Mr Guenter Breithardt,
Mr Arthur J Moss
Presenter | see Discussant report
List of Authors: Arthur J. Moss; W. Jackson Hall; David S. Cannom; Helmut Klein; Mary W. Brown; James P. Daubert; N.A. Mark Estes III; Elyse Foster; Henry Greenberg; Steven L. Higgins; Marc A. Pfeffer, David Wilber; Wojciech Zareba
This trial was designed to determine whether cardiac resynchronization therapy would reduce mortality and heart failure events in patients with mild cardiac symptoms, reduced ejection fraction, and wide QRS complexMethods: Over the course of 4.5 years, we enrolled and followed 1820 patients with ischemic or nonischemic cardiomyopathy, ejection fraction 0.30 or less, QRS 130 ms or more, and New York Heart class I or II symptoms. Patients were randomly assigned in a 3:2 ratio to receive cardiac resynchronization therapy with defibrillator (1089 patients) or an implanted defibrillator (731 patients). The primary end point was all cause mortality or heart failure event, whichever occurred first.Results: During an average follow-up of 2.4 years, 17.2 percent of patients in the resynchronization group and 25.3 percent in the defibrillator group experienced a primary end point. The hazard ratio in favor of resynchronization therapy was 0.66 (95 percent confidence interval, 0.52 to 0.84; P=0.001), with similar benefit in patients with ischemic and nonischemic cardiomyopathy. Superiority of cardiac resynchronization therapy was driven by 41 percent reduction in the risk of a first heart failure event, a finding that was evident primarily in patients with QRS of 150 ms or more. Resynchronization therapy was associated with significant reduction in left ventricular volumes and improvement in ejection fraction. Serious adverse events were infrequent.Conclusion: Cardiac resynchronization therapy decreases the risk of heart failure events in relatively asymptomatic patients with low ejection fraction and wide QRS complex. This therapy provides effective prevention for heart failure in these at-risk cardiac patients.
Discussant | see Presenter abstract
Breithardt, Guenter (Germany)Presentation webcast
Report: Cardiac resynchronisation therapy (CRT) induces progressive reverse LV remodeling and slows disease progression in patients with NYHA class III or IV heart failure. Whether it may also be beneficial in patients with less severe heart failure was tested in the the MADIT-CRT trial (Multicenter Automatic Defibrillator Implantation Trial – Cardiac Resynchronization Therapy) presented by A. Moss during the Hot Line Session. The trial randomised 1820 NYHA class I or II patients to CRT or no CRT. All patients were candidates for an ICD, had to have a QRS width of 0.13s or greater and a left ventriclar ejection fraction of 0.30 or less. During follow-up, 17.2% of patients in the resynchronization group and 25.3 % in the ICD group experienced the primary end point of all cause mortality or a heart failure event whichever occurred first (Hazard Ratio 0.66, 95% confidence interval 0.52 to 0.84; P=0.001), with similar benefit in patients with ischemic and non-ischemic cardiomyopathy (10). Superiority of resynchronization therapy was driven by a 41% reduction in the risk of a first heart failure event without an effect on the 3% annual mortality in each treatment group. Resynchronization therapy was associated with significant reduction in left ventricular volumes and improvement in ejection fraction.
MADIT-CRT has shown that CRT may delay disease progression in heart failure class I or II patients through left ventricular remodeling. This is consistent with a prior smaller trial (REVERSE, 610 patients), which, however, did not reach statistical significance of a heart failure clinical composite response that compared only the percentage of patients worsened (primary end point). However, secondary endpoints were in line with the much larger MADIT-CRT trial results concerning left ventricular remodelling and reduction in the need for heart failure hospitalisations. CRT is an effective therapy in improving heart failure-related manifestations in patients with poor left ventricular function (EF <0.30 like in MADIT-CRT or <0.40 like in REVERSE) who frequently are eligible for primary prevention ICD implantation with an ischemic or non-ischemic aetiology and broad QRS complexes of >0.12 s (REVERSE) or >0.13 s (MADIT-CRT) but with no or only minimal symptoms.
Is the evidence similarly strong for class I and II patients? This and other questions might be answered by merging the original data from both trials into a meta-analysis. Patient characteristics were not much different from previous ICD trials, especially with regard to ejection fraction. Should we re-define the present guidelines for primary ICD implantation to include CRT and, if so, to all patients with a QRS duration of >0.13s (or >0.12s like in REVERSE)? Or should there be a cut-off of about 0.15s as suggested by the subgroup analyses in both trials? Should parameters of dyssynchrony be added? Mortality in class I and II heart failure patients is low. However, if progression of the disease on the long-term is retarded by CRT, does this translate into a lower mortality as the disease would normally progress and as long as no competing risks occur? It may be difficult to find an answer to this issue since the present data by MADIT-CRT but also REVERSE may make it at least difficult if not impossible to do another randomised trial with and without CRT which, as a mortality trial, would require a very large population.
Reduction in the risk of heart failure with preventive cardiac resynchronization therapy: MADIT-CRT Trial
This congress report accompanies a presentation given at the ESC Congress 2009. Written by the author himself/herself, this report does not necessarily reflect the opinion of the European Society of Cardiology.
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