Transient QRS amplitude attenuation is associated with clinical recovery in patients with takotsubo cardiomyopathy

Abstract

Background/objectives: Low voltage QRS complexes (LQRSV) and amplitude attenuation of QRS voltage (AAQRS) have been described in takotsubo (TC) patients, and postulated as valuable pre-angiographic markers. The aim of this observational study is to evaluate potential diagnostic and prognostic features of QRS amplitude in TC and acute coronary syndrome (ACS) patients.

Methods: Fifty-eight patients with TC were matched with 58 patients with ACS according to age, gender, and presence or absence of ST elevation at hospital admission. A 12-lead ECG was recorded within 12h after symptoms onset, the day after coronary angiography (CA) and before hospital discharge. When available, ECGs prior and subsequent to the acute event were also collected.

Results: QRS amplitude showed a time related trend, with a first phase characterized by an initial decrease in amplitude in both groups and a second phase, with a progressive recovery of QRS amplitude in TC patients up to pre-event levels, while QRS amplitude in ACS patients remained substantially unchanged from admission onwards. Rise in AAQRS during hospitalization showed a positive linear association with systolic function recovery and both troponin I and CK-MB decrease (all p<0.01) in TC patients. A 20% increase of mean AAQRS from admission is able to predict LVEF recovery and troponin I and CK-MB normalization in TC patients with good sensitivity and specificity.

Conclusions: LQRSV and AAQRS are not reliable in differentiating ACS from TC. However, QRS amplitude attenuation in TC is transient, and is linearly associated with systolic function recovery and cardiac biomarkers normalization.

Keywords: Acute coronary syndrome; ECG; QRS amplitude; QRS voltage; Takotsubo cardiomyopathy.