ECG Criteria: Difference between revisions
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* qR pattern in lead aVL. | * qR pattern in lead aVL. | ||
* R peak time ≥ 45 ms in lead aVL. | * R peak time ≥ 45 ms in lead aVL. | ||
* QRS duration < 120 ms. | * QRS duration < 120 ms.<ref>Surawicz, Borys, Rory Childers, Barbara J. Deal, Leonard S. Gettes, James J. Bailey, Anton Gorgels, E. William Hancock, et al. “AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram: Part III: Intraventricular Conduction Disturbances: A Scientific Statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology.” Journal of the American College of Cardiology 53, no. 11 (March 17, 2009): 976–81. doi:10.1016/j.jacc.2008.12.013.</ref> | ||
==Left Posterior Fascicular Block== | ==Left Posterior Fascicular Block== | ||
===Criteria=== | ===Criteria=== | ||
* Frontal plane axis between 90° and 180° | * Frontal plane axis between +90° and +180°. | ||
:* Owing to the more rightward axis in children up to 16 years of age, this criterion should only be applied to them when a distinct rightward change in axis is documented. | |||
* rS pattern in leads I and aVL. | * rS pattern in leads I and aVL. | ||
* qR pattern in leads III and aVF. | * qR pattern in leads III and aVF. | ||
* QRS duration | * QRS duration < 120 ms.<ref>Surawicz, Borys, Rory Childers, Barbara J. Deal, Leonard S. Gettes, James J. Bailey, Anton Gorgels, E. William Hancock, et al. “AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram: Part III: Intraventricular Conduction Disturbances: A Scientific Statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology.” Journal of the American College of Cardiology 53, no. 11 (March 17, 2009): 976–81. doi:10.1016/j.jacc.2008.12.013.</ref> | ||
==Left Bundle Branch Block== | ==Left Bundle Branch Block== | ||
<div style="float:right;>[[File:Left_bundle_branch_block_ECG_characteristics.png|200px]]</div> | <div style="float:right;>[[File:Left_bundle_branch_block_ECG_characteristics.png|200px]]</div> | ||
===Criteria=== | ===Complete LBBB Criteria=== | ||
* QRS duration ≥ 120 ms (≥ 100 ms in children 4 to 16 years of age; ≥ 90 ms in children | * QRS duration ≥ 120 ms (≥ 100 ms in children 4 to 16 years of age; ≥ 90 ms in children < 4 years of age). | ||
* Broad notched or slurred R wave in leads I, aVL, V5, and V6 and an occasional RS pattern in V5 and V6 attributed to displaced transition of QRS complex. | * Broad notched or slurred R wave in leads I, aVL, V5, and V6 and an occasional RS pattern in V5 and V6 attributed to displaced transition of QRS complex. | ||
* | * Absence of q waves in leads I, V5, and V6 (or a narrow q wave in aVL in the absence of myocardial pathology). | ||
* R peak time ≥ 60 ms in leads V5 and V6 but normal in leads V1, V2, and V3 (when small initial r waves can be discerned). | * R peak time ≥ 60 ms in leads V5 and V6 but normal in leads V1, V2, and V3 (when small initial r waves can be discerned). | ||
* ST and T waves opposite in direction of QRS deflections. | * ST and T waves opposite in direction of QRS deflections.<ref>Surawicz, Borys, Rory Childers, Barbara J. Deal, Leonard S. Gettes, James J. Bailey, Anton Gorgels, E. William Hancock, et al. “AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram: Part III: Intraventricular Conduction Disturbances: A Scientific Statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology.” Journal of the American College of Cardiology 53, no. 11 (March 17, 2009): 976–81. doi:10.1016/j.jacc.2008.12.013.</ref> | ||
===Incomplete LBBB Criteria=== | |||
* QRS duration 110 - 120 ms (90 - 100 ms in children 4 to 16 years of age; 80 - 90 ms in children < 4 years of age). | |||
* Presence of left ventricular hypertrophy pattern. | |||
* R peak time ≥ 60 ms in leads V4, V5, and V6. | |||
* Absence of q wave in leads I, V5, and V6.<ref>Surawicz, Borys, Rory Childers, Barbara J. Deal, Leonard S. Gettes, James J. Bailey, Anton Gorgels, E. William Hancock, et al. “AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram: Part III: Intraventricular Conduction Disturbances: A Scientific Statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology.” Journal of the American College of Cardiology 53, no. 11 (March 17, 2009): 976–81. doi:10.1016/j.jacc.2008.12.013.</ref> | |||
