Sep 3 2012
By Eleanor McDermid, Senior medwireNews Reporter
The heart rate of stroke survivors may give an indication of their long-term prognosis, report researchers.
Their analysis of the Prevention Regimen for Effectively Avoiding Second Stroke (PRoFESS) trial shows reduced survival in patients with increased heart rate. Conversely, if patients had a recurrent stroke, those with lower heart rates had better neurologic outcomes.
Heart rate has previously been linked to outcomes in patients with cardiovascular conditions including hypertension and heart failure.
"The exciting news with the current PRoFESS data, however, is that that the prognostic impact of a high heart rate is brought forward into a population of stroke survivors," Sverre Kjeldsen (University of Oslo at Ullevaal Hospital, Norway) and Peter Okin (Weill Cornell Medical College, New York, USA) write in an editorial accompanying the study in the European Heart Journal.
"While the prognostic influence on cardiovascular disease and mortality was not unexpected, the prognostic relationship of heart rate to disability and early cognitive decline after recurrent stroke is a major new finding."
The researchers, led by Michael Böhm (Universitätskliniken des Saarlandes, Homburg/Saar, Germany), divided 20,165 PRoFESS participants into quintiles according to their heart rate at enrollment (within 120 days of stroke).
They found an elevated risk for all-cause death among patients in the top two quintiles (>82 and 77-82 bpm) relative to those in the bottom quintile (≤64 bpm), with this risk increased by 74% and 42%, respectively. These associations were independent of confounders including age, gender, smoking status, stroke subtype, blood pressure, and medication use.
Both vascular and nonvascular death were associated with heart rate. However, heart rate did not predict recurrent stroke, myocardial infarction, or new onset or worsening of heart failure.
A total of 1627 patients had a recurrent stroke. In this group, 3-month outcomes were better with lower baseline heart rate; for example, 58.7% of those in the lowest quintile had good functional outcomes (modified Rankin Scale 0-2), compared with 45.4% of those in the highest quintile. The same pattern was observed for outcomes on the Barthel Index.
Patients' cognitive performance on the Mini-Mental State Examination was also better if they had lower heart rates, and was significantly less likely to deteriorate over time.
"The significant relationship of neurological function after recurrent stroke to heart rate suggests a relationship with the cardiovascular system," say Kjeldsen and Okin. "Raised heart rate could be a marker of underlying cardiovascular disease or high blood pressure that is not yet detected in stroke survivors (eg, ambulatory hypertension or high out-of-office blood pressure)."
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