[Echocardiographic assessment of cardiac resynchronization therapy: two-year follow-up period]

The cardiac resynchronization therapy (CRT) is an effective option for patients with advanced heart failure (HF). Clinical, electrocardiographic and echocardiographic criteria have been studied in an attempt to find the patients that will benefit from the CRT, considering that the echocardiogram is the method that is used both in the selection and in the assessment of such therapy.

The objective of this work is to analyze the use of echocardiogram to assess the CRT, in a ten-day follow-up period and after two years of evolution.

The assessment considered 20 patients subjected to CRT, for a period of two years, 80% of which were male. The Minnesota Living with Heart Failure Questionnaire (MLWHF) was filled out. Patients underwent a six-minute walking test. Then, the two-dimensional echo-Doppler-cardiogram was performed. The initial assessment was repeated ten days after and two year after the implantation of the biventricular pacemaker.

In two years, 5 patients (25%) died; 4 had cardiomyopathy caused by the Chagas's disease. There was no statistically significant change in the ejection fraction between the pre-operation period and the following ten days, but there was a significant change between the pre-operation period and two years after that, and the ten-day period and two years after that. In the ten-day follow-up period, there was the worsening of the intraventricular dyssynchrony, as evaluated by the tissue Doppler method, and the 'living with heart failure' score was higher in the group of deaths.

Out of the echocardiographic parameters assessed, only the intraventricular dyssynchrony assessment through the tissue Doppler method, after the procedure, was capable of predict the CRT efficiency with respect to the death rate.