Humans ; Myocardial Ischemia ; etiology

Aged ; Electrocardiography ; Female ; Humans ; Hyperkalemia ; complications ; physiopathology ; Myocardial Ischemia ; etiology

This study evaluated the application of quantitative tissue velocity imaging (QTVI) in assessing regional myocardial systolic and diastolic functions in dogs with acute subendocardial ischemia. Animal models of subendocardial ischemia were established by injecting microspheres (about 300 microm in diameter) into the proximal end of left circumflex coronary artery in 11 hybrid dogs through cannulation. Before and after embolization, two-dimensional echocardiography, QTVI and real-time myocardial contrast echocardiography (RT-MCE) via intravenous infusion of self-made microbubbles, were performed, respectively. The systolic segmental wall thickening and subendocardial myocardial longitudinal velocities of risk segments before and after embolization were compared by using paired t analysis. The regional myocardial video intensity versus contrast time could be fitted to an exponential function: y=A.(1-exp(-beta.t)), in which the product of A and beta provides a measure of myocardial blood flow. RT-MCE showed that subendocardial normalized A.beta was decreased markedly from 0.99+/-0.19 to 0.35+/-0.11 (P<0.05) in 28 left ventricular (LV) myocardial segments after embolization, including 6 basal and 9 middle segments of lateral wall (LW), 8 middle segments of posterior wall (PW) and 5 middle segments of inferior wall (IW). However, there was no statistically significant difference in subepicardial layer before and after embolization. Accordingly, the ratio of A.beta of subendocardial myocardium to subepicardial myocardium in these segments was significantly decreased from 1.10+/-0.10 to 0.31+/-0.07 (P<0.05). Although the systolic wall thickening did not change 5 min after the embolization in these ischemic segments (29%+/-3% vs 31%+/-5%, P>0.05), the longitudinal peak systolic velocities (Vs) and early-diastolic peak velocities (Ve) recorded by QTVI were declined significantly (P<0.05). Moreover, the subendocardial velocity curves during isovolumic relaxation predominantly showed positive waves, whereas they mainly showed negative waves before the embolization. This study demonstrates that QTVI can more sensitively and accurately detect abnormal regional myocardial function and post-systolic systole caused by acute subendocardial ischemia.
Contrast Media ; Echocardiography/*methods ; Endocardium/physiopathology ; Microbubbles ; Myocardial Contraction/physiology ; Myocardial Ischemia/etiology ; Myocardial Ischemia/*physiopathology ; Myocardial Ischemia/*ultrasonography ; Myocardium/pathology ; Ventricular Function, Left/*physiology

Animals ; Humans ; Ischemic Preconditioning, Myocardial ; methods ; Myocardial Ischemia ; complications ; therapy ; Myocardial Reperfusion ; methods ; Myocardial Reperfusion Injury ; etiology ; prevention & control

Angioplasty, Balloon, Coronary ; Coronary Artery Disease ; etiology ; Coronary Disease ; etiology ; Humans ; Inflammation ; complications ; Microvascular Angina ; etiology ; Myocardial Ischemia ; etiology

The aim of this study was to determine if the potassium aspartate and magnesium (PAM) prevent reperfusion-induced ventricular arrhythmias (RIVA) in ischemia-reperfusion (IR) rabbit heart. Thirty rabbits were randomly divided into control, ischemia and PAM groups. Arterially-perfused rabbit left ventricular preparations were made, and transmural ECG as well as action potentials from both endocardium and epicardium were simultaneously recorded in the whole process of all experiments. In control group rabbit ventricular wedge preparations were continuously perfused with Tyrode's solution, and in ischemia group and PAM groups the perfusion of Tyrode's solution was stopped for 30 min. Then the ischemia group was reperfused with Tyrode's solution and the PAM group with Tyrode's solution containing 2.42 mg/L PAM, respectively. ECG, QT interval, transmural repolarization dispersion (TDR) and action potentials from epicardium and endocardium were simultaneously recorded, and the RIVA of the wedge preparation was observed. Compared with control group, TDR and incidence of RIVA were significantly increased in ischemia group (P<0.05). The incidence of RIVA in control, ischemia and PAM group was 0/10, 9/10 and 1/10, respectively. Compared with ischemia group, TDR and incidence of RIVA were significantly reduced in PAM group (P<0.05). Potassium aspartate and magnesium significantly reduce TDR and prevent ventricular arrhythmia in ischemic rabbit heart.
Arrhythmias, Cardiac/etiology ; Arrhythmias, Cardiac/*prevention & control ; Myocardial Ischemia/*complications ; Myocardial Ischemia/physiopathology ; Myocardial Reperfusion Injury/*complications ; Potassium Magnesium Aspartate/*therapeutic use ; Random Allocation

