Clinical and detailed angiographic findings in patients with ambulatory electrocardiographic ischemia without critical coronary narrowing: results from the Asymptomatic Cardiac Ischemia Pilot (ACIP) Study

BACKGROUND

Patients with ambulatory electrocardiographic (AECG) ST-segment depression and critical coronary narrowing are known to be at increased risk for adverse outcome, but little is known about patients with AECG ST-segment depression without critical coronary narrowing.

HYPOTHESIS

The objectives of this study were to characterize the coronary angiographic pathology in patients with AECG ST-segment depression but without critical (< 50% diameter stenosis) coronary narrowing and to compare demographic and clinical findings in these patients with those enrolled in the Asymptomatic Cardiac Ischemia Pilot Study with AECG ST-segment depression and critical (> or = 50% diameter stenosis) coronary narrowing.

METHODS

Coronary angiograms from patients with AECG ST-segment depression were reviewed in a central laboratory and quantitative measurement of percent stenosis was performed. Clinical and angiographic comparisons were made between patients with and without critical coronary narrowing.

RESULTS

Patients without critical coronary narrowing (n = 64) were younger (p = 0.02), less likely to be male (p < 0.001) or to have risk factors for coronary atherosclerosis or a history of myocardial infarction (p < 0.001), and had fewer ischemic episodes per 24 h on the screening AECG (p = 0.02) than patients with critical coronary narrowing (n = 441). Of patients without critical narrowing, one half had angiographic evidence for coronary artery disease (> or = 20% stenosis) and 60% had an ejection fraction > 70%.

CONCLUSIONS

Patients with AECG ST-segment depression without critical coronary narrowing are heterogeneous, with half having measurable coronary artery disease. Demographically and clinically, they appear to be different than patients with AECG ST-segment depression with critical coronary narrowing.

Deceleration-dependent shortening of the QT interval: a new electrocardiographic phenomenon?

In clinical cardiology, deceleration-dependent QT interval shortening is considered to be an extraordinary electrocardiographic phenomenon. We present an early premature born 4-year-old African-American girl with complications related to her premature birth, developmental delay, and several episodes of cardiac arrest. An episode of severe transient bradyarrhythmia was documented on Holter monitoring. The unique feature of the rhythm strips was paradoxical gradual shortening of the QT interval to 216 ms with accompanying transient T-waves abnormalities. The activation of the Ik, ACh due to an unusually high vagal discharge to the heart is proposed as a possible mechanism responsible for both slowing of the heart rate and shortening of the QT interval.

Bivalirudin versus heparin during coronary angioplasty for unstable or postinfarction angina: Final report reanalysis of the Bivalirudin Angioplasty Study

BACKGROUND

This study was a reanalysis of the Bivalirudin Angioplasty Study, which compared bivalirudin with high-dose heparin during coronary angioplasty for unstable angina.

METHODS

Differences in rates of death, myocardial infarction, or repeat revascularization were compared at 7, 90, and 180 days after angioplasty with intention-to-treat analysis.

RESULTS

The combined end point occurred in 135 of 2161 patients (6.2%) in the bivalirudin group and in 169 of 2151 patients (7.9%) in the heparin group at 7 days (P =.039). Differences persisted between the groups at 90 days (P =.012) and 180 days (P =.153). Bleeding occurred in 76 patients (3.5%) in the bivalirudin group versus 199 (9.3%) in the heparin group (P <.001).

CONCLUSIONS

This analysis supports the hypothesis that bivalirudin reduces ischemic complications and bleeding after angioplasty. Further trials are needed to evaluate bivalirudin versus heparin in conjunction with platelet-glycoprotein IIb/IIIa inhibitors and for coronary stenting.

Increased mortality after coronary artery bypass graft surgery is associated with increased levels of postoperative creatine kinase-myocardial band isoenzyme release: results from the GUARDIAN trial

OBJECTIVES

We sought to determine if elevated cardiac serum biomarkers after coronary artery bypass graft surgery (CABG) are associated with increased medium-term mortality and to identify patients that may benefit from better postoperative myocardial protection.

BACKGROUND

The relationship between the magnitude of cardiac serum protein elevation and subsequent mortality after CABG is not well defined, partly because of the lack of large, prospectively studied patient cohorts in whom postoperative elevations of cardiac serum markers have been correlated to medium- and long-term mortality.

METHODS

The GUARD during Ischemia Against Necrosis (GUARDIAN) study enrolled 2,918 patients assigned to the entry category of CABG and considered as high risk for myocardial necrosis. Creatine kinase-myocardial band (CK-MB) isoenzyme measurements were obtained at baseline and at 8, 12, 16 and 24 h after CABG.

RESULTS

The unadjusted six-month mortality rates were 3.4%, 5.8%, 7.8% and 20.2% for patients with a postoperative peak CK-MB ratio (peak CK-MB value/upper limits of normal [ULN] for laboratory test) of < 5, > or = 5 to <10, > or =10 to < 20 and > or =20 ULN, respectively (p < 0.0001). The relationship remained statistically significant after adjustment for ejection fraction, congestive heart failure, cerebrovascular disease, peripheral vascular disease, cardiac arrhythmias and the method of cardioplegia delivery. Receiver operating characteristic curve analysis revealed an area under the curve of 0.648 (p < 0.001); the optimal cut-point to predict six-month mortality ranged from 5 to 10 ULN.

CONCLUSIONS

Progressive elevation of the CK-MB ratio in clinically high-risk patients is associated with significant elevations of medium-term mortality after CABG. Strategies to afford myocardial protection both during CABG and in the postoperative phase may serve to improve the clinical outcome.

Risk stratification after successful coronary revascularization: the lack of a role for routine exercise testing

OBJECTIVE

The objective of this study was to evaluate the American College of Cardiology/American Heart Association (ACC/AHA) guidelines for exercise testing (EXT) after successful coronary revascularization (CR) using the Bypass Angioplasty Revascularization Investigation experience.

BACKGROUND

The ACC/AHA guidelines state that EXT within three years of successful CR is not useful.

METHODS

The 1,678 patients randomized to CR by either angioplasty or bypass surgery were required to take symptom-limited treadmill tests one, three and five years after revascularization.

RESULTS

Patients who took the test at each specified time had a much lower subsequent two-year mortality than those who did not (1.9% vs. 9.4%, 3.5% vs. 12.6% and 3.3% vs. 11.0% at one, three and five years, respectively, after CR [p < 0.0001 for each]). Exercise parameters at the one- and three-year test did not improve a multivariable model of survival after including clinical parameters. Exercising to Bruce stage 3 or generating a Duke score >-6 were independently predictive of two-year survival after the five-year test. ST depression on the one-year test was associated with more revascularizations (relative risk = 1.6; p < 0.001).

CONCLUSIONS

Patients with stable multivessel coronary disease who took a protocol-mandated exercise test at one, three and five years after revascularization were at low risk for mortality in the two years subsequent to each test. Exercise parameters did not improve prediction of mortality in the two years after the one- and three-year tests. The ACC/AHA guidelines on exercise testing after CR (no value for routine testing in stable patients for three years after revascularization) are supported by these results.

False-negative and false-positive ECG diagnoses of Q wave myocardial infarction in the presence of right bundle-branch block

Right bundle-branch block (RBBB) has not traditionally been seen as an obstacle to ECG diagnosis of Q wave myocardial infarction (MI)--in clinical electrocardiography and vectorcardiography--because this conduction disturbance is not believed to cause significant alterations in the spatial orientation of initial excitation wavefronts. In the era of large-scale clinical trials, however, where serial ECG analysis is among the major diagnostic tools in MI classification, both false-positive and false-negative diagnoses of MI in the presence of RBBB have become increasingly evident. Because of the limited detectability of Q wave MI by ECG in the presence of RBBB, the electrocardiographic finding of Q wave MI should not be regarded as an independent diagnostic tool. It is best to utilize independent corroboration to establish the diagnosis of transmural infarction when RBBB is present. Further investigations are warranted to better delineate sensitivity, specificity, and predictive value of Q wave MI in the presence of RBBB.

