A high heart rate is an independent risk factor for chronic heart failure ( HF ) patients and lowering the rate is an important treatment target, according to a sub-analysis of data from the SHIFT trial.

SHIFT ( Systolic Heart Failure treatment with the If inhibitor ivabradine ) has showen that heart rate is not only a risk marker but also a risk factor for subsequent cardiovascular events in patients with chronic heart failure. In what was the largest heart failure trial published to date, more than 6500 patients from 37 countries were randomly assigned to Ivabradine ( Procoralan ) or placebo in addition to standard heart failure treatments.

Michael Böhm from the Universitatsklinikum des Saarlandes, Germany, and the SHIFT authors assessed these findings further to determine whether resting heart rate at the start of the SHIFT trial increased the risk of repeat events. For this study, Böhm analysed the primary composite endpoint of SHIFT, which was cardiovascular death or hospitalisation for worsening heart failure. This included patients with the highest ( greater than 87 bpm ) and the lowest ( 70-72 bpm ) pretreatment heart rates, and those after 28 days of treatment with Ivabradine.

For patients in the placebo group, results of this study showed that patients with the highest heart rates ( n=682, 286 events ) were at more than two-fold higher risk for the primary composite endpoint than patients with the lowest heart rates ( 70 to less than 72 bpm, p<0.0001 ). The risk of primary composite endpoint events increased by 3% with every beat increase from baseline heart rate and 16% for every 5 bpm increase.

In the Ivabradine group, there was a direct association between heart rate achieved at 28 days and subsequent cardiac outcomes. Patients with heart rates lower than 60 bpm at 28 days on treatment had fewer primary composite endpoint events during the study ( 17.4% event rate ) than those with higher heart rates ( 75 bpm, 32.4% ).
Böhm reported that the risk reduction effect of Ivabradine ( relative to placebo ) was accounted for by heart-rate reduction, as reflected by the neutralisation of the treatment effect after adjustment for change of heart rate at 28 days.

Böhm said that the analysis confirmed high heart rate as a risk factor in heart failure and that selective lowering of heart rates with Ivabradine improves cardiovascular outcomes.

The primary SHIFT results and analysis have shown that heart-rate reduction with Ivabradine reduces clinical events in heart failure in relation to the heart rate achieved, confirming that heart rate is clearly a risk factor in heart failure.

Source: European Society of Cardiology Congress, 2010

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