QRS complex


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QRS complex

[¦kyü¦är′es ‚käm‚pleks]
(medicine)
The electrocardiographic deflection representing ventricular depolarization; the initial downward deflection is termed a Q wave; the initial upward deflection, an R wave; and the downward deflection following the R wave, an S wave. Also known as ventricular depolarization complex.
References in periodicals archive ?
The analysis of normal ECG waves of control smokers and non-smokers indicated significantly shortened QRS complex (P < 0.
Heart rate is recalculated and refreshed after each QRS complex is detected.
Wide QRS complex tachycardia (Figure 1a) was determined, and electrical cardioversion was performed several times.
Firstly, QT Pattern signal which will be used for determination of QRS complex starting and T wave end points was defined as
Thus the QRS complex overlaps with the muscle noise, P and T overlap with the respiration action [3].
This therapy has been implanted in about 3,000 patients to date and is the only device therapy available for patients with narrow QRS complex.
Care must be taken to examine all leads, looking for the widest QRS complex.
Additionally, Mobitz Type II AV block often is accompanied by a widened QRS complex (Surawicz & Knilans, 2008).
Nowadays, the selection of patients for cardiac resynchronization therapy is made according to electrical and electromechanical dyssynchronization criteria which include the following: electrocardiographic criteria (duration of the PR interval and morphology of the QRS complex, evaluation of basic rhythm) and echocardiographic parameters to evaluate the left ventricle ejection fraction, size of ventricles, incidence of mitral regurgitation and evaluation of intra--and inter-ventricular asynchrony.
The QRS complex represents activation of ventricular myocardium, and QRS prolongation may result from a wide range of processes involving the conduction system primarily, the myocardium, or both.
The primary endpoint of the present study was a composite of cardiac death (defined as intractable heart failure, sudden death, or documented arrhythmic death) or new-onset VT (defined as a wide QRS complex duration of >120 ms, three or more consecutive ventricular complexes, heart rate >100 bpm, and atrioventricular dissociation).