A global in vivo Drosophila RNAi screen identifies NOT3 as a conserved regulator of heart function.

Heart diseases are the most common causes of morbidity and death in humans. Using cardiac-specific RNAi-silencing in Drosophila, we knocked down 7061 evolutionarily conserved genes under conditions of stress. We present a first global roadmap of pathways potentially playing conserved roles in the cardiovascular system. One critical pathway identified was the CCR4-Not complex implicated in transcriptional and posttranscriptional regulatory mechanisms. Silencing of CCR4-Not components in adult Drosophila resulted in myofibrillar disarray and dilated cardiomyopathy. Heterozygous not3 knockout mice showed spontaneous impairment of cardiac contractility and increased susceptibility to heart failure. These heart defects were reversed via inhibition of HDACs, suggesting a mechanistic link to epigenetic chromatin remodeling. In humans, we show that a common NOT3 SNP correlates with altered cardiac QT intervals, a known cause of potentially lethal ventricular tachyarrhythmias. Thus, our functional genome-wide screen in Drosophila can identify candidates that directly translate into conserved mammalian genes involved in heart function.

Clinical Significance of Guanylate Cyclase Stimulator, Riociguat, on Right Ventricular Functional Improvement in Patients with Pulmonary Hypertension.

BACKGROUND: Riociguat is a soluble guanylate cyclase stimulator that improves hemodynamics in patients with pulmonary hypertension (PH). Accumulating evidence implicates the additional effect of riociguat on the increase in cardiac output. However, its mechanisms have not been fully understood. This study aimed to investigate whether riociguat could ameliorate right ventricular (RV) contraction as well as hemodynamics. METHODS: We studied 45 patients with pulmonary arterial hypertension (14) or chronic thromboembolic pulmonary hypertension (31) and evaluated hemodynamics, using right-sided heart catheterization, before and after the administration of riociguat. RV function was assessed by echocardiography, including speckle-tracking echocardiography. RESULTS: Riociguat significantly improved the WHO functional class and reduced the mean pulmonary arterial pressure and vascular resistance. In addition, the cardiac index increased. RV remodeling was ameliorated after riociguat administration as assessed by the echocardiographic parameters, such as RV diameter and RV area index. RV function, including RV fractional area change and RV global longitudinal strain, also significantly improved, and their improvement was even observed in patients with mild PH after pulmonary endarterectomy or balloon pulmonary angioplasty. Furthermore, covariance analysis revealed that RV global longitudinal strain and RV fractional area change improved after riociguat administration, even with the same mean pulmonary arterial pressure, implicating the improvement of RV contractile function by riociguat, regardless of RV loading. CONCLUSIONS: Riociguat not only improved the hemodynamics of patients with PH but also ameliorated the echocardiographic parameters with RV function. RV strain could detect the subtle improvement in mild PH, and riociguat may have a benefit even after intervention, as assessed by speckle-tracking echocardiography.

Preoperative right ventricular strain predicts sustained right ventricular dysfunction after balloon pulmonary angioplasty in patients with chronic thromboembolic pulmonary hypertension.

