ASSESSING CARDIAC PERFORMANCE IN PATIENTS UNDERGOING CARDIAC RESYNCHRONIZATION THERAPY

Aim. To analyze the effects (clinical, electrical and ultrasound) of cardiac resynchronization devices, with or without an implantable defibrillator (CRT-P or CRT-D) on the patients with heart failure in our clinic. Material and Methods: We retrospectively analyzed 56 patients with NYHA functional class II-IV heart failure who underwent CRT-P or CRT-D in our clinic in the interval January 1, 2010 -June 1, 2014. To evaluate the effects of cardiac resynchronization therapy (CRT) we focused on measuring the QRS complex duration on electrocardiogram, left ventricular ejection fraction (LVEF) and the NYHA functional class assessment. These parameters were assessed immediately before intervention and one month after device implantation. Patient characteristics were expressed as mean./. 1 standard deviation or as number and percentage. Variables were compared by paired t test. A p wave value less than 0.05 was considered statistically significant. Results: QRS complex duration decreased from an average of 155ms to 129ms, a statistically significant narrowing of 25.4ms (p< 0.0001). The LVEF increased from an average of 28% to 35% (p < 0.001). A statistically significant improvement (p< 0.0001) in NYHA functional class was recorded. Conclusions: CRT is an important therapeutic approach, in our study 82.56% of the patients being considered responders due to improvement in the NYHA functional class and at least a 5% increase in the LVEF. A narrowing of the QRS complex on electrocardiogram was obtained in all patients classified as responders, so this simple method for measuring QRS complex duration can be used to assess the response to biventricular stimulation.