023: presented with device shocks and was diagnosed with CES.

Diagnostic assessment: laboratory investigations included random blood glucose, serum electrolytes, urea and creatinine, serum magnesium, serum uric acids, cardiac troponin I and T, and a 4-in-1 cholesterol panel (total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides). Urine was taken for analysis, and her imaging studies included a bedside rest electrocardiography (ECG) and a 2D echocardiography. Her ECG tracing revealed a regular sinus rhythm with regular ventricular ectopic beats that occur after every fourth sinus beat (Figure 1). Reports of her 2D echocardiography revealed findings of left ventricular hypertrophy with a left ventricular ejection fraction of 45-50%. No other significant findings were reported.

Diagnosis: a preliminary diagnosis of premature ventricular contractions (Lown's grade II) was made.

Therapeutic interventions: she was managed with oral amiodarone 200 mg twice daily, low-molecular-weight heparin 40 mg daily and her routine medications. Same day, she became breathless and diaphoretic, blood pressure: 88/52 mmHg and a pulse rate: 180 beats per minute, and an ECG rhythm on the cardiac monitor that suggested ventricular tachycardia (Figure 2). A diagnosis of unstable monomorphic ventricular tachycardia was made, which was managed immediately with synchronized Direct Current (DC) cardioversion with an energy of 100 J. Intravenous form of amiodarone was commenced with a loading dose of 150 mg diluted in 200 ml of 5% dextrose saline solution, which was administered over 15 minutes. The maintenance dosing for the next 24 hours was done with an infusion pump, where 360 mg was administered over 6 hours at a rate of 1 mg per minute, and then 540 mg was administered over 18 hours at a rate of 0.5 mg per minute. Thereafter, amiodarone tablets were recommenced at a dose of 200 mg thrice daily. She was scheduled to do a coronary angiography, and during the procedure she had a total of 8 episodes of monomorphic ventricular tachycardia (Figure 3). About 4 days later she started complaining of electric shocks from the implanted ICD, which was causing her some discomfort, her ICD device was interrogated, and during the process, she had a normal and regular sinus rhythm with a rate of 77 beats per minute (Figure 4), but the final report was of 37 episodes of ventricular arrhythmia (ventricular tachycardia and ventricular fibrillation) that occurred within a two-hour period. The ICD device treated 26 out of the 37 episodes of ventricular arrhythmia with Anti-tachycardia Pacing (ATP) and the remaining 11 episodes with defibrillator shocks (Figure 5). She remained stable after the adjustments and was discharged about 3 days later.

Follow-up and outcome of interventions: she was seen twice in the cardiology outpatient clinic by cardiologists who were part of her management team, and on both occasions, there were no complaints. However, she presented a few months later with frequent device shocks which met the criteria for diagnosis of CES, and this prompted reprogramming of her device.

Patient perspective: "asides the residual chest pain caused by the external cardioversion process, and the anxieties experienced from the several device shocks, the therapies administered have generally improved my quality of life and daily functioning".

Informed consent: approval for this study was obtained from the head of the research committee of the hospital organization, the Limi Hospital group. Ethical approval number - LIMI/REC/2024/005. The patient also gave both oral and written consent.

Discussion     

Electrical storms are caused by the sympathetic nervous system's persistent activation, triggering conditions like acute myocardial ischemia, electrolyte imbalances, pro-arrhythmic medications, heart failure, hyperthyroidism, and cardiac inflammation [3]. Management requires a multi-disciplinary approach, ensuring hemodynamic stability and identifying triggers through laboratory investigation, imaging studies, and procedures like left-heart catheterization to rule out coronary artery disease.

Electrical storm management involves therapies to inhibit sympathetic nervous system activity, such as beta-adrenergic receptor blockers and anti-arrhythmia medications. Neuraxial modulation, deep sedation, electric cardioversion, thoracic epidural anesthesia, and cardiac sympathetic denervation are options [4]. The most definitive treatment is catheter ablation, which destroys abnormal electrical pathways responsible for ventricular arrhythmias [5].

The ICD on its own is not considered a treatment modality because it does not directly inhibit sympathetic nervous system activity, but it is considered part of the management of an electrical storm because it can terminate the lethal arrhythmias and prevent sudden death. Although the ICD is not a proposed method of treating cardiac electrical storms, it is nevertheless indispensable during its management because of its ability to abort lethal arrhythmias and prevent sudden death.

Conclusion     

The use of the ICD for secondary prevention of sudden death in patients with electrical storms should be temporal to allow time for identification of the possible triggers and developing a treatment. As soon as triggers are addressed, their removal should be planned, especially if there are no other indications for their use.

Competing interests     

The authors declare no competing interests.

Authors' contributions     

Patient management: Iseko Iyoko Iseko and Rupert Ndubuisi Chima. Data collection: Rupert Ndubuisi Chima, Okorie Chinedum Anya and Andrew Kamsoko Ndakotsu. Study design and concept: Okorie Chinedum Anya, Rupert Ndubuisi Chima, Olusayo Atilola Oketokun and Henry Rotimi Solanke. Initial manuscript drafting: Rupert Ndubuisi Chima, Adah David Adugba and Amarachi Godswill Ali-Okoro. Manuscript revision and proof-reading: Andrew Kamsoko Ndakotsu, Chidera Precious Chukwuneta, Ijedimma Waliwe Okafor and Akuchi Nwakego-Chiamaka Okafor. Final manuscript draft: Rupert Ndubuisi Chima, Chidera Precious Chukwuneta, Adah David Adugba, Okorie Chinedum Anya. All authors read and approved the final version of the manuscript.

Acknowledgments     

We would like to acknowledge the catheterization laboratory technicians and cardiac device programmers at Cardiocare Multispecialty Hospital for their support during this study.

Figures     

Figure 1: premature ventricular complexes: red arrow points to the premature ventricular complexes that occur after every four normal sinus beats

Figure 2: monomorphic ventricular tachycardia: red arrow shows the stretch of the regular broad complexed tachycardia

Figure 3: monomorphic ventricular tachycardia during the procedure of coronary angiography: red arrow shows the stretch of the regular broad complexed tachycardia

Figure 4: electrocardiography tracing during device interrogation: red circle points to the heart rate which is 77 beats per minute; yellow circle points to the P wave which precedes the narrow QRS complex (green circle)

Figure 5: final device interrogation report: red arrow points to the number of ventricular arrhythmias treated, including ventricular tachycardia and ventricular fibrillation; blue arrow: points to the total amount of shocks delivered

References