Residual Myocardial Ischemia Research Articles

Importance of Residual Myocardial Ischemia After Intervention in the Genesis of Cardiovascular Events Among Patients with Chronic Coronary Artery Disease

Recent randomized clinical trials support the strategy of ischemia-guided management for patients with stable ischemic heart disease. The application of serial testing to examine the efficacy of therapeutic intervention for ischemia suppression and to document the extent and severity of ischemia provides an important means to guide clinical decision making. This review provides a synopsis of available evidence on serial testing and meaningful thresholds for application of paired rest/stress myocardial perfusion single photon emission computed tomography imaging.

Off-Pump and On-Pump Coronary Artery Bypass Grafting Are Associated With Similar Graft Patency, Myocardial Ischemia, and Freedom From Reintervention: Long-Term Follow-Up of a Randomized Trial

The Surgical Management of Arterial Revascularization Therapies trial was conceived to rigorously compare completeness of revascularization, clinical outcomes and resource utilization in unselected patients referred for elective, primary coronary artery bypass grafting randomly assigned to undergo off-pump (OPCAB) or conventional on-pump coronary artery bypass grafting using cardiopulmonary bypass (CPB). The goal of this follow-up study was to compare long-term survival, graft patency, myocardial ischemia, and clinical outcomes among survivors who volunteered to return for clinical evaluation and imaging studies. Two hundred unselected patients with multivessel coronary artery disease were randomly assigned to OPCAB or CPB coronary artery bypass grafting between March 2000 and August 2001. All-cause mortality was determined by individual patient contact and referencing the Social Security Death Master File. Of 140 survivors, 87 volunteered to return after a minimum of 6.8 years (maximum, 8.4 years; mean, 7.5 years) for assessment of graft patency (computed tomographic angiography) and myocardial ischemia (cardiac positron emission tomography and 12-lead electrocardiogram). Age at follow-up ranged from 38 to 90 years (mean, 68 years). There were 26 deaths from all causes among OPCAB patients and 31 among CPB patients as of March 30, 2009. Graft patency was similar between groups among 622 grafts assessed by angiography before hospital discharge (99% OPCAB versus 97.7% CPB; p=0.22, Fisher's exact test), among 511 grafts assessed by angiography at 1 year (93.6% OPCAB versus 95.8% CPB; p=0.33), and among 190 grafts assessed by computed tomographic angiography at late follow-up (76% OPCAB versus 83.5% CPB; p=0.44). Twelve of 34 OPCAB (35.3%) and 16 of 39 CPB patients (41.0%) had any ischemia on positron emission tomography scanning (p=0.62). Four OPCAB patients (11.8%) and 9 CPB patients (23.1%) had an ischemic region in excess of 10% of myocardium (p=0.21). At late follow-up, recurrent angina had occurred in 11 of 43 (25.6%) OPCAB patients and 5 of 44 (11.4%) CPB patients (p=0.09). Percutaneous reintervention had been performed at the discretion of blinded local cardiologists in 1 of 43 (2.3%) OPCAB patients and 1 of 44 (2.3%) CPB patients (p=1.0). No patient in either group has undergone repeat CABG. In this randomized trial, off-pump and on-pump coronary artery bypass grafting were associated with similar early and late graft patency, incidence of recurrent or residual myocardial ischemia, need for reintervention, and long-term survival.

Management of multivessel coronary disease after ST-elevation myocardial infarction treated by primary coronary angioplasty

Primary percutaneous coronary intervention of the infarct-related artery is now considered the gold standard for patients with acute ST-elevation myocardial infarction. However, a sizable portion of patients with ST-elevation myocardial infarction have concomitant multivessel disease, which raises important therapeutic and prognostic issues. Indeed, it is still unclear whether percutaneous coronary intervention of the culprit vessel alone is superior, equivalent, or inferior in terms of risk-benefit balance in comparison to a strategy of complete revascularization, with percutaneous coronary intervention of nonculprit vessels as well. The present systematic review provides an updated prospective on the rationale, background, and outcomes of culprit-only versus multivessel percutaneous revascularization in subjects undergoing primary percutaneous coronary intervention. Our findings clearly demonstrate that multivessel coronary disease significantly and adversely impacts on patient prognosis, yet a culprit-only revascularization strategy should be sought after in most cases, unless patient instability or symptoms/signs of residual myocardial ischemia support nonculprit vessel intervention.

