Background: It is well known that left ventricular (LV) filling decreases on inspiration and increases on expiration; however, respiratory effects on diastolic function have not been fully investigated.
Aim: This study attempted to provide further information on the precise diagnosis of LV diastolic dysfunction when taking respiration into account.
Methods: Fifty-one patients with systemic hypertension and impaired LV diastolic function and 33 normal subjects were recruited. Respiratory transmitral Doppler flow parameters and the early-to-late diastolic tissue velocity ratio of the mitral annulus (e/a ratio) of the septal wall were recorded. The validity of the reversal ratio of early-to-late peak flow velocity (E/A ratio) on inspiration and on expiration for diagnosis of diastolic dysfunction was compared.
Results: The E velocity was much higher and its deceleration time was much shorter on expiration compared to that on inspiration, while the A velocity demonstrated no regular respiratory variations both in normal subjects and patients. Ten of the patients displayed a phenomenon characterized with an E/A ratio < 1 on inspiration and > 1 on expiration, eight of whom revealed abnormal LV filling by Tissue Doppler imaging.
Conclusion: Respiratory effects on transmitral Doppler flow parameters raise the necessity of adjustment of the existing standard for precise diagnosis of diastolic dysfunction, while the characteristic phenomenon reported here indicates that reversal E/A value on end-inspiration is a more sensitive and accurate indicator of abnormal LV diastolic function.