VALUE OF THE QRS MORPHOLOGY ANALYSIS IN LEAD V1DURING MAXIMUM AND MINIMUM HEART RATE IN 24-H HOLTER ECG IN PREDICTION OF CRT FUNCTION - PILOT STUDY
Background: Evaluation of the effectiveness of the CRT stimulation is usually based on the analysis of device interrogation. It can be also evaluated based on the assessment of the constancy of the QRS morphology in 24 h-ECG. The purpose of this research was to verify the hypothesis whether the analysis of QRS morphology during the minimum and maximum heart rate in 24 hours ECG may be helpfull in prediction of CRT function.
Material: We analyzed 59 12-lead Holter recordings in pts with implanted CRT pacemakers (56 with sinus rhythm). Effectivness of CRT was recorded from pacemaker and Holter for the same time period. In Holter ECG we analyzed QRS morphology in lead V1 - R wave amplitude, QRS polarity, QRS duration. Based on these measurements we calculated the % of beats with evident CRT and without. Arrhythias were also identified and counted. Separate QRS analysis was performed for ECG strips during minimal and maximal heart rate. More than 95% CRT beats was treated as effective CRT.
Results: Mean CRT during pacemaker interrogation was 97%, in Holter ECG 93,4%. CRT <95% was recorded in 6 pts during pacemaker interrogation and 13 pts based on Holter QRS morphology analysis. In 5 pts both methods showed decreased CRT pacing, only in Holter in 8, In 1 patient CRT<95% was observed only during pacemaker interrogation. Significant QRS variability during minimal and maximal heart rate was recorded in 16 pts. In 11 of them CRT<95% was defined. Only in 2 pts with CRT<95% we did not observe QRS morphology variability during minimal and maximal heart rate.
Conclusions: Analysis of the QRS morphology in 24-h Holter ECG during the maximal and minimal heart rate, seems to allow the initial estimation of CRT efficacy.