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Schematic representation of a normal sinus rhythm ECG wave. Diagram showing how the polarity of the QRS complex in leads I, II, and III can be used to estimate the heart's electrical axis in the frontal plane. The QRS complex is the combination of three of the graphical deflections seen on a typical electrocardiogram (ECG or EKG). It is usually ...
The sinus node should pace the heart – therefore, P waves must be round, all the same shape, and present before every QRS complex in a ratio of 1:1. Normal P wave axis (0 to +75 degrees) Normal PR interval, QRS complex and QT interval. QRS complex positive in leads I, II, aVF and V3–V6, and negative in lead aVR. [3]
Sinus tachycardia is another regular rhythm however the ventricular rate is quicker, between 100 - 160 bpm, with a normal PR interval and normal QRS complex. Sinus arrhythmia is an irregular rhythm with a ventricular rate of 60 - 100 normally, however a slow rhythm can be distinguished when the rate is less than 60, the PR interval and QRS ...
QRS wave duration between 100 and 120 ms. rsr, rsR, or rSR in leads V1 or V2. S wave of longer duration than R wave or greater than 40 ms in leads I and V6. Normal R wave peak time in both V5 and V6, but greater than 50 ms in V1. The first three criteria are needed for diagnosis. The fourth is needed when a pure dominant R waver is present on ...
When an individual is in normal sinus rhythm, the ECG characteristics of WPW are a short PR interval (less than 120 milliseconds in duration), widened QRS complex (greater than 120 milliseconds in duration) with slurred upstroke of the QRS complex, and secondary repolarization changes (reflected in ST segment-T wave changes). [citation needed]
In adults, it is seen as wide QRS complexes lasting ≥120ms with characteristic QRS shapes in the precordial leads, although narrower complexes are seen in children. [4] In lead V 1 , the QRS complex is often entirely negative (QS morphology), although a small initial R wave may be seen (rS morphology).
The first finding is that junctional rhythms are regular rhythms. This means that the time interval between beats stays constant. The next normal finding is a normal QRS. Since the impulse still travels down the bundle of His, the QRS will not be wide. Junctional rhythms can present with either bradycardia, a normal heart rate, or tachycardia. [9]
This refers to the appearance of leads I and II. If the QRS complex is negative in lead I and positive in lead II, the QRS complexes appear to be "reaching" to touch each other. This signifies right axis deviation. Conversely, if the QRS complex is positive in lead I and negative in lead II the leads have the appearance of "leaving" each other.