Represents ventricular depolarization, which results in ventricular contraction
For other uses of "S wave", see S wave.
"QRS" redirects here. For other uses, see QRS (disambiguation).
Schematic representation of a normal sinus rhythm ECG waveDiagram 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 central and most visually obvious part of the tracing. It corresponds to the depolarization of the right and left ventricles of the heart and contraction of the large ventricular muscles.
In adults, the QRS complex normally lasts 80 to 100 ms; in children it may be shorter. The Q, R, and S waves occur in rapid succession, do not all appear in all leads, and reflect a single event and thus are usually considered together. A Q wave is any downward deflection immediately following the P wave. An R wave follows as an upward deflection, and the S wave is any downward deflection after the R wave. The T wave follows the S wave, and in some cases, an additional U wave follows the T wave.
To measure the QRS interval start at the end of the PR interval (or beginning of the Q wave) to the end of the S wave. Normally this interval is 0.08 to 0.10 seconds. When the duration is longer it is considered a wide QRS complex.
The QRScomplex is the combination of three of the graphical deflections seen on a typical electrocardiogram (ECG or EKG). It is usually the central and...
characteristics. Most have a narrow QRScomplex, although, occasionally, electrical conduction abnormalities may produce a wide QRScomplex that may mimic ventricular...
an ECG: The P wave, which represents depolarization of the atria. The QRScomplex, which represents depolarization of the ventricles. The T wave, which...
frontal plane direction between −30° and −90°. This is reflected by a QRScomplex positive in lead I and negative in leads aVF and II. There are several...
a rate of greater than 120 beats per minute and at least three wide QRScomplexes in a row. It is classified as non-sustained versus sustained based on...
wide complex based on the QRScomplex. Equal or less than 0.1s for narrow complex. Presented in order of most to least common, they are: Narrow complex Sinus...
before every QRScomplex in a ratio of 1:1. Normal P wave axis (0 to +75 degrees) Normal PR interval, QRScomplex and QT interval. QRScomplex positive in...
ventricular myocardium produces the QRScomplex on the ECG. Atrial repolarization occurs and is masked during the QRScomplex by ventricular depolarization...
conduction through the bundle of His-Purkinje fibres, the QRScomplex is seen to be widened. The QRScomplex often shows an extra deflection that reflects the...
repolarization of the ventricles. The interval from the beginning of the QRScomplex to the apex of the T wave is referred to as the absolute refractory period...
the speed at which they are able to conduct an electrical impulse. The QRScomplex represents the conduction of the ventricles of the heart, the speed at...
electrocardiogram with a normal QRScomplex accompanied by an inverted P wave either before, during, or after the QRScomplex. An AV-junctional escape beat...
duration of the QRScomplex on the ECG exceeds 120 ms. A right bundle branch block typically causes prolongation of the last part of the QRScomplex and may shift...
wave (the onset of atrial depolarization) until the beginning of the QRScomplex (the onset of ventricular depolarization); it is normally between 120...
it is seen as wide QRScomplexes lasting ≥120ms with characteristic QRS shapes in the precordial leads, although narrower complexes are seen in children...
phenomenon, also known as Ashman beats, describes a particular type of wide QRScomplex, often seen isolated that is typically seen in atrial fibrillation. It...
ECG, there is no relationship between P waves and QRScomplexes, meaning the P waves and QRScomplexes are not in a 1:1 ratio. Third-degree AV block is...
QRScomplex). As a result, the time from the QRScomplex to the P wave (the RP interval) is short, less than 50% of the time between consecutive QRS complexes...
countries ST segment, the part of an electrocardiogram connecting the QRScomplex and the T wave Sulfotransferase, enzymes that catalyze the transfer of...
to: Monomorphism, an injective homomorphism in mathematics Monomorphic QRScomplex, a wave pattern seen on an electrocardiogram Monomorphic, a linguistic...
negative QRScomplex in leads II, III, and aVF). The delayed and unopposed activation of the remainder of the LV now results in a shift in the QRS axis leftward...
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