Early application of angiotensin converting enzyme inhibitors in acute myocardial infarction]

Inhibitors of angiotensin converting enzyme (ACE) were tried in patients early after myocardial infarction (MI) irrespective of the severity of circulation insufficiency. Monopril was used in 23 patients in the dose 7.6 mg/day. Ednit was given to 21 patients in the dose 5.3 mg/day. Control groups included 19 and 21 patients, respectively. All the patients underwent treadmill test and echocardiography on MI day 1 and 13-14. ACE inhibitors provide better exercise tolerance and favourable course of MI even in the absence of marked manifestations of cardiac failure though left ventricular ejection changed insignificantly. They may also prevent myocardial ischemia. The difference between monopril and ednit effects was insignificant.     

Improved quality of life with cardiac rehabilitation for post-myocardial infarction patients in Korea.

BACKGROUND: Health-related quality of life (HRQOL) has been used as a primary health outcome in cardiac rehabilitation programs (CRP). AIMS: This study aimed to evaluate the effects of an 8-week CRP on HRQOL and exercise capacity in myocardial infarction (MI) patients in Korea. METHODS: After matching on gender, age, and left ventricular ejection fraction, 60 subjects with a first acute MI were allocated to either a CRP group (n=31) or a Control group (n=29). The 8-week CRP included hospital-based, supervised exercise training (three times per week, average intensity of 65% VO(2peak)) and individual education sessions. The Control group was instructed on a home-based exercise regimen without contact during the 8 weeks. At baseline and 8 weeks, HRQOL was assessed by the Quality of Life Index (QLI)-cardiac version III; exercise capacity by a treadmill test. RESULTS: After adjusting for education level, the overall QLI, health/functioning and psycho/spiritual scores showed greater increases in the CRP group than the Control group (p=.014, p=.016, and p=.036, respectively). We observed significant improvements in VO(2peak) (p<.0001), anaerobic threshold (p<.0001), and maximal exercise duration (p<.0001) in the CRP group, compared to the Control group. CONCLUSIONS: These findings suggest that the Korean CRP can lead to significant improvements in HRQOL outcomes and exercise capacity.     

有氧运动对心肌梗死大鼠心肌能量代谢及线粒体呼吸功能的影响

目的 观察有氧运动对心肌梗死致慢性心力衰竭大鼠心脏能量代谢及线粒体呼吸功能的影响。方法 采用随机数字表法将45只SD大鼠分为假手术组、心衰对照组及心衰运动组。采用冠状动脉结扎术将心衰对照组及心衰运动组大鼠制成心肌梗死模型,术后4周时心衰运动组大鼠给予为期8周的跑台有氧运动。于运动干预结束后采用超声心动图检测各组大鼠心功能,采用递增负荷跑台实验测定大鼠运动能力,采用磁共振波谱法测定大鼠心肌磷酸肌酸（PCr）及三磷酸腺苷（ATP）含量,采用细胞呼吸测量仪评估大鼠心肌线粒体呼吸功能。结果 心衰对照组PCr含量、PCr/ATP比值、线粒体呼吸链复合体Ⅰ和Ⅱ的耗氧量、左心室缩短分数（FS）、射血分数（EF）以及递增负荷实验最高跑速、力竭距离和力竭时间等均不及假手术组水平（P<0.05）;心衰运动组ATP含量、复合体Ⅰ耗氧量、左心室FS和EF、递增负荷实验最高跑速、力竭距离和力竭时间均显著优于心衰对照组水平（P<0.05）,PCr/ATP比值组间差异无统计学意义（P>0.05）。结论 规律有氧运动能改善慢性心力衰竭大鼠心脏做功能力,表现为心功能及运动能力增强,其作用机制可能与上调心肌ATP水平及改善线粒体复合体Ⅰ功能有关;另外PCr/ATP比值可能不适合作为评估运动训练对心脏有益影响的生物标志物。     

Dobutamine Stress Echocardiography and Exercise Electrocardiography for Risk Stratification in Medically Treated Unstable Angina

