Wednesday, May 24, 2017

Aneurysmal left main coronary fistula to RA in asymptomatic Patient with normal Left Ventricular function ( Answer to the weekly case challenges ) .

Q: An asymptomatic 32 year old woman with a murmur. What is it?

A: Aneurysmal left main coronary fistula to RA in asymptomatic pt, normal LV function.

•Learning Tips:
•Coronary artery fistulae (CAF) are rare cardiac malformations. Their prevalence has been reported at 0.1% to 0.2% of patients who undergo coronary angiography.
•Coronary artery fistulae are either congenital or acquired coronary artery abnormalities, that have different anatomical appearance; with varying degree of shunting (Qp/ Qs); and associated cardiac anomalies .
•Etiologies include high cardiac output state and congestive heart failure with shunting of blood into a cardiac chamber, great vessel, or other structures, bypassing the myocardial capillary network .
•If the fistula is large, the intracoronary diastolic perfusion pressure diminishes progressively .
•The coronary vessel usually attempts to compensate by progressive enlargement of the ostia and feeding artery.
•Nevertheless, myocardium beyond the site of the fistula’s origin is at risk for ischemia, most frequently evident in association with increased myocardial oxygen demand during exercise or activity .
•Although aneurysm formation is common in patients with coronary artery fistulae, giant aneurysms have rarely been reported.
•They are often asymptomatic and small, however, but rupture of an aneurysmal fistula can be fatal.
•Moreover, a coronary steal phenomenon can occur owing to blood shunting and perfusion away from the myocardium. This phenomenon can be manifested in the patient as angina pectoris.
•With time, the coronary artery leading to the fistulous tract dilates progressively, that in turn, may progress to frank aneurysm formation, intimal ulceration, medial degeneration, intimal rupture, atherosclerotic deposition, calcification, side- branch obstruction, mural thrombosis, and, rarely, rupture.
•Treatment is recommended in the presence of symptoms, a giant aneurysm, or progressive enlargement of fistulae.
•In cases of small and easily accessible fistulae, transcatheter closure could be considered.

Sunday, May 14, 2017

Is his bundle pacing (HBP) a feasible alternative to RV pacing now or to CRT in future?

Dr. Nabil Paktin

The answer is, the Time and Market will prove it, NOT the Knowledge and Scholars!

Estimated that worldwide, about 1-3 million patients die annually due to a Lack of a Pacemaker.
 - By comparison, about 30.000 persons die annually from influenza, 1.6 million people died of HIV/AIDS in 2012.
Death from bradycardia is entirely preventable.

Right ventricular RV apical pacing has been the standard practice for patients requiring permanent ventricular pacing however long term RV apical pacing has its drawbacks.
 A prolonged PR interval results in reduced left ventricular filling, abnormal filling pattern, presystolic mitral regurgitation due to delayed and ineffective closure of the mitral valve. Prolongation of the PR interval results from cardiac conduction disease but may also be a marker of advanced structural heart disease associated with atrial electrical and structural remodeling of a long-standing RV apical or septal pacing.
 Prolongation of PR interval by itself independently associated with an increased risk of AF, increased mortality and heart failure hospitalization in the general population, in patients with CAD and in patients with left ventricular dysfunction.

Isolated RV pacing activates the interventricular septum before the LV lateral wall, seen as LBBB pattern on the ECG due to propagation of the electrical wave front away from the sternum result in LV dyssynchrony and mismatched timing between chamber walls, with deleterious effects on LV function and adverse clinical outcomes. Including heart failure and mortality. RV pacing-induced cardiomyopathy rates of up to 20% with frequent RV pacing among patients with preserved EF is reported.
RV apical pacing deleterious effects are as follows:

1,Altered left ventricular electrical and mechanical activation
2, Altered ventricular function
3, Remodeling
4, Cellular disarray
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