Fragmented QRS Complex as a Highly Informative Marker of Ventricular Depolarization Disorders

Introduction. Digital ECG analysis revealed new diagnostic qualities of this “golden method” of
diagnostics. The focus of attention of electrophysiologists and clinicians is the fragmented fQRS
complex, which is not visually detectable on a normal ECG recording at the speed of 25 mm/s. The
fQRS complex indicates defragmentation of the ventricular excitation wave because of the areas of
necrosis and ischemia.
Purpose. Development and clinical testing of the computer program for identifi cation of the
fragmented complex fQRS, which refl ects the electrical instability of the myocardium in the
depolarization phase.
Materials and methods. There was developed the algorithm and the “Intecard 7.3” software, which
reveals the fragmented fQRS complexes in 12 ECG leads. The algorithm is based on the analysis of
higher derivatives of ECG-signal. It lets to detect short fragmentation spikes on the fronts of the
R and S complexes. Clinical trials of the “Intecard 7.3” software were performed in 150 patients
with coronary artery disease, FC II–III according to NYHA. The average age was 57±14 years, the
observation period was 36±11 months.
Results and discussion. Tachyarrhythmic events and progressive angina pectoris were recorded in
66 (44%) patients. In these patients, in 90.1% of cases, fQRS complexes were detected. The risk ratio
was 13.8; 95% confi dence interval {6.4 – 29.9}; p<0.001; sensitivity – 91%; specifi city – 96%. Conclusions. Fragmented fQRS complexes reveal the presence of the areas of necrosis, ischemia and fi brosis. Their informative value is especially high when diagnosing non-Q and non-ST myocardial infarction. In addition, fQRS predicts dangerous tachyarrhythmic events in patients with coronary artery disease with high accuracy. The developed “Inteсard 7.3» software is focused on prevention of sudden cardiac death in primary health care units.