AIMS: Balloon pulmonary angioplasty (BPA) improves hemodynamics and exercise tolerance in patients with chronic thromboembolic pulmonary hypertension (CTEPH). However, its diagnostic and predictive values remain unclear. We investigated the diagnostic and predictive values of BPA by assessing the mechanism of right ventricular (RV) dysfunction. METHODS AND RESULTS: Hemodynamic improvement was maintained over 6 months in 99 patients with CTEPH who underwent BPA. Notably, 57 of 99 patients showed normalization of pulmonary vascular resistance (PVR) after BPA. The RV mid free wall longitudinal strain (RVMFS) was inversely correlated with the 6-min walk distance (r = -.35, P = .01) and serum levels of high-sensitivity cardiac troponin T (hs-cTNT) (r = -.39, P = .004) 6 months post-BPA in the PVR-normalized group. Among all variables analyzed, only the pre-BPA RVMFS was correlated with the post-BPA RVMFS (r = .40, P = .001), and the pre-BPA RVMFS (<-15.8%) was the strongest predictor of post-BPA normalization of RVMFS (area under the curve 0.80, P = .01, sensitivity 89%, and specificity 63%). The immediate post-BPA RVMFS showed worsening over 6 months after the procedure (-25.8% to -21.1%) in patients with high serum hs-cTNT levels (>0.0014 ng/mL). In contrast, we observed an improvement in these values in those with low serum hs-cTNT levels (-23.6% to -24.4%). CONCLUSION: RVMFS of -15.8% may be a useful cutoff value to categorize the refractory and non-refractory stages of disease. Sustained serum hs-cTNT elevation post-BPA indicates subclinical RV myocardial injury, with resultant RVMFS deterioration and poor exercise tolerance.

Increasing mixed venous oxygen saturation is a predictor of improved renal function after balloon pulmonary angioplasty in patients with chronic thromboembolic pulmonary hypertension.

Balloon pulmonary angioplasty (BPA) has emerged as an effective treatment for patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH). Renal function has been identified as a prognostic marker in patients with pulmonary hypertension in previous studies. We, therefore, aimed to investigate the clinical parameters associated with improvements in renal function in patients with CTEPH. A total of 45 consecutive patients with inoperable CTEPH undergoing BPA (mean age 62.2 ± 15.1 years) were included in the study. We evaluated the patients' clinical characteristics at baseline and at 1-year post-BPA, and investigated the association between renal function and hemodynamic parameters, including right heart function. Hemodynamics and renal function showed sustained improvements at 1 year after BPA in 64.4% of patients. Improved estimated glomerular filtration rate (eGFR) was significantly correlated with increased cardiac index (r = 0.433, p = 0.003) and mixed venous oxygen saturation (SvO2; r = 0.459, p = 0.002), and with decreased mean pulmonary arterial pressure (r = - 0.420, p = 0.004) and pulmonary vascular resistance (r = -- 0.465, p = 0.001). Multivariate analysis revealed that an increase in SvO2 immediately after the final BPA was associated with improved eGFR after the 1st year (odds ratio 1.041; 95% confidence interval 1.004-1.078; P = 0.027). The cut-off value for predicting improved eGFR was an increase in SvO2 after the final BPA of >125.4% over the baseline value (specificity 100%, sensitivity 24.1%). In conclusion, BPA improved symptoms, right heart function, hemodynamics, and renal function up to the chronic phase. Increasing SvO2 by >125.4% above baseline in the acute phase is important for improving renal function at 1 year after BPA in CTEPH patients.

Long-term outcomes in 3 cases of quadricuspid aortic valve, using a new classification system: A case series and literature review.

Quadricuspid aortic valve has been classified based on leaflet size. However, no association is seen between classification and severity of aortic regurgitation (AR). Bicuspid aortic valve is classified according to the number of cusps, with significantly higher prevalence of AR in cases with a raphe. We classified cases according to raphe number. In 1 patient with no raphe, AR severity did not change into the eighth decade. However, AR severity worsened in patients with a raphe, in 1 case requiring aortic valve replacement in the fifth decade. Unequal shear stress may lead to leaflet fibrosis and progressive AR.

Multiple papillary fibroelastomas attached to left ventricular side and aortic side of the aortic valve: A report of new case and literature review.

The aortic valve (AV) is the most commonly affected site in multiple papillary fibroelastomas, but the frequency of embolism caused by the attachment side of the AV has not been elucidated. According to the review of the previous literature, 16 cases have been found attached to the AV. Of these, 6 of these have been found to be attached on the aortic side and 4 on the left ventricular side, 1 was bilateral, and 5 cases were unknown. Of the cases found on the aortic side, embolism occurred in 3 of them, and of the left ventricular side cases, embolism occurred in 2 of them. The frequency of embolism is equivalent even if papillary fibroelastoma attached to either side of the AV.

