Reverse remodeling of left ventricle with CRT

Reverse remodeling of left ventricle with CRT

Cardiac resynchronization therapy (CRT) or biventricular pacing is now an established mode of therapy for severe heart failure, which has been shown to produce significant improvement in the clinical status and produces reverse remodeling of the left ventricle. The therapy is used mostly in those with severe left ventricular dysfunction and a wide QRS complex indicating dyssynchrony, though the correlation between mechanical dyssynchrony and the electrical counterpart may not always be absolute. A substudy of MADIT-CRT trial (Multicenter Automatic Defibrillator Implantation Trial: Cardiac Resynchronization Therapy) was published recently (Circulation. 2010;122:985-992), which evaluated the alterations in cardiac size and function echocardiographically in those who received CRT with an ICD (implantable cardioverter defibrillator). The study involved over 1800 patients who were randomly assigned to CRT plus an ICD or an ICD alone, in a 3:2 ratio. Echocardiographic data at baseline and at 1 year was available for about 1400 patients. The combo device (CRT + ICD) group had greater improvements in left ventricular end-diastolic volume index, left ventricular end-systolic volume index, left ventricular ejection fraction, left atrial volume index and right ventricular fractional area change. The P value was less than 0.001 for all the parameter comparisons. Forty percent reduction of risk of death or heart failure was noted with every 10% decrease in left ventricular end diastolic volume at one year.