![]() In this criterion, elderly subjects and subjects who had risk factors of atherosclerosis (diabetes, hypertension, etc) often had fQRS. Two control subjects (2.5%) were regarded as having fQRS by this criterion. We defined presence of fQRS in right BBB as 1) ≥4 spikes in one or 2) ≥8 spikes in all of the leads V1, V2 and V3. Most (64%) of the 80 control subjects with right BBB but without known heart disease and risk factors of atheroscrelosis (53 cases with complete right BBB and 27 cases with incomplete right BBB) had 2 to 3 spikes within the QRS complex in each of the right precordial leads (leads V1-V3) and a sum of 5.9 ± 1.0 (median: 6, range: 4-8) spikes in all V1-V3. When we reported fQRS in Brugada syndrome, we also defined fQRS in right BBB because patients with Brugada syndrome often had right BBB. ![]() Fragmented wide QRS complex in the bundle branch block (BBB), paced QRS complex and premature ventricular complex (PVC) have more than two notches. If the QRS complex of PVC only has 2 notches in the R waves, they considered the QRS complex to be fQRS-positive when the notches were > 40 ms apart and present in 2 contiguous leads ( Figure 3).įragmented wide QRS complex. Typical bundle branch block (BBB) pattern (QRS ≥ 120 ms) and incomplete right BBB were excluded from the their original definition ( Figure 1).įQRS on a 12-lead ECG was originally defined as narrow QRS complex duration (2 R' waves or notches in the R or S wave in a wide QRS complex of BBB, or paced QRS, or premature ventricular complexes (PVC) in 2 contiguous leads. defined fQRS as the QRS complexes with the presence of an additional R wave (R') or notching in the nadir of the R wave or the S wave, or the presence of >1 R' (fragmentation) in 2 contiguous leads, corresponding to a major coronary territory. Change of the cut-off frequency from 35 to 150 Hz unmasked 3 additional spikes within the QRS complex (right).ĭas et al. ![]() ECG recording with a low-pass filter of 35Hz showed only 2 spikes within the QRS complex (left). Since that report, the usefulness of fQRS for the diagnosis and prediction of prognosis has expanded to patients with ischemic and non-ischemic cardiomyopathy and patients with primary electrical diseases.Įffects of low-pass filter. fQRS improved identification of prior myocardial infarction in patients who are being evaluated for CAD. fQRS was defined by an additional R wave (R') or notching within the QRS complex ( Figure 1). proved fragmented QRS complex in patients with coronary artery disease (CAD) was associated with myocardial conduction block due to myocardial scar detected by myocardial single photon emission tomography (SPECT). ![]() However, the diagnostic and prognostic values of these subtle abnormalities within the QRS complex were not clarified in prior studies. Injured tissue around an infarct scar resulted in the RSR' pattern of the QRS complex. A notch in the QRS complex in patients with left ventricular hypertrophy has been suggested to be a result of an intraventricular conduction defect. It has been show in some studies that a subtle abnormality within the QRS complex can represent conduction disturbance and myocardial scar. Myocardial scar detected by fQRS is associated with subsequent ventricular dysfunction and heart failure and is a substrate for reentrant ventricular tachyarrhythmias. fQRS can be applied to patients with wide QRS complexes and is associated with myocardial scar and prognosis. The usefulness of fQRS for detecting myocardial scar and for identifying high-risk patients has been expanded to various cardiac diseases, such as cardiac sarcoidosis, arrhythmogenic right ventricular cardiomyopathy, acute coronary syndrome, Brugada syndrome, and acquired long QT syndrome. fQRS was also a predictor of mortality and arrhythmic events in patients with reduced left ventricular function. In patients with CAD, fQRS was associated with myocardial scar detected by single photon emission tomography and was a predictor of cardiac events. ![]() fQRS is defined as additional spikes within the QRS complex. Fragmented QRS (fQRS) is a convenient marker of myocardial scar evaluated by 12-lead electrocardiogram (ECG) recording. ![]()
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