==Right Bundle Branch Block== | ==Right Bundle Branch Block== | ||
<div style="float:right;>[[File:Right_bundle_branch_block_ECG_characteristics.png|200px]]</div> | <div style="float:right;>[[File:Right_bundle_branch_block_ECG_characteristics.png|200px]]</div> | ||
===Criteria=== | ===Complete RBBB Criteria=== | ||
* QRS duration ≥ 120 ms (≥ 100 ms in children 4 to 16 years of age; ≥ 90 ms in children | * QRS duration ≥ 120 ms (≥ 100 ms in children 4 to 16 years of age; ≥ 90 ms in children < 4 years of age). | ||
* rsr', rsR', or rSR' in leads V1 or V2. | * rsr', rsR', or rSR' in leads V1 or V2. | ||
:* The R' or r' deflection is usually wider than the initial R wave. | :* The R' or r' deflection is usually wider than the initial R wave. | ||
:* In a minority of patients, a wide and often notched R wave pattern may be seen in lead V1 and/or V2. | :* In a minority of patients, a wide and often notched R wave pattern may be seen in lead V1 and/or V2. | ||
* S wave of greater duration than R wave or ≥ 40 ms in leads I and V6. | * S wave of greater duration than R wave or ≥ 40 ms in leads I and V6. | ||
* R peak time ≥ 50 ms in lead V1 but normal in leads V5 and V6. | * R peak time ≥ 50 ms in lead V1 but normal in leads V5 and V6.<ref>Surawicz, Borys, Rory Childers, Barbara J. Deal, Leonard S. Gettes, James J. Bailey, Anton Gorgels, E. William Hancock, et al. “AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram: Part III: Intraventricular Conduction Disturbances: A Scientific Statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology.” Journal of the American College of Cardiology 53, no. 11 (March 17, 2009): 976–81. doi:10.1016/j.jacc.2008.12.013.</ref> | ||
===Incomplete RBBB Criteria=== | |||
* QRS duration 110 - 120 ms (90 - 100 ms in children 4 to 16 years of age; 80 - 90 ms in children < 4 years of age). | |||
* rsr', rsR', or rSR' in leads V1 or V2. | |||
* S wave of greater duration than R wave or ≥ 40 ms in leads I and V6. | |||
* R peak time ≥ 50 ms in lead V1 but normal in leads V5 and V6.<ref>Surawicz, Borys, Rory Childers, Barbara J. Deal, Leonard S. Gettes, James J. Bailey, Anton Gorgels, E. William Hancock, et al. “AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram: Part III: Intraventricular Conduction Disturbances: A Scientific Statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology.” Journal of the American College of Cardiology 53, no. 11 (March 17, 2009): 976–81. doi:10.1016/j.jacc.2008.12.013.</ref> | |||
==Nonspecific or Unspecified Intraventricular Conduction Disturbance== | |||
===Criteria=== | |||
* QRS duration ≥ 110 ms (≥ 90 ms in children 8 to 16 years of age; ≥ 80 ms in children < 8 years of age). | |||
* Absence of criteria for LBBB or BBBB.<ref>Surawicz, Borys, Rory Childers, Barbara J. Deal, Leonard S. Gettes, James J. Bailey, Anton Gorgels, E. William Hancock, et al. “AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram: Part III: Intraventricular Conduction Disturbances: A Scientific Statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology.” Journal of the American College of Cardiology 53, no. 11 (March 17, 2009): 976–81. doi:10.1016/j.jacc.2008.12.013.</ref> | |||
==Ventricular Preexcitation of Wolff-Parkinson-White Type== | |||
===Criteria=== | |||
* PR interval < 120 ms during sinus rhythm assuming no intra-atrial or interatrial conduction block (or < 90 ms in children). | |||
* Delta wave: slurring of initial portion of the QRS complex, which either interrupts the P wave or arises immediately after its termination. | |||
* QRS duration > 120 ms (or > 90 ms in children). | |||
* Secondary ST and T wave changes.<ref>Surawicz, Borys, Rory Childers, Barbara J. Deal, Leonard S. Gettes, James J. Bailey, Anton Gorgels, E. William Hancock, et al. “AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram: Part III: Intraventricular Conduction Disturbances: A Scientific Statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology.” Journal of the American College of Cardiology 53, no. 11 (March 17, 2009): 976–81. doi:10.1016/j.jacc.2008.12.013.</ref> | |||
