Cardiac Strains for Optimization of CRT in Non-Responders

The aim of this study is to investigate the possibility of optimizing the performance of CRT-D in non-responding patients through utilization of cardiac strain speckle tracking

In approximately 30% of patients, cardiac resynchronization therapy (CRT) fails to lead to any improvement of the patients' status. In this study, an investigation of a possible method of optimization through speckle tracking of cardiac strains is attempted. Patients not responding to Cardiac Resynchronization Therapy-Defibrillators (CRT-D) after 3 months are randomly divided into control and intervention groups. Atrioventricular interval is adjusted so that E and A waves do not overlap and the interventricular interval subsequently optimized to yield maximum improvement of the sum of longitudinal+radial+circumferential strains. The left ventricular ejection fraction (LVEF) and NYHA (New York Heart Association Classification improvement 3 months after optimization are evaluated and use of other strain combinations assessed.

Patients not responding to Cardiac Resynchronization Therapy-Defibrillators (CRT-D) after 3 months from implementation are randomly divided into control and intervention groups. Atrioventricular interval is adjusted so that E and A waves do not overlap, the interventricular interval iss subsequently optimized to yield maximum improvement of the sum of longitudinal+radial+circumferential strains. The left ventricular ejection fraction (LVEF) and NYHA (New York Heart Association Classification improvement 3 months after optimization are evaluated and the use of other strain combinations assessed.

The ineffective previously implanted CRT-D is reprogrammed under supervision of transthoracic echocardiography to: adjust the atrioventricular interval so that E and A waves do not overlap the interventricular interval is subsequently optimized to yield maximum improvement of the sum of longitudinal+radial+circumferential strains. Transthoracic echocardiography is performed prior to optimization and 3 months after optimization (i.e., 3 and 6 months after the CRT implantation) and and New York Heart Association Classification (NYHA Classification; total score range 1-4) is being determined in accordance with the standard NYHA methods re-programming of the interventricular interval

Only trans-thoracic echocardiography is performed during follow-ups at 3 and 6 months from CRT implantations performed and New York Heart Association Classification (NYHA Classification; total score range 1-4) is being determined in accordance with the standard NYHA methods

The previously implanted, ineffective CRT-D is reprogrammed under supervision of Trans-Thoracic Echocardiography (TTE) to: adjust the atrioventricular interval so that E and A waves do not overlap the interventricular interval is subsequently optimized to yield maximum improvement of the sum of longitudinal+radial+circumferential strains.

This intervention relates to the determination of strains and atrioventricular interval and supplies data for reprogramming the ineffective CRT-D Transthoracic echocardiography performed to determine the left ventricular ejection fraction as an outcome measure is not considered intervention here (as it is also performed in the control group and that would cause an error cross-referencing.

Left ventricular ejection fraction measured by transthoracic echocardiography prior to optimizing and during a follow-up examination three month after optimizing

NYHA (New York Heart Association Classification measured using the standard NYHA range I to IV - I being the best result, IV the worst) was evaluated using a standard NYHA questionnaire before optimization and 3 months after optimization during a follow-up examination

Inclusion Criteria: patients with symptomatic heart failure with NYHA III/IV, pharmacological treatment options exhausted, LVEF below 30%, and QRS duration over 130ms who did not respond to the implantation of CRT-D Exclusion Criteria: Age below 18 response to the original CRT implantation