Previous reports have demonstrated the superiority of exercise echocardiography over exercise electro-cardiography (ex-ECG) for risk stratification in patients with medically stabilized unstable angina (UA). We sought to analyze the prognostic value of dobutamine stress echocardiography (DSE) compared with ex-ECG for risk stratification in patients with UA. METHODS: Ninety-two patients with medically treated UA were studied (mean age 65 +/- 11 years, 24 women, 42% of patients had electrocardiographic abnormalities on admission). Dobutamine stress echocardiography and treadmill ex-ECG were performed on the third day after hospital admission. End points were recurrent UA, myocardial infarction (MI), or cardiac death. RESULTS: Mean follow-up was 24 +/- 7 months. During follow-up, 22 patients had cardiac events (18 recurrent UA, 2 MI, 2 cardiac deaths). The event-free survival rate was 80% for patients with negative DSE results for ischemia and 52% for those with positive DSE results (log rank 9.57; P =.002), compared with an event-free survival rate of 79% for patients with negative ex-ECG results and 66% for those with positive ex-ECG results (log rank 2.06; P = not significant). Left ventricular dysfunction (P =.01) and a positive dobutamine stress echocardiogram (P =.03), but not a positive exercise electrocardiogram, were independent predictors of cardiac events during follow-up. CONCLUSIONS: Dobutamine stress echocardiography performed early in medically treated patients with UA predicts cardiac events during follow-up more accurately and with more specificity than ex-ECG does in this population.     

Diagnostic and prognostic value of exercise electrocardiography for coronary artery disease

A positive exercise ECG with greater than or equal to 1.0 mm ischemic ST-segment depression, limited exercise duration, persistence of ischemic ST-segment depression past 8 minutes in the recovery period, and exertional hypotension is associated with increasing severity and extent of CAD. The sensitivity and specificity of the exercise ECG are not dependent on the prevalence of CAD in the population tested. The positive and negative predictive values of the exercise ECG are both dependent on the prevalence of CAD in the population tested. Exercise-induced ST-segment elevation greater than or equal to 1.0 mm is associated with severe myocardial ischemia, left ventricular aneurysm, left ventricular wall motion abnormalities, and coronary artery spasm in patients with variant angina. Ischemic ST-segment depression greater than or equal to 1.0 mm, exercise duration, maximal exercise heart rate, and blood pressure response to exercise are correlated with new coronary events in patients with documented CAD. Low-level exercise tests within 3 weeks of uncomplicated MI can identify patients at high risk for new cardiac events. Early post-MI patients with exercise-induced ischemic ST-segment depression greater than or equal to 1.0 mm, exercise-induced angina, an inadequate blood pressure response to exercise, or limited exercise duration during a low-level exercise test should undergo coronary angiography and be considered for possible coronary artery surgery or angioplasty. Exercise testing will also help in the medical treatment of patients with exercise-induced angina or malignant ventricular arrhythmias. An exercise test performed 6 months after MI also provides prognostic information not available from clinical evaluation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Characteristics and Outcomes of Patients Who Achieve High Workload (≥10 Metabolic Equivalents) During Treadmill Exercise Echocardiography

ObjectiveTo determine the frequency and prognostic significance of abnormal exercise echocardiographic results for patients achieving a workload of 10 or more metabolic equivalents during treadmill exercise echocardiography.Patients and MethodsPatients who underwent treadmill exercise echocardiography from November 1, 2003, through December 31, 2008, and exercised for 9 or more minutes using the Bruce protocol (N=7236) were included. Clinical and exercise echocardiographic characteristics and outcomes were evaluated. Variables associated with abnormal exercise echocardiographic results and mortality were identified.ResultsExercise echocardiographic results were positive for ischemia in 862 patients (12%). Extensive ischemia developed in 265 patients (4%). For patients with normal exercise echocardiographic results, all-cause and cardiovascular mortality rates were 0.30% and 0.05% per person-year of follow-up, respectively. For patients who had extensive ischemia, all-cause and cardiovascular mortality rates were 0.84% and 0.25% per person-year of follow-up, respectively. Patients at highest risk were those who had extensive and severe regional wall motion abnormalities at rest (n=58), and their all-cause and cardiovascular mortality rates were 2.65% and 0.76% per person-year of follow-up. Exercise echocardiographic variables did not identify sizable patient subgroups at risk for death and did not provide incremental prognostic information (C statistic was 0.74 compared with 0.73 for the clinical plus exercise electrocardiography model).ConclusionPatients achieving a workload of 10 or more metabolic equivalents during treadmill exercise testing do not often have extensive ischemic abnormalities on exercise echocardiography. Although exercise echocardiographic results provide some prognostic information, it is not of incremental value for these patients, whose short-term and medium-term prognosis is excellent.     