Incidence, predictors, and midterm clinical outcomes of left ventricular obstruction after transcatheter aortic valve implantation.

OBJECTIVES: We aimed to evaluate the incidence and midterm clinical outcomes of left ventricular obstruction (LVO) after transcatheter aortic valve implantation (TAVI). BACKGROUNDS: LVO is occasionally unmasked following valve replacement for severe aortic stenosis. However, little is known about the prevalence and effects of LVO after TAVI. METHODS: A total of 158 patients who underwent TAVI in our center between October 2013 and November 2015 received echocardiographic evaluations at baseline; before hospital discharge; and at 3, 6, and 12 months after TAVI. LVO was defined as a peak pressure gradient >30 mm Hg. RESULTS: Over 1 year of follow-up after TAVI, 21 patients (13.3%) demonstrated postprocedural LVO. The incidence was highest at 3-months follow-up and decreased at 6 months or later. Of the 21 patients with LVO, 20 (95.2%) demonstrated midventricular obstruction (MVO), whereas only 1 (4.8%) showed obstruction of the outflow tract (LVOT) with systolic anterior motion (SAM) of the mitral leaflet. In a multivariate analysis, the LVOT diameter (odds ratio [OR], 0.45; 95% confidence interval [CI], 0.30-0.67; P < 0.001), transvalvular velocity (OR, 2.44; 95% CI, 1.13-5.26; P = 0.023), and the presence of accelerated intraventricular flow at baseline (OR, 6.13; 95% CI, 1.49-25.2; P = 0.012) were associated with the occurrence of LVO. Postprocedural LVO was not associated with midterm all-cause death or heart failure events. CONCLUSION: In patients who underwent TAVI, MVO occurred more often than LVOT obstruction. However, the occurrence of postprocedural LVO was not associated with worsened clinical outcomes in these patients.

Comparison of Clinical Outcomes After Transcatheter vs. Minimally Invasive Cardiac Surgery Closure for Atrial Septal Defect.

BACKGROUND: Percutaneous closure has replaced surgery for the majority of cases of secundum atrial septal defect (ASD). However, technological advances have made contemporary minimally invasive cardiac surgery (MICS) less invasive than conventional surgery. The aim of this study was to compare clinical outcomes of percutaneous closure of secundum ASD with those of contemporary MICS.Methods and Results:We conducted a single-center retrospective study of 354 patients with ASD treated either with the Amplatzer Septal Occluder (134 patients) or MICS (220 patients) between 2000 and 2013. Success rates and the incidence of complications were compared. The success rates were 98% for percutaneous closure and 100% for MICS. There were no deaths in either group. Major complications occurred in 2 patients (1.5%) who underwent percutaneous closure and in 8 patients (3.6%) treated with MICS (P=0.16). Minor complications occurred in 15 patients (11.2%) who underwent percutaneous closure and in 46 patients (20.9%) treated with MICS (P=0.02). On multivariate analysis, MICS (odds ratio [OR]: 2.91, 95% confidence interval [CI]: 1.46-5.81; P=0.002) and age >70 years (OR: 3.50, 95% CI: 1.40-8.75; P=0.008) were independent predictors of complications. CONCLUSIONS: Percutaneous closure and MICS had high success rates without deaths. For ASD patients with a suitable anatomy, percutaneous closure can be considered as the first therapeutic option.

Ameliorating the severity of sleep-disordered breathing concomitant with heart failure status after percutaneous transluminal septal myocardial ablation for drug-refractory hypertrophic obstructive cardiomyopathy.