Risk Stratification for Sudden Cardiac Death after Acute Myocardial Infarction

Many patients who survive an acute myocardial infarction (AMI) remain at risk of recurrent cardiac events and sudden cardiac death after discharge, despite optimal medical treatment. Assessment of the degree of left ventricular dysfunction and residual myocardial ischaemia is useful to identify the patients at greatest risk. In addition, there is increasing evidence that a number of other cardiovascular tests can be used to detect autonomic dysfunction and myocardial substrate abnormalities postAMI that increase the risk of life-threatening ventricular arrhythmias. These investigations include ECG-based tests (signal averaged ECG and T-wave alternans), Holter-based recordings (heart rate variability and heart rate turbulence) and imaging techniques (echocardiography and cardiac magnetic resonance), as well as invasive electrophysiological testing. This article reviews the current evidence for the use of these additional cardiac investigations among survivors of AMI to aid in their risk stratification for malignant ventricular arrhythmias and sudden cardiac death.

Influence of previous myocardial infarction site on in-hospital outcome after primary percutaneous coronary intervention for repeat myocardial infarction

Recurrent acute myocardial infarction (AMI) is a disastrous condition with high in-hospital morbidity and mortality. However, the relation between location of previous myocardial infarction (MI) and in-hospital outcome in repeat-AMI patients undergoing primary percutaneous coronary intervention (PCI) remains unclear. Using the AMI-Kyoto Multi-Center Risk Study database, clinical background, angiographic findings, results of primary PCI, and in-hospital prognosis were retrospectively compared between primary PCI-treated AMI patients with previous anterior MI (anterior group, n=151) and those with previous non-anterior MI (non-anterior group, n=157). Clinical backgrounds, angiographic findings, results of primary PCI, and in-hospital outcome did not differ significantly between the two groups. On multivariate analysis, Killip class > or =3 at admission, number of diseased vessels > or =2 or diseased left main trunk at initial coronary angiography, and age were the independent predictors of in-hospital mortality in the recurrent-AMI patients, but not the anterior location of previous MI. These results suggest that among recurrent-AMI patients undergoing primary PCI, in-hospital prognosis mostly depends on the severity of acute heart failure at the onset and the residual myocardial ischemia rather than previous MI sites.

Impact of sleep on arrhythmogenesis.

Sleep is generally considered to be a protected period, when the cardiovascular system benefits from the restorative influences of the sleeping brain. However, the dynamics of cardiovascular control during sleep can tax the capacity of the diseased coronary circulation and myocardium with surges in sleep-state–related autonomic activity and disruptions in airway function and central nervous system regulation. In this regard, sleep may constitute an autonomic stress test for the heart. The scope of sleep-related risk for atrial and ventricular arrhythmias is substantial. The major subgroups susceptible to adverse influences of surges in autonomic activity during sleep are those with ischemic heart disease, heart failure, and channelopathies (Table).1 It is significant that 20% of myocardial infarctions and 15% of sudden deaths occur at night in the United States.2 Most atrial arrhythmias in patients younger than 61 years of age have nocturnal onset.3 The young are not immune to risk, as sudden infant death syndrome (SIDS) claims 2500 lives in the United States annually.4 Cardiovascular risk is compounded by comorbid factors, most notably apnea, which affects an estimated 4% to 9% of the general population5 and is considerably more prevalent among obese individuals.6 The more common form is obstructive sleep apnea (OSA), with partial or complete collapse of the pharynx. Half of heart failure patients experience either OSA or central sleep apnea (CSA) with central nervous system–mediated periodic breathing, commonly referred to as Cheyne-Stokes respiration. Such cardiorespiratory disturbances profoundly alter autonomic nervous system activity and increase risk of arrhythmia, hypertension, and myocardial infarction. View this table: Table. Patient Groups at Potentially Increased Risk for Nocturnal Cardiac Events It is surprising, as recently underscored by Malhotra and Loscalzo,7 that the significance of cardiovascular risk during sleep may not be duly recognized within the cardiology community. The reasons are …

