Machine learning-based detection of sleep-disordered breathing in hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is often concomitant with sleep-disordered breathing (SDB), which can cause adverse cardiovascular events. Although an appropriate approach to SDB prevents cardiac remodelling, detection of concomitant SDB in patients with HCM remains suboptimal. Thus, we aimed to develop a machine learning-based discriminant model for SDB in HCM.

METHODS

In the present multicentre study, we consecutively registered patients with HCM and performed nocturnal oximetry. The outcome was a high Oxygen Desaturation Index (ODI), defined as 3% ODI >10, which significantly correlated with the presence of moderate or severe SDB. We randomly divided the whole participants into a training set (80%) and a test set (20%). With data from the training set, we developed a random forest discriminant model for high ODI based on clinical parameters. We tested the ability of the discriminant model on the test set and compared it with a previous logistic regression model for distinguishing SDB in patients with HCM.

RESULTS

Among 369 patients with HCM, 228 (61.8%) had high ODI. In the test set, the area under the receiver operating characteristic curve of the discriminant model was 0.86 (95% CI 0.77 to 0.94). The sensitivity was 0.91 (95% CI 0.79 to 0.98) and specificity was 0.68 (95% CI 0.48 to 0.84). When the test set was divided into low-probability and high-probability groups, the high-probability group had a higher prevalence of high ODI than the low-probability group (82.4% vs 17.4%, OR 20.9 (95% CI 5.3 to 105.8), Fisher's exact test p<0.001). The discriminant model significantly outperformed the previous logistic regression model (DeLong test p=0.03).

CONCLUSIONS

Our study serves as the first to develop a machine learning-based discriminant model for the concomitance of SDB in patients with HCM. The discriminant model may facilitate cost-effective screening tests and treatments for SDB in the population with HCM.

Electrocardiogram Electrode Positioning on the Back During Echocardiography: An Exploratory Cross-Sectional Study

BACKGROUND

ECG interpretation is sometimes difficult due to baseline fluctuations and electrode detachments when placed on the subjects' front side, leading to misinterpretation of the rhythms and phases of the cardiac cycle. We aimed to compare the differences in the wave amplitudes and respiratory variations between conventional ECG electrode positioning on the front side of patients and an alternative position on the backs of patients.

METHODS

Echocardiography was performed in 85 patients lying in the left lateral position. We attached the red electrode to the right clavicle, the yellow to the left clavicle, and the green to the left lateral abdomen on the front side of the patients; on the back, we attached the electrode to the right clavicle, the right upper posterior iliac spine, and the left upper posterior iliac spine.

RESULTS

The ECG monitor amplitudes were greater on the front side compared to the back side, but the BF-breath values were smaller on the back side (6.0 pixels) compared to the front side (10.5 pixels, p<0.05). The P wave amplitude divided by the BF-breath on the back side was greater than that seen on the front side (2.8 vs. 1.8, p<0.05), whereas the QRS amplitude divided by the BF-breath was 15.0 and 16.3, respectively (p=ns).

CONCLUSION

As an alternative to front-side ECG monitoring, electrodes placed on the back can help avoid misinterpretation of the ECG rhythms and the phases of the cardiac cycle due to respiration during echocardiography.

Safety and feasibility of a novel total percutaneous post-closure technique after bedside Impella decannulation in patients with cardiogenic shock

OBJECTIVES

The Impella (Abiomed) is a widely used percutaneous mechanical circulatory support device for high-risk percutaneous coronary intervention in patients with cardiogenic shock. This study aimed to determine the safety and feasibility of a non-angio-guided post-closure approach using the Perclose ProGlide (Abbott) to decannulate the Impella in the intensive care unit.

METHODS

This retrospective study included consecutive patients who were successfully weaned from mechanical circulatory support using the Impella device between April 2019 and April 2022 at Hamamatsu University School of Medicine. Fifteen patients underwent complete post-closure of the femoral artery access sites at the bedside. Technical success of the post-closure hemostasis technique was defined as no evidence of bleeding or additional medical procedures after manual compression. The safety endpoints comprised the Valve Academic Research Consortium-3 and Bleeding Academic Research Consortium criteria.

RESULTS

All patients achieved successful hemostasis with this novel technique without surgical conversion. There was no significant bleeding; however, procedure-related vessel occlusion was observed in 1 patient who was recanalized with balloon angioplasty.

CONCLUSIONS

Bedside post-closure using the Perclose ProGlide device is a safe and feasible alternative to manual compression and surgical removal of the Impella device with low bleeding or vascular complications rates.

Nonbacterial Thrombotic Endocarditis Caused by Early-stage Lung Cancer: An Autopsy Case Report

Nonbacterial thrombotic endocarditis (NBTE) is a manifestation of prothrombotic status observed in patients with malignancy. Most cases are discovered only in the advanced stages. However, cancer in early stages may also induce NBTE development. We herein report an 87-year-old man with NBTE with multiple thromboembolization coexisting with lung cancer in early clinical stage. Autopsy findings revealed platelet- and fibrin-rich vegetations in both the tricuspid and mitral valves without evidence of bacterial infection. NBTE should be considered in cases with occult thromboembolization. Not only the presence of typical vegetation but irregular leaflet thickening should be monitored with careful echocardiographic examinations.

Association of Malnutrition and High Bleeding Risk with Long-Term Prognosis in Patients with Acute Coronary Syndrome following Percutaneous Coronary Intervention

BACKGROUND

Malnutrition in cardiovascular disease is associated with poor prognosis, especially in patients with heart failure and acute coronary syndrome (ACS). High bleeding risk is also linked to coronary artery disease prognosis, including ACS. However, whether the extent of malnutrition and high bleeding risk have a cumulative impact on the long-term prognosis of patients with ACS who undergo percutaneous coronary intervention remains unclear.

METHODS

We analyzed 275 patients with ACS treated with percutaneous coronary intervention. The Controlling Nutritional Status score and Japanese version of the Academic Research Consortium for High Bleeding Risk criteria (J-HBR) were retrospectively evaluated. The primary and secondary outcomes were adjusted using the inverse probability treatment weighting method.