The coexistence of sleep-disordered breathing (SDB) and hypertrophic obstructive cardiomyopathy (HOCM) has widely been recognized; however, the impact of percutaneous transluminal septal myocardial ablation (PTSMA) for HOCM on SDB remains unknown. Herein, we examine cardiorespiratory polygraph parameters in patients with drug-refractory HOCM before and after PTSMA. Forty consecutive drug-refractory HOCM patients, admitted to Keio University Hospital, and who underwent cardiorespiratory polygraphy were retrospectively analyzed. Cardiorespiratory polygraphy was performed before and after PTSMA if patients underwent PTSMA. Patients with an apnea-hypopnea index (AHI) ≥5/h were considered to have SDB. The total number of central sleep apneas, obstructive sleep apneas, and hypopnea events was evaluated. Thirty-two out of 40 patients (80%) with drug-refractory HOCM had SDB. All patients experienced relief of heart failure-associated symptoms after PTSMA. The severity of SDB was found to be correlated with left atrial diameter. The AHI decreased after PTSMA [before 15.4 (range 10.9-23.5)/h vs. after 13.1 (8.3-17.8)/h, P = 0.02]. Especially, the hypopnea index decreased after PTSMA. The average and lowest arterial oxygen saturation also increased after PTSMA (94.2 ± 1.9-95.7 ± 1.6%, P = 0.009; 81.3 ± 5.7-85.8 ± 4.8%, P = 0.012, respectively). In patients with drug-refractory HOCM, PTSMA decreased the AHI and improved arterial oxygen saturation measures. Thus, invasive treatment of the left ventricular obstruction ameliorates the severity of SDB, in addition to improving heart failure status.

Preservation of Mobility of the Posterior Mitral Leaflet After Mitral Valve Repair With Neochordae Using Loop Technique.

BACKGROUND: Recently, the loop technique has been standardized for mitral valve repair, with excellent long-term outcomes reported. This study thus analyzed whether the loop technique could preserve mitral leaflet mobility on trans-thoracic echocardiography. METHODS AND RESULTS: Among 367 concomitant patients who underwent mitral valve repair at Keio University Hospital between January 2007 and December 2014, 304 patients had a prolapse of the posterior leaflet. Of these, 84 cases assessed on echocardiography were retrospectively analyzed for this study. These patients were divided into 4 groups based on the procedure used: (1) group L1 (n=28), loop technique alone; (2) group L2 (n=14), loop technique with resection and suture; (3) group L3 (n=33), loop technique with plication of indentation; and (4) group R (n=9), resection and suture alone. The mean postoperative mobile posterior mitral leaflet (PML) angles in groups L1 and L2 (39.3±16.0°, 37.3±16.0°) were significantly larger than those in groups L3 and R (18.8±15.7°, 15.3±15.7°), respectively (P<0.01). Ring size, age, and mobile PML angle had a statistically significant correlation with the postoperative mean mitral valve pressure gradient (P<0.05). CONCLUSIONS: The loop technique preserved PML mobility and enabled implantation of a larger ring, resulting in a reduced mean mitral valve pressure gradient. (Circ J 2016; 80: 663-667).

Oral Nitrate Administration Ameliorates Cardiogenic Shock due to Eclipsed Mitral Regurgitation.

Eclipsed mitral regurgitation (MR) has been reported as transient massive functional MR caused by a sudden coaptation defect in the absence of left ventricular remodeling or epicardial coronary artery stenosis. Coronary spasm or microvascular dysfunction has been suggested to be associated with the pathogenesis. Here, we present a 68-year-old woman with eclipsed MR with cardiogenic shock ameliorated by nitrate. She was admitted for transient shock with massive functional MR. Transient MR was associated with a complete absence of mitral leaflet coaptation owing to tethering of the lateral posterior mitral leaflet. The leaflet tethering was triggered by transient myocardial ischemia around the anterolateral papillary muscle, which could have been caused by coronary spasm and/or microvascular dysfunction. During admission, she experienced similar repeated episodes, which were ameliorated by oral nitrate administration. This is the first described case of eclipsed MR with shock ameliorated by nitrate. Although eclipsed MR, a cause of life-threatening shock, is uncommon, we need to keep in mind that nitrate administration could be a treatment option even in patients with cardiogenic shock.

