Cardioversion of pre-excited atrial fibrillation leading to ventricular fibrillation- case report and review of literature

Atrial fibrillation is associated with increased risk of lethal ventricular arrhythmias

Atrial fibrillation (AF) is associated with various major adverse cardiac events such as ischemic stroke, heart failure, and increased overall mortality. However, its association with lethal ventricular arrhythmias such as ventricular tachycardia (VT), ventricular flutter (VFL), and ventricular fibrillation (VF) is controversial. We conducted this study to determine whether AF can increase the risk of VT, VFL, and VF. We utilized the Korean National Health Insurance Service database for this nationwide population-based study. This study enrolled people who underwent a nationwide health screen in 2009 for whom clinical follow-up data were available until December 2018. Primary outcome endpoint was the occurrence of VT, VFL, or VF in people who were and were not diagnosed with new-onset AF in 2009. We analyzed a total of 9,751,705 people. In 2009, 12,689 people were diagnosed with new-onset AF (AF group). The incidence (events per 1000 person-years of follow-up) of VT, VFL, and VF was 2.472 and 0.282 in the AF and non-AF groups, respectively. After adjustment for covariates, new-onset AF was associated with 4.6-fold increased risk (p < 0.001) of VT, VFL, and VF over 10 years of follow-up. The risk of VT, VFL, and VF was even higher if identification of AF was based on intensified criteria (≥ 2 outpatient records or ≥ 1 inpatient record; hazard ratio = 5.221; p < 0.001). In conclusion, the incidence of VT, VFL, and VF was significantly increased in people with new-onset AF. The potential risk of suffering lethal ventricular arrhythmia in people with AF should be considered in clinical practice.

Iatrogenic ventricular fibrillation caused by inappropriately synchronized cardioversion in a patient with pre-excited atrial fibrillation: A case report

Direct-current (DC) cardioversion is effective at terminating arrhythmias in an emergency. During treatment, energy delivery synchronizing with the QRS complex is essential to avoid ventricular fibrillation (VF) caused by a shock on the T wave, which is the vulnerable period of ventricular repolarization. However, distinguishing the QRS from the T wave is difficult in some patients with abnormal, irregular, and varying QRS complexes. We report the case of a 45-year-old man who had iatrogenic VF caused by inappropriate synchronization with the T wave during cardioversion of pre-excited atrial fibrillation due to high ventricular rates and varying R wave amplitude affected by an accessory pathway. <Learning objective: During direct-current cardioversion, energy delivery synchronizing with the QRS complex is essential to avoid ventricular fibrillation (VF) caused by a shock on the T wave. However, distinguishing the QRS from the T wave is difficult in some patients with abnormal, irregular, and varying QRS complexes. We report a case of iatrogenic VF caused by failed synchronization with the R wave in a patient with pre-excited atrial fibrillation (AF). Clinicians managing pre-excited AF should be aware of the possibility of iatrogenic VF triggered by cardioversion.>.

The use of intravenous amiodarone in patients with atrial fibrillation and Wolff-Parkinson-White syndrome

BACKGROUND

It was reported that intravenous amiodarone might induce ventricular fibrillation for acute treatment in patients with atrial fibrillation (AF) and Wolff-Parkinson-White (WPW) syndrome. No study was done to assess its application comprehensively in this population.

METHODS

This study was a retrospective analysis and undertaken by reviewing medical records and electronic databases to search for patients admitted with tachycardia resulting from WPW syndrome and AF, who have intravenously administrated amiodarone at the emergency department from January 2008 to June 2018.

RESULTS

Thirty patients were involved in this study, of which 27 were males. The mean age of the patients was 47.8 ± 17.0 years. The mean systolic blood pressure and diastolic blood pressure were 111.9 ± 18.3 mmHg and 76.1 ± 14.6 mmHg, respectively. The mean heart rate was 171 (150-189) beats per minute. Half of the patients (53.3%) had no comorbidities, and only one had prior syncope. Nearly 17 patients (56.7%) started with a loading dose of 150 mg. No ventricular acceleration or VF developed. The incidence of hypotension was 3.3% (1/30). Eighteen patients (60.0%) restored to sinus rhythm by amiodarone with the conversion time of 486.0 (229.0-1278.0) minutes.

CONCLUSIONS

Intravenous amiodarone might be an alternative for acute treatment of AF and WPW syndrome in patients characterized by stable hemodynamics, relatively low admission heart rate, few comorbidities, elder age, and no prior syncope. The loading dosage of 150 mg appeared to be preferred, and the maintenance period was better to less than 12 hours. Monitoring and electrolyte correction were also necessary. It is essential to keep a defibrillator nearby during pharmacologic cardioversion.