Title : Wide complex tachycardia: A clinical conundrum: VT versus WPW syndrome
Introduction: The accurate diagnosis and initial evaluation of Wide complex tachycardia (WCT) has been a traditional clinical dilemma. The differential diagnosis includes ventricular tachycardia (VT), supraventricular tachycardia (SVT with aberration and SVT with pre-excitation. Some of these findings can be life threatening arrhythmia and might potentially be the harbinger of sudden cardiac death. Identifying the etiology of a WCT is important to provide appropriate therapy.
Case report: We are presenting a case of 69-year-old female who was transferred from a nursing home because of an episode of cardia arrest. She had a past medical history of morbid obesity, sleep apnea, hypertension, and diabetes. She was found to have wide complex tachycardia, there after she had resuscitation per ACLS protocol. She was shocked x2 and she had return of spontaneous circulation at 8 minutes. She was transferred from the local hospital to our hospital for a defibrillator evaluation. She arrived intubated and sedated. On exam she was cold and wet. She had edema and mild crackles at the lung bases. On arrival initial labs showed elevated lactic acid of 6 mmol/lt. her creatinine was 3 mg/dl and mildly elevated WBC count of 13k/microlitre. She was initially treated with diuretics and vasopressors. Her echo showed left ventricular ejection fraction of 50%, which is low normal but otherwise normal. Coronary angiography revealed non obstructive coronary artery disease.
Her electrocardiography (ecg) showed Atrial fibrillation at 110 beats per minute, there was a short PR interval of 110 ms and there was a suspicion for a delta wave. Further, review of her strips from the first responders revealed that she had a wide complex tachycardia but that there was subtle beat to beat variation. Further the QRS duration varied from beat to beat. These findings differentiated this EKG strip from VT. She had similar finding in the hospital noted on telemetry. These findings were more in line with SVT with pre-excitation. This was called “Wolf Parkinson white syndrome in the past. She was subsequently taken for a electrophysiology study (EPS). During her EPS she was found to have anterograde conduction from the atrium to the ventricular through a accessory pathway. Meticulous 3D mapping localized the accessory pathway to be in infero-septal region. Radiofrequency ablation was performed at this region to eliminate the accessory pathway. Subsequently she did not develop any wide complex tachycardia and her Atrial fibrillation resolved too. She was discharged in a stable condition and on follow up she was still free of syncope or wide complex tachycardias.
Conclusion: The differential diagnosis of WCT might be challenging and includes both ventricular and supraventricular tachycardias. Current guideline support ablation of accessory pathway for treatment of Atrial fibrillation with accessory pathway. This is a rare presentation of a common ecg findings. The awareness of this ecg finding needs to be spread in practicing physicians. If the initial ecg poses a diagnostic challenge then an EP study should be offered before ICD implantation to make a final diagnosis with the potential to provide definitive treatment.
Audience Take away:
- An electrophysiological (EP) study should be considered in evaluation of the etiology of wide complex tachycardia (WCT)
- Ablation of the accessory pathway is the treatment for WCT , when the underlying cause is Atrial fibrillation with a participating anterograde accessory pathway
- Increase awareness of this ECG finding among all physicians. It is very common to miss classify the etiology of WCT. An ICD is not indicated in WCT from atrial fibrillation with preexcitation
- An EP study should be offered to every patient with WCT of unclear etiology before implantation of an implantable cardioverter-defibrillator.
- Baseline ecg should be searched for a delta wave in patients with WCT with unclear etiology