65例老年心肌梗死合并心律失常患者早期康复护理干预对其心功能及预后的影响分析

目的分析早期康复护理干预对老年心肌梗死合并心律失常患者心功能及近期预后情况的影响。方法选择本院收治的65例老年心肌梗死合并心律失常患者,将其随机分为对照组(32例)和观察组(33例),对照组患者采用传统心肌梗死康复法对患者实施常规康复护理,观察组患者采用早期康复护理干预。比较2组患者入组前、入组后4周、3个月、6个月后收缩压、Killip分级、心率、左室收缩功能、每博量,比较2组患者入组后4周、3个月、6个月的运动耐力(步行试验、踏车实验),比较2组患者入组后6个月内心律失常率、再梗死率、病死率。结果 2组患者入组前左室射血分数、Killip分级、心率、左室压力上升最大速率、每博量比较差异无统计学意义(P0.05);随着时间的推移,2组患者的左室射血分数、Killip分级、心率、左室压力上升最大速率、每博量均较入组前有显著改善,每一个观察时间点,观察组的左室射血分数、左室压力上升最大速率、每博量、均显著高于对照组,Killip分级、心率均小于对照组,上述指标组间比较差异有统计学意义(P0.05);观察组患者入组后4周、3个月、6个月步行试验完成率、踏车实验完成率均显著高于对照组,观察组患者入组6个月后心律失常率、心急再梗死率及病死率均显著低于对照组,组间比较差异有统计学意义(P0.05)。结论早期康复护理干预可有效改善老年心肌梗死合并心律失常患者的心功能,改善患者预后质量。     

Exercise echocardiography and thallium-201 single-photon emission computed tomography stress test for 5- and 10-year prognosis of mortality and specific cardiac events.

Limited data suggest that stress myocardial perfusion imaging and stress echocardiography have similar prognostic value for composite cardiac events. However, it is not known whether exercise echocardiography and stress thallium are similar in their prediction of specific cardiac events, eg, death, sudden death, myocardial infarction, unstable angina, and congestive heart failure. A total of 206 patients undergoing stress echocardiography and thallium-201 single-photon emission computed tomography imaging during the same exercise test were followed-up for 5 and 10 years. Multivariate Cox regression analyses incorporating clinical, exercise stress test, echocardiographic, and nuclear imaging parameters were used to predict mortality and specific cardiac events. A moderate to large amount of ischemia (> or =4 segments on the basis of a 16-segment model) by exercise stress echocardiography was the strongest predictor of overall mortality (relative risk [RR] 6.2; P <.0001), cardiac death (RR 17.6; P =.01), congestive heart failure (RR 17.4; P =.0005) or sudden death (RR 26.8; P =.003), whereas a moderate to large fixed defect (> or =2 segments on the basis of a 6-segment model) by nuclear imaging was the strongest predictor of myocardial infarction (RR 8.1; P =.0002) or unstable angina (RR 3.0; P =.005) at 5 years. The heterogeneity in the prediction of these specific cardiac events by these 2 modalities was similarly observed at 10 years. The extent of ischemia by stress echocardiography is a better predictor of overall mortality, cardiac death, congestive heart failure, or sudden death, whereas the extent of a fixed defect by nuclear imaging is a better predictor of myocardial infarction or unstable angina.     