Positional desaturation due to persistent left superior vena cava draining into the left atrium.

Persistent left superior vena cava (PLSVC) is a rare congenital anomaly whose prevalence is 0.3 % of general population. The majority of PLSVC drain into right atrium (RA) through the coronary sinus without clinical harm. However, in about 10 % of patients with PLSVC, it drains into left atrium (LA) causing right-to-left shunt. Here, we present a 60-year-old male patient with a PLSVC draining into LA, who developed dyspnea and desaturation depending on the body position after trans-catheter coil embolization of coronary to pulmonary artery fistulas. PLSVC draining into LA should be included in the differential diagnosis of positional desaturation.

Endomyocardial fibrosis: missing tricuspid valve and Fontan-like circulation.

Endomyocardial fibrosis (EMF) is a progressive type of obliterative/restrictive cardiomyopathy characterized by fibrosis of the apical endomyocardium of the ventricles. Although the prognosis of EMF patients is poor in tropical regions, the exact clinical course and pathogenesis of patients with EMF are not known. Here, we report the rare case with EMF in the seventh decade, who showed the disappearance of papillary muscles, chordae tendineae, and part of the tricuspid valves due to massive right ventricular thrombus. Because of those unusual findings of the isolated RV involvement, we observed continuous forward pulmonary artery flow, as occurring in a Fontan circulation.

Periodic Protrusion of Right Coronary Cusp into Left Ventricular Outflow Tract Due to Detachment from the Aortic Annulus Complicated with Infective Endocarditis.

We describe the imaging of unusual dislocation of right coronary cusp into left ventricular outflow tract (LVOT) due to the infective endocarditis. Although the two-dimensional echocardiography identified a protruding mass in LVOT, the three-dimensional echocardiography precisely demonstrated the spatial anatomy of the aortic root, which was confirmed by the surgical operation, implicating the usefulness of three-dimensional echocardiography in this rare anomaly.

Brugada syndrome behind complete right bundle-branch block.

BACKGROUND: The characteristic ECG of Brugada syndrome (BS) can be masked by complete right bundle-branch block (CRBBB) and exposed by resolution of the block or pharmacological or pacing maneuvers. METHODS AND RESULTS: The study consisted of 11 patients who had BS and CRBBB. BS was diagnosed before the development of CRBBB, on the resolution of CRBBB, or from new characteristic ST-segment changes that could be attributable to BS. Structural heart diseases were excluded, and coronary spasm was excluded on the basis of a provocation test at catheterization. In 7 patients, BS was diagnosed before the development of CRBBB. BS was diagnosed when CRBBB resolved spontaneously (n=1) or by right ventricular pacing (n=3). The precipitating cause for the spontaneous resolution of CRBBB, however, was not apparent. On repeated ECGs, new additional upward-convex ST-segment elevation was found in V2 or V3 in 3 patients. In 2 patients, new ST-segment elevation was induced by class IC drugs. The QRS duration was more prolonged in patients with BS and CRBBB compared with age- and sex-matched controls: 170±13 versus 145±15 milliseconds in V1 and 144±19 versus 128±7 milliseconds in V5 (both P<0.0001). The amplitude of R in V1 was smaller [corrected] in the BS patients than in the control subjects (P=0.0323), but that of R' was similar (P=0.0560). CONCLUSIONS: BS can coexist behind CRBBB, and CRBBB can completely mask BS. BS might be demonstrated by relief of CRBBB or by spontaneous or drug-induced ST-segment elevation. The prevalence, mechanism, and clinical significance of a combination of CRBBB and BS are yet to be determined.

Suppression of Rad leads to arrhythmogenesis via PKA-mediated phosphorylation of ryanodine receptor activity in the heart.

