A 67-year-old woman arrived via ambulance in ventricular tachycardia. She had been experiencing crushing substernal chest pain and shortness of breath that had worsened over the past several hours. She received oxygen (by mask) and lidocaine (100 mg intravenously) en route to the emergency department (ED), but there was no change in the rhythm.
The patient had several risk factors for coronary artery disease: hypertension, hyperlipidemia, a multiple pack-year smoking history, and a previous myocardial infarction (MI). Multiple medications had been prescribed, but she did not take them regularly.
In the ED, she was somnolent but arousable, with a heart rate of 230 beats per minute and blood pressure of 96/70 mm Hg. An ECG revealed a wide-complex tachycardia (Figure 1). Because her hemodynamic instability did not resolve and chemical cardioversion had no effect, synchronized electrical cardioversion was performed using 150 J of biphasic electricity, with the patient under conscious sedation from etomidate.
After the procedure, her mental status and vital signs improved. A second ECG revealed an anteroseptal MI (Figure 2). The patient was given aspirin, sublingual nitroglycerin, and a heparin bolus/drip. Results of laboratory tests performed at her arrival in the ED were normal, including a normal bedside troponin level.
The patient was taken to the catheterization suite for possible cardiac stent placement.
OVERVIEW OF VENTRICULAR TACHYCARDIA
Ventricular tachycardia is defined as a rhythm with a widened QRS duration (more than 120 milliseconds) and a rate greater than 100 beats per minute—usually greater than 150 beats per minute. The rhythm is typically regular, and the QRS axis is constant. To qualify as sustained ventricular tachycardia, the cycle must last longer than 30 seconds; when this happens, hemodynamic collapse becomes more likely and treatment should be considered.1
At times, ventricular tachycardia can be confused with supraventricular tachycardia with aberrancy.2,3 It can be difficult to distinguish between the 2 rhythms in an emergency situation. However, in a patient such as this woman, with chest pain, hemodynamic instability, and a wide-complex tachycardia, ventricular tachycardia is most likely and immediate cardioversion should be performed.
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