Biomedical subjects

B R Chaitman

Publications and source records attributed to B R Chaitman.

At least 37 records · Page 2Linked to original sources

PubMed1999

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.

Angioplasty, Balloon, Coronary↗

PubMed1999

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.

Angina Pectoris↗

PubMed1999

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.

Bradycardia↗

PubMed1999

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.

DNA Mutational Analysis↗

PubMed1999

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.

Activities of Daily Living↗

PubMed1999

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.

Aged↗

PubMed1999

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.

Bundle-Branch Block↗

PubMed1998

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.

Aged↗

PubMed1998

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.

Administration, Cutaneous↗

PubMed1998

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).

Electrocardiography↗

PubMed1998

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.

Angina, Unstable↗

PubMed1998

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.

Adult↗

PubMed1998

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.

Coronary Angiography↗

PubMed1998

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.

Angioplasty, Balloon, Coronary↗

PubMed1998

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.

Acyltransferases↗

PubMed1998

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.

Adult↗

PubMed1998

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.

Arrhythmias, Cardiac↗

PubMed1997

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.

Electrocardiography↗