Prognostic value of dobutamine stress echocardiography in patients with diabetes

OBJECTIVE: The aim of this study was to assess the incremental value of dobutamine stress echocardiography (DSE) for the risk stratification of diabetic patients who are unable to perform an adequate exercise stress test. Exercise capacity is frequently impaired in patients with diabetes. The role of pharmacologic stress echocardiography in the risk stratification of diabetic patients has not been well defined. RESEARCH DESIGN AND METHODS: We studied 396 diabetic patients (mean age 61 +/- 11 years, 252 men [64%]) with limited exercise capacity who underwent DSE for evaluation of known or suspected coronary artery disease (CAD). End points were hard cardiac events (cardiac death and nonfatal myocardial infarction) and all causes of mortality. RESULTS: During a median follow-up of 3 years, 97 patients (24%) died (55 cardiac deaths), and 27 patients had nonfatal myocardial infarction. In an incremental multivariate analysis model, clinical predictors of hard cardiac events were history of congestive heart failure, previous myocardial infarction, hypercholesterolemia, and ejection fraction at rest. The percentage of ischemic segments was incremental to the clinical model in the prediction of hard cardiac events (chi(2) = 37 vs. 18, P < 0.05). Clinical predictors of all causes of mortality were history of congestive heart failure, age, hypercholesterolemia, and ejection fraction at rest. Wall motion score index at peak stress was incremental to the clinical model in the prediction of mortality (chi(2) = 52 vs. 43, P < 0.05). CONCLUSIONS: DSE provides incremental data for the prediction of mortality and hard cardiac events in patients with diabetes who are unable to perform an adequate exercise stress test.     

Clinical and neurohormonal effects of nicardipine hydrochloride in patients with severe chronic heart failure receiving angiotensin-converting enzyme inhibitor therapy

It has been proposed that worsening of heart failure with dihydropyridines, such as nicardipine, is related to the activation of the neuroendocrine system. To test this, we evaluated 20 patients with severe heart failure (mean age, 55 +/- 13 years; New York Heart Association functional class III; left ventricular ejection fraction, 18% +/- 8% on maintenance therapy with captopril, digoxin, and diuretics) who were randomized to nicardipine (60 or 90 mg/d) or placebo during a 4-month double-blind protocol. The following measurements were obtained at baseline, monthly, and at 4 months or last follow-up visit: rest and exercise radionuclide ventriculography, maximal treadmill time, 6-minute walking test distance, serum norepinephrine and aldosterone concentrations, and plasma renin activity. During the follow-up period, worsening of heart failure occurred in 6 patients in the nicardipine group and in 2 patients in the placebo group (p = 0.06). The maximal treadmill time for a 6-minute walking distance and exercise radionuclide ejection fraction at the last follow-up visit did not change in patients who did not deteriorate with heart failure in the placebo or nicardipine groups as compared with baseline values. In this study group of patients with severe heart failure receiving therapy with digoxin, captopril, and diuretics, nicardipine was associated with worsening heart failure without an apparent activation of the neurohormones. However, because of the small number of patients and a significant number of patients who deteriorated during the follow-up period, no definitive conclusions can be made.     

