Short PR interval: Difference between revisions
No edit summary |
|||
| Line 14: | Line 14: | ||
:*The possibilities for short PR interval in [[LGL]] syndrome are faster AV nodal conduction due to the rapidly conducting fibers within the AV node or rapid conduction through [[Brechenmacher fibers]] that bypass the AV node connecting atria with [[bundle of His]] or the conduction through the accessory pathway [[James fibers]] that connect atria with low AV node. | :*The possibilities for short PR interval in [[LGL]] syndrome are faster AV nodal conduction due to the rapidly conducting fibers within the AV node or rapid conduction through [[Brechenmacher fibers]] that bypass the AV node connecting atria with [[bundle of His]] or the conduction through the accessory pathway [[James fibers]] that connect atria with low AV node. | ||
:*Short PR interval in [[WPW]] syndrome results from an accessory pathway, the [[bundle of Kent]] that directly connects the atria to the ventricles, bypassing the AV node. | :*Short PR interval in [[WPW]] syndrome results from an accessory pathway, the [[bundle of Kent]] that directly connects the atria to the ventricles, bypassing the AV node. | ||
The difference between both is that [[LGL]] syndrome has a normal [[QRS complex]] following ventricular activation via the normal conduction pathway ([[His Purkinje system]]) and [[WPW]] syndrome has a wide [[QRS complex]] due to the combined early ventricular activation via the abnormal accessory pathway and terminal ventricular activation via the normal conduction system. | :*The difference between both is that [[LGL]] syndrome has a normal [[QRS complex]] following ventricular activation via the normal conduction pathway ([[His Purkinje system]]) and [[WPW]] syndrome has a wide [[QRS complex]] due to the combined early ventricular activation via the abnormal accessory pathway and terminal ventricular activation via the normal conduction system. | ||
*[[Premature atrial beats]] arising close to the AV node (low atrial ectopics) activate the atria retrogradely, producing an inverted [[P wave]] with a relatively short PR interval. | *[[Premature atrial beats]] arising close to the AV node (low atrial ectopics) activate the atria retrogradely, producing an inverted [[P wave]] with a relatively short PR interval. | ||
*In AV [[junctional rhythms]] with retrograde atrial activation the retrograde P waves occur before the [[QRS complex]] shortening the PR interval. Negative P waves in leads II, III and aVF point towards this diagnosis. | *In AV [[junctional rhythms]] with retrograde atrial activation the retrograde P waves occur before the [[QRS complex]] shortening the PR interval. Negative P waves in leads II, III and aVF point towards this diagnosis. | ||
Revision as of 20:15, 24 August 2013
|
WikiDoc Resources for Short PR interval |
|
Articles |
|---|
|
Most recent articles on Short PR interval Most cited articles on Short PR interval |
|
Media |
|
Powerpoint slides on Short PR interval |
|
Evidence Based Medicine |
|
Cochrane Collaboration on Short PR interval |
|
Clinical Trials |
|
Ongoing Trials on Short PR interval at Clinical Trials.gov Trial results on Short PR interval Clinical Trials on Short PR interval at Google
|
|
Guidelines / Policies / Govt |
|
US National Guidelines Clearinghouse on Short PR interval NICE Guidance on Short PR interval
|
|
Books |
|
News |
|
Commentary |
|
Definitions |
|
Patient Resources / Community |
|
Patient resources on Short PR interval Discussion groups on Short PR interval Patient Handouts on Short PR interval Directions to Hospitals Treating Short PR interval Risk calculators and risk factors for Short PR interval
|
|
Healthcare Provider Resources |
|
Causes & Risk Factors for Short PR interval |
|
Continuing Medical Education (CME) |
|
International |
|
|
|
Business |
|
Experimental / Informatics |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Vendhan Ramanujam M.B.B.S [2]
Overview
PR interval below its normal interval of 0.10 to 0.21 seconds is called as short PR interval. Although short PR interval may be a normal variant, it has also been noted in numerous clinical conditions like cardiomyopathy, mitral valve prolapse, Duchenne's muscular dystrophy, Pompe disease, Fabry disease etc. It is also seen in number of electrophysiological disorders including preexcitation syndrome, premature atrial beats, AV junctional rhythms and isorhythmic A-V dissociation.
Pathophysiology
Clinical conditions
Short PR interval in most of the clinical conditions is due to the preexcitation and ectopics arising from dilated atria.
Electrophysiological disorders
- The two subsets of preexcitation syndrome, Lown-Ganong-Levine syndrome and Wolff-Parkinson-White syndrome are associated with short PR interval due to bypass tracts that bypass the AV node, directly connecting the atria with the ventricle.
- The possibilities for short PR interval in LGL syndrome are faster AV nodal conduction due to the rapidly conducting fibers within the AV node or rapid conduction through Brechenmacher fibers that bypass the AV node connecting atria with bundle of His or the conduction through the accessory pathway James fibers that connect atria with low AV node.
- Short PR interval in WPW syndrome results from an accessory pathway, the bundle of Kent that directly connects the atria to the ventricles, bypassing the AV node.
- The difference between both is that LGL syndrome has a normal QRS complex following ventricular activation via the normal conduction pathway (His Purkinje system) and WPW syndrome has a wide QRS complex due to the combined early ventricular activation via the abnormal accessory pathway and terminal ventricular activation via the normal conduction system.
- Premature atrial beats arising close to the AV node (low atrial ectopics) activate the atria retrogradely, producing an inverted P wave with a relatively short PR interval.
- In AV junctional rhythms with retrograde atrial activation the retrograde P waves occur before the QRS complex shortening the PR interval. Negative P waves in leads II, III and aVF point towards this diagnosis.
- In isorhythmic A-V dissociation P waves are dissociated from QRS complex but both their rates are similar resulting in P waves marching back and forth across the QRS complex creating an appearance of sinus P wave with a short PR interval.
Causes
Life Threatening Causes
Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.
- Acute respiratory failure
- Diabetic ketoacidosis
- Digitalis toxicity
- Myocardial infarction
- Pulmonary embolism
Common Causes
Causes by Organ System
Causes in Alphabetical Order
References
- ↑ MacKenzie, R. (2005). "Short PR interval". J Insur Med. 37 (2): 145–52. PMID 16060547.
- ↑ Perloff, JK. (1984). "Cardiac rhythm and conduction in Duchenne's muscular dystrophy: a prospective study of 20 patients". J Am Coll Cardiol. 3 (5): 1263–8. PMID 6707378. Unknown parameter
|month=ignored (help) - ↑ Efthimiou, J.; McLelland, J.; Betteridge, DJ. (1986). "Short PR intervals and tachyarrhythmias in Fabry's disease". Postgrad Med J. 62 (726): 285–7. PMID 3086855. Unknown parameter
|month=ignored (help) - ↑ Huang, SK.; Rosenberg, MJ.; Denes, P. (1984). "Short PR interval and narrow QRS complex associated with pheochromocytoma: electrophysiologic observations". J Am Coll Cardiol. 3 (3): 872–5. PMID 6693659. Unknown parameter
|month=ignored (help) - ↑ Castellanos, A.; Castillo, CA.; Agha, AS.; Tessler, M. (1971). "His bundle electrograms in patients with short P-R intervals, narrow QRS complexes, and paroxysmal tachycardias". Circulation. 43 (5): 667–78. PMID 5578843. Unknown parameter
|month=ignored (help)