Abstract 2932: Heart Rate and Anti-hypertensive Therapy- Kjekshus Hypothesis Revisited
Background: Kjekshus et al showed that in patients with myocardial infarction, reduction of heart rate using a beta-blocker is beneficial for secondary prevention of cardiovascular events. However, if this is true for primary prevention in patients with hypertension is not known.
Methods: We performed a MEDLINE search of studies published in peer-reviewed journals. We included Randomized controlled trials (RCTs) which evaluated β-blockers as first line therapy for hypertension with follow-up for at least 1 year and with data on heart rate and evaluating cardiovascular end-points.
Results: Out of 22 RCTs evaluating β-blockers for hypertension, only 9 studies reported heart rate data. The 9 studies evaluated 34096 patients on β-blockers against 30139 patients on other anti-hypertensive agents and 3987 patients on placebo. A lower heart rate (final attained in the β-blocker group) was not associated with greater risk reduction for the endpoints of all-cause mortality (r = -0.51; P<0.0001), cardiovascular mortality (r= -0.61; P<0.0001), myocardial infarction (r= -0.85; P<0.0001), stroke (r= -0.20; P=0.06) or heart failure (r= -0.64; P<0.0001) (Figure⇓). The negative correlation coefficient indicates that a lower heart rate was associated with a greater risk of cardiovascular events. The same was true when the heart rate difference between the two treatment modalities at the end of the study was compared to the relative risk reduction for cardiovascular events.
Conclusions: In contrast to patients with myocardial infarction, heart rate reduction with β-blocker for hypertension is associated with an increased risk of cardiovascular events.