不同时间窗介入运动训练对心肌梗死大鼠生存率及左室心功能变化的影响

目的 探讨不同时间窗介入运动训练对心肌梗死大鼠生存率及左室心功能变化的影响。 方法 选取健康雄性SD大鼠96只,按照随机数字表法将大鼠分为假手术不运动组、假手术前运动组、心梗不运动组、心梗前运动组、心梗后运动组、心梗前后联合运动组,每组16只。所有大鼠均接受急性心肌梗死造模手术或假手术。假手术不运动组大鼠假手术前后均不运动;假手术前运动组大鼠假手术前采用跑台训练5周,术后不进行运动训练;心梗不运动组大鼠在心肌梗死前后均不进行运动训练;心梗前运动组大鼠心肌梗死前采用跑台训练5周,术后不再进行运动训练;心梗后运动组大鼠心肌梗死前不进行运动训练,心肌梗死4周后采用跑台训练8周;心梗前后联合运动组大鼠心肌梗死前采用跑台训练5周,心肌梗死4周后采用跑台训练8周。上述所有运动训练每周5d,每日60min。术后4d、2周、4周、8周、12周,观察记录各组大鼠的生活情况及自发死亡率,到达实验终点前对其进行超声心动图检测,然后处死所有大鼠。 结果 假手术后4d,与假手术不运动组同时间点比较,心梗不运动组大鼠4d、2周、4周、8周及12周时的舒张末期左室内径（LVEDd）及收缩末期左室内径（LVEDs）较大,左室短轴缩短率（FS）及射血分数（EF）较低,差异均有统计学意义（P<0.05）。与心梗不运动组同时间点比较,心梗前运动组4d时LVEDd及LVEDs较小,FS及EF较高,差异有统计学意义（P<0.05）,2周时LVEDs较小,FS及EF较高,差异有统计学意义（P<0.05）。与心梗不运动组同时间点比较,心梗后运动组12周时FS、EF显著较高,差异有统计学意义（P<0.05）。心梗前后联合运动组4d时LVEDd及LVEDs较心梗不运动组小,FS及EF较高（P<0.05）。心梗前后联合运动组2周、8周、12周时LVEDs较心梗不运动组小,FS及EF较高（P<0.05）。与心梗前运动组同时间点比较,心梗前后联合运动组12周时LVEDs［（4.71±0.2）mm］较小,FS［（38.7±2.7）%］及EF［（62.7±3.2）%］较高（P<0.05）。 结论 心梗前运动可改善心梗后早期大鼠的心脏功能,但对于心梗晚期大鼠左室功能的改善效果并不明显,心梗后运动可改善心梗后晚期大鼠的左室功能,心梗前后联合运动可改善心梗后早期及晚期大鼠的左室功能。     

Reproducibility of stress echocardiography using intravenous injection of ultrasound contrast agent (by 963)

Despite the widespread use of stress echocardiography, its reproducibility is still limited by high interobserver variability. Therefore, the purpose of the present study was to improve the reproducibility of a stress (exercise) echocardiography using a new transpulmonary ultrasound agent (BY 963). Stress echocardiography was performed in 12 healthy volunteers with suboptimal endocardial border delineation during exercise echocardiography. A special 45° lateral tilted bike stress echocardiography table was used for exercise testing. Echocardiographic images were recorded on-line at rest and during exercise on a video tape and additionally digitized on-line on a stress echo computer. End-diastolic (EDVml), end-systolic (ESVml) volume and ejection fraction (EF%) were estimated in the 4-chamber view. The measurements were performed before and after injection of 2.5 ml and 5 ml BY963 at rest and in maximal exercise. A new contrast agent (BY 963) leads to a sufficient contrast effect for the left ventricular cavity after intravenous administration and permits a good delineation of left the endocardial border. The interobserver variability was determined using blinded investigation by two observers. The correlation of EDV and ESV determination at rest was r = 0.68/0.33, after 2.5 ml BY 963 r = 0.97/0.93 and after 5 ml BY 963 r = 0.90/0.93. The correlation for EDV and ESV during exercise was r = 0.52/0.33, after 2.5 ml BY 963 r = 0.88/0.80 and after 5 ml BY 963 r = 0.95/0.92. At rest mean EF without contrast was 61 ± 6%/67 ± 7% (r = 0. 130), after 2.5 ml BY 963 i.v. 69 ± 8%/72 ± 7% (r = 0.82) and after 5 ml BY 963 i.v. 73 ± 8%/73 ± 8% (r = 0.98%) respectively. In exercise, mean EF without contrast was 68 ± 8%/70 ± 6 (r = 0.013), after 2.5 ml BY 963 83 ± 6%/81 ± 5 and after 5 ml 83 ± 4%/82 ± 3 (r = 0.86). Summary: The estimation of the end-systolic volume in exercise will be improved significantly and the estimated EF values will be higher compared to EF values obtained without contrast application. Transpulmonary contrast echocardiography for analysis of left ventricular volumes and ejection fraction can be routinely used in stress echocardiography. Intravenous administration of BY 963 improves the reproducibility of quantitative analysis of left ventricular function in healthy volunteers. Further studies in patients with cardiac diseases are required to corroborate this observation.     

