Long-term effect of cardiac resynchronisation in patients reporting mild symptoms of heart failure: a report from the CARE-HF study.
BACKGROUND
Cardiac resynchronisation therapy (CRT) improves symptoms and prognosis in patients with heart failure and cardiac dyssynchrony. Guidelines from the National Institute of Health and Clinical Excellence in the United Kingdom recommend CRT for patients with recent or persistent moderate or severe symptoms of heart failure. This analysis investigated whether the severity of symptoms was an important determinant of the prognostic benefits of CRT.


METHODS
In CARE-HF, patients with left ventricular ejection fraction < or =35% and markers of cardiac dyssynchrony who were, in the investigators' opinion, in New York Heart Association (NYHA) class III/IV were randomly assigned to pharmacological treatment alone or with addition of CRT. This analysis investigated whether the severity of symptoms reported by patients, using Likert Scales from the EuroHeart Failure Questionnaire and self-assessed NYHA class, influenced prognosis and the response to CRT.


RESULTS
Of 813 patients, 175 (21.5%) assessed themselves to be in NYHA class I or II. These patients also reported less severe symptoms and better quality of life than patients who assessed themselves to be in NYHA class III or IV. No statistical interaction was observed between the severity of symptoms assessed in several ways and the benefits of CRT on morbidity and mortality.


CONCLUSIONS
The severity of symptoms was not an important determinant of the prognostic effects of CRT in patients with moderate or severe LVSD and markers of dyssynchrony in the CARE-HF study. This finding requires confirmation in an adequately powered prospective randomised controlled trial in patients with milder symptoms.