==Left Atrial Enlargement== | ==Left Atrial Enlargement== | ||
Latest revision as of 02:24, 11 November 2016
| ECG Criteria |
|---|
▸ Axis Deviation
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▸ Conduction Disturbance
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▸ Chamber Abnormality
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▸ Miscellaneous
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Left Axis Deviation
Criteria
- QRS axis between -30º and -90º
- Dominant S wave (S > R) in lead II and aVF
Causes
- Left bundle branch block
- Left anterior fascicular block
- Left ventricular hypertrophy
- Inferior myocardial infarction
- Ostium primum atrial septal defect
- Tricuspid atresia
- WPW syndrome with right-sided accessory pathway
- Ventricular pacing
- Ventricular ectopy
- Hyperkalemia
- Mechanical shifts, such as expiration, high diaphragm (pregnancy, ascites, abdominal tumor)
- Normal variation
Right Axis Deviation
Criteria
- QRS axis between +90º and +180º
- Dominant S wave (S > R) in lead I and aVL
Causes
- Right ventricular strain
- Lateral wall myocardial infarction
- Left posterior fascicular block
- Ventricular ectopy
- WPW syndrome with left-sided accessory pathway
- Mechanical shifts, such as inspiration and emphysema
- Normal variation in children or thin adults with a horizontally oriented heart
- Dextrocardia
- Pectus excavatum
- Reversed arm leads
Northwest Axis (No Man's Land)
Criteria
- QRS axis between -90º and -180º
Causes
- Lead misplacement
- Severe right ventricular hypertrophy
- Artificial pacemaker
- Ventricular tachycardia
- Ventricular ectopy
- Accelerated idioventricular rhythm
- Hyperkalemia
- Emphysema
Left Anterior Fascicular Block
Criteria
- Frontal plane axis between -45° and -90°.
- qR pattern in lead aVL.
- R peak time ≥ 45 ms in lead aVL.
- QRS duration < 120 ms.[1]
Left Posterior Fascicular Block
Criteria
- Frontal plane axis between +90° and +180°.
- Owing to the more rightward axis in children up to 16 years of age, this criterion should only be applied to them when a distinct rightward change in axis is documented.
- rS pattern in leads I and aVL.
- qR pattern in leads III and aVF.
- QRS duration < 120 ms.[2]
Left Bundle Branch Block
Complete LBBB Criteria
- QRS duration ≥ 120 ms (≥ 100 ms in children 4 to 16 years of age; ≥ 90 ms in children < 4 years of age).
- Broad notched or slurred R wave in leads I, aVL, V5, and V6 and an occasional RS pattern in V5 and V6 attributed to displaced transition of QRS complex.
- Absence of q waves in leads I, V5, and V6 (or a narrow q wave in aVL in the absence of myocardial pathology).
- R peak time ≥ 60 ms in leads V5 and V6 but normal in leads V1, V2, and V3 (when small initial r waves can be discerned).
- ST and T waves opposite in direction of QRS deflections.[3]
Incomplete LBBB Criteria
- QRS duration 110 - 120 ms (90 - 100 ms in children 4 to 16 years of age; 80 - 90 ms in children < 4 years of age).
- Presence of left ventricular hypertrophy pattern.
- R peak time ≥ 60 ms in leads V4, V5, and V6.
- Absence of q wave in leads I, V5, and V6.[4]
Right Bundle Branch Block
Complete RBBB Criteria
- QRS duration ≥ 120 ms (≥ 100 ms in children 4 to 16 years of age; ≥ 90 ms in children < 4 years of age).
- rsr', rsR', or rSR' in leads V1 or V2.
- The R' or r' deflection is usually wider than the initial R wave.
- In a minority of patients, a wide and often notched R wave pattern may be seen in lead V1 and/or V2.
- S wave of greater duration than R wave or ≥ 40 ms in leads I and V6.
- R peak time ≥ 50 ms in lead V1 but normal in leads V5 and V6.[5]
Incomplete RBBB Criteria
- QRS duration 110 - 120 ms (90 - 100 ms in children 4 to 16 years of age; 80 - 90 ms in children < 4 years of age).
- rsr', rsR', or rSR' in leads V1 or V2.
- S wave of greater duration than R wave or ≥ 40 ms in leads I and V6.