RESULTS

The prevalence of moderate or severe malnutrition in this cohort was 16%. Kaplan-Meier analysis showed a significantly higher incidence of major adverse cardiovascular and cerebrovascular events in patients who were moderately or severely malnourished than in those who were not. Notably, the incidence of these major events was similar between severely malnourished patients with J-HBR and those without.

CONCLUSION

Moderate or severe malnutrition has a significant impact on the long-term prognosis of patients with ACS who undergo percutaneous coronary intervention.

Association of an Increased Abnormal Mitochondria Ratio in Cardiomyocytes with a Prolonged Oxygen Uptake Time Constant during Cardiopulmonary Exercise Testing of Patients with Non-ischemic Cardiomyopathy

Objective The cardiac function, blood distribution, and oxygen extraction in the muscles as well as the pulmonary function determine the oxygen uptake (VO2) kinetics at the onset of exercise. This factor is called the VO2 time constant, and its prolongation is associated with an unfavorable prognosis for heart failure (HF). The mitochondrial function of skeletal muscle is known to reflect exercise tolerance. Morphological changes and dysfunction in cardiac mitochondria are closely related to HF severity and its prognosis. Although mitochondria play an important role in generating energy in cardiomyocytes, the relationship between cardiac mitochondria and the VO2 time constant has not been elucidated. Methods We calculated the ratio of abnormal cardiac mitochondria in human myocardial biopsy samples using an electron microscope and measured the VO2 time constant during cardiopulmonary exercise testing. The VO2 time constant was normalized by the fat-free mass index (FFMI). Patients Fifteen patients with non-ischemic cardiomyopathy (NICM) were included. Patients were divided into two groups according to their median VO2 time constant/FFMI value. Results Patients with a low VO2 time constant/FFMI value had a lower abnormal mitochondria ratio than those with a high VO2 time constant/FFMI value. A multiple linear regression analysis revealed that the ratio of abnormal cardiac mitochondria was independently associated with a high VO2 time constant/FFMI. Conclusion An increased abnormal cardiac mitochondria ratio might be associated with a high VO2 time constant/FFMI value in patients with NICM.

Diagnostic value of heart-to-mediastinum ratio in 99mTc-pyrophospate SPECT/CT for transthyretin cardiac amyloidosis

BACKGROUND

In transthyretin cardiac amyloidosis (ATTR-CA), 99mTc-pyrophosphate myocardial scintigraphy (99mTc-PYP) is a diagnostic tool that utilizes visual and quantitative evaluation. However, false positive cases can occur because of tracer accumulation in the blood. We investigated the effectiveness of the heart-to-mediastinum (H/M) ratio of 99mTc-PYP in ATTR-CA diagnosis.

METHODS

We retrospectively included 164 patients who underwent 99mTc-PYP single-photon emission computed tomography/computed tomography between March 2019 and January 2022. The diagnostic accuracy of ATTR-CA was examined by the heart-to-contralateral lung (H/CL) and H/M ratio calculated at 3 hours post-tracer administration.

RESULTS

After the exclusion of patients who did not undergo endomyocardial biopsy, 30 patients (15 each with ATTR-CA and without ATTR-CA) were included. The receiver operating characteristic curve used to distinguish ATTR-CA from non-ATTR-CA patients revealed an area under the curve of 0.986 and 0.943, respectively. A H/M ratio of > 1.41 identified ATTR-CA patients with a sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 100, 93.3, 93.3, and 100%, respectively. Conversely, an H/CL ratio of > 1.3 identified ATTR-CA patients with 100% sensitivity, 40.0% specificity, 62.5% PPV, and 100% NPV.

CONCLUSION

The H/M ratio obtained at 3 hours post-injection has the potential to be a novel indicator for ATTR-CA.

A Case of Coronary Arteritis and Myocardial Involvement With Associated IgG4-Related Disease

A 56-year-old male subject with bilateral eyelid swelling was diagnosed with an immunoglobulin G4-related disease. After whole-body surveillance, concomitant coronary arteritis with a mural thrombus and myocardial involvement were observed. In this case, multimodal diagnostic imaging assessment led to the diagnosis of both coronary arteritis and myocardial fibrosis associated with immunoglobulin G4-related disease. (Level of Difficulty: Advanced.).

Feasibility of Short-Term Aggressive Lipid-Lowering Therapy with the PCSK9 Antibody in Acute Coronary Syndrome

BACKGROUND

The guideline-recommended low-density lipoprotein cholesterol target level of <70 mg/dL may not be achieved with statin administration in some patients with acute coronary syndrome (ACS). Therefore, the proprotein convertase subtilisin-kexin type 9 (PCSK9) antibody can be added to high-risk patients with ACS. Nevertheless, the optimal duration of PCSK9 antibody administration remains unclear.

METHODS AND RESULTS

Patients were randomized to receive either 3 months of lipid lowering therapy (LLT) with the PCSK9 antibody followed by conventional LLT (with-PCSK9-antibody group) or 12 months of conventional LLT alone (without-PCSK9-antibody group). The primary endpoint was the composite of all-cause death, myocardial infarction, stroke, unstable angina, and ischemia-driven revascularization. A total of 124 patients treated with percutaneous coronary intervention (PCI) were randomly assigned to the two groups (n = 62 in each). The primary composite outcome occurred in 9.7% and 14.5% of the patients in the with- and without-PCSK9-antibody groups, respectively (hazard ratio: 0.70; 95% confidence interval: 0.25 to 1.97; p = 0.498). The two groups showed no significant differences in hospitalization for worsening heart failure and adverse events.

CONCLUSIONS

In ACS patients who underwent PCI, short-term PCSK9 antibody therapy with conventional LLT was feasible in this pilot clinical trial. Long-term follow-up in a larger scale clinical trial is warranted.