Predictors of Six-Month Major Adverse Cardiac Events in 30-Day Survivors After Acute Myocardial Infarction (from the Korea Acute Myocardial Infarction Registry)

Little is known about risk factors for 6-month major adverse cardiac events (MACEs) in 30-day survivors after acute myocardial infarction (AMI). We investigated predictors of 6-month MACE in 30-day survivors after MI from the Korea Acute Myocardial Infarction Registry (KAMIR). From November 2005 to January 2008, 9,706 patients (6,983 men, mean age 64.0 +/- 12.4 years) who survived >30 days after AMI were analyzed. The primary end point was 6-month MACEs including death, MI, and revascularization. During 6-month follow-up, 317 patients (3.2%) had MACEs including 66 (0.6%) deaths, 23 (0.2%) recurrent MIs, and 218 (2.2%) revascularizations. In multivariate logistic regression analysis, factors reflecting demographics (body mass index), severity of left ventricular systolic dysfunction (Killip class >I, in-hospital cardiogenic shock, use of intra-aortic balloon pump), residual myocardial ischemia (previous coronary heart disease, multivessel disease), and electrical instability (ventricular tachycardia/ventricular fibrillation on admission) were independent predictors of 6-month MACEs after adjustment for clinical, angiographic, and procedural data. Plasma level of N-terminal pro-B-type natriuretic peptide provided an additional prognostic value predicting 6-month MACEs. In conclusion, this study provides useful prognostic information for clinicians to advise patients who have survived the acute phase of MI. More intensive management is needed in survivors after MI with these high-risk features.

Sudden Cardiac Death in Patients With Silent Myocardial Ischemia After Myocardial Infarction (from the Swiss Interventional Study on Silent Ischemia Type II [SWISSI II

The occurrence of sudden cardiac death (SCD) in patients with silent ischemia after myocardial infarction (MI) and the factors facilitating SCD are unknown. This study aimed to determine the factors facilitating SCD in patients with silent ischemia after MI. In the Swiss Interventional Study on Silent Ischemia Type II (SWISSI II), 201 patients with silent ischemia after MI were randomized to percutaneous coronary intervention (PCI) or medical management. The main end point of the present analysis was SCD. Multivariable regression models were used to detect potential associations between baseline or follow-up variables and SCD. During a mean follow-up of 10.3 +/- 2.6 years, 12 SCDs occurred, corresponding to an average annual event rate of 0.6%. On multivariate regression analysis, the decline in the left ventricular ejection fraction (LVEF) during follow-up was the only independent predictor of SCD (p = 0.011), other than age; however, the baseline LVEF was not. The decline in LVEF was greater in patients receiving medical management than in those who had received PCI (p <0.001), as well as in patients with residual myocardial ischemia or recurrent MI compared with patients without these findings (p = 0.038 and p <0.001, respectively). Compared with medical management, PCI reduced the rate of residual myocardial ischemia (p <0.001) and recurrent MI (p = 0.001) during follow-up. In conclusion, patients with silent ischemia after MI are at a substantial risk of SCD. The prevention of residual myocardial ischemia and recurrent MI using PCI resulted in better long-term LVEF and a reduced SCD incidence.

Evaluation of the therapeutic effect of hyperbaric oxygenation and erythropoietin in the treatment of chronic heart failure using myocardial perfusion scintigraphy G-SPECT

