We now understand , heart rate reduction could be the single most important factor in the management of heart failure .Beta blockers have proved this time and again.We know heart rate has a linear relationship between survival .
SHIFT trial has proven that Ivabradine has a major role in the management of chronic heart failure therapy .It is an If current blocker . No hemodynamic side effects was noted.
How does Ivabradine act ?
It acts on the phase 4 diastolic depolarisation in SA node by slow I f currents.
In this trial , the usage of optimal Beta blockers was only in 25 % . Patients who received complete beta blockade did show much benefit with Ivabradine . Further, the usage of digoxin was only around 20% .This does not represent the realistic population of cardiac failure in many countries .In India , almost 70-80 % receive it . Digoxin , the wonder drug does have an important vago mimetic action, to reduce the heart rate .
Another contentious issue in SHIFT study is , the Class 4 patients constituted <2% of the study population .It is ironical , these are the patients , one would like to try a new rate control drugs like Ivabradine , because we are worried about beta blockers in this population .A great opportunity was lost as Ivabradine could have been tried in this population.
We need a study like this .
- One to one comparison of beta blocker and Ivabradine in cardiac failure . Such a study will ever happen ? My guess is , it is next to impossible !
- Efficacy of Ivabradine in patients with class 4 failure , where beta blockers were contraindicated or could not be administered.
Ivabradine , a new generation negative chronotropic agent is a great concept drug. But , the worthiness of this drug is questionable , when we have proven , well tolerated drugs namely , the beta blockers to reduce the heart rate.. However , if the beta blockers are poorly tolerated Ivabradine may be tried.Last , but not the least, never under-estimate the greatness of digoxin in heart failure.It is the only drug that has a positive inotropic properties coupled with negative chronotropic action . Both benefits patients in CHF . It can do wonders than any other drugs .(DIG trial was the most misunderstood by cardiologists!)