Idiopathic short QT interval: a new clinical syndrome?

In this first clinical report of an idiopathic familial persistently short QT interval (QTI), we describe three members of one family (a 17-year-old female, her 21-year-old brother, and their 51-year-old mother) demonstrating this ECG phenomenon, associated in the 17-year-old with several episodes of paroxysmal atrial fibrillation requiring electrical cardioversion. Similar ECG changes seen in an unrelated 37-year-old patient were associated with sudden cardiac death. Our report also describes other manifestations of abnormal shortening of the QTI and considers the possible arrhythmogenic potential of the short QTI.

Effects of atorvastatin on early recurrent ischemic events in acute coronary syndromes: the MIRACL study: a randomized controlled trial

CONTEXT

Patients experience the highest rate of death and recurrent ischemic events during the early period after an acute coronary syndrome, but it is not known whether early initiation of treatment with a statin can reduce the occurrence of these early events.

OBJECTIVE

To determine whether treatment with atorvastatin, 80 mg/d, initiated 24 to 96 hours after an acute coronary syndrome, reduces death and nonfatal ischemic events.

DESIGN AND SETTING

A randomized, double-blind trial conducted from May 1997 to September 1999, with follow-up through 16 weeks at 122 clinical centers in Europe, North America, South Africa, and Australasia.

PATIENTS

A total of 3086 adults aged 18 years or older with unstable angina or non-Q-wave acute myocardial infarction.

INTERVENTIONS

Patients were stratified by center and randomly assigned to receive treatment with atorvastatin (80 mg/d) or matching placebo between 24 and 96 hours after hospital admission.

MAIN OUTCOME MEASURES

Primary end point event defined as death, nonfatal acute myocardial infarction, cardiac arrest with resuscitation, or recurrent symptomatic myocardial ischemia with objective evidence and requiring emergency rehospitalization.

RESULTS

A primary end point event occurred in 228 patients (14.8%) in the atorvastatin group and 269 patients (17.4%) in the placebo group (relative risk [RR], 0.84; 95% confidence interval [CI], 0.70-1.00; P =.048). There were no significant differences in risk of death, nonfatal myocardial infarction, or cardiac arrest between the atorvastatin group and the placebo group, although the atorvastatin group had a lower risk of symptomatic ischemia with objective evidence and requiring emergency rehospitalization (6.2% vs 8.4%; RR, 0.74; 95% CI, 0.57-0.95; P =.02). Likewise, there were no significant differences between the atorvastatin group and the placebo group in the incidence of secondary outcomes of coronary revascularization procedures, worsening heart failure, or worsening angina, although there were fewer strokes in the atorvastatin group than in the placebo group (12 vs 24 events; P =.045). In the atorvastatin group, mean low-density lipoprotein cholesterol level declined from 124 mg/dL (3.2 mmol/L) to 72 mg/dL (1.9 mmol/L). Abnormal liver transaminases (>3 times upper limit of normal) were more common in the atorvastatin group than in the placebo group (2.5% vs 0.6%; P<.001).

CONCLUSION

For patients with acute coronary syndrome, lipid-lowering therapy with atorvastatin, 80 mg/d, reduces recurrent ischemic events in the first 16 weeks, mostly recurrent symptomatic ischemia requiring rehospitalization.

Standards for the function of an academic 12-lead electrocardiographic core laboratory

An academic 12-lead electrocardiogram (ECG) core laboratory aims to provide the highest possible quality ECG recording, measurement, and storage to aid clinicians in research into important cardiovascular outcomes and to maximize the credibility of scientific results based solely, or in part, on ECG data. This position paper presents a guide for the structure and function of an academic ECG core laboratory. The key functional aspects are: 1) Data collection, 2) Staff composition, 3) Diagnostic measurement and definition standards, 4) Data management, 5) Academic considerations, 6) Economic consideration, and 7) Accreditation. An ECG Core Laboratory has the responsibility for rapid and accurate analysis and responsible management of the electrocardiographic data in multicenter clinical trials. Academic Laboratories, in addition, provide leadership in research protocol generation and production of research manuscripts for submission to the appropriate peer-review journals.

Inhibition of the sodium-hydrogen exchanger with cariporide to prevent myocardial infarction in high-risk ischemic situations. Main results of the GUARDIAN trial. Guard during ischemia against necrosis (GUARDIAN) Investigators

BACKGROUND

The transmembrane sodium/hydrogen exchanger maintains myocardial cell pH integrity during myocardial ischemia but paradoxically may precipitate cell necrosis. The development of cariporide, a potent and specific inhibitor of the exchanger, prompted this investigation of the potential of the drug to prevent myocardial cell necrosis.

METHODS AND RESULTS

A total of 11 590 patients with unstable angina or non-ST-elevation myocardial infarction (MI) or undergoing high-risk percutaneous or surgical revascularization were randomized to receive placebo or 1 of 3 doses of cariporide for the period of risk. The trial failed to document benefit of cariporide over placebo on the primary end point of death or MI assessed after 36 days. Doses of 20 and 80 mg every 8 hours had no effect, whereas a dose of 120 mg was associated with a 10% risk reduction (98% CI 5.5% to 23.4%, P=0.12). With this dose, benefit was limited to patients undergoing bypass surgery (risk reduction 25%, 95% CI 3.1% to 41.5%, P=0.03) and was maintained after 6 months. No effect was seen on mortality. The rate of Q-wave MI was reduced by 32% across all entry diagnostic groups (2.6% versus 1.8%, P=0.03), but the rate of non-Q-wave MI was reduced only in patients undergoing surgery (7.1% versus 3.8%, P=0.005). There were no increases in clinically serious adverse events.

CONCLUSIONS

No significant benefit of cariporide could be demonstrated across a wide range of clinical situations of risk. The trial documented safety of the drug and suggested that a high degree of inhibition of the exchanger could prevent cell necrosis in settings of ischemia-reperfusion.

Association between new electrocardiographic abnormalities after coronary revascularization and five-year cardiac mortality in BARI randomized and registry patients

There are few data comparing the relative frequency of new electrocardiographic (ECG) abnormalities after coronary artery bypass grafting (CABG) compared with percutaneous transluminal coronary angioplasty (PTCA) and their association with long-term cardiac mortality. The study population consisted of 3,373 patients who were either randomized or eligible to be randomized to CABG or PTCA in the BARI trial. The frequency of new postprocedural ECG abnormalities was significantly greater after a CABG procedure than after PTCA. The incidence of new postprocedural major Q waves, ST-segment elevation, and T-wave abnormalities were significantly more frequent after CABG. After PTCA (n = 1,869), the 5-year cardiac mortality rates associated with the new development of major Q waves, ST-segment elevation, ST-segment depression, T-wave abnormalities, or no abnormality was 18.1%, 8.5%, 8.9%, 6.0%, and 5.4%, respectively. After CABG (n = 1,427), 5-year cardiac mortality rates were 8.0%, 4.2%, 3.8%, 2.8%, and 3.7%, respectively. The adjusted relative risk of 5-year cardiac mortality for new Q-wave abnormalities was 2.6 after CABG (p <0.04) and 4.6 after PTCA (p <0.01). Thus, patients who undergo CABG have more postinitial procedural ECG abnormalities than patients who undergo PTCA. Cardiac mortality is significantly increased by the new development of postprocedural Minnesota code Q-wave abnormalities regardless of whether patients undergo CABG or PTCA.

All-artery multigraft coronary artery bypass grafting with only internal thoracic arteries possible and safe: a randomized trial

BACKGROUND

The internal thoracic artery (ITA) bypass to the left anterior descending coronary artery is of proven benefit in multigraft coronary artery bypass. Total ITA grafts, if reoperation is averted by avoiding saphenous vein grafts (SVGs), are attractive. The safety of the total ITA graft operation (all-ITA) is a concern.

METHODS

A randomized trial of multiple-ITA bypass graftings with the use of bilateral sequential ITA without SVGs was performed. Control patients received 1 ITA plus SVG. Inclusion criteria were those used in the Coronary Artery Surgery Study, extended to age 76 years, and any angina class, except emergent. One hundred sixty-two patients were randomized (81 patients per group) from January 1, 1990, to December 31, 1994.