The most important predictors of long-term survival in patients with cardiac ischemic disease are left ventricular ejection fraction, left ventricular volumes, infarction size, presence and extent of residual myocardial ischemia. One of the most important recent developments in single photon emission computed tomography (SPECT) myocardial perfusion imaging is the ability to acquire these studies in conjunction with electrocardiogram (ECG) gating (G-SPECT). The ability to asses radionuclide myocardial perfusion and function with ECG G-SPECT imaging has revolutionized this field of nuclear cardiology. Study with G-SPECT development algorithms permits to quantify measures of left ventricular (LV) volume, ejection fraction (LVEF) and even regional myocardial wall motion and thickening. The American Society of Nuclear Cardiology (ASNC) in its position paper from March 1999 recommends the routine incorporation of G-SPECT during cardiac perfusion scintigraphy. We presented a 70-year-old male with ischemic heart disease (dilatative, cardiomyopathy and absolute arrhythmia). He was few times hospitally treated by medicamentous therapy with no evidence of improvement. After hospital treatment, we included hyperbaric oxygenation (HBO) and erythropoietin injections. Hyperbaric oxygenation was carried out in a monoplace hyperbaric chamber, BLK S-303, by a graduated protocol for patients with severe heart insufficiency, totally 15 treatments. Recombinant erythropoietin beta (RecormonR F. Hoffmann-La Roche) was applied deeply subcutaneously, every second day from 2000 IU to totally 16000 IU. Before the therapy G-SPECT study was performed with 99m technetium-MIBI, and we obtained the functional parameters and perfusion of the left ventricle to follow-up the therapy effects. The study was performed by an ADAC-VERTEX PLUS-EPIC two-head gamma camera with dedicated quantitatively algorithm Auto-QUANT. The results of LVEF were 15%, with severity abnormal motion and wall thickening for all segments. Left ventricle end-diastolic volume was 393 ml (normal < 142 ml), and LV end-systolic volume was 334 ml (normal < 65 ml). Four months after the therapy G-SPECT showed improvement in any parameters; LVEF 25%, with improvement in wall motion (normalized wall motion in the anterior, lateral area, and proximal septum) and wall thickening, LV end-diastolic volume was 390 ml, LV end-systolic volume was 289 ml. Using G-SPECT method before and after the therapy with hyperbaric oxygenation and erythropoietin we obtained objective improvement and good therapy effects in the treatment of chronic heart insufficiency.

Myocardial damage size assessment in the zone of infarction for indicating rescue percutaneous coronary intervention

The most important predictors of subsequent patients outcome after acute myocardial infarction (AIM) are infarct size, left ventricular ejection fraction, left ventricular volumes and presence and extent of residual myocardial ischemia. All of these variables can be directly determined through scintigraphic approaches. The presence and extent of myocardial ischemia are strong pre dictors for fatal and nonfatal cardiac events and improve risk statification beyound the information gleaned from clinical variables. We presented a case of 66-years-old male with myocardial infarction of anteroseptal localization. Myocardial perfusion imaging (MPI) detected a large zone of residual ischemia (culprit lesion) within infarction zone. It has an important role in risk stratification after myocardial infarction, and indicates subsequent therapeutic decision making, in this case rescue percutaneous coronary intervention (PCI). After PCI we followed the therapy effect by MPI, and we found practically normal perfusion with minimal zone of defect perfusion in the apex. Myocardial perfusion imaging has an important role in the initial evaluation and risk stratification of patients surviving myocardial infarction. It also plays a major role in guiding subsequent therapeutic decision making, and in monitoring the benefits of these therapeutic measures.

Recommandations de l’Académie nationale de médecine pour la prise en charge des patients après infarctus du myocarde

The mortality rate after myocardial infarction fell sharply with the advent of reperfusion methods and the use of efficient antithrombotic and antiischemic drugs. However, new infarcts, heart failure, arrythmias and sudden death remain frequent, especially in the first two years after the initial event. Large clinical studies have defined and validated therapies for secondary prevention, but the recommended measures are not always properly implemented. Patients with and without ST elevation after myocardial infarction share the same pathophysiologic mechanism, namely atherosclerotic plaque rupture or erosion, with different degrees of superimposed thrombosis and distal embolization. Secondary prevention is the same for these two patient categories. Acute coronary syndromes are associated with an increased risk of adverse cardiovascular outcomes (new myocardial ischemia, left ventricular dysfunction or sudden death) and require aggressive secondary prevention. However, risks factors such as smoking, hypertension, obesity, hypercholesterolemia and diabetes frequently persist. In addition, medical practice does not always respect consensus guidelines. Early risk stratification is necessary to detect residual myocardial ischemia in viable myocardium. After the acute phase, the prognosis depends on the degree of left ventricular dysfunction and the extent and severity of residual ischemia. Exercise and ambulatory electrocardiography, stress echocardiography, perfusion scintigraphy using vasodilator stress, magnetic resonance imaging and coronary angiography are all useful for identifying high-risk patients. Secondary prevention should include risk factor management with lifestyle modifications such as weight reduction, a reduction in saturated fats and an increase in monounsaturated fatty acids. Smoking cessation is crucial, and regular physical activity (30 min per day at least 5 days a week) is beneficial. Cardiac rehabilitation has been shown to improve exercise tolerance and cardiovascular outcome.

