Autonomic function and ventricular tachyarrhythmias during acute myocardial infarction

Most cases of sudden cardiac death are attributed to sustained ventricular tachyarrhythmias (VTs), triggered by acute coronary occlusion. Autonomic dysfunction, an important arrhythmogenic mechanism in this setting, is being actively investigated, aiming at the advent of preventive strategies. Recent experimental studies have shown vagal withdrawal after anterior myocardial infarction, coinciding with high incidence of VTs, followed by more gradual sympathetic activation coinciding with a second arrhythmia peak. This article summarizes recent knowledge on this intriguing topic, generating hypotheses that can be investigated in future experimental and clinical studies.     

空腹血糖升高对急性心肌梗死后左室射血分数的影响

目的 观察空腹血糖水平升高对急性心肌梗死(AMI)后左室射血分数(LVEF)的影响.方法 入选首次AMI患者共161例,以入院后24h内空腹8h后测定的血糖水平为空腹血糖水平.根据空腹血糖水平分为三组:1组,空腹血糖＜6.1mmol/L;2组,空腹血糖6.1-6.9 mmool/L;3组空腹血糖≥7.0 mmol/L,空腹血糖水平升高包括2组与3组.所有患者分别于发病后72h内、发病后30d行超声心动图检查测量LYEF.结果 2组和3组入院时及30d随访时的LVEF明显低于1组[入院时:(49.3±6.7)%、(45.8±7.4)%比(52.4±7.7)%,P＜0.05;30 d随访时:(52.7±7.3)%、(49.2士7.2)%比(55.8±7.4)%,P＜0.05].结论 AMI后空腹血糖水平升高是常见的临床特点,合并空腹血糖水平升高的AMI患者的LYEF降低更为明显.     

Beta-carotene supplementation results in adverse ventricular remodeling after acute myocardial infarction

OBJECTIVE: We studied the effects of beta-carotene (BC) on ventricular remodeling after myocardial infarction. METHODS: Myocardial infarction was induced in Wistar rats that were then treated with a BC diet (500 mg/kg of diet per day; MI-BC; n = 27) or a regular diet (MI; n = 27). Hearts were analyzed in vivo and in vitro after 6 mo. RESULTS: BC caused decreased left ventricular wall thickness (MI = 1.49 +/- 0.3 mm, MI-BC = 1.23 +/- 0.2 mm, P = 0.027) and increased diastolic (MI = 0.83 +/- 0.15 cm2, MI-BC = 0.98 +/- 0.14 cm2, P = 0.020) and systolic (MI = 0.56 +/- 0.12 cm2, MI-BC = 0.75 +/- 0.13 cm2, P = 0.002) left ventricular chamber areas. With respect to systolic function, the BC group presented less change in fractional area than did controls (MI = 32.35 +/- 6.67, MI-BC = 23.77 +/- 6.06, P = 0.004). There was no difference in transmitral diastolic flow velocities between groups. In vitro results showed decreased maximal isovolumetric systolic pressure (MI = 125.5 +/- 24.1 mmHg, MI-BC = 95.2 +/- 28.4 mmHg, P = 0.019) and increased interstitial myocardial collagen concentration (MI = 3.3 +/- 1.2%, MI-BC = 5.8 +/- 1.7%, P = 0.004) in BC-treated animals. Infarct sizes were similar between groups (MI = 45.0 +/- 6.6%, MI-BC = 48.0 +/- 5.8%, P = 0.246). CONCLUSION: Taken together, these data suggest that BC has adverse effects on ventricular remodeling after myocardial infarction.     

Valsartan in the treatment of heart failure or left ventricular dysfunction after myocardial infarction

