Barium carbonate is a whitish powder
It is used as a rodenticide
Symptoms develop within half an hour of poison ingestion
Fatal dose is 0.8g

Symptoms of barium carbonate poisoning:

Gastrointestinal

Diarrhoea
Vomiting
Abdominal pain

Cardiac

Arrhythmia
Hypertension
Heart failure

Areflexia, tetraplegia, flaccid paralysis

First you can review the Mechanism of normal split in second heart sound
In case of small ventricular septal defect, the blood flow through it is not large enough to cause a significant increase in right ventricular ejection time
Hence there is a normal split
But in case of large VSD, both the right ventricle and left ventricle act as a single chamber
The blood flow from both the ventricle occur for the same duration
Also because of the presence of pulmonary hypertension, hangout interval becomes negligible
Hence there is a single second heart sound with absent …

First you can review the Mechanism of normal split in second heart sound
In severe right heart failure, the right ventricle takes a longer time to eject the blood – hence the wide split
Also since it cannot accomodate the increased blood flow during inspiration, there is no increase in the split during inspiration

If you couldn’t grasp the rationale behind it, here’s an example:

Imagine the right ventricle to be a plane with 100 seats (seats referring to the capacity)
Lets first take the case of a normal right ventricle
Imagine that during the weekdays (expiration) …

First you can review the Mechanism of normal split in second heart sound
In case of atrial septal defect, the right atrium receives blood from the left atrium in addition to the normal venous return
Due to the increased amount of blood reaching the right ventricle, it takes a longer time to eject the blood
Hence the pulmonary valve takes longer to close and we appreciate a wide split (In both inspiration and expiration)

So, why does it cause a wide fixed split instead of a wide variable split?

During inspiration, the blood flow through …

During inspiration the aortic component of the second heart sound is heard about 0.02 to 0.08 seconds before the pulmonary component. The reason is as follows:

During inspiration, a negative intrathoracic pressure is created to inhale air into the lungs
This creates a vaccum effect which results in increased venous return to the right side of the heart
Hence the right ventricle takes a longer time to eject the blood into the pulmonary system
Also since pulmonary vasculature expands in capacity, lower amount of blood flows into the left atrium
Hence the left ventricle takes a …

The pulmonary valve remains open for some time even after the right ventricular pressure becomes equal to pulmonary artery pressure at end of systole
This time interval is known as hangout interval

Why does pulmonary valve remain open even after pressure equilisation?

According to Newton’s first law of motion, every body continues to move at constant speed unless acted upon by an external force
In this case, the blood continues to flow from the right ventricle even after the the pressure in the right ventricle and the pulmonary artery becomes equal
Just like a rolling …

Doxorubicin is an anti cancer drug which produces cardiotoxicity as side effect
Clinical features

Acute presentation with hypotension, arrhythmias, bundle branch block, ST changes
Delayed presentation with features of congestive cardiac failure

Pathology

Development of cardiac toxicity is due to cardiomyopathy

Risk increases beyond doses of 550mg/m2

There is bilateral symmetrical enlargement of the adrenals
Shape of the gland is preserved
Patient is usually asymptomatic
Some cases present with adrenal insufficiency
Diagnosis is by CT scan and CT directed biopsy

Alternate names :

Extranodal natural killer cell lymphoma
Nasal-type NK lymphoma
NK/T-cell lymphoma
Polymorphic/malignant midline reticulosis

It is a cutaneous lymphoma seen mostly in Korea
It is said to be the most common form of cutaneous lymphoma after mycosis fungoides
It is associated with Epstein Barr virus

Atrial fibrillation has been classified into 4 categories based on duration by the American heart association. They are:

Paroxysmal AF – Lasting upto 7 days. But usually it undergoes spontaneous resolution within 48 hours
Persistent AF – Lasting more than 7 days upto 1 year
Long standing persistent AF – If an AF lasts more than 1 year and we are planning to do rhythm control treatment (chemical cardioversion / electrical cardioversion / ablation of the excitation focus)
Permanent AF – If AF lasts for more than 1 year and we are not planning to do …