- R peak time ≥ 50 ms in lead V1 but normal in leads V5 and V6.[6]
Nonspecific or Unspecified Intraventricular Conduction Disturbance
Criteria
- QRS duration ≥ 110 ms (≥ 90 ms in children 8 to 16 years of age; ≥ 80 ms in children < 8 years of age).
- Absence of criteria for LBBB or BBBB.[7]
Ventricular Preexcitation of Wolff-Parkinson-White Type
Criteria
- PR interval < 120 ms during sinus rhythm assuming no intra-atrial or interatrial conduction block (or < 90 ms in children).
- Delta wave: slurring of initial portion of the QRS complex, which either interrupts the P wave or arises immediately after its termination.
- QRS duration > 120 ms (or > 90 ms in children).
- Secondary ST and T wave changes.[8]
Left Atrial Enlargement
Criteria
- P wave duration ≥ 110 ms (sensitivity 62%; specificity 86%)[9]
- Negative phase of P wave in V1 ≥ 40 ms (sensitivity 20%; specificity 98%)
- P terminal force in V1 ≥ 40 msec-mm (sensitivity 56%; specificity 95%)
- Negative phase of P wave in V1 > 1 mm
- Notched P wave with interpeak interval > 40 ms
- P wave/PR duration > 1.6
Right Atrial Enlargement
Criteria
- A tall upright P wave in lead II (> 2.5 mm), often with a peaked or pointed appearance.
- Prominent initial positivity of the P wave in V1 or V2 (≥ 1.5 mm).
Left Ventricular Hypertrophy
Criteria
- Romhilt-Estes criteria (4 points = probable, 5 points = definite):
- Largest R or S in limb leads ≥ 20 mm or S in V1 or V2 ≥ 30 mm or R in V5 or V6 ≥ 30 mm (3 points)
- ST displacement opposite to QRS deflection: without digoxin (3 points); with digoxin (1 point)
- LAA (3 points)
- LAD (2 points)
- QRS duration ≥ 90 ms (1 point)
- Intrinsicoid deflection (QRS onset to peak of R) in V5 or V6 ≥ 50 ms (1 point)
- Sokolow-Lyon criteria:
- S in V1 + R in V5 or V6 ≥35 mm
- R in aVL ≥11 mm
- Cornell criteria:
- R in aVL + S in V3 >28 mm in men or >20 mm in women
- If LAD or LAFB, S in lead III + max (R+S) in precordial leads ≥ 30 mm
Right Ventricular Hypertrophy
Criteria
- Increased R/S ratio in V1 (> 1)
- Tall R wave in V1 (> 6 mm)
- Deep S wave in V5 (> 10 mm) or V6 (> 3 mm)
- Drop in R/S ratio across precordium (R/S ratio in V1 > R/S ratio in V3 or V4)
Biventricular Hypertrophy
Criteria
- ECG criteria for LVH plus the presence of:
- Prominent S waves in V5 or V6
- Right axis deviation
- Tall biphasic R/S complexes
- Right atrial enlargement
Pathologic Q Wave
QT Prolongation
Criteria
Causes
- Congenital
- Medications
- Antiarrhythmics (amiodarone, disopyramide, dronedarone, flecainide, sotalol)
- Antibiotics such as macrolides (erythromycin, clarithromycin, azithromycin) and quinolones (levofloxacin, moxifloxacin)
- Antifungals (fluconazole, ketoconazole)
- Antimotility and antiemetic agents (domperidone, granisetron, ondansetron)
- Antimalarials (quinine, chloroquine)
- Antihistamines (hydroxyzine)
- Antipsychotics (chlorpromazine, clozapine, droperidol, fluphenazine, haloperidol, olanzapine, pimozide, paliperidone, quetiapine, risperidone)
- Antidepressants (amitriptyline, citalopram, escitalopram, dosulepin, doxepin, fluoxetine, imipramine, lofepramine)
- Miscellaneous (methadone, foscarnet, sorafenib, sunitinib)
- Autonomic dysfunction
- Electrolyte imbalances
- Miscellaneous
Poor R Wave Progression
Criteria
- Loss of anterior forces without frank Q waves in precordial leads (decrease in R wave amplitude from V1 to V2, or V2 to V3, or V3 to V4)
- R wave in V3 ≤ 3 mm
Causes
- Prior anterior myocardial infarction
- Ventricular hypertrophy
- Left bundle branch block
- WPW syndrome
- Cardiomyopathy
- Emphysema
- Pneumothorax
- Clockwise rotation of the heart
- Lead misplacement in a cranial direction
- Normal variant
ST Elevation
ST Depression
T Wave Inversion
Low Voltage
References
- ↑ Surawicz, Borys, Rory Childers, Barbara J. Deal, Leonard S. Gettes, James J. Bailey, Anton Gorgels, E. William Hancock, et al. “AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram: Part III: Intraventricular Conduction Disturbances: A Scientific Statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology.” Journal of the American College of Cardiology 53, no. 11 (March 17, 2009): 976–81. doi:10.1016/j.jacc.2008.12.013.