Three dimensional first-pass myocardial perfusion imaging at 3T: feasibility study

Treadmill exercise stress testing is an essential tool in the prevention, detection, and treatment of a broad spectrum of cardiovascular disease. After maximal exercise, cardiac images at peak stress are typically acquired using nuclear scintigraphy or echocardiography, both of which have inherent limitations. Although CMR offers superior image quality, the lack of MRI-compatible exercise and monitoring equipment has prevented the realization of treadmill exercise CMR. It is critical to commence imaging as quickly as possible after exercise to capture exercise-induced cardiac wall motion abnormalities. We modified a commercial treadmill such that it could be safely positioned inside the MRI room to minimize the distance between the treadmill and the scan table. We optimized the treadmill exercise CMR protocol in 20 healthy volunteers and successfully imaged cardiac function and myocardial perfusion at peak stress, followed by viability imaging at rest. Imaging commenced an average of 30 seconds after maximal exercise. Real-time cine of seven slices with no breath-hold and no ECG-gating was completed within 45 seconds of exercise, immediately followed by stress perfusion imaging of three short-axis slices which showed an average time to peak enhancement within 57 seconds of exercise. We observed a 3.1-fold increase in cardiac output and a myocardial perfusion reserve index of 1.9, which agree with reported values for healthy subjects at peak stress. This study successfully demonstrates in-room treadmill exercise CMR in healthy volunteers, but confirmation of feasibility in patients with heart disease is still needed.     

Cardiac function and myocardial perfusion immediately following maximal treadmill exercise inside the MRI room

Treadmill exercise stress testing is an essential tool in the prevention, detection, and treatment of a broad spectrum of cardiovascular disease. After maximal exercise, cardiac images at peak stress are typically acquired using nuclear scintigraphy or echocardiography, both of which have inherent limitations. Although CMR offers superior image quality, the lack of MRI-compatible exercise and monitoring equipment has prevented the realization of treadmill exercise CMR.It is critical to commence imaging as quickly as possible after exercise to capture exercise-induced cardiac wall motion abnormalities. We modified a commercial treadmill such that it could be safely positioned inside the MRI room to minimize the distance between the treadmill and the scan table. We optimized the treadmill exercise CMR protocol in 20 healthy volunteers and successfully imaged cardiac function and myocardial perfusion at peak stress, followed by viability imaging at rest. Imaging commenced an average of 30 seconds after maximal exercise. Real-time cine of seven slices with no breath-hold and no ECG-gating was completed within 45 seconds of exercise, immediately followed by stress perfusion imaging of three short-axis slices which showed an average time to peak enhancement within 57 seconds of exercise. We observed a 3.1-fold increase in cardiac output and a myocardial perfusion reserve index of 1.9, which agree with reported values for healthy subjects at peak stress. This study successfully demonstrates in-room treadmill exercise CMR in healthy volunteers, but confirmation of feasibility in patients with heart disease is still needed.     

BOSU球与平板练习对脑卒中患者下肢功能疗效的比较

目的比较BOSU球和平板运动对脑卒中患者下肢功能康复的影响。方法40 例脑卒中患者(病程>6 个月)随机分为BOSU球组(n=20)和平板组(n=20),分别在常规康复的基础上进行BOSU球和平板练习。治疗前和治疗12 周后,分别采用Berg 平衡量表(BBS)、30 s 坐站试验(CS-30)、坐位体前屈(SR)、6 min 步行试验(6MWT)、改良Barthel 指数(MBI)对患者进行评定。结果治疗后,两组患者各项评定均较运动前改善(P<0.05),BOSU球组BBS及MBI评分较平板组改善更多(P<0.05)。结论BOSU球运动能更有效提高脑卒中患者的平衡能力和日常生活活动能力。     

Comparison of echocardiographic and radionuclide methods with contrast angiography assessment of left ventricular function--response to isometric exercise in subjects without definite heart disease