RESULTS

Baseline traits were similar as were cross-clamp times, pump times, and number of arteries bypassed (average, 4.3 arteries). Patients who received multiple ITA grafts had no myocardial infarctions, per reference laboratory. One patient died, and 2 patients returned for bleeding. The ITA-SVG group had similar results. The all-ITA group experienced successful completion in 93% of cases. Complications did not differ from control patients.

CONCLUSIONS

Early and 5-year outcomes were not different between the all-ITA group and the ITA with SVGs group. We believe experienced surgeons can safely extend the ITA to multibypass coronary artery bypass without use of SVG to achieve an all-ITA operation.

Predictors of mortality and mortality from cardiac causes in the bypass angioplasty revascularization investigation (BARI) randomized trial and registry. For the BARI Investigators

BACKGROUND

The impact of percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass grafting (CABG) on long-term mortality rates in the presence of various demographic, clinical, and angiographic factors is uncertain in the population of patients suitable for both procedures.

METHODS AND RESULTS

In the Bypass Angioplasty Revascularization Investigation (BARI) randomized trial and registry, 3610 patients who were eligible to receive PTCA and CABG were revascularized between 1989 and 1992. Multivariate Cox models were used to identify factors associated with 5-year mortality and cardiac mortality, with particular attention to factors that interact with treatment. Diabetic patients receiving insulin had higher mortality and cardiac mortality rates with PTCA compared with CABG (relative risk [RR] 1.78 and 2.63, respectively, P<0.001), and patients with ST elevation had higher cardiac mortality rates with CABG than with PTCA (RR 4.08, P<0.001). Factors most strongly associated with high overall mortality rates were insulin-treated diabetes, congestive heart failure, kidney failure, and older age. Black race was also associated with higher mortality rates (RR 1.49, P=0.019).

CONCLUSIONS

A set of variables was identified that could be used to help select a revascularization procedure and to evaluate risk of long-term mortality in the population of patients considering revascularization.

The effect of previous coronary-artery bypass surgery on the prognosis of patients with diabetes who have acute myocardial infarction. Bypass Angioplasty Revascularization Investigation Investigators

BACKGROUND

Acute myocardial infarction in patients with diabetes is associated with high mortality. We studied whether previous revascularization by coronary-artery bypass grafting (CABG), as compared with percutaneous transluminal coronary angioplasty (PTCA), influences the prognosis in such patients.

METHODS

We classified all patients eligible for the Bypass Angioplasty Revascularization Investigation who underwent coronary revascularization within three months after entry into the study according to whether they had diabetes and whether they had undergone CABG, either initially or after PTCA. The protective effect of CABG with regard to mortality in the presence and in the absence of subsequent spontaneous Q-wave myocardial infarction was estimated with the use of Cox regression models.

RESULTS

Among the 641 patients with diabetes and the 2962 without diabetes, the cumulative five-year rates of death were 20 percent and 8 percent, respectively (P<0.001), and the five-year rates of spontaneous Q-wave myocardial infarction were 8 percent and 4 percent (P<0.001). CABG greatly reduced the risk of death after spontaneous Q-wave myocardial infarction in the patients with diabetes (relative risk, 0.09; 95 percent confidence interval, 0.03 to 0.29). Among patients with diabetes who had undergone CABG but did not have spontaneous Q-wave myocardial infarctions, the corresponding relative risk of death was 0.65 (95 percent confidence interval, 0.45 to 0.94). Among the patients without diabetes, no protective effect of CABG was evident.

CONCLUSIONS

Among patients with diabetes, previous coronary bypass surgery, as compared with coronary angioplasty, has a highly favorable influence on prognosis after acute myocardial infarction and a smaller beneficial effect among patients who do not have infarction. These findings should influence the type of coronary revascularization procedure selected for patients with diabetes who have multivessel coronary artery disease.

Rapid ventricular repolarization in rodents: electrocardiographic manifestations, molecular mechanisms, and clinical insights

This article examines specific electrocardiographic (ECG) and electrophysiological features of ventricular repolarization in rats and mice, and the role of depolarization-activated potassium currents in mediating the unique features of ECG recordings in these rodents. This article describes the currents that underlie ventricular repolarization in these rodents, identifies terminology that appropriately describes the unique features of murine ECG recordings, and correlates these unique findings with selected human ECG ventricular repolarization abnormalities. The absence of a distinct isoelectric interval between the QRS complex and the T wave, accompanied by a relatively short QT interval, are common features of ECG recordings in mice and rats, but not in ECGs in guinea pigs. The murine ECG morphology is apparently attributable to the presence of large outward K+ currents that dominate the early phase of ventricular repolarization. In rats and mice, the predominant current underlying the early phase of repolarization appears to be the rapidly activating and inactivating 4-aminopyridine-sensitive transient outward current (ie, I(to)). Importantly, the density of I(to) in rats and mice is high, whereas this current is not evident in the ventricular myocytes of guinea pigs. The high density of I(to) appears to underlie the prominent J wave or downsloping ST-segment elevation seen in rats and mice, whereas the ST-segment is isoelectric in guinea pigs. The unusual J wave and ST-segment pattern in murine ECGs, however, does bear some resemblance to ECG features observed in humans with Brugada syndrome, and with hypothermia and ischemia. These patterns in rats and mice might, therefore, serve as an experimental model for the idiopathic J wave.

Cost estimates for treatment of cardiac ischemia (from the Asymptomatic Cardiac Ischemia Pilot [ACIP] study)

Costs for management of myocardial ischemia are enormous, yet comparison cost and outcome data for various ischemia treatment strategies from randomized trials are lacking and will require cost and resource utilization data from a large prospective trial. The Asymptomatic Cardiac Ischemia Pilot provided feasibility data for planning such a trial and an opportunity to estimate the long-term costs of different treatment strategies. Economic implications for ischemia management were compared in 558 patients with stable coronary artery disease and myocardial ischemia during both stress testing and daily life. Participants were randomized to 3 different initial treatment strategies and followed for 2 years. Based on cost trends over follow-up, costs for subsequent care were estimated. As expected, due to initial procedural costs, at 3 months, estimated costs for revascularization were approximately 10 times greater than costs for a medical care strategy. Extrapolated costs for anticipated resource consumption for care beyond 2 years, however, were approximately 2 times greater for an initial medical care strategy than for initial revascularization. This was due to increased need for drugs and hospitalizations for both late revascularizations and other ischemia-related events. Estimated costs for anticipated care in the medical strategies reached the anticipated cost of the revascularization strategy within 10 years. Because this cost-equal time period is well within the median life expectancy for such a patient population, these findings could have important public health implications and require testing in a full-scale prognosis trial. We anticipate that over the patients' life expectancy, early revascularization is likely to become either cost-neutral or cost-effective.

Relationship of extent of revascularization with angina at one year in the Bypass Angioplasty Revascularization Investigation (BARI)

OBJECTIVES

To determine the relative degree of revascularization obtained with bypass surgery versus angioplasty in a randomized trial of patients with multivessel disease requiring revascularization (Bypass Angioplasty Revascularization Investigation [BARI]), one-year catheterization was performed in 15% of patients.

BACKGROUND

Complete revascularization has been correlated with improved outcome after coronary artery bypass grafting (CABG) but not with percutaneous transluminal coronary angioplasty (PTCA). Relative degrees of revascularization after PTCA and surgery have not been previously compared and correlated with symptoms.

METHODS

Consecutive patients at four BARI centers consented to recatheterization one year after revascularization. Myocardial jeopardy index (MJI), the percentage of myocardium jeopardized by > or =50% stenoses, was compared and correlated with angina status.

