ABSTRACT
Background: Achieving optimal angiographic coronary flow after acute ST elevation myocardial infarction
(STEMI) isn't the best parameter of success. Perfusion of the microvasculature is more important. QRS score
plays an important role for early risk stratification for STEMI. It is a simple electrocardiographic (ECG)
parameter for assuring the presence or absence of microvascular obstruction.
Aim of the work: The aim of this clinical study is to validate the 90 minutes modified Selvester QRS score
reduction as a reliable predictor of myocardial salvage, represented by 3 months global longitudinal strain (GLS)
value, following successful reperfusion of acute STEMI.
Material/Methods: The study population included 400 patients presented with first acute STEMI with
successful reperfusion by thrombolysis (Group I- 200 patients: mean age=57.1 ± 11.6 years) or primary
percutaneous intervention (PPCI) (Group II- 200 patients: mean age=58.2±9.8 years). Basal and 90 minutes after
reperfusion electrocardiography was done with assessment of ST resolution and modified Selvester QRS score.
Basal and 3 months follow up echocardiography was performed with assessment of ejection fraction (EF) and
GLS as an indicator for myocardial salvage with its impact on long-term clinical outcome.
Results: 90 minutes ST resolution and QRS score reduction were significantly higher in PPCI group (P.: 0.04*,
0.03*). Patients in group I had non-significant improvement of EF (P.: 0.22) during follow-up, but highly
significant improvement of GLS (P.: ˂0.001**) compared to the basal echocardiographic study. Patients in
group II had significant improvement of EF (P.: 0.01*) during follow-up, and highly significant improvement of
GLS (P.: ˂0.001**) compared to the basal echocardiographic study. As regarding correlation with 3 months
GLS value, there was highly significant negative correlation between 3months GLS and (ST resolution and QRS
score reduction) (P.: ˂0.001**). Receiver operating characteristics (ROC) curve analysis shows that 90 minutes
QRS score reduction has the best cut off value of 70% to predict 3months GLS improvement with 80%
sensitivity and 79% specificity.
Conclusions: Modified Selvester QRS score reduction 90 minutes after reperfusion is a cheap bedside ECG
parameter added to ST resolution, can be considered as a reliable predictor of future myocardial salvage with its
impact on long-term clinical outcome and modifying management strategies.