In order to study the validity of non-invasive assessment of left ventricular response to isometric exercise, 21 subjects with chest pain, but without any cardiac abnormalities performed an isometric handgrip test during cardiac catheterization, M-mode echocardiography and radionuclide angiography. Fourteen of the subjects were suitable for comparison of all the three methods. In response to handgrip exercise the ejection fraction (EF) remained unchanged in contrast angiography (68 +/- 9% at rest; 68 +/- 9% during exercise) and echocardiography (74 +/- 4% at rest; 74 +/- 5% during exercise), but showed a small increase on radionuclide angiography (from 57 +/- 5% to 60 +/- 7% (p less than 0.01). Individual changes in ejection fraction during the handgrip exercise had a reasonable correlation between contrast angiography and radionuclide angiography (r = 0.63, p less than 0.01). In order to validate the reproducibility of M-mode echocardiography and radionuclide angiography, the haemodynamic and left ventricular responses during two consecutive handgrip tests were compared in eight subjects. No significant differences were seen in the haemodynamic responses or between the changes in ejection fraction or fractional shortening in the two tests. Thus, in subjects without heart disease the non-invasively determined results of the left ventricular response to the handgrip exercise were similar to those obtained invasively and could be reliably reproduced.     

Guidelines and Implications for Selecting Preoperative Cardiac Stress Tests

Nurse practitioners frequently manage patients who have cardiac risks and need further evaluation before their elective surgery. Cardiac stress testing can provide important needed data. Cardiac stress testing includes exercise treadmill testing; echocardiography, with exercise or pharmacologically; myocardial perfusion stress testing; and magnetic resonance angiography. Although a number of factors need to be considered, including prior cardiovascular history and type of surgical risk, a nurse practitioner’s selection of the appropriate cardiac stress test needs to include the benefit-risk ratio and the level of evidence supporting the clinical decision-making process.     

Beneficial effects of beta‐blockers on left ventricular function and cellular energy reserve in patients with heart failure

Beta‐blockers have been shown to improve left ventricular (LV) function in patients with heart failure. The aim of this study is to non‐invasively assess, by means of in vivo 31P‐magnetic resonance spectroscopy (31P‐MRS), the effects of beta‐blockers on LV cardiac phosphocreatine and adenosine triphosphate (PCr/ATP) ratio in patients with heart failure. Ten heart failure patients on full medical therapy were beta‐blocked by either carvedilol or bisoprolol. Before and after 3 months of treatment, exercise testing, 2D echocardiography, MRS, New York Heart Association (NYHA) class, ejection fraction (EF), maximal rate–pressure product and exercise metabolic equivalent system (METS) were evaluated. Relative concentrations of PCr and ATP were determined by cardiac 31P‐MRS. After beta‐blockade, NYHA class decreased (from 2.2 ± 0.54 to 1.9 ± 0.52, P = 0.05), whereas EF (from 33 ± 7 to 44 ± 6%, P = 0.0009) and METS (from 6.74 ± 2.12 to 8.03 ± 2.39, P = 0.01) increased. Accordingly, the mean cardiac PCr/ATP ratio increased by 33% (from 1.48 ± 0.22 to 1.81 ± 0.48, P = 0.03). Beta‐blockade‐induced symptomatic and functional improvement in patients with heart failure is associated to increased PCr/ATP ratio, indicating preservation of myocardial high‐energy phosphate levels.     

Absence of severe exercise-induced ischemia does not identify low-risk patients with three-vessel coronary artery disease.

The purpose of this study was to determine the prognosis of medically treated patients with three-vessel coronary artery disease and normal left ventricular function who do not have severe ischemia on exercise radionuclide angiography. The absence of severe ischemia was defined prospectively (in accordance with previously published criteria) as the presence of at least one of the following: (1) workload more than 600 kg-m/min, (2) ST-segment depression of less than 1 mm, or (3) unchanged or increased left ventricular ejection fraction during exercise. Of 42 patients (33% in functional class III or IV) followed up for a median duration of 53 months (range, 1 to 84 months), 22 had initial cardiac events during follow-up, including 6 cardiac deaths, 5 nonfatal myocardial infarctions, and 11 late (a median of 29 months after the exercise study) coronary revascularization procedures. At 4 years of follow-up, the overall survival was 83%. Survival free of cardiac death or myocardial infarction was 77%, and survival free of all cardiac events was 59%. Even in the absence of severe exercise-induced ischemia, medically treated patients with three-vessel coronary artery disease and normal left ventricular function still have a poor long-term outcome.