RESULTS

Angiography was completed in 270 of 362 consecutive patients (75%) after initial CABG (n = 135) or PTCA (n = 135). Coronary artery bypass grafting patients had 3+/-0.9 distal anastomoses and PTCA patients had 2.4+/-1.1 lesions attempted at initial revascularization. At one year, 20.5% of CABG patients had > or =1 totally occluded graft and 86.9% of vein graft, and 91.6% of internal mammary artery distal anastomotic sites had <50% stenosis. One year jeopardy index in surgery patients was 14.1+/-11%, 46.6+/-20.3% improved from baseline. Initial PTCA was successful in 86.9% of lesions and repeat revascularization was performed in 48.4% of PTCA patients by one year. Myocardial jeopardy index one year after PTCA was 25.5+/-22.8%, an improvement of 33.8+/-26.1% (p<0.01 for greater improvement with CABG than PTCA). At one year, 29.6% of PTCA patients had angina versus 11.9% of surgery patients, p = 0.004. One-year myocardial jeopardy was predictive of angina (odds ratio 1.28 for the presence of angina per every 10% increment in myocardial jeopardy, p = 0.002). Randomization to PTCA rather than CABG also predicted angina (odds ratio 2.19, p = 0.03).

CONCLUSIONS

In this one-year angiographic substudy of BARI, CABG provided more complete revascularization than PTCA, and CABG likewise improved angina to a greater extent than PTCA.

Right bundle branch block as a cause of false-negative ECG classification of inferior myocardial infarction

It is generally accepted in clinical electrocardiography that a right bundle branch block (RBBB) does not interfere with the electrocardiographic (ECG) diagnosis of myocardial infarction (MI). The basic assumption is that the initial excitation wavefronts are relatively unchanged in RBBB. This study compared serial changes in Q wave duration in inferior leads II, III, and aVF in 9 patients who developed RBBB within 3 weeks after myocardial revascularization procedure (RBBB group) and in 41 revascularized patients without RBBB in the same observation period (control group). Q wave durations in the electrocardiograms obtained before the patients' procedures were not significantly different between the study and control groups. However, Q wave durations shortened significantly more in the RBBB group than in the control group. The most pronounced Q wave duration shortening took place in lead aVF, -18.2 ms in the RBBB group versus -3.8 ms in the control group (P = .0001). The shortening was less pronounced, although significant, in leads II and III: II, -7.6 +/- -10.9 ms in the RBBB group vs -2.3 +/- -3.5 ms in the control group (P = .01); III, -11.3 +/- -10.5 ms vs -2.6 +/- -6.5 ms (P = .002); aVF, -18.2 +/- -13.5 ms vs -3.8 +/- -5.3 ms (P < .0001). It is concluded that incident RBBB complicating revascularization procedures may cause significant alterations in spatial orientation of the initial excitation wavefronts. This may be a potential source of false-negative ECG diagnosis of inferior MI, particularly in clinical trials where serial ECG analysis is an important part in MI classification.

Relationship among mental stress-induced ischemia and ischemia during daily life and during exercise: the Psychophysiologic Investigations of Myocardial Ischemia (PIMI) study

OBJECTIVES

The purposes of this database study were to determine: 1) the relationship between mental stress-induced ischemia and ischemia during daily life and during exercise; 2) whether patients who exhibited daily life ischemia experienced greater hemodynamic and catecholamine responses to mental or physical stress than patients who did not exhibit daily life ischemia, and 3) whether patients who experienced daily life ischemia could be identified on the basis of laboratory-induced ischemia using mental or exercise stress testing.

BACKGROUND

The relationships between mental stress-induced ischemia in the laboratory and ischemia during daily life and during exercise are unclear.

METHODS

One hundred ninety-six stable patients with documented coronary disease and a positive exercise test underwent mental stress testing and bicycle exercise testing. Radionuclide ventriculography and electrocardiographic (ECG) monitoring were performed during the mental stress and bicycle tests. Patients underwent 48 h of ambulatory ECG monitoring. Hemodynamic and catecholamine responses were obtained during mental stress and bicycle tests.

RESULTS

Ischemia (reversible left ventricular dysfunction or ST segment depression > or = 1 mm) developed in 106 of 183 patients (58%) during the mental stress test. There were no significant differences in clinical characteristics of patients with, compared with those without, mental stress-induced ischemia. Patients with mental stress ischemia more often had daily life ischemia than patients without mental stress ischemia, but their exercise tests were similar. Patients with daily life ischemia had higher ejection fraction and cardiac output, and lower systemic vascular resistance during mental stress than patients without daily life ischemia. Blood pressure and catecholamine levels at rest and during the mental stress tests were not different in patients with, compared with those without, daily life ischemia. Patients with daily life ischemia had a higher ejection fraction at rest and at peak bicycle exercise compared with patients without daily life ischemia, but there were no other differences in peak hemodynamic or catecholamine responses to exercise. The presence of ST segment depression during routine daily activities was best predicted by ST segment depression during mental or bicycle exercise stress, although ST segment depression was rare during mental stress.

CONCLUSIONS

Patients with daily life ischemia exhibit a heightened generalized response to mental stress. ST segment depression in response to mental or exercise stress is more predictive of ST segment depression during routine daily activities than other laboratory-based ischemic markers. Therapeutic management strategies might therefore focus on patients with these physiologic responses to stress and on whether lessening such responses reduces ischemia.

Is a strategy of intended incomplete percutaneous transluminal coronary angioplasty revascularization acceptable in nondiabetic patients who are candidates for coronary artery bypass graft surgery? The Bypass Angioplasty Revascularization Investigation (BARI)

OBJECTIVES

Our objective was to determine whether a strategy of intended incomplete percutaneous transluminal coronary angioplasty revascularization (IR) compromises long-term patient outcome.

BACKGROUND

Complete angioplasty revascularization (CR) is often not planned nor attempted in patients with multivessel coronary disease, and the extent to which this influences outcome is unclear.

METHODS

Before randomization, in the Bypass Angioplasty Revascularization Investigation, all angiograms were assessed for intended CR or IR via angioplasty. Outcomes were compared among patients with IR intended if assigned to angioplasty, randomized to coronary artery bypass graft surgery (CABG) versus angioplasty; and within angioplasty patients only, among patients with IR versus CR intended.

RESULTS

At 5 years, there was a trend for higher overall (88.6% vs. 84.0%) and cardiac survival (94.5% vs. 92.1%) in CABG versus angioplasty patients with IR intended. The excess mortality in angioplasty patients occurred solely in diabetic subjects; overall and cardiac survival were similar among nondiabetic CABG and angioplasty patients. Freedom from myocardial infarction (MI) at 5 years was higher in nondiabetic CABG versus angioplasty patients (92.4% vs. 85.2%, p = 0.02), vet was similar to the rate observed (85%) in nondiabetic CABG and angioplasty patients with CR intended. Five-year rates of death, cardiac death, repeat revascularization and angina were similar in all angioplasty patients with IR versus CR intended. However, a trend for greater freedom from subsequent CABG was seen in CR patients (70.3% vs. 64.0%, p = 0.08).

CONCLUSIONS

Intended incomplete angioplasty revascularization in nondiabetic patients with multivessel disease who are candidates for both angioplasty and CABG does not compromise long-term survival; however, subsequent need for CABG may be increased with this strategy. Whether the risk of long-term MI is also increased remains uncertain.

The Brugada syndrome: clinical, electrophysiologic and genetic aspects

This review deals with the clinical, basic and genetic aspects of a recently highlighted form of idiopathic ventricular fibrillation known as the Brugada syndrome. Our primary objective in this review is to identify the full scope of the syndrome and attempt to correlate the electrocardiographic manifestations of the Brugada syndrome with cellular and ionic heterogeneity known to exist within the heart under normal and pathophysiologic conditions so as to identify the cellular basis and thus potential diagnostic and therapeutic approaches. The available data suggest that the Brugada syndrome is a primary electrical disease resulting in abnormal electrophysiologic activity in right ventricular epicardium. Recent genetic data linking the Brugada syndrome to an ion channel gene mutation (SCN5A) provides further support for the hypothesis. The electrocardiographic manifestations of the Brugada syndrome show transient normalization in many patients, but can be unmasked using sodium channel blockers such as flecainide, ajmaline or procainamide, thus identifying patients at risk. The available data suggest that loss of the action potential dome in right ventricular epicardium but not endocardium underlies the ST segment elevation seen in the Brugada syndrome and that electrical heterogeneity within right ventricular epicardium leads to the development of closely coupled premature ventricular contractions via a phase 2 reentrant mechanism that then precipitates ventricular tachycardia/ventricular fibrillation (VT/VF). Currently, implantable cardiac defibrillator implantation is the only proven effective therapy in preventing sudden death in patients with the Brugada syndrome and is indicated in symptomatic patients and should be considered in asymptomatic patients in whom VT/VF is inducible at time of electrophysiologic study.

