Assessment of long-range cross-correlations in cardiorespiratory and cardiovascular interactions.

We propose higher-order detrending moving-average cross-correlation analysis (DMCA) to assess the long-range cross-correlations in cardiorespiratory and cardiovascular interactions. Although the original (zeroth-order) DMCA employs a simple moving-average detrending filter to remove non-stationary trends embedded in the observed time series, our approach incorporates a Savitzky-Golay filter as a higher-order detrending method. Because the non-stationary trends can adversely affect the long-range correlation assessment, the higher-order detrending serves to improve accuracy. To achieve a more reliable characterization of the long-range cross-correlations, we demonstrate the importance of the following steps: correcting the time scale, confirming the consistency of different order DMCAs, and estimating the time lag between time series. We applied this methodological framework to cardiorespiratory and cardiovascular time series analysis. In the cardiorespiratory interaction, respiratory and heart rate variability (HRV) showed long-range auto-correlations; however, no factor was shared between them. In the cardiovascular interaction, beat-to-beat systolic blood pressure and HRV showed long-range auto-correlations and shared a common long-range, cross-correlated factor. This article is part of the theme issue 'Advanced computation in cardiovascular physiology: new challenges and opportunities'.

Acute Pericarditis Following Acute Pulmonary Thromboembolism.

We describe the case of a 45-year-old Japanese man who developed acute pericarditis following an acute pulmonary thromboembolism. He had developed shortness of breath 7 days prior to hospitalization and was admitted with severe dyspnea. Echocardiography and laboratory results were compatible with acute pulmonary thromboembolism, which was confirmed by contrast-enhanced chest computed tomography. On the third hospital day, he experienced chest pain exacerbated by inspiration. On the fourth hospital day, his body temperature increased to 39°C and echocardiography revealed circumferential pericardial effusion. A diagnosis of acute pericarditis was made and the patient was treated with colchicine and aspirin. On the fifth hospital day, his symptoms largely subsided. Auscultation revealed pericardial friction rub. Electrocardiography demonstrated diffuse ST-segment elevations. Twenty-four days later, computed tomography revealed the disappearance of both the pericardial effusion and pulmonary arterial emboli. This case was thought to be one of acute pericarditis following acute pulmonary thromboembolism.

Extrathoracic subclavian venipuncture by using only the J-type guidewire for permanent pacemaker electrode placement.

Extrathoracic subclavian/axillar venipuncture is an accepted method for implanting pacemaker leads. Although several procedures have been reported, no standard method has been established yet. We evaluated the usefulness of a method in which only J-type guidewires are used. Between August 2011 and November 2012, 33 patients (20 men and 13 women; age, 77.5 ± 10.3 years) underwent permanent pacemaker lead insertion by extrathoracic subclavian venipuncture at our hospital. Thirty-two of the patients underwent primary implantation, whereas 1 patient required an additional lead because of lead fracture. The guidewires were inserted from the cubital vein to the subclavian vein. After the pacemaker pockets were created, we set the X-ray projection in the ipsilateral anterior oblique view. The distal edge of the guidewire was positioned on the ventral side of the first rib on fluoroscopy. The needle tip was positioned within the Ushaped distal tip of the J-type guidewire. The needle was held parallel to the X-ray angle and advanced towards the first rib until the tip entered the subclavian vein. The guidewire was inserted through the cubital vein in 31 patients, and through the femoral vein in 2 patients. Using this method, we successfully performed subclavian venipunctures in all 33 patients (total, 60 punctures) without any complications. Extrathoracic subclavian venipuncture using only a J-type guidewire is an easy, safe, and economical method for pacemaker lead implantation.

[Cardiac angiosarcoma resected after definitive diagnosis by thoracoscope-assisted biopsy].

A 31-year-old woman presented with cardiac tamponade. Contrast-enhanced chest computed tomography(CT) revealed an inhomogeneously-enhanced soft tissue mass measuring 50×35×30 mm, which was in contact with the right atrial wall. The mass was definitely diagnosed as cardiac angiosarcoma by thoracoscope-assisted biopsy. The right atrial wall, including the tumor, was extensively resected, and then reconstructed with the equine pericardium. Postoperative radiation therapy was performed, but the patient developed malignant ascites with an intra-pericardial ectopic tumor recurrence. Additional radiation therapy was performed, but she died 177 days after the operation. Although thoracoscopeassisted biopsy is considered to be a useful diagnostic method for cardiac tumors on the surface of the heart, it carries the risk of spreading tumor cells. In the present case, the tumor should have been resected immediately after the prompt pathological diagnosis.

Primary Cardiac Lymphoma Arising from Both Sides of the Heart.

Primary cardiac lymphomas (PCLs) are extremely rare tumors with a poor prognosis. They usually involve the pericardium and the right side of the heart. PCLs arising from the left side of the heart are relatively rare, with bilateral cases being even rarer. We herein report a case of PCL arising from both the right and left sides of the heart in a 65-year-old man. Multiple imaging modalities clearly demonstrated the tumors at the initial evaluation. The pathological diagnosis was diffuse large B-cell lymphoma.

Cross-correlated fractal components of H-wave amplitude fluctuations in medial gastrocnemius and soleus muscles.

