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Posts Tagged ‘research ideas in cardiology’

Curiously, the management of VT is simple if the patient is unstable. Just, we need to shock. Cardiologists are troubled only with a hemodynamically stable patient with VT. Some of us still think Amiodarone is a universal antidote for any VT. Though It is effective in both ischemic and non -Ischemic VT, the success rate is not uniform.

The mechanism of action of the Initial IV bolus is not a class 3 K + blocking action, instead, it is thought to be its beta-blocking action. If amiodarone fails, we may try Lignocaine,  magnesium, Flecainide. .Many times it is the cumulative dose of amiodarone that reverts the VT. In some patients, it may reduce the ventricular rate instead of reverting to sinus rhythm. This is due to the prolongation of re-entrant circuit time. The question of amiodarone worsening polymorphic VT with a deleterious effect on the QT interval is still not clear yet.

Why Amiodarone fails to revert VT in some ?(Up to 40 % ?)

One of the factors we looked at some 15 years back was the relationship between IRA patency and amiodarone efficacy. Presented in CSI meet 2004.

It was a simple conclusion. For Amiodarone to be effective IRA must be at least partially patent to enable the drug to reach the target tissue. I am not aware of any study on this issue. Request anyone to expand this study and publish it as a full paper. (Royalty-free research topic!) Please acknowledge the concept if you think it’s original.

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Coronary collateral circulation is one of the major determinants of symptoms and outcomes in chronic CAD. But, we generally shrug off the value of coronary collateral circulation in acute coronary syndrome. The fact is, it has a myocardial mitigating effect following sudden total occlusion.

When does it appear? We did a small analysis (PDF version)

We found it is noted in 25% of patients. With reference time of appearance,  6% had it within 12hrs and in few, it was noted as early as 6 hrs. One caveat is,  we may not know whether its preexisting collateral due to chronic multivessel CAD. I am sorry to note this study did not address the outcome analysis. We however documented patients with good collaterals had negligible wall motion defect and near-normal function post PCI. Some of you can pursue research in this area. 

Potential role of collaterals in ACS

  1. It limits the infarct size
  2. Keep the myocardium alive and give us time to intervene
  3. Can converts a potential Q-MI to non-Q MI
  4. Possibly prevent primary VT/VF and hence dreaded sudden death in early STEMI
  5. Prevent early adverse remodeling of the left ventricle.

When these points appeared just my assumptions, Dr. Ali Aldujeli, (Lithuanian University of Health Sciences, Kaunas) in his presentation, at TCT 2020 confirms many of them are  Indeed true

Final message

I agree, in the era of instant gratification with primary PCI,  relying on coronary collaterals may appear a lesser professional virtue. Still, we may need to respect nature. Many times it bails us out.

Current update 2020

Alsanjari, O., Chouari, T., Williams, T.,  Angiographically visible coronary artery collateral circulation improves prognosis in patients presenting with acute ST segment‐elevation myocardial infarction. Catheterization and Cardiovascular Interventions.  Volume96, IssueSeptember 1, 2020 Pages 528-533

 

 

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