Factors influencing clinical outcomes after revascularization in the asymptomatic cardiac ischemia pilot (ACIP). ACIP Study Group

BACKGROUND AND AIM

The Asymptomatic Cardiac Ischemia Pilot is the first randomized trial where revascularization involved choice of either coronary bypass or angioplasty used in an early or a delayed symptom-driven approach. One-year outcomes were favorable (reduced recurrent ischemia and adverse outcomes) for an early revascularization strategy (within 4 weeks), compared with an early medical strategy when revascularization was delayed until symptom-driven. This ancillary study examined variables influencing outcomes after these 2 revascularization approaches (early vs. delayed until symptom-driven).

METHODS

Participants were clinically stable coronary disease patients with stress-induced and daily life ischemia who underwent revascularization. Characteristics associated with clinical outcomes occurring within the year following revascularization were examined using Cox regression analysis.

RESULTS

A total of 262 patients received revascularization; 170 in the early approach and 92 in the delayed symptom-driven approach. Thirty-three patients had adverse outcomes (death, nonfatal myocardial infarction, or repeat revascularization) during 1-year follow-up. The most important independent predictor of improved outcome during the follow-up year was attempted revascularization of > or = 66% of vessels with significant stenosis for the early (risk ratio [RR] 0.25, 95% confidence interval [CI] 0.09-0.67) and the delayed (RR 0.21, CI 0.08-0.58) approaches. Factors such as age, stress test results, and coronary angiographic findings did not predict clinical outcome.

CONCLUSIONS

Our findings are important in the planning of a large trial with longer follow-up.

Better outcome for women compared with men undergoing coronary revascularization: a report from the bypass angioplasty revascularization investigation (BARI)

BACKGROUND

Numerous studies have shown that women undergoing coronary revascularization procedures do so at a higher risk for an adverse outcome compared with men. However, the impact of advances in technology and improvements in techniques on in-hospital and long-term outcome after revascularization in women is unclear.

METHODS AND RESULTS

We evaluated 1829 patients with symptomatic multivessel coronary disease randomized to CABG or PTCA in the Bypass Angioplasty Revascularization Investigation (BARI), of whom 27% were women. As expected, women were older (64.0 versus 60.5 years), with more congestive heart failure (14% versus 7%), hypertension (68% versus 42%), treated diabetes mellitus (31% versus 15%), and unstable angina (67% versus 61%) than men but had similar preservation of left ventricular function and extent of multivessel disease. Women assigned to surgery received the same number of total grafts but fewer internal mammary artery grafts (72% versus 85%, P<0. 01), and those assigned to angioplasty had more intended lesions (76% versus 71%, P<0.01) successfully dilated than men. At an average of 5.4 years' follow-up, crude mortality rates were similar in women (12.8%) and men (12.0%). The Cox regression model adjusting for baseline differences revealed that women had a significantly lower risk of death (relative risk, 0.60; 95% CI, 0.43 to 0.84; P=0. 003) but not a significantly lower risk of death plus myocardial infarction (relative risk, 0.84; 95% CI, 0.66 to 1.07; P=0.16) than men.

CONCLUSIONS

Although the unadjusted mortality rate suggests that women and men undergoing CABG and PTCA have a similar 5-year mortality, women have higher risk profiles; consequently, contrary to previous reports, female sex is an independent predictor of improved 5-year survival after we control for multiple risk factors.

The Novacode criteria for classification of ECG abnormalities and their clinically significant progression and regression

Electrocardiographic (ECG) manifestations of clinical and subclinical cardiovascular disease are used as an important component in the evaluation of clinical trials, and there is an increasing demand for well-defined criteria for clinically significant evolution of ECG abnormalities. The Novacode ECG classification system provides a comprehensive hierarchical set of criteria for prevalent ECG abnormalities and for clinically significant serial ECG changes, both adverse and favorable, as a response to pharmacologic, surgical, and other interventions. These criteria are used to grade Q wave and ischemic abnormalities in order to achieve stable classification of both prevalent and incident myocardial infarctions by minimizing false classifications due to clinically insignificant ECG variations. This approach differs from the traditional Minnesota Code classification system, in which incident events are determined by changes in classification categories, with the application of additional elaborate validation rules to exclude frequent false classifications. Novacode hierarchy is so structured that for each abnormality, a general class is first determined with the simplest possible classification criteria and more specific abnormality subgroups are then classified with more elaborate criteria. This approach will satisfy differing needs of clinical trials for detail in classification. Explicit definition of ECG variables and condition statements for the classification criteria facilitate implementation of the Novacode with computer ECG programs.

Transdermal nitroglycerin patch therapy improves left ventricular function and prevents remodeling after acute myocardial infarction: results of a multicenter prospective randomized, double-blind, placebo-controlled trial

BACKGROUND

Nitrates are widely used in the treatment of angina in patients with acute myocardial infarction (AMI). Short-term administration prevents left ventricular (LV) dilation and infarct expansion. However, little information is available regarding their long-term effects on LV remodeling in patients surviving Q-wave AMI.

METHODS AND RESULTS

This was a randomized, double-blind, placebo-controlled trial designed to investigate the long-term (6-month) efficacy of intermittent transdermal nitroglycerin (NTG) patches on LV remodeling in 291 survivors of AMI. Patients meeting entry criteria had baseline gated radionuclide angiography (RNA) followed by randomization to placebo or active NTG patches delivering 0.4-, 0.8-, or 1.6-mg/h. RNA was repeated at 6 months and 6.5 days after withdrawal of double-blind medication. The primary study end point was the change in end-systolic volume index (ESVI). Both ESVI and end-diastolic volume index (EDVI) were significantly reduced with 0.4-mg/h NTG patches (-11.4 and -11.6 mL/m2, respectively, P<.03). This beneficial effect was observed primarily in patients with a baseline LV ejection fraction < or =40% (deltaESVI, -31 mL/m2; deltaEDVI, -33 mL/m2; both P<.05) and only at the 0.4-mg/h dose. After NTG patch withdrawal, ESVI significantly increased but did not reach pretreatment values.

CONCLUSIONS

Transdermal NTG patches prevent LV dilation in patients surviving AMI. The beneficial effects are limited to patients with depressed LV function and only at the lowest (0.4-mg/h) dose. Continued administration is necessary to maintain efficacy. Whether these remodeling effects confer a clinical or survival advantage will need to be addressed in an adequately powered cardiac event trial.

