|Hoseini SS et al.|
Designing Nomogram for Determining the Heart's QRS Axis
Journal of Clinical and Basic Cardiology 2011; 14 (1-4): 12-15
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Keywords: heart axis, nomogram, QRS
Background: Electrocardiogram is a recording of the heartís electrical activity which could be very informative in the approach to patients with cardiac or non-cardiac problems. Determining the electrical axis of the heart (mainly QRS complex axis) is the first step in interpreting the electrocardiogram of a patient and has important applications in both clinical and epidemiological studies. Aim: This study was performed to design a nomogram for the exact determination of the heartís QRS axis. Settings and Design: We used the corrected formula to determine the heartís QRS axis. Materials and Methods: In order to calculate the electrical axis of the heart in the frontal plane, we used the combination of leads I and aVF. We used MATLAB m-code programming to design the nomogram according to the corrected formula. Results: Our work is a nomogram which uses leads I and aVF to calculate the heartís electrical QRS axis. This nomogram covers the mean QRS complex between Ė30 and +30 small squares. Conclusion: This recording helps in the long-term assessment of physiological axis changes during treatment and followup. By means of this nomogram, the effects of pathological factors on the heartís axis could be evaluated more accurately.