Prevalence and Characteristics of Inspiration-Induced Negative Left Atrial Pressure during Pulmonary Vein Isolation

Background: Atrial fibrillation (AF) ablation is performed under deep sedation, which may cause inspiration-induced negative left atrial pressure (INLAP) associated with deep inspiration. INLAP could be the cause of periprocedural complications. Methods: We retrospectively enrolled 381 patients with AF (mean age, 63.9 ± 10.8 years; 76 women; 216 cases of paroxysmal AF) who underwent CA under deep sedation using an adaptive servo ventilator (ASV). Patients whose LAP was not obtained were excluded. INLAP was defined as <0 mmHg of mean LAP during inspiration immediately after the transseptal puncture. The primary and secondary endpoints were the presence of INLAP and the incidence of periprocedural complications. Results: Among 381 patients, INLAP was observed in 133 (34.9%). Patients with INLAP had higher CHA2DS2-Vasc scores (2.3 ± 1.5 vs. 2.1 ± 1.6) and 3% oxygen desaturation indexes (median 18.6 (interquartile range 11.2–31.1) vs. 15.7 (8.1–25.3)), and higher prevalence of diabetes mellitus (23.3 vs. 13.3%) than patients without INLAP. Air embolism occurred in four patients with INLAP (3.0 vs. 0.0%). Conclusion: INLAP is not rare in patients undergoing CA for AF under deep sedation with ASV. Much attention should be paid to the possibility of air embolism in patients with INLAP.

Drug-refractory Heart Failure in Female Carrier of Duchenne Muscular Dystrophy: A Case of X-linked Dilated Cardiomyopathy

A 56-year-old woman was referred to our hospital for the further evaluation of drug-refractory heart failure with a reduced ejection fraction. A family history interview revealed that men in her family had died of Duchenne muscular dystrophy (DMD), whereas she had no skeletal muscle disorder. Myocardial histopathology revealed a reduced dystrophin expression in the cardiomyocyte membrane, and a dystrophin (DMD) gene analysis identified a duplication in exon 8-9 on Xp21, suggesting that she had a cardiac-specific phenotype of dystrophinopathy, i.e. X-linked dilated cardiomyopathy (XLDCM). In conclusion, careful family history interviews and an investigation of dystrophinopathy are required to detect XLDCM in women.

Individualised left anterior oblique projection for lead implantation into interventricular septum

Objective

We sought to investigate whether it is possible to obtain individualised left anterior oblique (LAO) by preprocedural electrocardiographic parameters and, if so, whether these parameters can help to improve the success rate of right ventricular (RV) lead implantation into the interventricular septum.

Methods

In this observational study, we assessed the relationship between preoperative electrocardiographic parameters and the angle of the interventricular septum obtained using thoracic CT. The participants were divided into two groups: a retrospective derivation cohort to derive the optimal formula for the individual septum axis, and a prospective internal validation cohort to which we applied the optimal formula and implanted using the new method.

Results

In the retrospective derivation cohort (n=39), the mean angle of individualised LAO assessed by thoracic CT was 53.1°±8.9°, and the preoperative ECG QRS axis was strongly correlated with the interventricular septum axis (R²=0.490). LAO projection derived from the preoperative ECG QRS axis confirmed that the RV lead was placed in the interventricular septum during the pacemaker procedure in the prospective internal validation group (n=30). The success rate for placing the RV lead into the interventricular septum was significantly improved in the internal validation cohort (93% vs 64%, p<0.05). In addition, the N-terminal pro-brain natriuretic peptide level decreased significantly after surgery in the interventricular septal indwelling group.

Conclusions

Individualised LAO angle derived from the preoperative ECG QRS axis is a new useful and simple method for RV lead implantation into the interventricular septum.

Trial registration number

UMIN000045741.

Pre-procedural predictors of left atrial low-voltage zones in patients undergoing catheter ablation of atrial fibrillation

Pulmonary vein isolation has become a cornerstone treatment for catheter ablation of atrial fibrillation (AF). Recent reports show that additional ablation targeting low-voltage zones reduces AF recurrence. However, the pre-procedural predictors of low-voltage zones remain elusive. We retrospectively enrolled 359 patients (mean age 63.7 ± 10.8 years; 73 females; and 149 had persistent atrial fibrillation) who underwent catheter ablation for AF and left atrial (LA) voltage mapping during sinus rhythm or atrial pacing. Low-voltage zones were defined as area of > 5 cm2 with a bipolar electrogram amplitude of < 0.50 mV. Overall, 51 (14.2%) patients had low-voltage zones. Patients with low-voltage zones were older (67.9 ± 9.9 vs. 63.0 ± 10.8 years; P = 0.003), predominantly female (33.3% vs. 18.2%; P = 0.013), had higher prevalence of dilated cardiomyopathy (DCM) (11.8% vs. 1.6%; P = 0.002) and hypertrophic cardiomyopathy (HCM) (9.8% vs. 2.6%; P = 0.025), and had larger LA volumes (153.6 ± 46.4 vs. 117.7 ± 67.8 mL; P < 0.001) than those without low-voltage zones. Multivariate logistic regression analysis revealed that age (OR 1.060; 95% CI 1.022–1.101, P = 0.002), female sex (OR 2.978; 95% CI 1.340–6.615, P = 0.007), DCM (OR 8.341; 95% CI 1.381–50.372, P = 0.021), HCM (OR 5.044; 95% CI 1.314–19.363, P = 0.018), persistent AF (OR 4.188; 95% CI 1.928–9.100, P < 0.001), and larger LA volume (OR 3.215; 95% CI 1.378–7.502, P = 0.007) were independently associated with the presence of low-voltage zones. Patient age, female sex, DCM, HCM, persistent AF and larger LA volume may predict the presence of low-voltage zones and could be useful in selecting the appropriate ablation strategy for AF.

