Narrow Complex Ventricular Tachycardia.

Area of Science:

• Cardiology
• Electrophysiology
• Internal Medicine

Background:

• Myocardial infarctions (MIs) often present with tachyarrhythmias, complicating patient recovery.
• Differentiating ventricular tachycardia (VT) from supraventricular tachycardia (SVT) is critical for appropriate management.
• Established criteria exist for distinguishing VT from SVT based on QRS duration and morphology.

Observation:

• A 61-year-old male with coronary artery disease experienced cardiac arrest due to in-stent thrombosis.
• Post-resuscitation and re-stenting, the patient developed sustained tachycardia with nausea and lightheadedness.
• Electrocardiogram revealed regular tachycardia at 173 bpm with a narrow QRS duration (115-120 ms) and slurred upstroke, atypical for VT.

Findings:

• Initial treatment with diltiazem was ineffective; amiodarone successfully terminated the tachycardia.
• Electrophysiology study confirmed inducible VT with atrioventricular (AV) dissociation, despite the narrow QRS duration.
• The patient received an implantable cardioverter-defibrillator (ICD) for secondary prevention.

Implications:

• This case underscores that VT can occur with narrow QRS complexes, challenging traditional diagnostic criteria.
• Accurate diagnosis of VT is crucial, even in the presence of atypical electrocardiographic findings.
• Management strategies, including antiarrhythmic drugs and ICD implantation, are vital for patients with coronary artery disease and VT.