Discussion
To our knowledge, this study is the first to evaluate the relationship
between f-QRS and microvascular dysfunction in inferior MI patients who
underwent successful PPCI. In this study, the presence of f-QRS was
demonstrated in patients with impaired microvascular perfusion despite
normal TIMI flow. Multivariate logistic regression models revealed that
fragmented QRS is the development of myocardial blushing.
Fragmented QRS represents myocardial scarring and has been found to be
associated with poor prognostic outcomes in heart disease (5,19-22). Das
et al. found that all causes of death and cardiac events were higher in
patients with fragmented QRS compared to patients with non-fragmented
QRS (5). In addition, a recent meta-analysis showed that initially
fragmented QRS was associated with increased all-cause deaths in heart
failure patients with reduced ejection fraction (23). In our study, we
found that ejection fraction was lower in patients with fragmented QRS.
Ejection fraction is an important parameter in determining the short-
and long-term prognosis.
In this study, fragmented QRS after angioplasty was associated with
microvascular dysfunction in patients with acute inferior myocardial
infarction whose infarct-related artery is the right coronary artery, as
evidenced by angiographic results. Impaired microvascular perfusion was
significantly associated with adverse cardiovascular events and
mortality in patients with acute myocardial infarction. The success of
primary PCI in myocardial infarction is assessed by different methods
such as ST segment resolution, TIMI flow, and MBG. These microvascular
perfusion markers represent a better predictor of clinical outcomes
(12,13). In this study, we used ST segment resolution and MBG to assess
the success of reperfusion therapy. We found that impaired microvascular
reperfusion was higher in patients with fragmented QRS. Similarly,
previous studies have shown a negative relationship between fragmented
QRS and reperfusion parameters (14,15,16). In addition, Sridharan et al.
found that fragmented QRS predicted impaired microvascular myocardial
perfusion as assessed by ST segment resolution (17). In another study,
Fatma et al. found that the presence of fragmented QRS in patients with
myocardial infarction was associated with inadequate myocardial
reperfusion, and they recommended its use as a simple, non-invasive
parameter to evaluate myocardial perfusion (18).
Microvascular dysfunction is responsible for morbidity and mortality in
many different cardiovascular diseases. Fibrosis is caused by
irreversible damage to the cellular elements of the microvascular bed
that feed the myocardium. This leads to delays in interventricular
conduction. Thus, it may cause fragmented QRS formation. Therefore, it
is possible that f-QRS represent impulse conduction abnormalities and
create a setting for malignant reentrant ventricular arrhythmias and
death. Das et al. showed that f-QRS in patients with coronary artery
disease was associated with ventricular conduction delay due to
myocardial scar detected by myocardial single photon emission tomography
(24). In addition, in patients with known coronary artery disease, f-QRS
was associated with major adverse cardiac events and was demonstrated as
an independent predictor for all-cause mortality, and f-QRS was found to
be associated with significantly higher arrhythmic events (25). We can
say that the f-QRS seen on the ECG represents the conduction delay
caused by the inhomogeneous activation of the ventricles due to
myocardial scar.