Wednesday, May 18, 2016

What is rotating inotrope therapy ? A lifesaving regimen for decompensated heart failure of both adult and pediatric population!

The catecholamine neurotransmitters  mediate their physiological responses through the family of adrenergic receptors. Three types or subfamilies of adrenergic receptors have been identified: the alpha-1, alpha-2 and beta. Within each of these subfamilies are receptor subtypes, including the subtypes of alpha-2 adrenergic receptors: alpha-2A, -2B and -2C (Bylund et al., 1994).

The expression of these receptors is not static and can change with disease, aging or therapeutic treatment. Alteration of receptor density can occur at any of the steps from gene transcription to degradation of the receptor protein itself. Continued agonist stimulation of a receptor population often causes a rapid reduction in response to the agonist, a phenomenon known as desensitization. Short-term desensitization is characterized as a rapid (minutes) and reversible uncoupling of the receptor-G protein complex mediated by receptor phosphorylation. This is followed by sequestration and internalization of receptors from the cell surface. Receptors are not lost during short-term desensitization because removal of agonist rapidly restores receptor function. Downregulation, on the other hand, is defined as a decrease in receptor density and displays a much longer time course (hours) which is thought to result from an actual loss of receptors. Removal of agonist will allow recovery of receptor density, but this recovery takes longer, requiring synthesis of new receptors in most cases (Hein and Kobilka, 1995; Toews et al., 1991).

Please Click on images to be maximized , 

Monday, May 9, 2016

Tips on Clubbing

s classified into five phases:

nPhase I   - increase swaftening and fluctuation of the ungua bed;
nPhase II    - loss of the natural 15° angle between the nail and cuticle;
nPhase III   - increased convexity of the ungual bed;
nPhase IV   - clubbed appearance of the digital extremity;   drumstick appearance

nPhase V     - increase of the extremity, with thickening of  the distal phalange and longitudinal striations on the fingernail.

n The specific pathophysiologic mechanism of digital clubbing remains unknown. Many theories have been proposed, yet none have received widespread acceptance as a comprehensive explanation for the phenomenon of digital clubbing.
n  As stated best by Samuel West in 1897, "Clubbing is one of those phenomena with which we are all so familiar that we appear to know more about it than we really do.
n Theories suggested for the pathogenesis of Hypertrophic osteoarthropathy & clubbing
1.   Neurogenic
2.   Humoral
3.   Role of megakaryocytes and large platelet particles
4.   Genetic & familial
5.   Hypoxia

Friday, May 6, 2016

When ONE error can cause Four Errors ! What is Monology of Tetralogy ?

The antero-cephalad deviation of the outlet septum, coupled with an anomalous relationship to the septoparietal trabeculations, results in a narrowing of the subpulmonary outflow tract. The obstructive muscular subpulmonary area thus created is a dynamic entity. The degree of stenosis created can be exacerbated by catecholamines, or a state of low intravascular volume, predisposing the patients to sudden and acute episodes of desaturation known as hypercyanotic spells .The obstruction to flow into the lungs often extends beyond the subpulmonary outflow tract itself. The pulmonary valve may be hypoplastic, with abnormally functioning leaflets, often having a bifoliate configuration. Not infrequently, the pulmonary trunk, and the right and left pulmonary arteries, are diminutive, exhibiting additional focal areas of narrowing .


Sunday, May 1, 2016

Longer PR after the PVCs is expression of concealed penetration into the AV node.

Interpolated PVCs with "sort of compensatory pause" due to sinus bradycardia and PR quite prolonged at baseline.

Not all PVCs are followed by a pause. If a PVC occurs early enough (especially if the heart rate is slow), it may appear sandwiched in between two normal beats. This is called an interpolatedPVC. 

The sinus impulse following the PVC may be conducted with a longer PR interval because of retrograde concealed conduction by the PVC into the AV junction slowing subsequent conduction of the sinus impulse. 

PVC may retrogradely capture the atrium, reset the sinus node, and be followed by an incomplete pause. Often the retrograde P wave can be seen on the ECG, hiding in the ST-T wave of the PVC

Tips on ASD

-As a rule, an ASD must be at least 10 mm in diameter to carry a significant left-to-right shunt.
• CAVEAT: symptoms may develop with increasing age even with small defects owing to an increase in shunting caused by a decrease in LV compliance secondary to coronary artery disease, acquired valvular disease, or hypertension


-Although small ASDs of <5 mm and no evidence of RV volume overload do not impact the natural history of the individual and thus may not require closure because :
–Paradoxical embolism may occur
–Some small defects however may have progressive increase in left-to-right shunt depending on LV and LA pressures.
-Magnitude of and direction of flow depends on –Size of the defect
–Relative diastolic filling properties of the left and right ventricles.
• Increased left-to-right shunting results from reduced LV compliance (eg, LVH) and mitral stenosis.
• Reduced left-to-right shunt and/or reversal of shunt (rightto-left shunt) results from reduced RV compliance (eg, pulmonary hypertension or pulmonary stenosis) and tricuspid stenosis.
-Definite and Potential Benefits of ASD Closure :
•RV and RA size ↓
•LV size ↑
•PA pressure ↓
•Right-to-left shunting and embolism ↓
•Exercise capacity ↑
•NYHA class ↓
•Atrial arrhythmias ↓