Following the depolarizationThe rapid influx of positive ions (sodium and/or calcium) into a cell – depolarization is necessary for contraction to occur. A depolarizing wave moves through the myocardium on average along a trajectory or vector. A vector is a force moving... of the interventricular septum, ventricular depolarizationThe depolarization of the myocardium is represented on an ECG by a series of waveforms, one for atrial depolarization and soon after a larger waveform for ventricular depolarization. Normal ventricular depolarization begins with the septal fascicle of the left bundle... then progresses from the endocardiumThe smooth innermost layer of the heart covers the inner chambers and the cardiac valves. The mechanical structures of the heart include the heart’s layers, chambers, septum, valves, and the major vessels (including the coronary arteries). Each of these structures... through to the epicardiumThe external layer that covers the heart – also called the visceral layer of the heart; between the visceral layer and the outer parietal layer is the pericardial sac; note that the coronary arteries travel along the epicardium before burrowing... across both ventriclesThe larger chambers of the heart (3 times the volume and muscle thickness than the atria), responsible for the pumping of blood to the lungs and the rest of the body. producing an R wave and an S waveAn S wave is the first wave after the R wave that dips below the baseline (isoelectric line). The end of the S wave occurs where the S wave begins to flatten out. This is called the J point. Figure.... An R wave is the first positive deflection of the QRS complexThe electrical representation of ventricular depolarization; the atrial repolarization is also a part of the QRS. ECG interpretation relies heavily on the QRS complex. The QRS complex represents the depolarization of the ventricles. The repolarization of the atria is also....
Figure 4.13 depicts the component parts of the QRS complexA collection of waveforms (i.e. QRS complex and the ECG complex). 1. Six Second ECG Guidebook (2012), T Barill, p. 194. The QRS complex consists of a series of waves, the ‘Q’, ‘R’, and ‘S’ waves. The ‘Q’ wave is the first negative deflection from baselineThe baseline or isoelectric line is a reference point for the waves, intervals and segments. While the PR segment is often used as the baseline, the TP segment - between the end of the T wave and the beginning of.... The ‘R’ wave is the first positive deflection above baseline. The ‘S’ wave follows the ‘R’ wave with a negative deflection. A QRS complex may or may not have all three waveforms. The ST segmentSegment (line) between the end of the QRS complex and the beginning of the T wave; the end of the QRS is marked by the J point. Between the QRS complex and the T wave, lies the ST segment. The... begins at the J pointA small notch in the QRS where the ST segment begins. The point where the S Wave ends and begins to flatten out. Figure 4.13 The QRS Complex, ST Segment and the T Wave Figure 4.13 depicts the component parts... and continues to the beginning of the T waveThe wave that arrives after the QRS; is a graphical presentation of ventricular repolarization. Expect a T wave to follow every QRS complex. The T wave is a graphic representation of the repolarization of the ventricle. The T wave is....
1. Six Second ECG GuidebookA Practice Guide to Basic and 12 Lead ECG Interpretation, written by Tracy Barill, 2012 Introduction The ability to correctly interpret an electrocardiogram (ECG), be it a simple six second strip or a 12 lead ECG, is a vital skill... (2012), T Barill, p. 83