Prognostic value of dipyridamole thallium-201 screening to minimize perioperative cardiac complications in diabetics undergoing kidney or kidney-pancreas transplantation

To minimize perioperative cardiac events, we utilize a screening protocol consisting of intravenous dipyridamole thallium-201 myocardial imaging (DPT), with the selective use of coronary angiography based on the presence of reversible defect(s) on DPT test. A retrospective study was performed to determine the prognostic value of this protocol and to identify any clinical parameters predictive of an abnormal DPT test. To accomplish this, a detailed chart analysis of 176 consecutive kidney (n = 89) and kidney-pancreas (n = 87) transplant recipients who had undergone pretransplant DPT testing was performed. The results of the DPT test were interpreted as normal in 111, fixed defect in 15, and reversible defect(s) in 50 patients. Forty-two of the 50 patients with reversible defect(s) underwent coronary angiography. Twelve of the 27 patients with significant coronary artery disease (CAD, > 50% stenosis in one or more coronary arteries) underwent pretransplant revascularization and the remaining 15 were treated medically. Cardiac events (documented acute myocardial infarction or sudden cardiac death) within 6 wk of transplant were stratified by the results of this protocol. Also, various clinical parameters were compared between patients with normal and abnormal (fixed and reversible defect) DPT tests. Only one of the 111 (0.9%) transplant recipients with a normal DPT test had a perioperative cardiac event. None of the 15 (0%) patients with a fixed defect and none of the 15 (0%) patients with reversible defect(s), but a nonsignificant (< 50% narrowing) coronary angiogram, had a perioperative cardiac event. Three of the 27 (11.1%) patients with reversible defect(s) and significant disease on coronary angiography, who had undergone pre-transplant revascularization or were managed medically, had a perioperative coronary event. Of 14 recipients parameters analyzed, age > 50 yr was the only variable predictive of an abnormal DPT test. We conclude that the incidence of perioperative cardiac events in patients with a normal or fixed defect, or reversible defect(s) but a nonsignificant (< 50% narrowing) coronary angiogram is very low, indicating the high correlation of these findings on DPT and an uneventful (cardiac) post-transplant course. The incidence of perioperative cardiac complications amongst the high-risk transplant recipients with reversible defect(s) and significant CAD on coronary angiogram may be minimized by appropriate preoperative medical management or revascularization. None of the clinical variables except age > 50 yr was predictive of an abnormal DPT test.

Comparison of the various electrocardiographic scoring codes for estimating anatomically documented sizes of single and multiple infarcts of the left ventricle

It is clinically important to estimate the size of a myocardial infarction (MI) to predict patient prognosis, to determine the ability of a therapy to limit its size, and to evaluate its effect on left ventricular function. Various electrocardiographic methods have been used for these purposes but their accuracies have not been compared with each other using an identical reference population of anatomically measured infarcts. The capability of 4 electrocardiographic scoring methods (the Selvester score, the Minnesota code, the Novacode, and the Cardiac Infarction Injury Score) to estimate MI size was compared using anatomic MI size in a group of 100 deceased patients. All patients had a standard 12-lead electrocardiogram of sufficient quality to perform manual waveform measurements and without confounding factors such as ventricular hypertrophy, fascicular block, or bundle branch block. The location and size of the left ventricular infarction was measured postmortem using the anatomic method of Ideker et al. All methods' size estimates correlated best with anatomic MI size in the anterior location (r = 0.65 to 0.89). The Selvester score was superior in estimating the sizes of inferior (r = 0.70) and posterolateral (r = 0.74) infarcts. For multiple infarcts all methods performed poorly (r = 0.18 to 0.44).

Mutagenesis and characterization of specific residues in fatty acid ethyl ester synthase: a gene for alcohol-induced cardiomyopathy

Fatty acid ethyl ester synthase-III metabolizes both ethanol and carcinogens. Structure-function studies of the enzyme have not been performed in relation to site specific mutagenesis. In this study, three residues (Gly 32, Cys 39 and His 72) have been mutated to observe their role in enzyme activity. Gly to Gln, Cys to Trp and His to Ser mutations did not affect fatty acid ethyl ester synthase activity, but His to Ser mutant had less than 9% of control glutathione S-transferase activity. The apparent loss of transferase activity reflected a 28 fold weaker binding constant for glutathione. Thus, this study indicates that Gly and Cys may not be important for synthase or transferase activities however, histidine may play a role in glutathione binding, but it is not an essential catalytic residue of glutathione S-transferase or for fatty acid ethyl ester synthase activity.

Cardiopulmonary exercise testing identifies low risk patients with heart failure and severely impaired exercise capacity considered for heart transplantation

OBJECTIVES

The 3-year survival rates of 500 patients with congestive heart failure (CHF) referred for heart transplantation were assessed to evaluate the clinical and exercise variables most useful for estimating prognostic risk.

BACKGROUND

Detailed prognostic risk stratification of patients with a peak exercise oxygen consumption (VO2) < or = 14 ml/min per kg to identify lower risk patient subsets has been limited in earlier series by relatively small sample size.

METHODS

Cardiopulmonary exercise testing was performed in 500 patients with CHF referred for heart transplantation; 154 (31%) had a peak exercise VO2 < or = 14 ml/min per kg. Univariate and multivariate analyses were performed to identify the 3-year prognostic risk.

RESULTS

The 55% 3-year survival rate of the 77 patients with a peak exercise VO2 < or = 14 ml/min per kg unable to reach a peak exercise systolic blood pressure (SBP) of 120 mm Hg was significantly lower than the 83% survival rate in the 74 patients able to reach this exercise blood pressure (p = 0.004). Multivariate analysis revealed that peak exercise SBP (p = 0.0005) and percent predicted peak VO2 < or = 50% (p = 0.04) were the two most important predictors for the combined end point of death or listing as Status 1.

CONCLUSIONS

Peak exercise SBP and percent predicted peak exercise VO2 are two inexpensive and easily measured noninvasive variables that can be used to further prognostically risk stratify ambulatory patients with CHF referred for heart transplantation with a peak exercise VO2 < or = 14 ml/min per kg.

Rationale and design of the Myocardial Ischemia Reduction with Aggressive Cholesterol Lowering (MIRACL) study that evaluates atorvastatin in unstable angina pectoris and in non-Q-wave acute myocardial infarction

The goal of the Myocardial Ischemia Reduction with Aggressive Cholesterol Lowering (MIRACL) study is to determine whether early, rapid, and profound cholesterol lowering therapy with atorvastatin can reduce early recurrent ischemic events in patients with unstable angina or non-Q-wave acute myocardial infarction. Within 1 to 4 days of hospitalization for one of these conditions, 2,100 patients will be randomly assigned to receive atorvastatin, 80 mg/day, or placebo in a double-blind design. Both groups receive dietary counseling. Over a 16-week follow-up period, the primary outcome measure is the time to occurrence of an ischemic event, defined as death, nonfatal acute myocardial infarction, cardiac arrest with resuscitation, or recurrent symptomatic myocardial ischemia requiring emergency rehospitalization. Secondary outcome measures are the time to occurrence and incidence of each of the primary outcome components, as well as nonfatal stroke, worsening angina, congestive heart failure requiring hospitalization, and need for coronary revascularization not anticipated before randomization. The sample size of 1,050 patients in each group is expected to provide 95% power to detect a 30% reduction in the primary outcome measure with a 5% level of significance. The results of the MIRACL study will determine the utility of profound cholesterol lowering as an early intervention in acute coronary syndromes.

Perioperative cardiac evaluation for noncardiac surgery noninvasive cardiac testing

Prognostic risk stratification to identify perioperative and long-term cardiac risk in selected patients undergoing noncardiac surgery is part of good clinical practice. Exercise variables associated with significant increased risk include poor functional capacity (eg, <4 metabolic equivalents), marked exercise-induced ST segment shift or angina at low workloads, and inability to increase or actually decrease systolic blood pressure with progressive exercise. Approximately 40% of patients tested before peripheral vascular surgery will have an abnormal exercise electrocardiogram (ECG). The predictive value for a perioperative event, ie, death or myocardial infarction, ranges from 5% to 25% for a positive test and 90% to 95% for a negative test. Whereas exercise cardiac imaging is the modality of choice in patients with a noninterpretable exercise ECG, pharmacological stress imaging should be used in the 30% to 50% of patients who require perioperative noninvasive risk stratification and are unable to perform an adequate level of exercise to test cardiac reserve. Myocardial perfusion variables predictive of increased cardiac events include severity of the perfusion defect, number of reversible defects, extent of fixed and reversible defects, increased lung uptake of thallium-201, and marked ST segment changes associated with angina during the test. The reported sensitivity and specificity of dobutamine-induced echocardiographic wall motion abnormalities in patients with peripheral vascular disease is similar to myocardial perfusion scintigraphy, but the confidence limits are wider due to the smaller sample size in these more recent studies. In conclusion, noninvasive cardiac testing should be used selectively in patients undergoing noncardiac surgery; the results provide useful estimates of short- and long-term risk of cardiac events, and the magnitude of abnormal response on noninvasive testing should be used to formulate decisions regarding the need for coronary angiography and subsequent revascularization.

