Background: Congestive heart failure is a significant medical problem in public health. About 30% of patients suffering from severe cardiac insufficiency demonstrate electrical conduction disorders (especially CLBBB) that cause asynchronous mechanical contraction of the heart muscle and heart failure exacerbation.
Cardiac resynchronization therapy leads to hemodynamic improvement that improves systolic function without an increase in wall stress, increases the energy efficiency of the heart, decreases and even reverses remodeling and improves electrical stability of the heart.
Controlled multicenter studies have shown that dual ventricular pacing resulted in a significant improvement in functional class, effort and quality of life of patients , resulted in a reduction of 2/3 hospitalizations due to heart failure and reduced mortality.
The timing between right and left ventricular pacing (=optimization) is very important and can effect many hemodynamic measures specifically cardiac output and determine if the patient will respond or not respond to the treatment by the CRT.
There are several methods to perform the optimization of CRT device - the most common is by echocardiography which relies primarily on measuring the maximum left ventricular output, however, this method is time consuming and observer dependence.
Objectives: We suggest a new method for CRT optimization by non-invasive assessment of cardiac output using the NICAS system (Non Invasive Cardiac System, NI Medical, Inc), which is reliable and easy to perform.
Methods : 23 patients with heart failure who have CRT pacemaker (M \F = 16 \ 7, age = 64 ± 10 years) underwent optimization of the VV delay by finding the maximum cardiac output using the NICAS and by echocardiography test by finding maximal aortic velocity time integral (AVTI).
Results: The accuracy of finding the optimal VV delay by the two methods reached 86.9%. Also there were no significant differences in hemodynamic parameters measured by each method: LVEF (left ventricular ejection fraction), LVEDV (left ventricular end diastolic volume), LVESV (left ventricular end systolic volume) and LVEDD (left ventricular end diastolic diameter).
Conclusions: Finding the optimal VV delay of a CRT device by evaluating cardiac output in a noninvasive way through the NICAS system is an effective method and is equivalent to the optimization by echocardiography examination.