Intra-Left Ventricular Hemodynamics Assessed with 4D Flow Magnetic Resonance Imaging in Patients with Left Ventricular Thrombus

Left ventricular thrombus (LVT) has been identified to be crucial in patients with reduced ejection fraction (EF). Three-dimensional cine phase-contrast magnetic resonance imaging (4D flow MRI) can visualize the intra-LV vortex during diastole and quantify the maximum flow velocity (Vmax) at the apex. In this study, we investigated whether the change in the intra-LV vortex was associated with the presence of LVT in patients with cardiac disease.In total, 36 patients (63.5 ± 11.9 years, 28 men, 12/24 with/without LVT) with diffuse LV dysfunction underwent 4D flow MRI. The relative vortex area using streamline images and Vmax of blood flow toward the apex at the apical left ventricle were evaluated. The correlation between the relative vortex area and Vmax was assessed using Pearson's correlation coefficient. The ability to detect LVT was evaluated using the area under the curve (AUC) of the receiver operating characteristic.The relative vortex area was found to be smaller (27 ± 10% versus 45 ± 11%, P = 0.000026), whereas Vmax at the apical left ventricle was lower (19.1 ± 4.4 cm/second versus 27.4 ± 8.9 cm/second, P = 0.0006) in patients with LVT. Vmax at the apical left ventricle demonstrated significant correlations with the relative vortex area (r = 0.43, P = 0.01) and relative transverse length of the vortex (r = 0.45, P = 0.007). The AUC was 0.91 for the relative vortex area, whereas it was 0.80 for Vmax in the apical left ventricle.A smaller LV vortex and lower flow velocity at the LV apex were associated with LVT in patients with reduced EF.

An enantiomeric quantitative LC-MS/MS method for tolvaptan and its monohydroxylates in human plasma using a reversed-phase separation procedure

Racemic tolvaptan possessing an asymmetric carbon is metabolized to three pairs of monohydroxylate enantiomers of diol form with V₂ receptor antagonistic activity via CYP3A. This study aimed to develop a simultaneous quantitative liquid chromatography-tandem mass spectrometry method for 5R- and 5S-tolvaptan and their monohydroxylate enantiomers in human plasma and to apply it to patient samples. Deproteinized plasma specimens were separated using a polysaccharide derivative chiral column in a reversed-phase elution mode. The mass spectrometer was run in positive ion electrospray ionization mode. The chromatographic peaks of tolvaptan monohydroxylate enantiomers were identified by the recombinant CYP3A4/5 digestion of 5R- and 5S-tolvaptan. The calibration curves ranged over the plasma concentrations of 0.25-125 ng/mL for 5R- and 5S-tolvaptan, 0.025-12.5 ng/mL for 4R5R- and 4S5S-diols, and 0.025-38.15 ng/mL for 4S5R-, 4R5S-, 3S5R-, and 3R5S-diols with a large variation. Their pre-treatment recovery rates and matrix factors in human plasma were 85.2-112.9 % and 86.9-113.1 %, respectively. The intra- and inter-day accuracy and imprecision were 92.3-113.8 % and 3.5-14.6 % for all analytes, respectively. The plasma concentration ranges of 5R- and 5S-tolvaptan, 4R5R-, 4S5S-, 4S5R-, 4R5S-, 3S5R-, and 3R5S-diols in heart failure patients with a 5-fold dilution procedure were 0.634-28.4, 2.37-131, 0.525-15.4, 0.0970-4.08, 6.82-108, 0.271-6.49, 0.394-4.18, and 4.81-39.8 ng/mL, respectively. In conclusion, the present method has an acceptable analytical performance level and can be helpful for characterization of the plasma 5R- and 5S-tolvaptan and their monohydroxylate enantiomers in heart failure patients.

P585Intra left ventricular hemodynamics assessed using 4D flow MRI in the patient with left ventricular thrombus

Background

Early detection of left ventricular mural thrombus (LVT) in patients with reduced ejection fraction (EF) is crucial in prevention of arterial embolism. 3D-cine phase-contrast magnetic resonance imaging (4D flow MRI) can visualize the intra-LV vortex flow in diastole and quantify the maximum flow velocity (Vmax) at the apex. it remains, however, unknown whether 4D flow MRI is useful for detecting LVT.

Purpose

The purpose of our study is to examine the intra-LV vortex formation and flow velocity in patients with severe LV dysfunction using 4D Flow MRI, and to compare differences in intra-LV flow dynamics between patients with and without LVT. We also examined the diagnostic accuracy to detect LVT by 4D flow MRI.

Methods

Twenty-nine patients with impaired LV function (LVEF 25.8±7.4%, 62.5±12.3 years old, 24 males, 11 with ischemic cardiomyopathy, 9 with LVT) underwent 4D flow MRI from January 2012 to August 2018 in our institution. Intra-LV vortex size was evaluated as vortex/LV area ratio by streamline imaging (Figure 1). The diagnostic accuracy to predict LVT by vortex size and Vmax at the apex was determined by ROC analysis.

Results

The vortex was smaller (vortex/LV area ratio; 30.6±7.0% vs. 45.1±9.0%, p<0.05) and Vmax at the apex was lower (0.20±0.04 m/s vs. 0.28±0.09 m/s, p=0.013) in patients with LVT compared to those without LVT. The AUC was 0.789 for Vmax (cut-off value=0.226 m/s, sensitivity=0.889, specificity=0.650) and was 0.900 for vortex/LV area ratio (cut-off value=34.7%, sensitivity=0.889, specificity=0.850).

Figure 1

Conclusion

The smaller size of intra-LV vortex and the lower flow velocity at the LV apex may have association with LVT formation in patients with reduced EF. 4D flow MRI might be useful to predict LVT formation. Large scale longitudinal study is warranted to evaluate the incidence of LVT in the patients with lower flow velocity.

Acknowledgement/Funding

None

Marine-Derived Omega-3 Polyunsaturated Fatty Acids and Heart Failure: Current Understanding for Basic to Clinical Relevance

Heart failure (HF) is a rapidly growing global public health problem. Since HF results in high mortality and re-hospitalization, new effective treatments are desired. Although it remains controversial, omega 3 polyunsaturated fatty acids (n-3 PUFAs), such as the eicosapentaenoic acid and docosahexaenoic acid, have been widely recognized to have benefits for HF. In a large-scale clinical trial regarding secondary prevention of HF by n-3 PUFA (GISSI-HF trial), the supplementation of n-3 PUFA significantly reduced cardiovascular mortality and hospitalization. Other small clinical studies proposed that n-3 PUFA potentially suppresses the ventricular remodeling and myocardial fibrosis, which thereby improves the ventricular systolic and diastolic function both in ischemic and non-ischemic HF. Basic investigations have further supported our understanding regarding the cardioprotective mechanisms of n-3 PUFA against HF. In these reports, n-3 PUFA has protected hearts through (1) anti-inflammatory effects, (2) intervention of cardiac energy metabolism, (3) modification of cardiac ion channels, (4) improvement of vascular endothelial response, and (5) modulation of autonomic nervous system activity. To clarify the pros and cons of n-3 PUFA on HF, we summarized recent evidence regarding the beneficial effects of n-3 PUFA on HF both from the clinical and basic studies.