To compare the effects on hemodynamics of univentricular support with that of biventricular support on experimental ischemic biventricular dysfunction so as to provide experimental basis for clinical usage of the Luo-Ye pump. Eight canines were placed with a left ventricular assist device (LVAD; left atrial-aorta bypass) and a right ventricular assist device (RVAD; right atrial-pulmonary artery bypass). Left anterior descending coronary artery(LAD) was ligated, three minutes later, the proximal of right coronary artery (RCA) was ligated to establish animal madel of acute ischemic biventricular dysfunction. First start the LVAD, and then RVAD was started five minutes later. The hemodynamic data were recorded including central venous pressure(CVP), cardiac output (CO), mean artery pressure(MAP), and pulmonary artery pressure(PAP) and pulmonary capillary wedge pressure (PCWP). During biventricular assist devices (BVAD) the hemodynamics were improved remarkably, MAP increased from 37.4 +/- 8.8 mmHg to 84.2 +/- 9.7 mmHg (P < 0.01) (the normal level), CO increased from 0.82 +/- 0.1 L/min to 1.33 +/- 0.12 L/min (P < 0.01), CVP decreased from 14.6 +/- 2.3 cmH2O to 4.2 +/- 1.5 cmH2O (P < 0.01), PCWP decreased significantly from 14 +/- 3.9 mmHg to 1.6 +/- 0.9 mmHg. These data suggest that LVAD during biventricular dysfunction could not improve the hemodynamics to normal level. Howere BVAD could increase CO and MAP to normal level and decrease heart work and myocardial oxygen consumption, which could help to improve myocardial metabolism and myocardial function. Therefore, BVAD is the first choice in treating severe biventricular dysfunction which was not respond to drug therapy and intra-aortic balloon pump (IABP).
Animals ; Dogs ; Heart-Assist Devices ; Hemodynamics ; Myocardial Ischemia ; complications ; Ventricular Dysfunction ; etiology ; physiopathology ; surgery

Burns ; complications ; pathology ; physiopathology ; Humans ; Mitochondria, Heart ; pathology ; Myocardial Ischemia ; etiology ; prevention & control

BACKGROUND: Ischemic heart disease (IHD/ICD10: I20-I25) is the second leading cause of deaths in Japan and accounts for 40% of deaths due to heart diseases. This study aimed to calculate the economic burden of IHD using the cost of illness (COI) method and to identify key factors that drive the change of the economic burden of IHD. METHODS: We calculated the cost of illness (COI) every 3 years from 1996 to 2014 using governmental statistics. We then predicted the COI for every 3 years starting from 2017 up to 2029 using the fixed and variable model estimations. Only the estimated future population was used as a variable in the fixed model estimation. By contrast, variable model estimation considered the time trend of health-related indicators over the past 18 years. We derived the COI from the sum of direct and indirect costs (morbidity and mortality). RESULTS: The past estimation of COI slightly increased from 1493.8 billion yen in 1996 to 1708.3 billion yen in 2014. Future forecasts indicated that it would decrease from 1619.0 billion yen in 2017 to 1220.5 billion yen in 2029. CONCLUSION The past estimation showed that the COI of IHD increased; in the mixed model, the COI was predicted to decrease with the continuing trend of health-related indicators. The COI of IHD in the future projection showed that, although the average age of death increased by social aging, the influence of the number of deaths and mortality cost decreased.
Aged ; Cost of Illness ; Female ; Forecasting ; Humans ; Japan ; Male ; Middle Aged ; Models, Theoretical ; Myocardial Ischemia ; economics ; etiology

Myocardial ischemia (MI) causes somatic referred pain and sympathetic hyperactivity, and the role of sensory inputs from referred areas in cardiac function and sympathetic hyperactivity remain unclear. Here, in a rat model, we showed that MI not only led to referred mechanical hypersensitivity on the forelimbs and upper back, but also elicited sympathetic sprouting in the skin of the referred area and C8-T6 dorsal root ganglia, and increased cardiac sympathetic tone, indicating sympathetic-sensory coupling. Moreover, intensifying referred hyperalgesic inputs with noxious mechanical, thermal, and electro-stimulation (ES) of the forearm augmented sympathetic hyperactivity and regulated cardiac function, whereas deafferentation of the left brachial plexus diminished sympathoexcitation. Intradermal injection of the α₂ adrenoceptor (α₂AR) antagonist yohimbine and agonist dexmedetomidine in the forearm attenuated the cardiac adjustment by ES. Overall, these findings suggest that sensory inputs from the referred pain area contribute to cardiac functional adjustment via peripheral α₂AR-mediated sympathetic-sensory coupling.
Animals ; Ganglia, Spinal ; Hyperalgesia/etiology* ; Myocardial Ischemia/complications* ; Pain, Referred/complications* ; Rats ; Sympathetic Nervous System