Lown-Ganong-Levine syndrome

Lown-Ganong-Levine syndrome

Infobox_Disease
Name = PAGENAME


Caption =
DiseasesDB = 7599
ICD10 = ICD10|I|45|6|i|30
ICD9 = ICD9|426.81
ICDO =
OMIM = 108950
MedlinePlus =
eMedicineSubj = med
eMedicineTopic = 2954
MeshID = D008151

Lown-Ganong-Levine syndrome (LGL) is a syndrome of pre-excitation of the ventricles due to an accessory pathway providing an abnormal electrical communication from the atria to the ventricles. It is grouped with Wolff-Parkinson-White syndrome as an atrioventricular re-entry tachycardia (AVRT).

Pathophysiology

In normal individuals, electrical activity in the heart is initiated in the sinoatrial (SA) node (located in the right atrium), propagates to the atrioventricular (AV) node, and then through the bundle of His to the ventricles of the heart. (See electrical conduction system of the heart).

The AV node acts as a gatekeeper, limiting the electrical activity that reaches the ventricles of the heart. This is an important function of the AV node, because if the signals generated in the atria of the heart were to increase in rate (such as during atrial fibrillation or atrial flutter), the AV node will limit the electrical activity that conducts to the ventricles. For instance, if the atria are electrically activated at 300 beats per minute, half those electrical impulses are blocked by the AV node, so that the ventricles are activated at 150 beats per minute (giving a pulse of 150 beats per minute). Another important property of the AV node is that it slows down individual electrical impulses. This is manifest on the EKG as the PR interval, the time from activation of the atria (manifest as the P wave) and activation of the ventricles (manifest as the QRS complex).

Individuals with LGL syndrome are thought to have an accessory pathway that connects the atria directly to the bundle of His. As in WPW syndrome, the accessory pathway does not share the rate-slowing properties of the AV node, and may conduct electrical activity at a significantly higher rate than the AV node. For instance, in the example above, if an individual had an atrial rate of 300 beats per minute, the accessory bundle may conduct all the electrical impulses from the atria to the ventricles, causing the ventricles to activate at 300 beats per minute. Because the ventricles are the main pumping chambers of the heart, the body depends on the proper filling and emptying (contraction) of them. When conducted too rapidly (i.e. 300 beats per minute), the body would become hemodynamically unstable. If not corrected quickly, the ventricles can fibrillate causing VF (ventricular fibrillation)- leading to sudden cardiac death (SCD).

Diagnosis

LGL syndrome is commonly diagnosed on the basis of the surface EKG in an asymptomatic individual. In this case it is manifest as a PR interval less than or equal to 0.12 second (120 ms) with normal QRS complex duration.

It can be distinguished from WPW syndrome because:
* The QRS complexes in LGL syndrome are normal because ventricular contraction is initiated in the normal manner. The broad complexes seen in the asymptomatic individual with WPW are not a feature of LGL.
* The delta waves seen in WPW syndrome are not seen in LGL syndrome as the accessory pathway does not connect to the ventricles and so ventricular contraction does not start early.

ee also

* Wolff-Parkinson-White syndrome
* Cardiac electrophysiology
* Electrical conduction system of the heart
* Electrocardiogram
* Electrophysiologic study


Wikimedia Foundation. 2010.

Игры ⚽ Поможем сделать НИР

Look at other dictionaries:

  • Lown-Ganong-Levine syndrome — Lown Gan·ong Le·vine syndrome lau̇n gan .ȯŋ lə vīn , vēn n LGL SYNDROME * * * Lown Gan·ong Le·vine syndrome (lounґ ganґong lə vīnґ) [Bernard Lown, American cardiologist, born 1921; William F. Ganong, American physiologist, born 1924;… …   Medical dictionary

  • Lown-Ganong-Levine-Syndrom — Klassifikation nach ICD 10 I45.6 Präexzitations Syndrom Lown Ganong Levine Syndrom …   Deutsch Wikipedia

  • Syndrome de wolff-parkinson-white — Pour les articles homonymes, voir WPW. Nom du symptôme/signe : Syndrome de Wolff Parkinson White Code CIM 10 : I45.6 Décrit en 1930 par les Docteurs Wolff …   Wikipédia en Français

  • short PR syndrome — Lown Ganong Levine syndrome …   Medical dictionary

  • Syndrome de Wolff-Parkinson-White — Pour les articles homonymes, voir WPW. Syndrome de Wolff Parkinson White Classification et ressources externes Décrit en 1930 par les Docteurs Wolff, Parkinson et White[1], le syndrome de Wolff Parkinson Whit …   Wikipédia en Français

  • syndrome — The aggregate of symptoms and signs associated with any morbid process, and constituting together the picture of the disease. SEE ALSO: disease. [G. s., a running together, tumultuous concourse; (in med.) a concurrence of symptoms, fr. syn,… …   Medical dictionary

  • Ganong — William F., U.S. physiologist, *1924. See Lown G. Levine syndrome …   Medical dictionary

  • Levine — Samuel A., U.S. cardiologist, 1891–1966. See Lown Ganong L. syndrome …   Medical dictionary

  • Lown — Bernard, U.S. cardiologist, *1921. See L. Ganong Levine syndrome …   Medical dictionary

  • LGL syndrome — el (.)jē .el n a preexcitation syndrome characterized by atrial tachycardia together with a short P R interval and a QRS complex of normal duration called also Lown Ganong Levine syndrome Lown lau̇n Bernard (b 1921) American cardiologist. Lown en …   Medical dictionary

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”