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Background: This study evaluated the diagnostic capability of on-site coronary computed tomography-derived computational fractional flow reserve (CT-FFR) determinations for detecting coronary artery disease (CAD), as assessed by invasive fractional flow reserve (FFR).Methods and Results:Seventy-four patients with coronary artery calcium scores <1,500 who underwent coronary CT angiography (CTA) and invasive FFR measurements within 90 days were retrospectively reviewed. CT-FFR was computed using a prototype machine-learning (ML) algorithm in 91 vessels; 47 vessels of 42 patients were determined to have significant CAD (FFR ≤0.8). Correlation between CT-FFR and FFR was good (r=0.786, P<0.001). Per-vessel area under the curve was significantly larger for CT-FFR (0.907, 95% confidence interval: 0.828-0.958) than for CTA stenosis ≥50% (0.595, 0.487-0.697) or ≥70% (0.603, 0.495-0.705) (both P<0.001). Standard coronary CTA classifications recommended further functional tests in 57 patients with moderate or worse stenosis on CTA. CT-FFR analysis (mean analysis time: 16.4±7.5 min) corrected the standard coronary CTA classification in 18 of 74 patients and confirmed it in 45 of 74 patients. Thus, the per-patient diagnostic accuracy of the classifications was improved from 66% (54-77%) to 85% (75-92%)., Conclusions: On-site CT-FFR based on a ML algorithm can provide good diagnostic performance for detecting hemodynamically significant CAD, suggesting the high value of coronary CTA for selected patients in clinical practice.

Background: Fractional flow reserve (FFR) is widely used for the assessment of myocardial ischemia. Intravascular ultrasound (IVUS) is an intracoronary imaging method that provides information about lumen and vessel morphology. Previous studies on the expanded use of IVUS to identify functional ischemia have noted an association between anatomy and physiology, but IVUS-derived minimum lumen area (MLA) has a weak-moderate correlation with myocardial ischemia compared with FFR. We developed a method to calculate FFR using IVUS-derived anatomical information for the assessment of myocardial ischemia. The aims of this study were to investigate the relationship between wire-based FFR and IVUS-derived FFR (IVUS-FFR) and to compare the usefulness of IVUS-FFR and IVUS-derived MLA for functional assessment.Methods and Results:We retrospectively analyzed 50 lesions in 48 patients with coronary stenosis who underwent IVUS and FFR simultaneously. IVUS-FFR was calculated using our original algorithm and fluid dynamics. Mean percent diameter stenosis determined on quantitative coronary angiography and on FFR was 56.4±10.7 and 0.69±0.08, respectively. IVUS-FFR had a stronger linear correlation with FFR (R=0.78, P<0.001; root mean square error, 0.057 FFR units) than with IVUS-derived MLA (R=0.43, P=0.002)., Conclusions: IVUS-FFR may be a more valuable method to identify myocardial ischemia, compared with IVUS-derived MLA.

Background: Right ventricular (RV) pacing alters left ventricular (LV) mechanical activation, resulting in adverse impacts on LV function. This study was aimed to investigate the acute effect of RV apical (RVA) and septal pacing (RVS) on LV dyssynchrony and function using speckle tracking echocardiography., Methods and Results: The 103 patients (749 years) with symptomatic bradyarrhythmia and preserved LV ejection fraction, and 50 age-matched control subjects were studied. All patients received a permanent pacemaker and were randomly assigned into 2 groups (RVA: n = 51, RVS: n = 52). After insertion, patients underwent an echocardiographic study during RV pacing. LV dyssynchrony and global strain parameters were analyzed using speckle tracking echocardiography. The QRS width and dyssynchrony indices by longitudinal and radial strain were significantly greater in RVA than in both the control and RVS. The LV longitudinal dyssynchrony index was significantly related to global longitudinal strain (GLS) among 103 patients receiving RV pacing (R² = 0.25, P < 0.0001). The GLS in RVA were the lowest among the 3 groups (GLS:, Control: -18.22.4%, RVA: -14.33.1%, P < 0.001 vs. control, RVS: -16.82.7%, P<0.01 vs. RVA)., Conclusions: RVA created heterogeneous LV contraction, which resulted in deteriorated LV longitudinal contraction. RVS could be a better pacing alternative in terms of less LV dyssynchrony and better longitudinal function compared to RVA.

Background: Cibenzoline is able to improve left ventricular (LV) diastolic dysfunction in patients with hypertrophic cardiomyopathy (HCM), but the exact mechanism remains to be determined., Methods and Results: The present study was designed to elucidate the effect of intravenous administration of 1.4 mg/kg of cibenzoline on aortic and LV pressures, and transmitral Doppler flow pattern in 7 patients with hypertrophic obstructive cardiomyopathy (HOCM) and 9 patients with hypertrophic nonobstructive cardiomyopathy (HNCM). Before and at the end of the administration, aortic and LV pressures, LV pressure gradient (LVPG) and transmitral Doppler velocity profiles were examined. After the administration of cibenzoline, LV minimal and end-diastolic pressures decreased from 9+/-4 mmHg to 1+/-5 mmHg (p=0.0049) and from 22+/-7 mmHg to 14+/-5 mmHg (p=0.0106) in patients with HOCM, and from 9+/-5 mmHg to 5+/-3 mmHg (p=0.0036) and from 20+/-6 mmHg to 14+/-3 mmHg (p=0.0033) in patients with HNCM. LVPG decreased in all patients with HOCM. E-wave velocity increased, A-wave velocity decreased, and thus the E/A ratio increased from 0.77+/-0.29 to 1.20+/-0.48 (p=0.0004)., Conclusions: Reduction of LV diastolic pressures by intravenous administration of cibenzoline may be related to an improvement in the E/A ratio in patients with HCM.

Background: Recent interventional and surgical therapies to attenuate left ventricular pressure gradient (LVPG) can be difficult to perform in patients with hypertrophic obstructive cardiomyopathy (HOCM) caused by midventricular obstruction (MVO), owing to the risk of inducing or deteriorating mitral regurgitation., Methods and Results: The effects of the antiarrhythmic drug, cibenzoline, on LVPG and left ventricular (LV) diastolic function estimated by the change in the transmitral Doppler flow pattern were examined in 23 patients with HOCM and MVO. Hemodynamic changes 2 h after a single dose of 200 mg of cibenzoline and 3 months after oral administration of 300-450 mg of cibenzoline per day were examined. At 2 h after the treatment, LVPG decreased from 79+/-37 mmHg to 24+/-21 mmHg (p < 0.0001). E-wave velocity significantly increased and A-wave velocity significantly decreased, and thus the E/A ratio increased from 0.83+/-0.39 to 1.36+/-0.50 (p < 0.0001). After 3 months of treatment, LVPG remained decreased, and the E-wave and A-wave velocities and the E/A ratio remained improved., Conclusions: Cibenzoline can attenuate LVPG and ameliorate LV diastolic dysfunction in patients with HOCM caused by MVO, which suggests a new strategy for the management of this condition.