Quantification of myocardial fibrosis using noninvasive T2-mapping magnetic resonance imaging: Preclinical models of aging and pressure overload

Noninvasive imaging of cardiac fibrosis is important for early diagnosis and intervention in chronic heart diseases. Here, we investigated whether noninvasive, contrast agent-free MRI T₂-mapping can quantify myocardial fibrosis in preclinical models of aging and pressure overload. Myocardial fibrosis and remodeling were analyzed in two animal models: (i) aging (15-month-old male CF-1 mice vs. young 6- to 8-week-old mice), and (ii) pressure overload (PO; by transverse aortic constriction in 4- to 5-month-old male C57BL/6 mice vs. sham-operated for 14 days). In vivo T₂-mapping was performed by acquiring data during the isovolumic and early diastolic phases, with a modified respiratory and ECG-triggered multiecho TurboRARE sequence on a 7-T MRI. Cine MRI provided cardiac morphology and function. A quantitative segmentation method was developed to analyze the in vivo T₂-maps of hearts at midventricle, apex, and basal regions. The cardiac fibrosis area was analyzed ex vivo by picro sirius red (PSR) staining. Both aged and pressure-overloaded hearts developed significant myocardial contractile dysfunction, cardiac hypertrophy, and interstitial fibrosis. The aged mice had two phenotypes, fibrotic and mild-fibrotic. Notably, the aged fibrotic subgroup and the PO mice showed a marked decrease in T₂ relaxation times (25.3 ± 0.6 in aged vs. 29.9 ± 0.7 ms in young mice, p = 0.002; and 24.3 ± 1.7 in PO vs. 28.7 ± 0.7 ms in shams, p = 0.05). However, no significant difference in T₂ was detected between the aged mild-fibrotic subgroup and the young mice. Accordingly, an inverse correlation between myocardial fibrosis percentage (FP) and T₂ relaxation time was derived (R² = 0.98): T₂ (ms) = 30.45 – 1.05 × FP. Thus, these results demonstrate a statistical agreement between T₂-map–quantified fibrosis and PSR staining in two different clinically relevant animal models. In conclusion, T₂-mapping MRI is a promising noninvasive contrast agent-free quantitative technique to characterize myocardial fibrosis.     

Resiniferatoxin reduces cardiac sympathetic nerve activation to exert a cardioprotective effect during myocardial infarction

Background and objective: Myocardial infarction (MI) is a common critical disease of the cardiovascular system. The process of MI is often accompanied by the excessive activation of cardiac sympathetic nerves, which leads to arrhythmia. Resiniferatoxin (RTX) is a transient receptor potential vanilloid 1 (TRPV1), involved in the cardiac sympathetic afferent reflex. However, whether RTX can reduce the occurrence of arrhythmia and exert a cardioprotective effect by inhibiting the sympathetic reflex during MI is still unknown. Methods: The left anterior descending artery of cardiac was clamped to construct a model of MI. RTX (50 μg/ml) was used by epicardial application in MI rats. Ventricular electrophysiologic properties were continuously monitored by a body surface ECG. Yrosine hydroxylase (TH) and growth associated protein 43 (GAP43) were detected by Immunofluorescence staining. Connexin43 and transforming growth factor beta receptor 1 (TGF-β1) were detected by western blot. Norepinephrine (NE) and BNP levels in blood and tissue were determined by ELISA. Cardiac function was assessed by echocardiography. Results: The ERP, APD90, QRS, QT and the Tend-Tpeak intervals in MI rats were all prolonged, but decreased after RTX treatment (n = 3, P<0.05). In contrast, the RR interval was shortened in the MI group, but prolonged in the MI+RTX group (n = 3, P<0.05). RTX treatment significantly reduced ventricular arrhythmias after MI. TH- and GAP43-positive nerve densities and TGF-β1, and cx-43 protein expression were up-regulated in the MI group compared to the sham group, and they were decreased in the MI+RTX group compared to the MI group (n = 3, P<0.05). RTX can decrease serum and tissue NE and BNP levels (n = 3, P<0.05). RTX pretreatment significantly decreased heart rate, HW/BW ratio and LVIDS, and increased LVEF andLVFS values (n = 3, P<0.05). Conclusion: RTX improved cardiac dysfunction, ventricular electrophysiologic properties, and sympathetic nerve remodeling in rats with MI by inhibiting the excessive cardiac sympathetic drive.     