Ras-related small G-protein Rad plays a critical role in generating arrhythmias via regulation of the L-type Ca(2+) channel (LTCC). The aim was to demonstrate the role of Rad in intracellular calcium homeostasis by cardiac-Specific dominant-negative suppression of Rad. Transgenic (TG) mice overexpressing dominant-negative mutant Rad (S105N Rad TG) were generated. To measure intracellular Ca(2+) concentration ([Ca(2+)]i), we recorded [Ca(2+)]i transients and Ca(2+) sparks from isolated cardiomyocytes using confocal microscopy. The mean [Ca(2+)]i transient amplitude was significantly increased in S105N Rad TG cardiomyocytes, compared with control littermate mouse cells. The frequency of Ca(2+) sparks was also significantly higher in TG cells than in control cells, although there were no significant differences in amplitude. The sarcoplasmic reticulum Ca(2+) content was not altered in the S105N Rad TG cells, as assessed by measuring caffeine-induced [Ca(2+)]i transient. In contrast, phosphorylation of Ser(2809) on the cardiac ryanodine receptor (RyR2) was significantly enhanced in TG mouse hearts compared with controls. Additionally, the Rad-mediated RyR2 phosphorylation was regulated via a direct interaction of Rad with protein kinase A (PKA).

Nongenetic method for purifying stem cell-derived cardiomyocytes.

Several applications of pluripotent stem cell (PSC)-derived cardiomyocytes require elimination of undifferentiated cells. A major limitation for cardiomyocyte purification is the lack of easy and specific cell marking techniques. We found that a fluorescent dye that labels mitochondria, tetramethylrhodamine methyl ester perchlorate, could be used to selectively mark embryonic and neonatal rat cardiomyocytes, as well as mouse, marmoset and human PSC-derived cardiomyocytes, and that the cells could subsequently be enriched (>99% purity) by fluorescence-activated cell sorting. Purified cardiomyocytes transplanted into testes did not induce teratoma formation. Moreover, aggregate formation of PSC-derived cardiomyocytes through homophilic cell-cell adhesion improved their survival in the immunodeficient mouse heart. Our approaches will aid in the future success of using PSC-derived cardiomyocytes for basic and clinical applications.

De-escalation of Oxygen Therapy and Medication in Patients With Chronic Thromboembolic Pulmonary Hypertension After Balloon Pulmonary Angioplasty.

BACKGROUND: There is no consensus on the adjustment of home oxygen therapy (HOT) and pulmonary hypertension (PH)-specific medications after balloon pulmonary angioplasty (BPA) in patients with chronic thromboembolic pulmonary hypertension (CTEPH). We aimed to examine the status of de-escalation and discontinuation of HOT and PH-specific medications post-BPA and clarify its effect on hemodynamics, biomarkers, and long-term outcomes. METHODS: From November 2012 to May 2018, 135 consecutive patients with CTEPH who underwent BPA at a single university hospital were enrolled (age, 63.5 ± 13.5 years; World Health Organization functional class (WHO-FC) II, III, IV; 34, 92, 9). RESULTS: The mean pulmonary arterial pressure decreased from 37.7 ± 11.3 to 20.4 ± 5.1 mm Hg 1 year post-BPA (P < 0.01). The proportion of patients who required HOT and combination medical therapy (≥ 2 PH-specific medications) decreased 1 year post-BPA (from 58.5% to 7.4% and from 40.0% to 10.4%, respectively). Baseline factors influencing the requirement of HOT and combination medical therapy post-BPA were almost identical (ie, lower exercise capacity and pulmonary diffusion capacity and worse hemodynamics). Regardless of their discontinuation, the improved hemodynamics, functional capacity (WHO-FC), and biomarkers (B-type natriuretic peptide and high-sensitivity troponin T) were almost maintained, and no adverse 1-year clinical outcomes (all-cause death and PH-related hospitalization) were observed. CONCLUSIONS: Most patients with CTEPH discontinued HOT and PH-specific combination medical therapy post-BPA, which was not associated with the deterioration of hemodynamics, functional capacity, or biomarkers. No long-term adverse outcomes were observed.