Mechanisms of Sudden Cardiac Death in Myocardial Infarction Survivors

Sudden death is a catastrophic but unpredictable complication of coronary artery disease and is frequently the consequence of an acute ischemic event.1–3 The efficacy of the implantable cardioverter-defibrillator (ICD) in reducing sudden cardiac death incidence is irrefutable and strongly supported by evidence from randomized trials of both primary and secondary prevention (Figure 1).4–8 Nonetheless, the 2 neutral trials9,10 raise intriguing and puzzling issues in regard to the temporal relationship between myocardial infarction (MI), coronary revascularization, residual myocardial ischemia, and severe left ventricular dysfunction and its impact on the mechanisms of presumed sudden cardiac death and the efficacy of the ICD. In this respect, this commentary addresses current knowledge regarding the mechanisms of death early and late after MI, limitations in our abilities to stratify risk, and analyses from the randomized trials in an attempt to reconcile the apparently paradoxical observation that the highest rate of sudden cardiac death occurs the first few weeks after MI and that the only ICD trial to address this population was neutral.10 Figure 1. The efficacy of ICD for the primary prevention of death. Data were derived from the study by Solomon et al26 and from the randomized ICD trials for both primary and secondary prevention of sudden cardiac death.4–8 The causes of death after MI are multifactorial and depend in part on the duration of time that has elapsed since the initial MI. During the acute phase of the MI, sudden death is typically the result of ischemia that provokes lethal ventricular arrhythmias.11,12 Mechanical complications resulting in profound hemodynamic derangements such as ventricular or papillary muscle rupture, pericardial tamponade, septal defects, and ischemic valvular dysfunction also may mimic sudden arrhythmic death, even if the rhythm is not ventricular fibrillation. A similar sequence of events may occur …

Reevaluation of Routine Invasive Strategy versus Noninvasive Testing following Uncomplicated ST-Elevation Myocardial Infarction

Background and Aims: While current guidelines recommend a selective invasive approach after low-risk ST-elevation myocardial infarction (STEMI) treated by thrombolysis, based on noninvasive identification of patients with residual or inducible myocardial ischemia, in many instances physicians employ a strategy of routine angiography. The present study was undertaken to reexamine the correlation between noninvasive testing and coronary angiography in patients recovering from uncomplicated STEMI with regard to detection and management of residual infarct artery stenosis and to identify patients with multivessel (MVD) or high-risk coronary disease. Methods: We prospectively performed predischarge exercise testing (ETT) and myocardial perfusion scintigraphy (MPS) prior to routine predischarge coronary angiography in 83/276 consecutive STEMI patients, who after treatment with initial and early thrombolysis, were defined as low risk by ACC/AHA risk classification. Results: ETT was positive for myocardial ischemia in 11/43 (26%) patients with single-vessel disease (SVD) and 11/22 (50%) patients with MVD, but normal or nondiagnostic in the remainder. MPS revealed significant reversible perfusion defects in 13/40 (32%) patients with SVD and 13/22 (59%) patients with MVD. A selective strategy of ETT followed by MPS for nondiagnostic ETT missed residual infarct-related artery stenosis and/or MVD in 31/81 (38%) of the cohort. Among patients who may not otherwise have been referred for angiography, severe (≧70%) residual stenosis of the infarct-related artery was present in 56% and MVD in 16%. Conclusions: Early predischarge ETT and/or MPS had limited sensitivity for the detection of coronary disease in low-risk post-STEMI patients. The study supports a simpler strategy of routine coronary angiography in most patients after low-risk STEMI.