Myonecrosis after revascularization procedures

The detection of elevated cardiac enzyme levels and the occurrence of electrocardiographic (ECG) abnormalities after revascularization procedures have been the subject of recent controversy. This report represents an effort to achieve a consensus among a group of researchers with data on this subject. Creatine kinase (CK) or CK-MB isoenzyme (CK-MB) elevations occur in 5% to 30% of patients after a percutaneous intervention and commonly during coronary artery bypass graft surgery (CABG). Although Q wave formation is rare, other ECG changes are common. The rate of detection is highly dependent on the intensity of enzyme and ECG measurement. Because most events occur without the development of a Q wave, the ECG will not definitively diagnose them; even the ECG criteria for Q wave formation signifying an important clinical event have been variable. At least 10 studies evaluating > 10,000 patients undergoing percutaneous intervention have demonstrated that elevation of CK or CK-MB is associated not only with a higher mortality, but also with a higher risk of subsequent cardiac events and higher cost. Efforts to identify a specific cutoff value below which the prognosis is not impaired have not been successful. Rather, the risk of adverse outcomes increases with any elevation of CK or CK-MB and increases further in proportion to the level of intervention. This information complements similar previous data on CABG. Obtaining preprocedural and postprocedural ECGs and measurement of serial cardiac enzymes after revascularization are recommended. Patients with enzyme levels elevated more than threefold above the upper limit of normal or with ECG changes diagnostic for Q wave myocardial infarction (MI) should be treated as patients with an MI. Patients with more modest elevations should be observed carefully. Clinical trials should ensure systematic evaluation for myocardial necrosis, with attention paid to multivariable analysis of risk factors for poor long-term outcome, to determine the extent to which enzyme elevation is an independent risk factor after considering clinical history, coronary anatomy, left ventricular function and clinical evidence of ischemia. In addition, tracking of enzyme levels in clinical trials is needed to determine whether interventions that reduce periprocedural enzyme elevation also improve mortality.

Prognostic significance of myocardial ischemia detected by ambulatory electrocardiography, exercise treadmill testing, and electrocardiogram at rest to predict cardiac events by one year (the Asymptomatic Cardiac Ischemia Pilot [ACIP] study)

Myocardial ischemia identified by ambulatory electrocardiography (AECG), exercising treadmill testing, (ETT), or 12-lead electrocardiogram at rest is associated with an adverse prognosis, but the effect of improving these ischemic manifestations by treatment on outcome is unknown. The Asymptomatic Cardiac Ischemia Pilot (ACIP) study was a National Heart, Lung, and Blood Institute funded study to determine the feasibility of conducting a large-scale prognosis study and to assess the effect of 3 treatment strategies (angina-guided strategy, AECG ischemia-guided strategy, and revascularization strategy) in reducing the manifestations of ischemia as indicated by AECG and ETT. The study cohort for this database study consisted of 496 randomized patients who performed the AECG, ETT, and 12-lead electrocardiogram at rest at both the qualifying and week 12 visits. The effect of modifying ischemia by treatment on the incidence of cardiac events (death, myocardial infarction, coronary revascularization procedure, or hospitalization for an ischemic event) at 1 year was examined. In the 2 medical treatment groups (n = 328) there was an association between the number of ambulatory electrocardiographic ischemic episodes at the qualifying visit and combined cardiac events at 1 year (p = 0.003). In the AECG ischemia-guided patients there was a trend associating greater reduction in the number of ambulatory electrocardiographic ischemia episodes with a reduced incidence of combined cardiac events (r = -0.15, p = 0.06). In the revascularization strategy patients this association was absent. In the medical treatment patients the exercise duration on the baseline ETT was inversely associated with an adverse prognosis (p = 0.02). The medical treatment strategies only slightly improved the exercise time and the exercise duration remained of prognostic significance. In the revascularization group strategy patients this association was absent. Thus, myocardial ischemia detected by AECG and an abnormal ETT are each independently associated with an adverse cardiac outcome in patients subsequently treated medically.

Using automated analysis of the resting twelve-lead ECG to identify patients at risk of developing transient myocardial ischaemia--an application of an adaptive logic network

The aim of this study was to introduce an adaptive logic network computing method for detecting patients who were likely to show transient ischaemic episodes during ambulatory Holter monitoring, using parameters from a previously recorded standard twelve-lead resting electrocardiogram (ECG). In the present study, the adaptive logic network computing method is compared with other commonly used classification methods, such as backpropagation network and discriminant analysis techniques. Of 1367 study subjects aged 65 and above, 733 were women and 634 were men. Ambulatory Holter recordings were made to detect episodic ischaemia in study patients. Those subjects showing ischaemic episodes were classified as 'ischaemic' patients, and the remaining subjects were 'non-ischaemic'. Accuracy was 67% using the adaptive logic network computing method, 56% using the backpropagation network computing method, and 65% using statistical discriminant analysis. We concluded that the adaptive logic network technique offers a slightly higher accuracy and shows several potential advantages for automated detection of ischaemia in resting electrocardiograms.

Myocardial infarction and cardiac mortality in the Bypass Angioplasty Revascularization Investigation (BARI) randomized trial

BACKGROUND

Cardiac mortality and myocardial infarction (MI) rates are used to evaluate the efficacy of coronary artery bypass grafting (CABG) and percutaneous transluminal coronary angioplasty (PTCA). We compared 5-year cardiac mortality and MI rates in 1829 patients with multivessel disease randomized to CABG or PTCA.

METHODS AND RESULTS

The 5-year cardiac mortality rate was 8.0% in patients assigned to PTCA compared with 4.9% in those assigned to CABG (relative risk [RR] of 1.55 with a 95% confidence interval [CI] of 1.07 to 2.23; P=.022). In a subgroup of 1476 nondiabetic patients, there were no significant differences between treatment groups in cardiac mortality either overall (4.6% versus 4.2%; RR= 1.04, 95% CI, 0.65 to 1.66; P=.908) or in subgroups based on symptoms, left ventricular function, number of diseased vessels, or stenotic proximal left anterior descending artery. The two treatment groups had similar event rates for the combined end point of cardiac death or MI. The RR for cardiac mortality in 264 patients who sustained an MI compared with those who did not was 5.9 (P<.001). MIs were more common after CABG during index hospitalization (P=.004), but in the PTCA group, they were more common after discharge (P<.001).

CONCLUSIONS

The Bypass Angioplasty Revascularization Investigation (BARI) trial indicates 5-year cardiac mortality in patients with multivessel disease was significantly greater after initial treatment with PTCA than with CABG. The difference was manifest in diabetic patients on drug therapy. There were no significant differences overall for the composite end point of cardiac mortality or MI between treatment groups or for cardiac mortality in nondiabetic patients regardless of symptoms, left ventricular function, number of diseased vessels, or stenotic proximal left anterior descending artery.

Human fatty acid ethyl ester synthase-III gene: genomic organization, nucleotide sequencing and chromosomal localization

The complete gene for human fatty acid ethyl ester Synthase-III (FAEES-III) was isolated from a human genomic lambda phage library for functional and structural determination. The gene spans approximately 3.3 kb which includes 791 base pairs of the 5' and 124 base pairs of the 3' flanking regions. The gene is comprised of seven exons and is interrupted by six introns. Several transcription regulatory sequences were identified in the promoter region. Primer extension experiments demonstrated the existence of two possible transcription initiation sites at nucleotide -29 and 32 position, 5' to the start of the translation. In addition to a TATA box at position-29 relative to the transcription initiation site and two Spl GGGCGG recognition sequences at nucleotide positions -42 to -37 and -50 to -45, the promoter contains a sequence motif matching the transcription activating factor AP-1. We also found an A + T rich region between nucleotide -505 and -390 which contained twenty-two AAAAT tandem repeats. The gene for FAEES-III was localized to human chromosome 11 by hybridizing the genomic fragment Xh01 to Chinese hamster/human somatic cell hybrid panels. These data extend our knowledge of non-oxidative alcohol metabolism and permit linkage analyses between this pathway and alcohol-related phenotypes.