The physiological role of the renin angiotensin aldosterone system (RAAS) is to maintain the integrity of the cardiovascular system. The effect of angiotensin II is mediated via the angiotensin type I receptor (AT1 ) resulting in vasoconstriction, sodium retention and myocyte growth changes. This causes myocardial remodeling which eventually leads to left ventricular hypertrophy, dilation and dysfunction. Inhibition of the RAAS with angiotensin converting enzyme (ACE) inhibitors after acute myocardial infarction has been shown to reduce cardiovascular morbidity and mortality. Angiotensin receptor blockers (ARBs) specifically inhibit the AT1 receptor. It has not been known until the performance of the VALIANT (valsartan in acute myocardial infarction trial) whether blockade of the angiotensin receptor with an ARB or combination of an ACE inhibitor and ARB leads to similar outcomes as an ACE inhibitor. The VALIANT trial demonstrated equal efficacy and non-inferiority of the ARB valsartan 160 mg bid compared with captopril 50 mg tds, when administered to high risk patients with left ventricular dysfunction or heart failure in the immediate post myocardial infarction period. The combination therapy showed no incremental benefit over ACE inhibition or an ARB alone and resulted in increased adverse effects. This review examines the role of valsartan in left ventricular dysfunction post myocardial infarction. We also discuss pharmacokinetics, dosing, side effects, and usage in the elderly.     

Functional decline after congestive heart failure and acute myocardial infarction and the impact of psychological attributes. A prospective study

This article examines the influence of three pre-morbidly assessed psychological attributes (i.e. neuroticism, mastery and self-efficacy expectancies) on functional decline after congestive heart failure (CHF; n = 134) and acute myocardial infarction (AMI; n = 79) in late middle-aged and older persons. Due to the prospective design of the study initial baseline levels of functional disability and number of chronic medical conditions could be adjusted, next to age, gender and the severity of either CHF or AMI. Functional disability was re-assessed 8 weeks after the diagnosis of either CHF or AMI. Significant unique contributions of self-efficacy expectancies were found for functional decline after CHF, while mastery significantly contributes to functional decline after AMI: those patients with higher levels of mastery or self-efficacy expectancies showed less decline. In conclusion, pre-morbidly assessed psychological attributes substantially influence functional decline after cardiac disease in late middle-aged and older persons, but the impact of specific attributes is somewhat different for CHF and AMI.     

Right ventricular involvement in acute myocardial infarction.

The presence of right ventricular dysfunction in patients with acute myocardial infarction has important implications. It is a marker for in-hospital mortality and failure to recognize it may lead to inappropriate treatment with serious consequences for the patient. Patients surviving the acute event do, however, have a relatively good long-term prognosis.     

高龄低危急性心肌梗死患者急诊行PCI与左室功能关系的临床研究

目的探讨高龄低危急性心肌梗死(AMI)患者急诊冠状动脉介入治疗(PCI)与左室功能的临床关系。方法应用超声心动图(ECHO)评价45例高龄AMI患者,将45例AMI患者分为PCI组(20例)及对照组(25例),均于梗死后第4、24周进行ECHO检查。结果经统计学分析,术后第24周PCI组收缩末容积指数(ESVI)及舒张末容积指数(EDVI)与术后第4周比较差异有统计学意义(P<0.05),左室射血分数(LVEF)显著增加(P<0.05),室壁节段运动指数(WMSI)降低(P<0.05);对照组EDVI、WMSI治疗后第24周与治疗后第4周比较,差异有统计学意义(P<0.05)。结论高龄低危AMI患者急诊行PCI开通梗死相关动脉,可明显改善左室重构,提高左室功能。     

盐酸法舒地尔对急性心肌梗死患者脑钠肽及左心室功能的影响

目的 探讨盐酸法舒地尔对急性心肌梗死患者脑钠肽(BNP)及左心室功能的影响. 方法 收集AMI合并心力衰竭患者82例,左室射血分数≤45％,心功能Ⅱ～Ⅲ级,常规治疗基础上将病人分为治疗组和对照组.治疗组加用盐酸法舒地尔.对2组患者治疗前后血BNP水平、有关心功能等指标进行比较. 结果 2组血BNP较治疗前降低,但治疗组比对照组BNP水平明显降低(P＜0.05或P＜0.01).治疗组较对照组心功明显改善,LVEF有显著提高(P＜0.01),左室收缩末容量指数(LVEDS)、左室舒张末容量指数(LVEDd)、左室重量指数明显缩小(P＜0.01).结论 盐酸法舒地尔治疗急性心肌梗死患者,对改善心功能优于对照组.     