Relationship Between the Mismatch of 123I-BMIPP and 201Tl Myocardial Single-Photon Emission Computed Tomography and Autonomic Nervous System Activity in Patients With Acute Myocardial Infarction

The purpose of this study was to elucidate the relationship between the mismatch of thallium-201(Tl) and iodine-123-beta-methyl-iodophenyl-pentadecanoic acid (BMIPP) myocardial single-photon emission computed tomography (SPECT) and autonomic nervous system activity in myocardial infarction (MI) patients. The subjects were 40 patients (34 males, 6 females) who underwent examinations by 123I-BMIPP and 201Tl myocardial SPECT imaging and 24-hour Holter monitoring within a 3-day period 3 weeks after the onset of their first MI. R-R intervals were analyzed every hour over a period of 24 hours by fast Fourier transformation (FFT). High frequency (HF) and low frequency (LF) were defined as markers of cardiac vagal activity in the former and the LF/HF ratio as sympathetic activity. Greater or more extensive decreases in the BMIPP image than that in the Tl image were defined as a positive mismatch. Patients were divided into positive and negative mismatch groups of 20 patients each. There were no significant differences between the 2 groups in age, sex, site of infarction, max CK (creatine kinase), max CK-MB, or left ventricular ejection fraction. The incidences of clinical signs suggesting residual myocardial ischemia were significantly greater in the positive than in the negative mismatch group (P < 0.05). The mean values for HF over the entire 24-hour period and over the 5-hour nocturnal period (0-5 AM) in the positive mismatch group were both significantly lower than those in the negative mismatch group (P < 0.001 in both groups). The 24-hour mean HF and mean nighttime HF in patients with signs of residual ischemia were both significantly lower than in those without signs of residual ischemia in the positive mismatch group (P < 0.05 in both groups). The mean LF/HF ratio for both the entire 24-hour and the nocturnal period in the positive mismatch group were significantly higher than those in the negative mismatch group (P < 0.001, P < 0.05, respectively). The daily profile of hourly HF measurements was significantly lower in the positive mismatch group than in the negative mismatch group (P < 0.02). The mean values of HF for 24-hour and 5-hour periods were significantly lower in patients with signs of residual ischemia in the positive mismatch group than in those with signs of residual ischemia in the negative mismatch group (P < 0.01, P < 0.02, respectively). There were no significant differences between the patients with signs of residual ischemia in the negative mismatch group and those without signs of residual ischemia in the positive and negative mismatch group with regard to the mean values of HF and the LF/HF ratio measured every hour for 24 hours and 5 hours. It is concluded from the present study that the findings of a mismatch on 123I-BMIPP and 201Tl myocardial SPECT 3 weeks after a first acute myocardial infarction with uncomplicated moderate or severe heart failure and decreased heart rate variability are related to residual myocardial ischemia. A combined assessment of heart rate variability in 24-hour Holter ECG monitoring and perfusion-metabolism mismatch in 123I-BMIPP and 201Tl myocardial SPECT is useful for determining residual myocardial ischemia in the follow-up of those with acute myocardial infarction.

Comparison of Prognostic Value of Negative Dobutamine Stress Echocardiography Versus Single-Photon Emission Computed Tomography After Acute Myocardial Infarction

We enrolled 196 patients who had myocardial infarction and no ischemia on dobutamine stress echocardiography (DSE) and/or single-photon emission computed tomography (SPECT). Negative studies were observed in 125 patients on DSE and in 159 on SPECT. Patients were followed for 43 +/- 14 months. Cardiac events occurred in 14% of patients who did not have ischemia on DSE and in 9% of patients who did not have ischemia on SPECT. Event-free survival rate was higher in the presence of negative findings on SPECT compared with DSE (p <0.05). The lack of residual myocardial ischemia on SPECT identifies patients at low risk of events, and a negative finding on stress SPECT is superior to a negative finding on DSE.

