A 45-year-old woman with a history of medication-controlled essential hypertension, stage 2 chronic kidney disease, type 2 diabetes mellitus, and a pack-a-day cigarette habit presented less than 60 minutes after acute onset of severe shortness of breath that awoke her from sleep. She had felt well the previous day, and went to bed with no complaints. Around 4 a.m., she woke up from sleep very dyspneic, with moderate chest “discomfort” over her left chest that radiated to her back and was unchanged by position or respirations.
The ECG is consistent with a supraventricular tachycardia (SVT), likely to be atypical atrioventricular nodal reentrant tachycardia (AVNRT). The key feature to note is the absence of P waves before the QRS complex and retrograde P-waves evident following the QRS as part of the T-wave. The discomfort in her chest and neck is likely secondary to atrial contraction against the closed AV valves during ventricular systole. She was successfully cardioverted to sinus rhythm with adenosine, with resolution of her symptoms.
Find the diagnosis, a complete case discussion, ECG interpretation, and the patient's outcome by reading Spontaneous Circulation in EMN's iPad App on Sept. 5 or in the Spontaneous Circulation blog at http://bit.ly/EMNblogPage on Sept. 12, where additional EKGs are also available.
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