Right Ventricular Hypertrophy
The electrical activity of the heart: the electrocardiogram
Electrical activity is a basic characteristic of the heart and is the stimulus for cardiac contraction. Disturbances of electrical function are common in heart disease. Their registration as an electrocardiogram (ECG) plays an essential role in the diagnosis and management of heart disorders.
THE GENESIS OF THE ELECTROCARDIOGRAM Pathways of conduction and the electrocardiogram
The sinus node is situated in the right atrium close to the entrance of the superior vena cava. The atrioventricular node lies in the right atrial wall immediately above the tricuspid valve. The fibres of the AV bundle (of His) arise from the atrioventricular node and run along the posterior …show more content…
1.12 Right ventricular hypertrophy. Note the tall R waves in leads V1 and V2, and associated T wave inversion extending across the chest leads to V5. There is right axis deviation. R in V5 or V6 greater than 25 mm R in aVL greater than 13 mm R in aVF greater than 20 mm.
Right ventricular hypertrophy (Fig. 1.12)
When the right ventricle becomes hypertrophied, the leads facing the right ventricle (particularly in V1, V3R and V4R) show dominant R waves instead
of the usually dominant S wave. The diagnostic criterion for right ventricular hypertrophy is:
R wave in V1 equal to or greater than the S wave and at least 5 mm tall.
As with left ventricular hypertrophy, ST depression and T wave inversion may develop in the leads with tall R waves.
Left bundle branch block (Fig. 1.13) When the left branch of the bundle is blocked, the interventricular septum is activated from the right instead of from the left side and the initial vector (phase 1) is directed to the left. Because of this, the normal initial q wave in the left ventricular leads is lost, being replaced by a small r wave. Right ventricular depolarization, which follows, produces an r in V1 and an s in V6. The left ventricle is finally depolarized resulting in an R′ in V6 and a broad S in V1. The QRS duration is increased to 0.12 s or
Electrical activity is a basic characteristic of the heart and is the stimulus for cardiac contraction. Disturbances of electrical function are common in heart disease. Their registration as an electrocardiogram (ECG) plays an essential role in the diagnosis and management of heart disorders.
THE GENESIS OF THE ELECTROCARDIOGRAM Pathways of conduction and the electrocardiogram
The sinus node is situated in the right atrium close to the entrance of the superior vena cava. The atrioventricular node lies in the right atrial wall immediately above the tricuspid valve. The fibres of the AV bundle (of His) arise from the atrioventricular node and run along the posterior …show more content…
1.12 Right ventricular hypertrophy. Note the tall R waves in leads V1 and V2, and associated T wave inversion extending across the chest leads to V5. There is right axis deviation. R in V5 or V6 greater than 25 mm R in aVL greater than 13 mm R in aVF greater than 20 mm.
Right ventricular hypertrophy (Fig. 1.12)
When the right ventricle becomes hypertrophied, the leads facing the right ventricle (particularly in V1, V3R and V4R) show dominant R waves instead
of the usually dominant S wave. The diagnostic criterion for right ventricular hypertrophy is:
R wave in V1 equal to or greater than the S wave and at least 5 mm tall.
As with left ventricular hypertrophy, ST depression and T wave inversion may develop in the leads with tall R waves.
Left bundle branch block (Fig. 1.13) When the left branch of the bundle is blocked, the interventricular septum is activated from the right instead of from the left side and the initial vector (phase 1) is directed to the left. Because of this, the normal initial q wave in the left ventricular leads is lost, being replaced by a small r wave. Right ventricular depolarization, which follows, produces an r in V1 and an s in V6. The left ventricle is finally depolarized resulting in an R′ in V6 and a broad S in V1. The QRS duration is increased to 0.12 s or