The time series of the H-wave amplitude in soleus muscle (SOL) shows fractal (long-range) correlation, which is attributed to input from supraspinal centers. However, whether such long-range power-law correlated input also contributes to the synergistic muscles remains unclear. The purpose of this study was therefore to examine the correlation in the fractal components of H-wave amplitude fluctuations between the synergistic muscles used for plantar flexion, i.e., the medial head of the gastrocnemius muscle (MG) and SOL. In eight young male participants, consecutive H-reflexes were recorded almost simultaneously from the MG and SOL at a stimulation frequency of 0.5 Hz for 30 min. We performed detrending moving-average cross-correlation analysis (DMCA) for each of the H- and M-wave amplitude time series between MG and SOL to assess the existence of a common noise input contributing to these long-range correlations. The cross-correlation coefficient ρDMCA (-1 to 1) was calculated to quantify the strength of the correlation between two different time series. The results indicated a significant long-range power-law correlation between H-wave amplitudes in MG and SOL (ρDMCA: 0.50 (0.22) and 0.22 (0.17), mean (standard deviation) for the original and randomly shuffled surrogate data, respectively, P < 0.05). This was not the case for M-wave amplitudes (ρDMCA: 0.29 (0.23) and 0.20 (0.15), P > 0.05). We conclude that there is a common noise input governing these synergistic muscles, possibly due to supraspinal origin, causing long-range power-law correlations in monosynaptic reflexes.

Detection of oriented fractal scaling components in anisotropic two-dimensional trajectories.

We propose a novel class of mixed fluctuations with different orientations and fractal scaling features as a model for anisotropic two-dimensional (2D) trajectories hypothesized to appear in complex systems. Furthermore, we develop the oriented fractal scaling component analysis (OFSCA) to decompose such mixed fluctuations into the original orientation components. In the OFSCA, the original orientations are detected based on the principle that the original angles are orthogonal to the angles with the minimum and maximum scaling exponents of the mixed fluctuations. In our approach, the angle-dependent scaling properties are estimated using the Savitzky-Golay-filter-based detrended moving-average analysis (DMA), which has a higher detrending order than the conventional moving-average-filter-based DMA. To illustrate the OFSCA, we demonstrate that the numerically generated time-series of mixed fractional Gaussian noise (fGn) processes with non-orthogonal orientations and different scaling exponents is successfully decomposed into the original fGn components. We demonstrate the existence of oriented components in the 2D trajectories by applying OFSCA to real-world time-series, such as human postural fluctuations during standing and seismic ground acceleration during the great 2011 Tohoku-oki earthquake.

Clinical Usefulness of New R-R Interval Analysis Using the Wearable Heart Rate Sensor WHS-1 to Identify Obstructive Sleep Apnea: OSA and RRI Analysis Using a Wearable Heartbeat Sensor.

Obstructive sleep apnea (OSA) is highly associated with cardiovascular diseases, but most patients remain undiagnosed. Cyclic variation of heart rate (CVHR) occurs during the night, and R-R interval (RRI) analysis using a Holter electrocardiogram has been reported to be useful in screening for OSA. We investigated the usefulness of RRI analysis to identify OSA using the wearable heart rate sensor WHS-1 and newly developed algorithm. WHS-1 and polysomnography simultaneously applied to 30 cases of OSA. By using the RRI averages calculated for each time series, tachycardia with CVHR was identified. The ratio of integrated RRIs determined by integrated RRIs during CVHR and over all sleep time were calculated by our newly developed method. The patient was diagnosed as OSA according to the predetermined criteria. It correlated with the apnea hypopnea index and 3% oxygen desaturation index. In the multivariate analysis, it was extracted as a factor defining the apnea hypopnea index (r = 0.663, p = 0.003) and 3% oxygen saturation index (r = 0.637, p = 0.008). Twenty-five patients could be identified as OSA. We developed the RRI analysis using the wearable heart rate sensor WHS-1 and a new algorithm, which may become an expeditious and cost-effective screening tool for identifying OSA.

A patient with Graves' disease accompanied by bloody pericardial effusion.

A hyperthyroid patient with bloody pericardial effusion is presented. He was hospitalized for severe dyspnea. Pericardiocentesis yielded 1.2 liters of bloody fluid. Biochemical, cytologic, and radiologic examinations failed to identify the etiology of the effusion. Upon normalization of thyroid function using antithyroid drugs, the pericardial effusion resolved without recurrence. The patient was diagnosed as Graves' disease, which rarely is complicated by bloody pericardial effusion. As it is rarely reported and not widely known, this association may be underdiagnosed.

Sinus of Valsalva thrombosis causing renal infarction.

A 72-year-old man was admitted to our hospital with a renal infarction. On admission, computed tomography (CT) of the abdomen revealed total occlusion of the right renal artery, which was found to be recanalized with residual thrombus 7 days later. Transesophageal echocardiography and chest CT demonstrated crescent-shaped thrombus in the non-coronary sinus of Valsalva without evidence of aneurysm. After coumadin treatment the patient did not experience recurrent episodes of systemic embolization. Five months after the initiation of anticoagulation, transesophageal echocardiography and chest CT demonstrated disappearance of the thrombus. This is a rare case of renal infarction caused by a thrombus in the non-coronary sinus of Valsalva without aneurysm.

Central retinal artery occlusion following cardiac catheterization.

We describe a 66-year-old Japanese man in whom central retinal artery occlusion followed cardiac catheterization. After the procedure, blurred vision was noted in the right eye, and ophthalmological examination revealed an occlusion. Central retinal artery occlusion is a very rare but serious complication of cardiac catheterization. We should anticipate this potential risk to ensure prompt detection and treatment.