A theoretical analysis for pulse wave in a blood vessel with an inhomogeneous part has been conducted by using a one-dimensional lattice model associated with the material nonlinearity of the arterial vessel wall. In the present study, from the viewpoint of mechanics, a certain part of blood vessel, which has the different configuration and mechanical properties of the arterial vessel wall, is regarded as the inhomogeneous part by a generalization. The pulse wave is modeled by the solitary wave. The integrability of the solitary wave is applied in order to analyze the behaviors of the pulse wave. As a result, the behaviors of the pulse wave which propagates through the inhomogeneous part in the blood vessel are shown analytically. The factor which has the effects on the propagation of the pulse wave is revealed clearly. Moreover, the relations between the behaviors of the pulse wave and the properties of the inhomogeneous part are clarified theoretically.
Essential thrombocythemia (ET) can cause systemic vascular thrombosis, but involvement of coronary arteries in the setting of ET is rare. This report describes a case of acute myocardial infarction (MI) in a patient with ET. A 67-year-old man with ET complained of severe acute chest pain. Emergent coronary angiography revealed subtotal thrombotic occlusion of the left main trunk (LMT) coronary artery. Coronary angioplasty and stenting were performed successfully. Coronary angiography 4 weeks later revealed no significant restenosis. The patient has done well after primary coronary stenting with the use of only an antiplatelet agent to treat the thrombocythemia.
The scale properties of a one-dimensional lattice model for the blood vessel with a heterogeneous part (an extended Sakanishi model) have been investigated. In the present study, from the viewpoint of mechanics, a part of the blood vessel, which has the different mechanical properties of the vessel wall, that is, a part of arteriosclerosis, prosthesis and so on, is regarded as the heterogeneous part by a generalization for the one-dimensional lattice model. The stability of the solitary wave is applied in order to obtain the reliable results by the numerical analysis of the pulse wave which propagates through the heterogeneous part in the blood vessel. As a result, we show the behaviors of the pulse wave through the blood vessel with the heterogeneous part under the condition that the scale of the pulse wave, the length of the heterogeneous part and the mechanical properties of the vessel wall are changed.
The relationship between local unipolar voltage (UV) in the pulmonary vein (PV)-ostia and left atrial wall thickness (LAWT) and the utility of these parameters as indices of outcome after atrial fibrillation (AF) ablation remain unclear.Two-hundred seventy-two AF patients who underwent AF ablation were enrolled. Unipolar voltage of PV-ostia was measured using a CARTO system, and LAWT was measured using computed tomography. The primary endpoint was atrial tachyarrhythmia (ATA) recurrence including AF. The ATA recurrence was documented in 74 patients (ATA-Rec group). The UV and LAWT of the bilateral superior PV roof to posterior and around the right-inferior PV in the ATA-Rec group were significantly greater than in patients without ATA recurrence (ATA-Free group) (P < 0.001). The UV had a strong positive correlation with LAWT (R2 = 0.446, P < 0.001). The UV 2.7 mV and the corresponding LAWT 1.6 mm were determined as the cut-off values for ATA recurrence (P < 0.001, respectively). Multisite LA high UV (HUV, ≥4 areas of >2.7 mV) or multisite LA wall thickening (≥5 areas of >1.6 mm), defined as LA hypertrophy (LAH), was related to higher ATA recurrence. Among 92 LAH patients, 66 had HUV (LAH-HUV) and the remaining 26 had low UV (LAH-LUV), characterized by history of non-paroxysmal AF and heart failure, reduced LV ejection fraction, or enlarged LA. In addition, LAH-LUV showed the worst ablation outcome, followed by LAH-HUV and No LAH (log-rank P < 0.001).Combining UV and LAWT enables us to stratify recurrence risk and suggest a tailored ablation strategy according to LA tissue properties.
Introduction: Bipolar ablation has been reported to be able to create deep myocardial ablation lesion as compared to unipolar ablation, however, the incidence of steam-pop can lead to undesirable periprocedural complication. Hypothesis: Steam-pop occurrence during bipolar ablation can be predicted by the settings of bipolar ablation and the myocardial tissue characteristics such as tissue thickness and initial impedance prior to RF. Methods: Using porcine cardiac tissues ex-vivo ablation experiments were conducted. We adopted the commercially available radiofrequency (RF) ablation catheters. Each ablation catheter was placed on both sides of the myocardial slice at an angle of 45 degrees under targeted contact force of 10g. We recorded the occurrence of steam-pop under the multiple settings of tissue thickness, RF power and ablation duration. We created a generalized linear model (GLM) to predict steam-pop based on the bipolar ablation settings and the myocardial tissue characteristics. Results: In total 194 bipolar applications were analyzed. Steam-pops were observed in 11 out of 194 applications (5.7%). In the applications with steam-pop, the RF energy was higher (median 40W [q1-q3: 30-50] vs 30W [20-40], P=0.017), the initial impedance was lower (88 [86.75 - 91.5] vs 93 Ohm [89.75 - 95.75], P=0.0042) and the tissue thickness was thinner (9.4 [8.43 - 9.89] vs 12.9 mm [10.06 - 15.47], P<0.0001) as compared to the applications without steam-pop. Using tissue thickness, RF energy and initial impedance, the constructed GLM achieved sensitivity of 100%, specificity of 93% and the area under the receiver-operator-characteristics curve of 0.969. Conclusion: Our data showed that the steam-pop occurrence during bipolar ablation may be predicted based on the initial RF settings and the tissue characteristics in the ex-vivo porcine myocardial model. Further studies are necessary to validate the feasibility of predicting steam-pops using the RF and tissue characteristics in the beating heart and human heart, which may enable us to titrate the RF settings and lead to safer bipolar ablation.
