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Glite Dictionary
QRS complex

QRS complex

6.5
A pattern on a heart test that shows electrical activity when the lower chambers contract
  • noun
  • /ˈkjuːˌɑːrˈɛs ˈkɒmplɛks/
  • Specialized
translation icon : complejo QRS
  • The QRS complex shows the ventricular depolarization, which causes a contraction of the ventricles.

Examples

  • Figure 2 shows a normal ECG where the rate and rhythm are normal and a P wave is clearly visible before each of the QRS complexes. Each PR interval is less than five of the small squares, which indicates that the electrical signal is traveling in a normal fashion through the heart.

    Academic text (2012)

  • When analyzing the ECG, I noticed that the QRS complex appears wider in patients with certain heart conditions.

  • The doctor explained that the QRS complex indicates the electrical activity occurring during the heart's ventricular contraction.

  • Understanding the QRS complex is crucial for accurately interpreting the heart's electrical activity during an ECG.

Surface Forms

QRS complex singular
QRS complexes plural

Morphology

QRS + complex

The form 'QRS' is an arbitrary technical abbreviation with no lexical meaning a B1 learner could compose, while 'complex' only indicates a group or cluster. Knowing 'complex' plus the letters 'QRS' does not allow a learner to infer the specific medical sense (ventricular activity on an ECG); this is domain-specific jargon rather than a compositional phrase.

Etymology

QRS complex comes from the three marked waves Q, R, and S that make a quick up-and-down shape on the line doctors draw from the heart called the ECG. Together these waves show the 'electrical activity' when the heart's lower chambers squeeze, so the name points to the part of the ECG for that 'contraction'.