- ↑ Surawicz, Borys, Rory Childers, Barbara J. Deal, Leonard S. Gettes, James J. Bailey, Anton Gorgels, E. William Hancock, et al. “AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram: Part III: Intraventricular Conduction Disturbances: A Scientific Statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology.” Journal of the American College of Cardiology 53, no. 11 (March 17, 2009): 976–81. doi:10.1016/j.jacc.2008.12.013.
- ↑ Surawicz, Borys, Rory Childers, Barbara J. Deal, Leonard S. Gettes, James J. Bailey, Anton Gorgels, E. William Hancock, et al. “AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram: Part III: Intraventricular Conduction Disturbances: A Scientific Statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology.” Journal of the American College of Cardiology 53, no. 11 (March 17, 2009): 976–81. doi:10.1016/j.jacc.2008.12.013.
- ↑ Surawicz, Borys, Rory Childers, Barbara J. Deal, Leonard S. Gettes, James J. Bailey, Anton Gorgels, E. William Hancock, et al. “AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram: Part III: Intraventricular Conduction Disturbances: A Scientific Statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology.” Journal of the American College of Cardiology 53, no. 11 (March 17, 2009): 976–81. doi:10.1016/j.jacc.2008.12.013.
- ↑ Surawicz, Borys, Rory Childers, Barbara J. Deal, Leonard S. Gettes, James J. Bailey, Anton Gorgels, E. William Hancock, et al. “AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram: Part III: Intraventricular Conduction Disturbances: A Scientific Statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology.” Journal of the American College of Cardiology 53, no. 11 (March 17, 2009): 976–81. doi:10.1016/j.jacc.2008.12.013.
- ↑ Surawicz, Borys, Rory Childers, Barbara J. Deal, Leonard S. Gettes, James J. Bailey, Anton Gorgels, E. William Hancock, et al. “AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram: Part III: Intraventricular Conduction Disturbances: A Scientific Statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology.” Journal of the American College of Cardiology 53, no. 11 (March 17, 2009): 976–81. doi:10.1016/j.jacc.2008.12.013.
- ↑ Surawicz, Borys, Rory Childers, Barbara J. Deal, Leonard S. Gettes, James J. Bailey, Anton Gorgels, E. William Hancock, et al. “AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram: Part III: Intraventricular Conduction Disturbances: A Scientific Statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology.” Journal of the American College of Cardiology 53, no. 11 (March 17, 2009): 976–81. doi:10.1016/j.jacc.2008.12.013.
- ↑ Surawicz, Borys, Rory Childers, Barbara J. Deal, Leonard S. Gettes, James J. Bailey, Anton Gorgels, E. William Hancock, et al. “AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram: Part III: Intraventricular Conduction Disturbances: A Scientific Statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology.” Journal of the American College of Cardiology 53, no. 11 (March 17, 2009): 976–81. doi:10.1016/j.jacc.2008.12.013.
- ↑ Hazen MS, Marwick TH, Underwood DA (1991). "Diagnostic accuracy of the resting electrocardiogram in detection and estimation of left atrial enlargement: an echocardiographic correlation in 551 patients". Am Heart J. 122 (3 Pt 1): 823–8. PMID 1831587.
- ↑ Rautaharju PM, Surawicz B, Gettes LS, Bailey JJ, Childers R, Deal BJ; et al. (2009). "AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part IV: the ST segment, T and U waves, and the QT interval: a scientific statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology". J Am Coll Cardiol. 53 (11): 982–91. doi:10.1016/j.jacc.2008.12.014. PMID 19281931.
- ↑ Drug and Therapeutics Bulletin (2016). "QT interval and drug therapy". BMJ. 353: i2732. doi:10.1136/bmj.i2732. PMID 27334640.