Usefulness of the pulmonary vein flow velocity-time profile as an estimate of left atrial storage fraction

Left ventricular stroke volume decreases due to surgical procedures of anatomical lung resection

OBJECTIVES

The influence of lung resection on cardiac function has been reported, and previous studies have mainly focused on right ventricular (RV) dysfunction. As few studies have analyzed changes in left ventricular hemodynamic variables caused by lung resection, we aimed to investigate the perioperative changes in left ventricular stroke volume (LVSV) caused by anatomical lung resection.

METHODS

We enrolled 61 patients who underwent anatomical lung resection and perioperative LVSV monitoring. The Flo Trac system was used for dynamic monitoring. We investigated changes in LVSV after lung resection and the factors that affected these changes. The operative procedures that contributed to these changes were also investigated.

RESULTS

LVSV decreased after anatomical lung resection in the majority of patients (n = 38, 62.2%). Operative procedures affecting this change were (a) taping the superior pulmonary vein (SPV; right: V1-3) before dorsal part procedure (e.g., major fissure division of right upper lobectomy, A1 + 2c, and A4 + 5 division of left upper lobectomy); (b) division of the SPV (right: V1-3, V4 + 5); (c) division of A6-10 (in lower lobectomy); and (d) finish division of all vessels.

CONCLUSIONS

LVSV decrease was caused by anatomical lung resection in the majority of patients owing to the intraoperative procedures described above.

Evaluation of left atrial function by the functional volume change curve derived from Doppler flow spectra

The objective of this study was to clarify the left atrial (LA) reservoir and booster pump function in patients with left ventricular (LV) diastolic dysfunction. To determine LA reservoir and booster pump function, a new algorithm to determine LA functional volume change curve (FVC) was developed from Doppler flow spectra of pulmonary venous flow and LV inflow by transthoracic echocardiography in 110 patients. Patients were classified into normal (N), and abnormal (AB) and pseudonormal (PN) groups on the basis of their Doppler flow patterns. From the indices of FVC, atrial reservoir volume (ARV), passive emptying volume (PEV) and active emptying volume (AEV) were obtained. ARV/stroke volume (SV) was increased in the AB group, but decreased in the PN group compared with N (N, 0.61+/-0.09; AB, 0.73+/-0.10; PN, 0.52+/-0.13, p<0.05). PEV/SV was significantly decreased in AB, but increased in PN compared with N (N, 0.27+/-0.07; AB, 0.19+/-0.07; PN, 0.31+/-0.18, p<0.05). AEV/SV was significantly increased in AB, but decreased in PN compared with N (N, 0.41+/-0.08; AB, 0.56+/-0.10; PN, 0.26+/-0.19, p<0.05). Thus, in patients with an abnormal relaxation pattern, the LA reservoir and booster pump function are augmented, but in patients with a pseudonormal pattern, both LA reservoir and booster pump function are deteriorated, suggesting a vulnerability to pulmonary congestion.

Atrial reservoir and active transport function after cardioversion of chronic atrial fibrillation

Atrial reservoir function has not been studied after successful cardioversion of chronic atrial fibrillation. Using transthoracic and transesophageal Doppler echocardiography, we measured flow velocity-time integrals of the systolic forward (Sa), diastolic forward (Da), and diastolic reversed (rAa) waves of flow velocity waveforms in the pulmonary vein and the superior vena cava, and those of the early diastolic (Ea) and late diastolic (Aa) waves of the transmitral and transtricuspid flow velocity waveforms. The left and right atrial storage fractions (LASF, RASF), indexes of atrial reservoir function, were determined as the ratios of the atrial storage volume to the ventricular stroke volume; (Sa - rAa)/(Sa - rAa + Da). The left and right atrial active contraction fractions (LAACF, RAACF), indexes of atrial active transport function, were also determined as the ratios of the atrial active contraction volume to the left ventricular stroke volume; Aa/(Ea + Aa). These indices were evaluated periodically in 12 patients with non-valvular chronic atrial fibrillation before and 1-4 days after direct current cardioversion of atrial fibrillation; in 8 of the patients, the indices were also evaluated 1-3 months after the cardioversion. An additional 10 patients in sinus rhythm served as controls. Both the LASF and RASF were low during atrial fibrillation; the values increased significantly 14 days after successful cardioversion (P < 0.01 P < 0.01), and continued to increase at 1-3 months. The LASF and RASF values 1-3 months after cardioversion were comparable to those in control subjects. Both the LAACF and RAACF also increased significantly from 1-4 days to 1-3 months after cardioversion (P < 0.05, P < 0.01), becoming comparable to those in control subjects. During the 3 months after successful cardioversion of non-valvular chronic atrial fibrillation, left and right atrial reservoir function and left and right atrial active transport function increased progressively, becoming comparable to values in the control subjects.