Cardiotoxicity of Carfilzomib in Two Japanese Patients with Relapsed Multiple Myeloma

Although multiple myeloma (MM) had been an incurable hematological malignancy with a poor prognosis, recent advances in novel anti-neoplastic agents, including carfilzomib (a proteasome inhibitor), have improved the prognosis. We herein report two cases of congestive heart failure in patients treated with carfilzomib. Although there are some reports on the cardiotoxicity of carfilzomib, to our knowledge, this is the first report on the cardiac involvement of carfilzomib in Japanese MM patients. We review the critical points from our two cases, with the aim of avoiding carfilzomib-associated heart failure in MM patients.

Pinacidil, a KATP channel opener, stimulates cardiac Na+/Ca2+ exchanger function through the NO/cGMP/PKG signaling pathway in guinea pig cardiac ventricular myocytes

Pinacidil, a nonselective ATP-sensitive K⁺ (KATP) channel opener, has cardioprotective effects for hypertension, ischemia/reperfusion injury, and arrhythmia. This agent abolishes early afterdepolarizations, delayed afterdepolarizations (DADs), and abnormal automaticity in canine cardiac ventricular myocytes. DADs are well known to be caused by the Na⁺/Ca²⁺ exchange current (I_NCX). In this study, we used the whole-cell patch-clamp technique and Fura-2/AM (Ca²⁺-indicator) method to investigate the effect of pinacidil on I_NCX in isolated guinea pig cardiac ventricular myocytes. In the patch-clamp study, pinacidil enhanced I_NCX in a concentration-dependent manner. The half-maximal effective concentration values were 23.5 and 23.0 μM for the Ca²⁺ entry (outward) and Ca²⁺ exit (inward) components of I_NCX, respectively. The pinacidil-induced I_NCX increase was blocked by L-NAME, a nitric oxide (NO) synthase inhibitor, by ODQ, a soluble guanylate cyclase inhibitor, and by KT5823, a cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG) inhibitor, but not by N-2-mercaptopropyonyl glycine (MPG), a reactive oxygen species (ROS) scavenger. Glibenclamide, a nonselective KATP channel inhibitor, blocked the pinacidil-induced I_NCX increase, while 5-HD, a selective mitochondria KATP channel inhibitor, did not. In the Fura-2/AM study pinacidil also enhanced intracellular Ca²⁺ concentration, which was inhibited by L-NAME, ODQ, KT5823, and glibenclamide, but not by MPG and 5-HD. Sildenafil, a phosphodiesterase 5 inhibitor, increased further the pinacidil-induced I_NCX increase. Sodium nitroprusside, a NO donor, also increased I_NCX. In conclusion, pinacidil may stimulate cardiac Na⁺/Ca²⁺ exchanger (NCX1) by opening plasma membrane KATP channels and activating the NO/cGMP/PKG signaling pathway.

Validated liquid chromatography coupled to tandem mass spectrometry method for simultaneous quantitation of tolvaptan and its five major metabolites in human plasma

Background

Tolvaptan is converted to major metabolites including three monohydroxylates (DM-4110, DM-4111 and DM-4119), an oxidate (MOP-21826) and a carboxylate (DM-4103) in humans. This study developed a simultaneous quantitative method for tolvaptan and its five major metabolites in human plasma using liquid chromatography coupled to tandem mass spectrometry.

Methods

Deproteinized plasma specimens using acetonitrile were separated using a 3- μm particle size octadecylsilyl column with 250 mm length and a simple linear gradient program at a flow rate of 0.3 mL/min with a total run time of 15 min. This method was applied to the determination of plasma samples collected from 20 heart failure patients treated with 3.75–15 mg tolvaptan.

Results

No interfering peak was found in drug-free plasma specimens. The calibration curves of tolvaptan, DM-4110, DM-4111, DM-4119, MOP-21826 and DM-4103 were linear over the concentration ranges of 3.125–1000, 0.3125–100, 1.25–400, 0.625–200, 0.125–40 and 31.25–10,000 ng/mL, respectively. Their pretreatment recovery rates and matrix factors were 94.1–113.9% and 86.9–108.0%, respectively. The intra- and inter-day accuracies and imprecisions were 91.6–106.5% and 0.9–10.9%, respectively, for all analytes. The plasma concentration ranges of tolvaptan, DM-4110, DM-4111, DM-4119, MOP-21826 and DM-4103 were 9.37–280, 1.91–16.3, 3.43–88.9, 1.43–10.4, 0.160–1.01 and 40.2–1471 ng/mL, respectively, in heart failure patients.

Conclusions

This validated method with acceptable analytical performance can be utilized for evaluating the pharmacokinetics of oral tolvaptan, including the determination of its major metabolites, in heart failure patients.

Glycogen synthase kinase-3β opens mitochondrial permeability transition pore through mitochondrial hexokinase II dissociation

Accumulating evidence has revealed pivotal roles of glycogen synthase kinase-3β (GSK3β) inactivation on cardiac protection. Because the precise mechanisms of cardiac protection against ischemia/reperfusion (I/R) injury by GSK3β-inactivation remain elusive, we investigated the relationship between GSK3β-mediated mitochondrial hexokinase II (mitoHK-II; a downstream target of GSK3β) dissociation and mitochondrial permeability transition pore (mPTP) opening. In Langendorff-perfused hearts, GSK3β inactivation by SB216763 improved the left ventricular-developed pressure and retained mitoHK-II binding after I/R. In permeabilized myocytes, GSK3β depolarized mitochondrial membrane potential with accelerated mitochondrial calcein release (suggesting GSK3β-mediated mPTP opening) and decreased mitoHK-II bindings. GSK3β-mediated mPTP opening depended on mitoHK-II binding, i.e., it was accelerated by dissociation of mitoHK-II (dicyclohexylcarbodiimide) and attenuated by enhancement of mitoHK-II binding (dextran). However, inactivation of mitoHK-II by glucose-depletion or glucose-6-phosphate inhibited the GSK3β-mediated mPTP opening. We conclude that GSK3β-mediated mPTP opening may be involved in I/R injury and regulated by mitoHK-II binding and activity.