Case Report: Transient Stress Hyperglycemia in the Patient With ST-Elevation Myocardial Infarction

Transient stress hyperglycemia in the setting of acute myocardial infarction is a frequent phenomenon. Its transient nature should not dissuade the clinician from management of elevated blood glucose in a patient after an ST-elevation myocardial infarction. This case presents an adult patient after an ST-elevation myocardial infarction with transient stress hyperglycemia and the evidence used to identify optimal pharmacologic management and secondary prevention.     

活血化瘀方联合针灸治疗对脑梗后遗症患者脑血管血液流变动力学及神经功能的影响

目的:探讨血化瘀方联合针灸治疗对脑梗后遗症患者脑血管血液流变动力学及神经功能的影响。方法:选取2016年1月至2017年1月沈阳市第二中医医院收治脑梗后遗症患者120例作为研究对象,对照组61例患者接受针灸治疗;观察组59例患者接受活血化瘀方联合针灸治疗。2组连续治疗30 d。比较2组患者脑血流流变学指标、神经功能评分、中医证候积分、临床疗效。结果:治疗前2组患者脑部平均血流速度、左侧椎动脉血流量、右侧椎动脉血流量、基底动脉血流量比较,差异无统计学意义(P 0. 05)。治疗后观察组患者脑部平均血流速度、左侧椎动脉血流量、右侧椎动脉血流量、基底动脉血流量大于对照组(P 0. 05)。治疗前2组患者NIHSS评分、MMSE评分比较,差异无统计学意义(P 0. 05)。治疗后观察组患者NIHSS评分显著低于对照组,MMSE评分高于对照组(P 0. 05)。治疗前2组患者头晕目眩、语言謇涩、半身不遂、患侧麻木、舌苔白腻证候评分比较,差异无统计学意义(P 0. 05)。治疗后研究患者头晕目眩、语言謇涩、半身不遂、患侧麻木、舌苔白腻证候评分显著低于对照组(P 0. 05)。2组患者临床疗效比较,差异有统计学意义(Z=-5. 626,P=0. 000)。结论:活血化瘀方联合针灸能改善脑梗后遗症患者脑血管血液流变动力学指标,保护神经功能。     

CT与MRI对脑梗死后出血性转变的诊断价值

目的探讨CT与MRI在脑梗死后出血性转变(HT)中的诊断价值。方法对2011-01—2014-04我院收治的45例HT患者的临床资料进行回顾性分析,对CT与MRI的检查结果进行对比。结果45例患者中,脑内血肿34例(75.6%),脑梗死病灶内片状、斑点状或条状出血11例(24.4%)。其中大面积脑梗死继发出血24例(53.3%),中等面积继发出血15例(33.3%),小面积脑梗死继发出血6例(13.3%);CT检出HT 10例(22.2%),MRI检出45例(100%),差异有统计学意义(P0.05);在对不同部位的HT检查中,CT检出幕上出血9例(20.0%),幕下出血1例(2.2%);MRI检出幕上出血39例(86.7%),幕下出血6例(13.3%)。MRI对幕上及幕下出血的检出率均优于CT(P0.05)。结论在HT的诊断中,MRI比CT更加准确和敏感,在判断出血时间、指导临床治疗以及预后判断中具有重要意义。     

Discordant Electrocardiogram Left Ventricular Wall Thickness and Strain Findings in Influenza Myocarditis

A 42‐year‐old man presented with a viral prodrome and tested positive for influenza A. He rapidly deteriorated developing cardiogenic shock, rhabdomyolysis, and acute kidney injury. Patient improved 1 week later with supportive measures including vasopressors, inotropes, and an intraaortic balloon pump. We report this case as it highlights the discordance between echocardiographic ventricular wall thickening as a result of myocardial edema, and electrocardiographic findings at presentation, with a reversal in findings at time of resolution. Additionally, there was some suggestion of a regional pattern to the reduced longitudinal strain.