The presence of fragmented QRS complexes (FQRS) on a routine 12-lead ECG is an interesting marker of depolarization abnormality.
There is convincing data suggesting that the FQRS represents conduction delay from inhomogeneous activation
of the ventricles due to myocardial scar. However, FQRS is not specific for coronary artery disease and is also encountered
in other myocardial diseases such as cardiomyopathy and congenital heart disease. FQRS has also been described in other
entities such as arrhythmogenic right ventricular cardiomyopathy and Brugada syndrome.
The significance and the predictive
value of FQRS complex as an ECG marker of cardiovascular events seem to be different in different entities. In patients
with stable coronary artery disease and in patients with acute MI, FQRS seems to be a good predictor of cardiac events. In
patients with non-ischemic cardiomyopathy, fragmentation of narrow QRS complex seems to correlate with the degree of
fibrosis and dys-synchrony, and importantly may influence the response for cardiac resynchronization therapy. However,
based on clinical studies with larger number of patients with current indications for cardiac resynchronization, FQRS does
not influence and is not associated with poor response of resynchronization therapy. In patients with LV dysfunction, there
is no clear evidence that the presence of FQRS could predict arrhythmic events. On the other hand, there was a statistical
significant difference in mortality associated to the presence of fragmented QRS in patients with acute coronary syndrome
and myocardial necrosis.
Invasive and non-invasive tests for risk stratification of cardiovascular
events were studied in the context of coronary artery
disease, cardiomyopathy and heart failure. One of the
recent non-invasive tests, microwave T-wave alternans and
signal-averaged electrocardiogram have high negative predictive
values but have a low positive predictive value in patients
with history of myocardial infarction (MI) or cardiomyopathy. A low left ventricular ejection fraction in patients with
structural heart disease is used routinely in clinical practice
for risk stratification with a major limitation being the lack of
desirable positive predictive value for the risk of cardiovascular
events. The presence of fragmented QRS complexes
(FQRS) on a routine 12-lead ECG is another marker of depolarization
abnormality. There is convincing data suggesting
that the FQRS represents conduction delay from inhomogeneous
activation of the ventricles due to myocardial scar. However,
FQRS is not specific for coronary artery disease and is
also encountered in other myocardial diseases such as cardiomyopathy
and congenital heart disease. FQRS has also been
described in other entities such as arrhythmogenic right ventricular
cardiomyopathy and Brugada syndrome.
In 1969, Flowers et al. named high-frequency components to
the presence of fragmented QRS (FQRS) complexes.
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