The potential of leg-foot chest compression as an alternative to conventional hands-on compression during cardiopulmonary resuscitation

Background:

Conventional hands-on chest compression, in cardiopulmonary resuscitation, is often inadequate, especially when the rescuers are weak or have a small physique.

Objectives:

This study aimed to investigate the potential of leg-foot chest compression, with and without a footstool, during cardiopulmonary resuscitation.

Methods and Results:

We prospectively enrolled 21 medical workers competent in basic life support. They performed cardiopulmonary resuscitation on a manikin for 2 min using conventional hands-on compression (HO), leg-foot compression (LF), and leg-foot compression with a footstool (LF + FS). We analyzed the compression depths, changes in the rescuers’ vital signs, and the modified Borg scale scores after the trials. The compression depth did not differ between the cases using HO and LF. In the case of LF + FS, compression depths ⩾5 cm were more frequently observed (median, inter-quartile range: 93%, 81%–100%) than in HO (9%, 0%–57%, p < 0.01) and LF (28%, 11%–47%, p < 0.01). The increase in the heart rate or modified Borg scale scores, after the trials, did not differ between the HO and LF group; however, the values were the lowest in the case of LF + FS (49 ± 18 beats/min and 5 (4–7) in HO, 46 ± 18 and 6 (5–7) in LF, and 32 ± 11 and 2 (1–3) in LF + FS, respectively, p < 0.01). However, the increase in blood pressure, SpO2, and respiratory rate were not different among each group. The increases in the heart rate and modified Borg scale scores negatively were correlated with the rescuers’ body size, in the case of HO and LF, but not LF + FS.

Conclusion:

LF can be used as an alternative to HO, when adequate HO is difficult. LF + FS could be used when rescuers are weak or have a small physique and when the victims are bigger than the rescuers.

Mitochondrial fission protein, dynamin-related protein 1, contributes to the promotion of hypertensive cardiac hypertrophy and fibrosis in Dahl-salt sensitive rats

BACKGROUND

Hypertension promotes cardiac hypertrophy which finally leads to cardiac dysfunction. Although aberrant mitochondrial dynamics is known to be a relevant contributor of pathogenesis in heart disease, little is known about the relationship between mitochondrial dynamics and cardiac hypertrophy. We investigated the pathophysiological roles of Dynamin-related protein1 (Drp1, a mitochondrial fission protein) on the hypertensive cardiac hypertrophy.

METHODS & RESULTS

Dahl salt-sensitive rats were fed with a low-salt (0.3% NaCl) or a high-salt (8% NaCl) chow to promote hypertension with and without administration of mdivi1 (an inhibitor of Drp1: 1 mg/kg/every alternative day), and then the hypertensive cardiac hypertrophy was assessed. High-salt fed rats exhibited left ventricular hypertrophy (LVH), myocytes hypertrophy, and cardiac fibrosis, and mdivi-1 suppressed them without alteration of the blood pressure. Mdivi1 also reduced ROS production by hypertension, which subsequently suppressed the Ca²⁺-activated protein phosphatase calcineurin and Ca²⁺/calmodulin-dependent kinase II (CaMKII).

CONCLUSIONS

Our results suggest that Drp1 contributes to the pathogenesis of hypertensive cardiac hypertrophy via ROS production and the Drp1 suppression may be effective to prevent the hypertensive cardiac hypertrophy.

Eicosapentaenoic acid ameliorates palmitate-induced lipotoxicity via the AMP kinase/dynamin-related protein-1 signaling pathway in differentiated H9c2 myocytes

BACKGROUND

Emerging evidence suggested the preferable effects of eicosapentaenoic acid (EPA; n-3 polyunsaturated fatty acid) against cardiac lipotoxicity, which worsens cardiac function by means of excessive serum free fatty acids due to chronic adrenergic stimulation under heart failure. Nonetheless, the precise molecular mechanisms remain elusive. In this study, we focused on dynamin-related protein-1 (Drp1) as a possible modulator of the EPA-mediated cardiac protection against cardiac lipotoxicity, and investigated the causal relation between AMP-activated protein kinase (AMPK) and Drp1.

METHODS AND RESULTS

When differentiated H9c2 myocytes were exposed to palmitate (PAL; saturated fatty acid, 400µM) for 24h, these myocytes showed activation of caspases 3 and 7, enhanced caspase 3 cleavage, depolarized mitochondrial membrane potential, depleted intracellular ATP, and enhanced production of intracellular reactive oxygen species. These changes suggested lipotoxicity due to excessive PAL. PAL enhanced mitochondrial fragmentation with increased Drp1 expression, as well. EPA (50µM) restored the PAL-induced apoptosis, mitochondrial dysfunction, and mitochondrial fragmentation with increased Drp1 expression by PAL. EPA activated phosphorylation of AMPK, and pharmacological activation of AMPK by 5-aminoimidazole-4-carboxamide ribonucleotide ameliorated the PAL-induced apoptosis, mitochondrial dysfunction, and downregulated Drp1. An AMPK knockdown via RNA interference enhanced Drp1 expression and attenuated the protective effects of EPA against the PAL-induced lipotoxicity.

CONCLUSION

EPA ameliorates the PAL-induced lipotoxicity via AMPK activation, which subsequently suppresses mitochondrial fragmentation and Drp1 expression. Our findings may provide new insights into the molecular mechanisms of EPA-mediated myocardial protection in heart failure.

