II. Definitions
- QRS Interval
- Electrical signal on EKG representing depolarization of the ventricle (immediately preceding contraction)
- Interval from the start of the Q Wave to the end of the S Wave
III. Normal findings: Duration
- Limb leads (I, II, III): 0.05 to 0.10
- Precordial leads (V1 to V6): 0.06 to 0.12
IV. Causes: Wide QRS or Prolonged QRS Complex (over 0.12)
- Intraventricular Conduction Delay (IVCD)
- See Bundle Branch Block
- Hypothermia
- Hyperkalemia
- Wolff-Parkinson-White Syndrome (WPW)
- Ventrciular ectopy
- Ventricular Tachycardia
- Left Ventricular Hypertrophy
- Pacemaker with ventricular pacing
- Non-specific Intraventricular Conduction Delay (IVCD)
- IVCD does not meet criteria for other diagnoses
- QRS-T Complex (pseudo-Wide QRS)
- QRS-T Complex is a fusion of the QRS, ST, and T Wave (Shark Fin)
- Appears as a very Wide QRS in some leads with the appearance of a "shark fin"
- Some leads will demonstrate a discernable elevated J-Point between the QRS and the ST Segment
- Seen in massive acute Myocardial Infarction and are at high risk of Arrhythmia, decompensation and Cardiac Arrest
- Medications (e.g. Toxin Ingestion or Overdose)
- Results from Sodium channel blockade
- Emergency management
- See Toxin Ingestion
- See Tricyclic Overdose
- Sodium Bicarbonate 1-2 amps IV push with repeat bolus until QRS narrows (adults)
- Causes
- See Sodium Channel Blocker
- Tricyclic Antidepressants
- Dry and sedated
- Cocaine
- Diaphoretic and agitated
- Diphenhydramine (Benadryl)
- Local Anesthetics (esp. Bupivacaine)
- Antiarrhythmics (e.g. Quinidine, Flecainide)
- Propoxyphene (not available in U.S.)
- Digoxin Toxicity
- Associated with frequent PVCs and sagging ST depression
V. Causes: Low QRS Amplitude or Voltage (<5 mm in limb leads)
- Cardiac
- Diffuse Coronary Artery Disease or Myocardial Infarction
- Congestive Heart Failure or Pulmonary Edema
- Pericardial Effusion
- Constrictive Pericarditis
- Infiltrative Cardiomyopathy (e.g. Cardiac Amyloidosis)
- Myocarditis
- Respiratory
- Miscellaneous Extracardiac
- Normal variant
- Myxedema (severe Hypothyroidism)
- Obesity
- Anasarca
VI. Causes: High QRS amplitude
- Evaluate for Left Ventricular Hypertrophy (LVH)
- Avoid using QRS amplitude alone to diagnose LVH in age <40-45 years old
- High Left Ventricular Voltage (HLVV)
- Large amplitude QRS Complexes are a normal finding in young, healthy athletes (not LVH)
VII. References
- Berberian, Brady and Mattu (2024) Crit Dec Emerg Med 33(1): 14-5
- Berberian, Brady and Mattu (2024) Crit Dec Emerg Med 38(5): 12-3
- Mattu (2016) Crit Dec Emerg Med 30(8):16
- Mattu (2021) Crit Dec Emerg Med 35(5):16
Images: Related links to external sites (from Bing)
Related Studies
| Concepts | Organism Attribute (T032) |
| SnomedCT | 251208001 |
| LNC | LP31031-5, MTHU019811 |
| English | QRS complex duration (observable entity), QRS duration, QRS complex duration |
| Spanish | duración del complejo QRS (entidad observable), duración del complejo QRS |
Ontology: QRS complex feature (C0429097)
| Definition (NCI) | An electrocardiographic finding that represents depolarization of the ventricular myocardium. Normally the ventricles are activated simultaneously. |
| Concepts | Finding (T033) |
| SnomedCT | 142119004, 164949005 |
| LNC | LP31569-4, MTHU024513 |
| Dutch | QRS-complex |
| French | Complexe QRS |
| German | QRS-Komplex |
| Italian | Complesso QRS |
| Portuguese | Complexo QRS |
| Spanish | Complejo QRS, característica del complejo QRS (entidad observable), característica del complejo QRS, complejo QRS (entidad observable), complejo QRS |
| Japanese | ＱＲＳ群, QRSｸﾞﾝ |
| Czech | QRS komplex |
| English | qrs complex, QRS Complex, QRS complex (observable entity), QRS complex, QRS complex feature (observable entity), QRS complex feature |
| Hungarian | QRS komplex |
Ontology: Electrocardiogram QRS complex (C0429098)
| Concepts | Finding (T033) |
| SnomedCT | 164954001, 142126004 |
| English | ECG: QRS complex NOS, ECG: QRS complex NOS (observable entity), ECG QRS, Electrocardiogram QRS complex, electrocardiogram QRS complex, electrocardiogram: QRS complex, electrocardiogram: QRS complex (procedure), Electrocardiogram: QRS complex NOS, Electrocardiogram: QRS complex NOS (observable entity), ECG: QRS complex NOS (finding) |
| Italian | Complesso QRS dell'elettrocardiogramma |
| Japanese | 心電図ＱＲＳ群, ｼﾝﾃﾞﾝｽﾞQRSｸﾞﾝ |
| Czech | QRS komplex na elektrokardiogramu |
| Hungarian | Elektrokardiogram QRS komplex |
| Spanish | ECG: QRS complex NOS, electrocardiograma: complejo QRS, SAI, electrocardiograma: complejo QRS, SAI (entidad observable), electrocardiograma: complejo QRS, SAI (hallazgo), ECG: complejo QRS, SAI, Complejo QRS del electrocardiograma |
| Portuguese | Complexo QRS (ECG) |
| Dutch | elektrocardiogram QRS-complex |
| French | Complexe QRS à l'électrocardiogramme |
| German | Elektrokardiogramm QRS-Komplex |
Ontology: electrocardiogram: QRS interval (C2168881)
| Concepts | Finding (T033) |
| English | electrocardiogram intervals QRS, ECG intervals QRS, QRS interval on ECG, QRS interval, electrocardiogram: QRS interval (procedure), electrocardiogram: QRS interval |
