Difference between revisions of "Bundle Branch Block"

Revision as of 16:56, 15 March 2011

Introduction

This condition is an abnormal ventricular excitation as the result of blockage to the right bundle branch, the left bundle branch, or left anterior fascicular block.

Right bundle branch block is characterised by the failure or delay of conduction through the right bundle branch. The left ventricle is unaffected. Some causes of this condition include pulmonary embolism, heart worm, electrolyte disturbances, congenital diseases etc.

In left bundle branch block, there is failure of conduction through the left bundle branch and the right ventricle is unaffected. Causes of this include congenital abnormalities and myocardial diseases.

There can also be a left anterior fasicular block, which is characterised by the failure of conduction through the anterior fascicle of the left bundle branch. Causes of this include electrolyte abnormalities and cardiomyopathies e.g. in the cat.

Signalment

The disease is described in both cats and dogs.

Clinical Signs

Many cases of bundle branch block are asymptomatic and are only detected on ECG. However, more severe cases will cause ventricular muscle damage and therefore signs of heart disease will occur. Some animals may present due to syncope, weakness or exercise intolerance.

Diagnosis

An Electrocardiograph (ECG) is the diagnostic method of choice. In a right bundle branch block, one may see a wide QRS complex and a wide S wave. In left anterior fasicular block there will be a normal QRS wave, a tall R waves and deep S waves.

Treatment

Unless the condition is congenital, treatment is by treating the underlying cause.

References

Ettinger, S.J. and Feldman, E. C. (2000) Textbook of Veterinary Internal Medicine Diseases of the Dog and Cat Volume 2 (Fifth Edition) W.B. Saunders Company
Ettinger, S.J, Feldman, E.C. (2005) Textbook of Veterinary Internal Medicine (6th edition, volume 2)W.B. Saunders Company
Fossum, T. W. et. al. (2007) Small Animal Surgery (Third Edition) Mosby Elsevier
Merck & Co (2008) The Merck Veterinary Manual (Eighth Edition) Merial
Nelson, R.W. and Couto, C.G. (2009) Small Animal Internal Medicine (Fourth Edition) Mosby Elsevier.

@@ Line 1: / Line 1: @@
-*Abnormal ventricular excitation as the result of blockage to the right bundle branch, the left bundle branch, or left anterior fascicular block.
+== Introduction<br> ==
+This condition is an abnormal ventricular excitation as the result of blockage to the right bundle branch, the left bundle branch, or left anterior fascicular block.&nbsp;<br>
-====Right Bundle Branch Block====
+Right bundle branch block is characterised by the failure or delay of conduction through the right bundle branch. The left ventricle is unaffected. Some causes of this condition include pulmonary embolism, heart worm, electrolyte disturbances, congenital diseases etc.<br>
-Characterised by the failure or delay of conduction through the right bundle branch.  Left ventricle is unaffected.
+In left bundle branch block, there is failure of conduction through the left bundle branch and the right ventricle is unaffected. Causes of this include congenital abnormalities and myocardial diseases.<br>
-=====Causes=====
+There can also be a left anterior fasicular block, which is characterised by the failure of conduction through the anterior fascicle of the left bundle branch. Causes of this include electrolyte abnormalities and cardiomyopathies e.g. in the cat.<br>
-Pulmonary embolism, heart worm, electrolyte disturbances, congenital diseases etc.
+<br>
-'''ECG Appearance:''' Wide QRS complex, Wide S wave
+== Signalment<br> ==
+The disease is described in both cats and dogs.<br>
-=====Treatment=====
+<br>
-Treat the underlying cause
+== Clinical Signs<br> ==
-====Left Bundle Branch Block====
+Many cases of bundle branch block are asymptomatic and are only detected on ECG. However, more severe cases will cause ventricular muscle damage and therefore signs of heart disease will occur. Some animals may present due to syncope, weakness or exercise intolerance.<br>
-Characterised by the failure of conduction through the left bundle branch.  Right ventricle is unaffected.
+<br>
-=====Causes=====
+== Diagnosis<br> ==
-Congenital abnormalities, myocardial diseases etc.
-=====Treatment=====
+An Electrocardiograph (ECG) is the diagnostic method of choice. In a right bundle branch block, one may see a wide QRS complex and a wide S wave. In left anterior fasicular block there will be a normal QRS wave, a tall R waves and deep S waves.<span style="font-weight: bold;"></span><span style="font-weight: bold;" /><span style="font-weight: bold;" />'''<span style="font-weight: bold;" />'''<span style="font-weight: bold;" /><span style="font-weight: bold;" /><span style="font-weight: bold;" /><span style="font-weight: bold;" />
-Treat the underlying cause
+<br>
-'''Left Anterior Fascicular Block'''=characterised by the failure of conduction through the anterior fascicle of the left bundle branch.
+== Treatment<br> ==
+Unless the condition is congenital, treatment is by treating the underlying cause.<br>
-'''Causes:''' Electrolyte abnormalities, hypertrophic cardiomyopathy (cat), etc.
+<br>
+== References<br> ==
-'''ECG Appearance:''' Normal QRS, tall R waves, deep S waves
+Ettinger, S.J. and Feldman, E. C. (2000) Textbook of Veterinary Internal Medicine Diseases of the Dog and Cat Volume 2 (Fifth Edition) W.B. Saunders Company<br>Ettinger, S.J, Feldman, E.C. (2005) Textbook of Veterinary Internal Medicine (6th edition, volume 2)W.B. Saunders Company<br>Fossum, T. W. et. al. (2007) Small Animal Surgery (Third Edition) Mosby Elsevier <br>Merck &amp; Co (2008) The Merck Veterinary Manual (Eighth Edition) Merial<br>Nelson, R.W. and Couto, C.G. (2009) Small Animal Internal Medicine (Fourth Edition) Mosby Elsevier. <br><br>
+<br>
-'''Treatment:''' Treat the underlying cause[[Category:Impulse_Conduction_Abnormalities]][[Category:To_Do_-_Cardiovascular]]
+<br>
+[[Category:Impulse_Conduction_Abnormalities]] [[Category:To_Do_-_Review]]