科素压与安体舒通合用对大鼠急性心肌梗死后心室重构及心功能的影响

目的观察科素压、安体舒通及科素压与安体舒通联合用对大鼠心肌梗死后运动及静息心功能及心室重构的影响。方法通过建立大鼠急性心肌梗死模型,将AM I后存活的大鼠随机分为科素压组、安体舒通组、联合用药组及安慰剂组,并同时设假手术组。心肌梗死后6周,对各组大鼠进行运动及静息心功能、心室重构指标的观察。结果⑴心肌梗死后6周,安慰剂组静息心功能及运动心功能LVSP、dp/dt-、dp/dt均较假手术组降低(P<0.05),LVEDP较假手术组增高(P<0.05);科素亚组、安体舒通组及联合用药组静息心功能及运动心功能LVSP、dp/dt-、dp/dt较安慰剂组增高(P<0.05),LVEDP较安慰剂组降低(P<0.05);在联合用药组静息心功能及运动心功能LVSP、dp/dt-、dp/dt较科素亚组、安体舒通组增高(P<0.05),LVEDP降低(P<0.05)。⑵心肌梗死后6周末,安慰剂组VW/BW、LVW、LVW I及TDM均较假手术组增高(P<0.05);科素亚组、安体舒通组及联合用药组VW/BW、LVW、LVW I及TDM均较安慰剂组降低(P<0.05);联合用药组VW/BW、LVW、LVW I及TDM均较科素亚组、安体舒通组降低更显著(P<0.05)。结论科素亚、安体舒通均可通过延缓急性心肌梗死后心室重构过程,改善运动及静息心功能;二者具有协同作用。     

运动幅度曲线直观评价心肌梗死患者左心室局域舒张功能

目的 探讨冠心病患者左心室舒张各期局部心肌运动幅度曲线特点及其评价左心室局域舒张功能的可能性.方法 对54例前壁心肌梗死患者(MI组)和78例健康对照者(NOR组)左心室心肌进行组织多普勒成像检查.记录心尖二腔动态图像,应用运动幅度曲线描记技术获取左心室各阶段心肌同步运动幅度曲线,测量等容舒张期、快速充盈期、缓慢充盈期、心房收缩期局部心肌运动变化幅度,对两组结果进行对比分析.结果在整个舒张期,NOR组从前壁心尖、中间到心底部,76例(97.44%)幅度呈正值逐渐减小的梯度变化;MI组梯度变化规律消失,52例(96.30%)梗死区域幅度为负值.在等容舒张期,NOR组76例(97.44%)为缓慢下降波;MI组则有27例(50.00%)为缓慢下降波,两组比较差异有统计学意义(P<0.05).在快速充盈期,NOR组76例(97.44%)为向下波;MI组梗死区域运动幅度为负值.在缓慢充盈期,NOR组多数为靠近基线的水平波;MI组无明显的水平波.结论 局部心肌梗死导致主动舒张期的局部心肌运动幅度显著异常.运动幅度曲线能敏感、直观、无创地定量评价左心室局域舒张功能,并可整体判断心脏舒张功能.     

Return to work after acute myocardial infarction

OBJECTIVES: The aim of this work was to study the professional repercussions of acute myocardial infarction and to analysis medical, social and occupational factors which could influence return to work. MATERIAL AND METHODS: Our study concerns 70 patients less than 66 years old, working before their hospitalization and having been admitted for acute myocardial infarction between January 1-st, 1999 and December 31, 2000 in the Department of Cardiac Resuscitation of hospital La Rabta of Tunis. Data were collected from retrospective review of folders and answers to a questionnaire for which the patients have been summoned in 2002. RESULTS: There were 70 patients almost exclusively men (n=69). The mean age was 49.0 +/- 6.8 years. The mean follow-up was 27.2 +/- 7.7 months. Sixty one patients (87.1%) have initially been back to work and eight of them lost it secondarily. The average delay of return to work has been 91+/- 111 days. The direct repercussions of myocardial infarction on the professional capacities was observed at the majority of patients. CONCLUSION: Despite an important professional repercussions of acute myocardial infarction, our study showed a high rate of return to work with relatively short delays.     

