Concordance between QRS duration & left ventricular mechanical dyssynchrony in patients with severe LV dysfunction and its relation to its etiology
Keywords:Heart Failure, Cardiac Resynchronization Therapy, Left Ventricular Dysfunction, Coronary Artery Bypass Surgery, Septal to Posterior Wall Motion Delay, Interventricular Mechanical Delay, Percutaneous Coronary Intervention, Guideline Derived Medical Therapy
Objective: This study aimed to compare the relationship between QRS duration (Electrical dyssynchrony) and conventional ECHO measures (Mechanical dyssynchrony) done in our hospital and other factors relating to this dyssynchrony. Materials & Methods: This is an analytical cross-sectional study and it was conducted for a period of two years conducted among the severe Left ventricular (LV) dysfunction patients with complete Left Bundle Branch Block (LBBB). Correlation coefficient was used to study the relationship between electrical and mechanical dyssynchrony. t test was used to study the difference among the means between the two variables. Results: Our results showed that (i) Electrical dyssynchrony exists similarly among the subjects irrespective of the NYHA classification and MR grading, (ii) Proportion of patients with QRS duration less than and more than or equal to 160 ms among patients with different mechanical dyssynchrony parameters were not statistically significant, (iii) All patients with septal to lateral delay more than 65 ms have QRS duration more than or equal to 160 ms, (iv) None of the parameters of mechanical dyssynchrony have a significant correlation with QRS duration, (v) Ischemic subjects have a strong correlation between the mechanical and electrical dyssynchrony parameters except septal to lateral delay parameter and interventricular mechanical dyssynchrony, however there is no correlation between electrical and mechanical dyssynchrony among the non-ischemic subjects, (vii) There is a weak relationship between QRS duration and measured BNP, mean PA pressure, LVESV, LVESV and BNP. Conclusion: Our results revealed that there is a strong correlation between electrical and certain parameters of mechanical dyssynchrony among the patients with severe LVD with complete LBBB with ischemic etiology.
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