Intra-cardiac distribution of late gadolinium enhancement in cardiac sarcoidosis and dilated cardiomyopathy

Cardiac involvement of sarcoid lesions is diagnosed by myocardial biopsy which is frequently false-negative, and patients with cardiac sarcoidosis (CS) who have impaired left ventricular (LV) systolic function are sometimes diagnosed with dilated cardiomyopathy (DCM). Late gadolinium enhancement (LE) in magnetic resonance imaging is now a critical finding in diagnosing CS, and the novel Japanese guideline considers myocardial LE to be a major criterion of CS. This article describes the value of LE in patients with CS who have impaired LV systolic function, particularly the diagnostic and clinical significance of LE distribution in comparison with DCM. LE existed at all LV segments and myocardial layers in patients with CS, whereas it was localized predominantly in the midwall of basal to mid septum in those with DCM. Transmural (nodular), circumferential, and subepicardial and subendocardial LE distribution were highly specific in patients with CS, whereas the prevalence of striated midwall LE were high both in patients with CS and with DCM. Since sarcoidosis patients with LE have higher incidences of heart failure symptoms, ventricular tachyarrhythmia and sudden cardiac death, the analyses of extent and distribution of LE are crucial in early diagnosis and therapeutic approach for patients with CS.

Coronary Ectasia with Slow Flow Related to Apical Hypertrophic Cardiomyopathy

Coronary ectasia (CE) has been reported to be associated with a high risk of coronary events and caused by several etiologies. The authors present a patient with CE who was noted to have an ECG abnormality in routine health check. Coronary angiography revealed diffuse ectasia in all 3 coronary arteries. The flow of contrast medium was slow and focal squeezing signs were observed in the left coronary artery. Echocardiography indicated mild apical hypertrophy and significant reduction of coronary flow reserve. Exercise thallium scintigraphy exhibited a transient perfusion defect in the inferior region. This is the first case report that a mild apical hypertrophy induced severe CE with slow coronary flow. The authors recommend a long-term prophylaxis of thrombotic complications with antiplatelet agents in patients with CE.

Intra-left ventricular flow dynamics in patients with preserved and impaired left ventricular function: Analysis with 3D cine phase contrast MRI (4D-Flow)

PURPOSE

To examine how left ventricular (LV) volume and function affect flow dynamics by analyzing 3D intra-LV vortex features using 4D-Flow.

MATERIALS AND METHODS

Twenty-one patients with preserved (LVEF > 60%) and 14 with impaired LV function (LVEF < 40%) underwent 4D-Flow (at 3T).

RESULTS

In patients with preserved LV function, the intra-LV vortices developed in both the early and late diastolic phases. The shift of inflow vectors at the basal LV toward the posterior-lateral side of the LV and the mid-ventricular turn of inflow vectors toward the LV outflow could explain clearer vortex formation in the late diastolic phase. In patients with impaired LV function, the intra-LV vortices during the diastolic phase located at the more apical LV were larger and more spherically shaped. Both the distance to the vortex core and the vortex area correlated significantly with LV end-diastolic volume (r = 0.66 and 0.73), LVEF (r = -0.74 and -0.68), LV sphericity index (r = -0.60 and -0.65), and peak filling rate (r = -0.61 and -0.64), respectively (P < 0.01). The intra-LV vortices developed during the systolic phase in 10 cases. In those, some of the particles at the apical LV rotated within the LV, whereas in patients with preserved LV function, all of the particles were directed straight to the ascending aorta with accelerated flow velocity (256.8 ± 120.2 cm/s vs. 414.3 ± 88.2 cm/s, P < 0.01).

CONCLUSION

Vortex formation during the diastolic phase may be critical for both LV filling and ejection. 4D-Flow showed the 3D alterations of intra-LV flow dynamics by LV dilatation and dysfunction in a noninvasive and comprehensive manner. J. Magn. Reson. Imaging 2016;44:1493-1503.

Aberrant serum polyunsaturated fatty acids profile is relevant with acute coronary syndrome

Although a robust relationship between aberrant serum polyunsaturated fatty acids (PUFAs) profile and coronary artery disease (CAD) has been reported, the details concerning the association between aberrant PUFAs profile and clinical feature of CAD are not fully discovered. Therefore, we investigated the relationship between serum PUFAs and clinical profiles in CAD patients. We classified 595 consecutive CAD patients, who underwent coronary angiography into 3 groups according to the clinical profiles of CAD (group A: early phase ACS, n = 96; group B: stable CAD with previous history of ACS, n = 259; group C: stable CAD without previous history of ACS, n = 240) and measured serum n-3 [eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA)] and n-6 [arachidonic acid (AA)] PUFAs. Serum EPA, DHA, and EPA/AA ratio were significantly low in the order of group A < B < C [EPA; 48.1 (34.1-60.3) μg/ml, 61.7 (41.2-94.5) μg/ml, and 74.4 (52.7-104.9) μg/ml, DHA; 113.1 (92.8-135.1) μg/ml, 125.8 (100.4-167.2) μg/ml, and 140.1 (114.7-177.0) μg/ml, EPA/AA ratio; 0.31 (0.22-0.45), 0.39 (0.26-0.62), and 0.44 (0.31-0.69), medians with interquartile range, p < 0.01]. Multiple regression analysis revealed that EPA (p = 0.009) and EPA/AA ratio (p = 0.023), but not DHA and DHA/AA ratio, were negatively associated with clinical profiles of ACS in CAD patients. Significant correlation was not observed between PUFAs profile and severity of coronary stenosis. Low serum EPA and EPA/AA ratio correlates with clinical profiles of ACS in patients with CAD, regardless of the extent and severity of coronary artery stenosis.

Characteristics of intra-left atrial flow dynamics and factors affecting formation of the vortex flow – analysis with phase-resolved 3-dimensional cine phase contrast magnetic resonance imaging

BACKGROUND

The intra-left atrial (LA) blood flow from pulmonary veins (PVs) to the left ventricle (LV) changes under various conditions and might affect global cardiac function. By using phase-resolved 3-dimensional cine phase contrast magnetic resonance imaging (4D-Flow), the intra-LA vortex formation was visualized and the factors affecting the intra-LA flow dynamics were examined.

