Background: Atrial fibrillation (AF) is common in HCM yet the mechanisms are poorly understood but are likely secondary to either the consequences of left atrial structural remodeling (LASR) or myopathy, or triggers arising from pulmonary and other thoracic veins. The presence and severity of LASR as characterized by left atrial strain (LA ϵ), and its relationship to AF in HCM, has not been determined. Therefore, we measured LA ϵ and strain rate (SR) in Pts with HCM both with (AF+) and without (AF−) prior AF and compared these measures to those in age and gender matched controls without HCM or AF.
Methods: Two-dimensional speckle-derived LA longitudinal peak ϵ, SR during systole (SR
S
), early (SR
E
) and late diastole (SR
A
) were measured at the basal and mid portions of the lateral, septal, and posterior LA walls using Vector Velocity Imaging during sinus rhythm and were averaged.
Results: Mean age of Pts in each of the matched groups was 56 ± 2 years (16 males; 59%). Significant left ventricular outflow tract obstruction was present in all Pts with HCM. Diastolic dysfunction was similar in both HCM groups and worse when compared to controls. Peak LA
3
, SR
S
, SR
E
, and SR
A
for each group is shown (table 1
). HCM was associated with significantly lower LA ϵ and SR compared to controls. Although LA size was increased in Pts with HCM when compared to controls there was no correlation between LA size and ϵ or SR (p>0.05 for all). No differences in LA ϵ and SR were found between AF+ versus AF− Pts.
Conclusion: HCM is associated with LASR as determined by decreased LA ϵ and SR. However, LA ϵ and SR were similar in AF+ versus AF− Pts suggesting that the occurrence of AF in HCM is not due to LASR alone.
Table 1.
Left Atrial Strain and Strain Rate in Hypertrophic Cardiomyopathy
ASSOCIATION OF DECREASED LEFT ATRIAL STRAIN AND STRAIN RATE WITH STROKE IN CHRONIC ATRIAL FIBRILLATION
