Relationships between P wave dispersion, atrial electromechanical delay, left atrial remodeling, and NT-proBNP levels, in patients with hypertrophic cardiomyopathy.

Background: We evaluated the associations among the well-known atrial fibrillation (AF) predictors including P-wave dispersion (PWD), intra- and inter-atrial electromechanical dyssynchrony (EMD), left atrial (LA) phasic functions, and plasma N-terminal prohormone of B-type natriuretic peptide (NT-proBNP) levels, in patients with hypertrophic cardiomyopathy (HCM).

Methods: Seventy patients with HCM and age and sex matched 70 subjects were enrolled. PWD, LA total emptying fraction (LATEFr), active emptying fraction (LAAEFr), passive emptying fraction (LAPEFr), expansion index (LAEI) intra- and inter-atrial EMD were calculated. Levels of NT-proBNP of all subjects were determined.

Results: Higher PWD (p = 0.006), significantly decreased LAEI (p < 0.001), LATEFr, and LAPEFr (both p values < 0.001) values and significantly increased inter-atrial (p < 0.001), LA (p = 0.001), and right atrial dyssynchrony (p < 0.001) were observed in the HCM group compared to controls. PWD was negatively correlated with LAEI (r = -0.236, p = 0.005) and LATEFr (r = -0.242, p = 0.04), however not with LAPEFr (p = 0.7), or LAAEFr (p = 0.3). Except for the LA lateral wall PA' (r = 0.283, p = 0.02), PWD was not correlated with any atrial EMD parameter. Inter-atrial dyssynchrony was related to LAEI (r = -0.272, p = 0.001), LATEFr (r = -0.256, p = 0.03), and LAPEFr (r = -0.332, p = 0.006), but not, however, to LAAEFr (p = 0.4). The plasma NT-proBNP levels of patients were not correlated with either PWD (p = 0.927) or inter-atrial dyssynchrony (p = 0.102).

Conclusions: PWD and inter-atrial dysynchrony seem to independently promote AF, although both are associated with LA reservoir function in HCM populations. The NT-proBNP level is not associated with these two AF predictors in patients with HCM. NT-proBNP seems to be a poor marker of atrial electrical remodeling in HCM patients.