METHODS AND RESULTS

Thirty-two patients with or without organic heart diseases underwent 4D-Flow and transthoracic echocardiography. The intra-LA velocity vectors from each PV were post-processed to delineate streamline and pathline images. The vector images revealed intra-LA vortex formation in 20 of 32 patients. All the vortices developed during the late systolic and early diastolic phases and were directed counter-clockwise when viewed from the subjects' cranial side. The flow vectors from the right PVs lengthened predominantly toward the mitral valves and partly toward the LA appendage, whereas those from the left PVs directed rightward along the posterior wall and joined the vortex. Patients with vortex had less organic heart diseases, smaller LV and LA volume, and greater peak flow velocity and volume mainly in the left PVs, although the flow directions from each PV or PV areas did not differ.

CONCLUSIONS

4D-Flow can clearly visualize the intra-LA vortex formation and analyze its characteristic features. The vortex formation might depend on LV and LA volume and on flow velocity and volume from PVs.

Functional, morphological and electrocardiographical abnormalities in patients with apical hypertrophic cardiomyopathy and apical aneurysm: correlation with cardiac MR

Objective

The prognosis of apical hypertrophic cardiomyopathy (APH) has been benign, but apical myocardial injury has prognostic importance. We studied functional, morphological and electrocardiographical abnormalities in patients with APH and with apical aneurysm and sought to find parameters that relate to apical myocardial injury.

Methods

Study design: a multicentre trans-sectional study. Patients: 45 patients with APH and 5 with apical aneurysm diagnosed with transthoracic echocardiography (TTE) in the database of Hamamatsu Circulation Forum. Measure: the apical contraction with cine-cardiac MR (CMR), the myocardial fibrotic scar with late gadolinium enhancement (LGE)-CMR, and QRS fragmentation (fQRS) defined when two ECG-leads exhibited RSR’s patterns.

Results

Cine-CMR revealed 27 patients with normal, 12 with hypokinetic and 11 with dyskinetic apical contraction. TTE misdiagnosed 11 (48%) patients with hypokinetic and dyskinetic contraction as those with normal contraction. Apical LGE was apparent in 10 (83%) and 11 (100%) patients with hypokinetic and dyskinetic contraction, whereas only in 11 patients (41%) with normal contraction (p<0.01). Patients with dyskinetic apical contraction had the lowest left ventricular ejection fraction, the highest prevalence of ventricular tachycardia, and the smallest ST depression and depth of negative T waves. The presence of fQRS was associated with impaired apical contraction and apical LGE (OR=8.32 and 8.61, p<0.05).

Conclusions

CMR is superior to TTE for analysing abnormalities of the apex in patients with APH and with apical aneurysm. The presence of fQRS can be a promising parameter for the early detection of apical myocardial injury.

Distribution of late gadolinium enhancement in various types of cardiomyopathies: Significance in differential diagnosis, clinical features and prognosis

The recent development of cardiac magnetic resonance (CMR) techniques has allowed detailed analyses of cardiac function and tissue characterization with high spatial resolution. We review characteristic CMR features in ischemic and non-ischemic cardiomyopathies (ICM and NICM), especially in terms of the location and distribution of late gadolinium enhancement (LGE). CMR in ICM shows segmental wall motion abnormalities or wall thinning in a particular coronary arterial territory, and the subendocardial or transmural LGE. LGE in NICM generally does not correspond to any particular coronary artery distribution and is located mostly in the mid-wall to subepicardial layer. The analysis of LGE distribution is valuable to differentiate NICM with diffusely impaired systolic function, including dilated cardiomyopathy, end-stage hypertrophic cardiomyopathy (HCM), cardiac sarcoidosis, and myocarditis, and those with diffuse left ventricular (LV) hypertrophy including HCM, cardiac amyloidosis and Anderson-Fabry disease. A transient low signal intensity LGE in regions of severe LV dysfunction is a particular feature of stress cardiomyopathy. In arrhythmogenic right ventricular cardiomyopathy/dysplasia, an enhancement of right ventricular (RV) wall with functional and morphological changes of RV becomes apparent. Finally, the analyses of LGE distribution have potentials to predict cardiac outcomes and response to treatments.

Characteristics and clinical relevance of late gadolinium enhancement in cardiac magnetic resonance in patients with systemic sclerosis

Cardiac involvement in systemic sclerosis (SSc) is considerably frequent in autopsy, but the early identification is clinically difficult. Recent advantages in cardiac magnetic resonance (CMR) enabled to detect myocardial fibrotic scar as late gadolinium enhancement (LGE). We aimed to examine the prevalence and distribution of LGE in patients with SSc, and associate them with clinical features, electrocardiographic abnormalities and cardiac function. Forty patients with SSc (58 ± 14 years-old, 35 females, limited/diffuse 25/15, disease duration 106 ± 113 months) underwent serological tests, 12-lead electrocardiogram (ECG) and CMR. Seven patients (17.5 %) showed LGE in 26 segments of left ventricle (LV). LGE distributed mainly in the basal to mid inter-ventricular septum and the right ventricular (RV) insertion points, but involved all the myocardial regions. More patients with LGE showed NYHA functional class II and more (71 vs. 21 %, p < 0.05), bundle branch blocks (57 vs. 6 %, p < 0.05), LV ejection fraction (LVEF) < 50 % (72 vs. 6 %, p < 0.01), LV asynergy (43 vs. 0 %, p < 0.01) and RVEF < 40 % (100 vs. 39 %, p < 0.01). There was no difference in disease duration, disease types, or prevalence of positive autoimmune antibodies or high serum NT-proBNP level (>125 pg/ml). When cardiac involvement of SSc was defined as low LVEF, ECG abnormalities or high NT-proBNP, the sensitivity, specificity positive and negative predictive values of LGE were 36, 92, 71 and 72 %, respectively. We could clarify the prevalence and distribution of LGE in Japanese patients with SSc. The presence of LGE was associated with cardiac symptom, conduction disturbance and impaired LV/RV contraction.