Noninvasive Dynamic Assessment With Transthoracic Echocardiography of a Composite Arterial Y-Graft Achieving Complete Myocardial Revascularization

Composite arterial grafts are increasingly used in coronary artery bypass surgery. We assessed with transthoracic echocardiography the composite radial artery and in situ left internal thoracic artery Y-graft. In 53 of 60 consecutive patients who underwent complete myocardial revascularization using only this composite arterial graft, good transthoracic echocardiographic images and pulsed Doppler signals of the Y-graft main stem were obtained at rest and early after standard exercise. Stress/rest 99mTc-sestamibi myocardial perfusion single-photon emission computed tomography (SPECT) was the gold standard for residual myocardial ischemia. The patients with negative SPECT were divided into groups according to the number of coronary artery systems grafted, and history of preoperative myocardial infarction. Diastolic peak velocity, diastolic velocity-time integral, the diastolic-to-systolic ratio of the peak velocities and velocity-time integrals, and the stress-to-rest ratio of the diastolic peak velocities and diastolic velocity-time integrals in the negative-SPECT patients were significantly greater than in the 6 positive-SPECT patients. Sensitivity and specificity for ischemia of the stress-to-rest ratio of the diastolic peak velocities less than 1.5 were 100%. The stress-to-rest ratio of the diastolic velocity-time integrals in the patients with three coronary systems grafted, and in those without preoperative myocardial infarction, were respectively greater than in the patients with two systems grafted (p < 0.0001), and in those with preoperative myocardial infarction (p = 0.0048). Noninvasive dynamic assessment with transthoracic echocardiography of a composite arterial graft, including in situ left internal thoracic artery, is feasible and correlates with myocardial perfusion SPECT. The Y-graft used was able to regulate its flow capacity to myocardial demand.

Usefulness of ambulatory electrocardiographic monitoring for myocardial ischemia after coronary bypass

Cardiac patients with asymptomatic myocardial ischemia have a poor prognosis. Ambulatory electrocardiographic monitoring can help to ensure that these patients, who are unaware of their high-risk status, are relieved of residual myocardial ischemia in response to cardioprotective medication, and rendered as low cardiac risk.

Estratificación pronóstica tras infarto agudo de miocardio

In recent years, the characteristics of patients who suffer acute myocardial infarction without complications during hospitalization have changed. In addition, the range of non-invasive studies available for evaluating left ventricular systolic function, residual myocardial ischemia, and myocardial viability in these patients has improved. Left ventricular systolic function and residual ischemia should be evaluated in all patients before release. The non-invasive technique used (exercise test, echocardiography, nuclear cardiology, magnetic resonance imaging) depends on availability, experience, and results at each institution. Coronary arteriography should be performed in patients with significant ischemia or severe left ventricular systolic dysfunction in non-invasive studies. In these cases coronary angiography must be performed to determine if coronary arteries are suitable for revascularization before performing a test of myocardial viability.

Management After Myocardial Infarction.

Individuals who survive an acute myocardial infarction (MI) have up to a ninefold greater risk of cardiovascular morbidity and mortality compared with the general population. The modification of traditional coronary risk factors, including hypertension, hyperlipidemia, tobacco use, and diabetes mellitus, constitutes one of the cornerstones of management after acute MI. Therapies aimed at reversing the pathophysiologic disorders that lead to endothelial dysfunction, thrombosis, and atherosclerotic plaque instability may improve the prognosis for patients after acute MI. Aggressive risk stratification diagnostic testing can identify patients at the highest risk for adverse events. Prior to hospital discharge, patients should have an evaluation of left ventricular systolic function, an assessment for the risk for residual myocardial ischemia, and a clinical assessment of the risk for serious ventricular arrhythmias. An array of pharmaceutical agents is available for the secondary prevention of MI, including antiplatelet agents, beta-blockers, angiotensin-converting enzyme inhibitors, and statins.

Residual myocardial ischaemia as a contributor to electrical instability after myocardial infarction

Residual myocardial ischaemia as a contributor to electrical instability after myocardial infarction