Restrictions on the conventional evaluation of diastolic function have been recognized, especially under various loading conditions. Recently, new noninvasive ventricular vortex indexes have been introduced and are expected to reflect the cardiac function. Physiologically, there is a hypothesis that the intraventricular pressure difference (IVPD) is related to the formation of vortexes. IVPD and vortex indexes were simultaneously measured, and the relationship between the two was investigated. To verify the possibility of diastolic vorticity as an index of diastolic relaxation, a correlation between diastolic vorticity and the load dependency of vorticity [time constant (τ)] was examined. Six healthy dogs were studied using transthoracic echocardiography, pressure, and a conductance catheter. Vorticity was analyzed using vector flow mapping (VFM). IVPD was determined using Euler’s equation with color M-mode Doppler images. Data were obtained at baseline, at balloon dilatation in the thoracic aorta to alter afterload, at hydroxyethyl starch infusion to alter preload, and at milrinone administration to alter ventricular relaxation. Peak vorticity at early diastole (E-Vor) and IVPD of the midventricle (MIVPD) decreased under pressure loading, were unchanged under volume loading, and increased during milrinone administration. In multivariate analysis, the independent predictors of τ were global longitudinal strain, strain rate at early diastole, and E-Vor. MIVPD was strongly correlated with E-Vor ( r = 0.84). VFM-derived peak E vorticity was strongly related to IVPD, especially MIVPD, under various loading conditions. Both of these novel indexes are promising as reliable indexes of ventricular relaxation, independent from preload. NEW & NOTEWORTHY We showed the close relationship of vortex and intraventricular pressure difference and showed that both of them can become new markers of the left ventricular relaxation property. Our present study creates a paradigm for future studies in the field of intraventircular flow physiology and clinical diastology.

Early detection of doxorubicin (DXR)-induced cardiomyopathy (DXR-ICM) is crucial to improve cancer patient outcomes and survival. In recent years, the intraventricular pressure gradient (IVPG) has been a breakthrough as a sensitive index to assess cardiac function. This study aimed to evaluate the usefulness of IVPG for the early detection of chemotherapy-related cardiac dysfunction. For this purpose, six dogs underwent conventional, speckle tracking, and color M-mode echocardiography concomitantly with pressure-and-volume analysis by conductance catheter. The cardiac function measurements were assessed before DXR administration (baseline, Pre), at the end of treatment protocol (Post), and at 1.5 years follow-up (Post2). The result showed a significant reduction in the left ventricular end-systolic pressure-volume (Emax: 4.4 ± 0.7, 6.1 ± 1.6 vs. 8.4 ± 0.8 mmHg/mL), total-IVPG (0.59 ± 0.12, 0.62 ± 0.15 vs. 0.86 ± 0.12 mmHg), and mid-IVPG (0.28 ± 0.12, 0.31 ± 0.11 vs. 0.48 ± 0.08 mmHg), respectively in Post2 and Post compared with the baseline (p < 0.05). Mid-to-apical IVPG was also reduced in Post2 compared with the baseline (0.29 ± 0.13 vs. 0.51 ± 0.11). Meanwhile, the fraction shortening, ejection fraction, and longitudinal strain revealed no change between groups. Total and mid-IVPG were significantly correlated with Emax (R = 0.49; p < 0.05, both) but only mid-IVPG was a predictor for Emax (R2 = 0.238, p = 0.040). In conclusion, this study revealed that impairment of contractility was the initial changes observed with DXR-ICM in dogs and only IVPG could noninvasively detect subclinical alterations in cardiac function. Color M-mode echocardiography-derived IVPG could be a potential marker for the early detection of doxorubicin cardiomyopathy.

This study investigated the utility of patent ductus arteriosus (PDA) closure with hemostatic clip by comparing with traditional PDA closure. Medical records of 51 dogs with surgical closure of PDA were reviewed and retrospective study was conducted. 29 dogs were treated by procedure with hemostatic clip (Group HC), and 22 dogs were treated by surgical ligation (Group SL). Data pertaining to breed, sex, age and body weight at the time of surgery, echocardiographic minimal ductal diameter, duration of surgery, hemostatic clip size, echocardiographic findings, hemorrhage, residual ductal flow and recanalization were collected from records. The results showed that procedure with hemostatic clip had been selected in lighter dogs than traditional PDA closure. Duration of surgery performed only hemostatic clip technique was significantly shorter than that in group SL. Preoperative LVIDd, E-wave and FS were significantly lower than postoperative ones. As regard all parameters, the differences between pre-and postoperative periods were not significantly different between group HC and group SL. Hemorrhage, residual ductal flow, and recanalization were not significantly different in both groups. The present study showed that procedure with hemostatic clip is beneficial in that it is available in smaller dogs and can make shorter operation duration than traditional PDA closure. Moreover, the procedure is effective for the resolution of volume overload of the left atrium and ventricle in short-term outcome. Complications including hemorrhage, residual ductal flow and recanalization were not significantly different with both techniques.