Bundle of His divides into right and left branches. The left branch divides into three divisions:
1. Anterior.
2. Posterior, and
3. Septal All these branches may be involved singly or in combinations.
Causes Right bundle branch block
N.B. : It is a normal finding in all ages.
1. Emphysema and fibrosis of lung.
2. Right ventricular enlargement
3. Atrial septal defect, VSD
4. Ebstein’s anomaly
5. Pulmonary embolism.
6. Ischaemic heart disease.
7. Carditis from any cause.
8. Endomyocardial fibrosis and cardiomyopathy
9. Drugs, e.g. Quinidine and Procainamide, others.
10. Congenital heart, disease including coarctation of aorta.
11. Idiopathic fibrosis.
12. Surgery and trauma.
13. Brugada syndrome and Rv dysplasia.
.Left bundle branch block
1. Ischaemic and hypertensive heart disease.
2. Left ventricular enlargement
3. Carditis.
4. Endomyocardial fibrosis and cardiomyopathy.
HYPERTENSION
Definition Systemic hypertension is the persistent rise of basal blood pressure above the arbitrary level of 140/90 mm of Hg
recorded on three or more successive occasions. There may be only systolie hypertension. In such cases systolic BP
becomes 140 mm of Hg or above Classification of Hypertension Essential or Idiopathic hypertension
Here no obvious cause is found to account for high blood pressure (90%-95% of cases). Secondary or Symptomatic hypertension (5%-10% of cases)
1. Renal causes (common): Acute nephritic syndrome, Chronic nephritis, Polycystic kidney, Hydronephrosis Chronic pyelonephritis, Renal artery stenosis, Reninsecreting tumour, Renal embolism
2. Endocrine causes: Thyrotoxicosis and myxoedema Acromegaly, Cushing’s syndrome, Primary aldosteronism (Conn’s syndrome), Phaeochromocytoma.
3. Metabolic causes: Diabetes mellitus, Chronic gout Toxaemias of pregnancy, Atherosclerosis
4. Drugs: Contraceptive pills, Steroids, Liquorice
5. Collagenosis and miscellaneous diseases: SLE Polyarteritis nodosa, Scleroderma, DermatomyositisPseudoxanthoma elasticum
6. Congenital: Coarctation of the aorta
7. Psychogenic
8. Neurological Encephalitis, Brain tumour,Cerebrovascular accidents, Diencephalic syndrome
