Discussion
Prolongation of the QT interval as a result of deep, global T-wave inversions after resolution of acute pulmonary edema has been minimally reported.4,5 This phenomenon has been described in the cardiology literature but has not been discussed in the emergency medicine literature and bears consideration in this case.4,5 As noted, an extensive evaluation did not reveal another cause of QTc prolongation. The patient had normal electrolytes and temperature, his neurologic examination and computed tomography were not remarkable. The patient had no obstructive coronary artery disease on catheterization, no evidence of acute myocarditis on cardiac MRI, no prescribed medications associated with QT prolongation, and no evidence of genetic mutations associated with QT prolongation on testing. The minimal troponin elevation was felt to represent a type II myocardial infarction related to ischemia due to supply-demand mismatch rather than acute plaque rupture.
Littmann published a case series of 9 cases of delayed onset T-wave inversion and extreme QTc prolongation in the 24 to 48 hours following treatment and symptomatic improvement in acute pulmonary edema.4 In each of his patients, an ischemic cardiac insult was ruled out as the etiology of the pulmonary edema by laboratory assessment, echocardiography, and left heart catheterization.All of the patients in this case series recovered without incident and with normalization of the QTc interval.4 Similarly, in our patient, significant QT T changes occurred approximately 22 hours after presentation and with resolution of symptoms of pulmonary edema. Pascale and colleagues also published a series of 3 patients developing similar ECG patterns following a hypertensive crisis with resolution of ECG findings and without any morbidity.5 In contrast, our patient experienced significant morbidity secondary to the extreme QTc prolongation.
Conclusions
We believe this is the first reported case of excessive prolongation of the QTc with VF arrest secondary to resolution of acute pulmonary edema. The pattern observed in our patient follows the patterns outlined in the previous case series—patients present with acute pulmonary edema and hypertensive crisis but develop significant ECG abnormalities about 24 hours after the resolution of the high catecholamine state. Our patient did have a history of prior cardiac insult, given the QTc changes developed acutely, with frequent premature ventricular contractions, and the cardiac arrest occurred at maximal QTc prolongation, yet after resolution of the high catecholamine state, the treatment team felt there was likely an uncaptured and short-lived episode of TdP that degenerated into VF. This theory is further supported by the lack of recurrent VF episodes, confirmed by AICD interrogation, after normalization of the QTc in our patient.