Moderate alcohol feeding attenuates postinjury vascular cell proliferation in rabbit angioplasty model

Our studies in the cholesterol-fed rabbit model indicate that moderate alcohol consumption reduces the risk of restenosis by preventing low-density lipoprotein (LDL) oxidation. Eighteen hypercholesterolemic rabbits underwent arterial injury by Fogerty balloon endothelial denudation of iliac arteries. Two weeks later, balloon angioplasty of atherogenic or atherosclerotic arterial segments was performed. Nine rabbits (control) received water ad lib, whereas nine rabbits (moderate alcohol treated) received an average of 2.5 ml alcohol per 500 ml water daily, from the day of feeding hypercholesterolemic diet until they were killed, 10 weeks later. There was a 26% increase in lumen size of the moderate alcohol-treated group compared with the control group. The percentage neointima formation (NI) values of the moderate alcohol-treated and control groups were 77 +/- 2.1 and 61 +/- 1.9, respectively (p < 0.001). The lumen/neointima (L/NI) ratio of the moderate alcohol-treated group was 0.71 +/- 0.07 compared with the control group, 0.33 +/- 0.04 (p < 0.001). The number of foam cells in the moderate alcohol-treated group was threefold less than the control group [i.e., 1.4 +/- 0.4 and 3.9 +/- 0.8, respectively (p = 0.005)]. The arterial lesion malondialdehyde (MDA) values of the control and the moderate alcohol-treated groups were 13.6 +/- 2.8 and 4.4 +/- 0.5 (p = 0.004), respectively. By radioimmunoassay, the moderate alcohol-treated group had less macrophage chemotactic protein-1 (MCP-1; 3,277 cpm/microg protein) and platelet-derived growth factor (PDGF; 2,261 cpm/microg protein) compared with the controls (MCP-1, 4,529 cpm/microg protein; PDGF, 3,583 cpm/microg protein). Thus we conclude that low concentrations of alcohol reduce neointimal formation, and the extent of lipid oxidation, the number of foam cells in the neointimal area and may decrease the expression of MCP-1 and PDGF by reducing LDL oxidation in an animal model of postangioplasty restenosis.

Ischemic cerebral infarction after rt-PA and heparin therapy for acute myocardial infarction. The TIMI-II pilot and randomized clinical trial combined experience

BACKGROUND AND PURPOSE

Ischemic cerebral infarction (CI) is a serious complication of acute myocardial infarction (MI). Little information exists on CI after thrombolytic therapy for MI.

METHODS

Of 3924 MI patients treated with recombinant tissue plasminogen activator (rt-PA) and heparin, 29 (0.7%) developed CI after treatment. All CI patients had detailed neurological evaluations, and 27 (93%) had CT scans centrally reviewed.

RESULTS

Age range was 40 to 74 years (mean, 60 years); 25 patients (86%) were men, and 22 (76%) were white. The electrocardiographic location of MI was anterior in 22 (76%) and nonanterior in 7 (24%). Five CIs occurred within 6 hours, 4 between 6 to 24 hours, 8 during the remainder of the first week, 10 during the second week, and 2 others distributed over the 4 weeks after study entry. Six of 29 CIs did not involve the cerebral cortex; 9 patients (31%) had multiple CIs. Of 28 CIs thought to be embolic in origin, 17 showed strong evidence for at least one cardiac abnormality (mural clot, wall-motion abnormality, aneurysm, or atrial fibrillation) known to be associated more specifically with embolism than MI. Eight of 27 CIs (30%) with CT scans had hemorrhagic transformation of varying degrees; 5 were symptomatic.

CONCLUSIONS

The time of occurrence and sites of CI after rt-PA and heparin therapy for acute MI are similar to those reported during the prethrombolytic era.

Long-term cardiopulmonary exercise performance after heart transplantation

Functional capacity is an important outcome variable for heart transplantation, but there are few data that examine the temporal relation and duration of improvement in cardiopulmonary exercise performance after cardiac transplantation. Cardiopulmonary exercise performance was measured in 140 patients who underwent 426 treadmill exercise tests up to 9 years after cardiac transplantation. Univariate and multivariate analyses were used to predict postoperative improvement in functional capacity. Peak oxygen consumption (VO2) significantly improved from 14.2 +/- 3.7 ml/min/kg before to 21.4 +/- 5.6 ml/min/kg at a mean of 11.2 +/- 3.0 months after the transplant procedure (p < 0.001). When peak aerobic capacity was compared with a normal population, peak VO2 was < 50% of predicted in only 9 patients (12%), from 50% to 70% in 34 patients (44%), from 70% to 90% of predicted in 24 patients (31%); 10 patients (13%) were able to achieve > 90% of peak predicted VO2. The improvement seen at 6 months did not significantly change over 9 years of follow-up. Significant preoperative univariate predictors of.1-year postoperative improvement in peak VO2 were preoperative peak VO2 (p = 0.004), age (p < 0.001), ischemic cardiomyopathy (p = 0.007), and preoperative left ventricular ejection fraction (p < 0.001). Peak VO2 at 1 year in patients able to perform the test was not significantly influenced by acute rejection episodes, donor body surface area, or donor/recipient size ratio. In conclusion, exercise capacity is significantly improved within 6 months after cardiac transplantation, and maintained as long as 9 years after procedure. The magnitude of postoperative improvement is inversely related to preoperative peak VO2 and age.

Long-term survival of African Americans in the Coronary Artery Surgery Study (CASS)

OBJECTIVES

This study sought to determine the long-term (> 15 years) outcome of a clinically well characterized cohort of African Americans with known or suspected coronary artery disease (CAD).

BACKGROUND

The mortality rate from CAD is higher in African Americans than in whites. An earlier analysis of data from the Coronary Artery Surgery Study (CASS) registry suggested that African American and white patients treated surgically had equal 5-year survival rates.

METHODS

Survival data from the CASS registry were analyzed to determine whether 1) African American race is an independent predictor of mortality; and 2) initial therapy is predictive of mortality among African American patients.

RESULTS

Overall, 60% of white and 52% of African American patients survived 16 years (p < 0.00001). Multivariate Cox models confirmed that African American race was independently associated with higher mortality in both the medical group (hazard ratio [HR] 1.34, 95% confidence interval [CI] 1.11 to 1.63) and the surgical group (HR 1.63, 95% CI 1.19 to 2.23). Initial therapy was not predictive of survival among African American patients (p = 0.81). However, smoking status significantly influenced survival: African Americans who did not smoke experienced significantly improved survival (60% vs. 48% for smokers), which equaled survival for white nonsmokers (61%, p = NS).

CONCLUSIONS

In contrast to results from shorter term studies, African Americans experienced higher overall mortality rates than whites over the long term, regardless of the type of initial treatment. Survival among nonsmoking African Americans at 16 years equaled survival among nonsmoking whites.

Circadian variation in the onset of unstable angina and non-Q-wave acute myocardial infarction (the TIMI III Registry and TIMI IIIB)

Circadian variation has been demonstrated in several types of acute cardiovascular disease, including acute myocardial infarction (AMI), sudden cardiac death, silent ambulatory ischemia, and thrombotic stroke. In contrast, no diurnal variation was observed in 1 study of non-Q-wave AMI, and limited data are available for unstable angina. To assess whether circadian variation is present in unstable angina and non-Q-wave AMI, we examined the time of onset of ischemic pain in 7,731 patients who were prospectively identified in the Thrombolysis in Myocardial Ischemia (TIMI) III Registry, 3,318 of whom were enrolled in the prospective study, and in 1,473 patients enrolled in the TIMI IIIB trial. A circadian variation in the onset of pain was observed, with an increase in the number of patients experiencing the onset of pain in the morning hours between 6 A.M. and 12 noon (p <0.001). This circadian variation was observed both in patients with unstable angina and in those with evolving non-Q-wave AMI. A similar circadian pattern was observed in all subgroups tested. These findings were confirmed in the TIMI IIIB trial and complement previous studies suggesting that circadian variation exists in the onset of the full spectrum of myocardial ischemic syndromes.