The Effect of the Administration of Nitroglycerin and Atropine on the Pattern of Left Ventricular Diastolic Filling as Assessed by Doppler Echocardiography in Normal Human Subjects

ABSTRACT

BACKGROUND: The diastolic transmitral flow velocity pattern has been commonly used to assess left ventricular(LV) diastolic function. The effects of multiple factors(such as, LV preload, afterload and heart rate, etc.) make difficulties in accurate interpretation. METHODS: In order to investigate the diastolic transmitral filling patterns according to the changes of the proload or heart rate, we studied 27 normal subjects with pulsed Doppler echocardiography after the administration of nitroglycerin(0.6mg/tab.) sublingually or atropine(0.5mg/amp.) intravenously. RESULTS: 1) After nitroglycerin administration, the folowings were obtained. ; The systolic blood pressure and LV diastolic filling time(DFT) decreased by 10.1% and 15.3%, respectively(p<0.001), compared with baseline data. The ratio of peak early to late diastolic transmitral flow velocities (E/A) and time-velocity integrals(TVIE/TVIA) decreased by 10.3% and 14.8%, respectively(p<0.01). The early diastolic filling time(Time E) was unchanged. Therefore, we suggest that time E is helpful, compared with the increments of the preload or the diastolic dysfunction. 2) After atropin administration, the heart rate, peak late diastolic transmitral flow velocity(PA) and percent atrial contribution(%AC) significantly increased by 43.6%, 25.1% and 41.4%, respectively(p<0.001). The E/A, TVIE/TVIA and DFT significantly decreased by 42.9%, 38.9% and 43.0%, respectively(p<0.001) compared to the data before drug administration. 3) The heart rate correlated negatively to the E/A, TVIE/TVIA and DFT. It was correlated positively to %AC(r=+0.63; p<0.001). The normalized E/A ratio by DFT(E/A/DFT) didn't correlate. Therefore, E/A/DFT is helpful on the exclusion of the influences of heart rate by the administration of the atropine. CONCLUSION: The decrement of preload or the increment of heart rate changes the diastolic transmitral flow velocity patterns. Therefore, when the diastolic function is assessed by interpretation of the Doppler transmitral flow velocity pattern with pulsed Doppler echocardiogram, the potential influences of preload and heart rate must be taken into account.