比较早期和晚期骨髓单个核细胞移植对猪急性心肌梗死后左室重构的影响

目的对比观察猪急性心肌梗死后早期（1周）和延期（3个月）进行的骨髓单个核细胞移植对心肌梗死后左室重构的影响。方法前降支球囊封堵法成功建立15头猪急性心肌梗死模型,随机均分为对照组、早期移植组和延期移植组。造模1周后急性移植组行自体骨髓单个核细胞移植,对照组注射1640培养基10ml作为对照;造模3个月后延期移植组行自体骨髓单个核细胞移植,造模后1周、造模后3个月、造模后6个月各组分别行心脏超声和SPECT检测,超声检查分析左室舒张末期内径,SPECT分析左室舒张末期容积、射血分数。结果造模6个月后延期移植组的LVd值[（54．20±3．70）mm]低于对照组[（63．20±5．63）mm],但高于早期移植组[（47．40±1．14）mm];EDV值[（163．00±6．96）ml]低于对照组[（209．40±18．69）ml],但高于早期移植组[135．40±4．93）ml];EF值（O．25±0．02）高于对昭组（0．19±0．02）,但低于早期移植组（0．37±0．02）。结论猪急性心梗3月后骨髓干细胞移植的有效抑制左室重构的进一步恶化,但其疗效不如早期移植组。     

高龄低危急性心肌梗死患者急诊行PCI与左室功能关系的临床研究

目的探讨高龄低危急性心肌梗死（AMI）患者急诊冠状动脉介入治疗（PCI）与左室功能的临床关系。方法应用超声心动图（ECHO）评价45例高龄AMI患者，将45例AMI患者分为PCI组（20例）及对照组（25例），均于梗死后第4、24周进行ECHO检查。结果经统计学分析，术后第24周PCI组收缩末容积指数（ESVI）及舒张末容积指数（EDVI）与术后第4周比较差异有统计学意义（P〈0．05），左室射血分数（LVEF）显著增加（P〈0．05），室壁节段运动指数（WMSI）降低（P〈0．05）；对照组EDVI、WMSI治疗后第24周与治疗后第4周比较，差异有统计学意义（P〈0．05）。结论高龄低危AMI患者急诊行PCI开通梗死相关动脉，可明显改善左室重构，提高左室功能。     

猪急性心肌梗死后骨髓干细胞自体移植对左心室重构的影响

目的 观察猪心肌梗死(心梗)后冠脉内注射移植骨髓干细胞时心室重_构的影响.方法 前降支球囊封堵法成功建立10头猪急性心肌梗死动物模型,随机均分为安慰刺组和移植组.造模1周后,移植组冠脉内注自体骨髓干细胞,安慰剂组注射1640培养基作为对照.造模前、造模后1周、造模后3月分别行心脏超声和SPECT检查,对比观察骨髓干细胞自体移植对急性心梗后左室重构的影响.结果与安慰剂组相比,移植组造模后3月时左室舒张内径更小,心尖室壁厚度更大,左室舒张末期容积更小,射血分数更高.结论 骨髓干细胞自体移植能有效减轻急性心肌梗死后左室重构.     

Quality of life after acute myocardial infarction: A comparison of diabetic versus non-diabetic acute myocardial infarction patients in Quebec acute care hospitals

Background  

Previous studies have evaluated the individual effects of acute myocardial infarction (AMI) and diabetes mellitus on health-related quality of life outcomes (QOL). Due to the rising incidence of these comorbid conditions, it is important to examine the synergistic impact of diabetes mellitus and AMI on QOL.     

A study of left ventricular function of workers exposed to fluorine

The left ventricular function of 26 workers exposed to fluorine was investigated. The results demonstrated that the LVET in the higher urine fluorine group (greater than 1.5 mg/L) was significantly shorter than the control group (P less than 0.01), the PEP was much longer than the control group (P less than 0.05), and the rate of PEP/LVET compared with the control group was increased. The difference was statistically significant (P less than 0.01). In the lower urine fluorine group (less than 1.5 mg/L) the time of LVET and PEP and the rate of PEP/LVET was not significantly different from the control group. The results showed that excessive fluorine ion in the body could cause decrease of myocardial contraction. The reason may be, that the fluorine ion inhibits the activities of certain enzymes in the body, thereby producing inhibition of ATP supply and utilization.