Wayne Warnica

Myocardial infarction patients in the 1990s—their risk factors, stratification and survival in Canada: The Canadian assessment of myocardial infarction (CAMI) study

OBJECTIVES This study sought to evaluate the in-hospital and postdischarge mortality of patients with an acute myocardial infarction in the 1990s. BACKGROUND The widespread implementation of therapeutic interventions that modify the natural history of coronary artery disease has led to changes in the profile and survival of patients with an acute myocardial infarction. Although data exist for selected subsets of patients with an acute myocardial infarction, at this time there is little recent prospective information on all patients presenting with an acute myocardial infarction, particularly for survival after hospital discharge. METHODS All patients < or = 75 years old presenting with an acute myocardial infarction between July 1, 1990 and June 30, 1992 at nine Canadian hospitals were prospectively evaluated and followed up for 1 year. From November 1991, patients of all ages were included. In two centers, recruitment continued until December 31, 1992. A total of 3,178 patients were recruited. RESULTS The in-hospital mortality rate of patients < or = 75 years old was 8.4%, and that at 1 year after hospital discharge was 5.3%. For patients of all ages recruited after November 1, 1991, the in-hospital mortality rate was 9.9% and 7.1% for 1 year after hospital discharge. For patients < or = 75 years old, age carried an independent in-hospital but no post discharge risk. Female patients had a twofold greater risk of dying in hospital. After hospital discharge, only 1.7% of patients < or = 75 years old and 1.9% of patients of all ages died of a presumed arrhythmic death. Premature ventricular contractions had no independent prognostic value. The relatively low in-hospital (5.3%) and postdischarge (6.1%) reinfarction rate may have contributed to improved survival. A greater reinfarction rate in patients >75 years old (17.4% vs. 9.6%, p < 0.001) may have contributed to their poorer outcome. CONCLUSIONS One-year mortality after acute myocardial infarction continues to decrease, and changes in the prognostic value of traditional methods of risk stratification have occurred.

Is Variant Angina the Coronary Manifestation of a Generalized Vasospastic Disorder

IN VARIANT angina, myocardial ischemia is caused by transient coronary-arterial spasm.1 , 2 Although altered adrenergic activity has been proposed as the cause of coronary spasm3 , 4 and high circu...

Effects of Angiotensin-Converting Enzyme Inhibition in Low-Risk Patients Early After Coronary Artery Bypass Surgery

Background— Early after coronary artery bypass surgery (CABG), activation of numerous neurohumoral and endogenous vasodilator systems occurs that could be influenced favorably by angiotensin-converting enzyme inhibitors. Methods and Results— The Ischemia Management with Accupril post–bypass Graft via Inhibition of the coNverting Enzyme (IMAGINE) trial tested whether early initiation (≤7 days) of an angiotensin-converting enzyme inhibitor after CABG reduced cardiovascular events in stable patients with left ventricular ejection fraction ≥40%. The trial was a double-blind, placebo-controlled study of 2553 patients randomly assigned to quinapril, target dose 40 mg/d, or placebo, who were followed up to a maximum of 43 months. The mean (SD) age was 61 (10) years. The incidence of the primary composite end point (cardiovascular death, resuscitated cardiac arrest, nonfatal myocardial infarction, coronary revascularization, unstable angina or heart failure requiring hospitalization, documented angina, and stroke) was 13.7% in the quinapril group and 12.2% in the placebo group (hazard ratio 1.15, 95% confidence interval 0.92 to 1.42, P=0.212) over a median follow-up of 2.95 years. The incidence of the primary composite end point increased significantly in the first 3 months after CABG in the quinapril group (hazard ratio 1.52, 95% confidence interval 1.03 to 2.26, P=0.0356). Adverse events also increased in the quinapril group, particularly during the first 3 months after CABG. Conclusions— In patients at low risk of cardiovascular events after CABG, routine early initiation of angiotensin-converting enzyme inhibitor therapy does not appear to improve clinical outcome up to 3 years after CABG; however, it increases the incidence of adverse events, particularly early after CABG. Thus, early after CABG, initiation of angiotensin-converting enzyme inhibitor therapy should be individualized and continually reassessed over time according to risk.

Risk Stratification After Myocardial Infarction Using Signal-Averaged Electrocardiographic Criteria Adjusted for Sex, Age, and Myocardial Infarction Location

BACKGROUND The objectives were to investigate the factors influencing signal-averaged ECGs (SAECGs) recorded in patients after myocardial infarction (MI) and to develop criteria for predicting arrhythmic events (AEs) that account for these factors. METHODS AND RESULTS SAECGs were recorded 5 to 15 days after MI in 2461 patients without bundle-branch block. The duration (QRSd), terminal potential (VRMS), and terminal duration (LAS) of the filtered QRS were measured. During follow-up (17 +/- 8 months), AEs (arrhythmic death; ventricular tachycardia, VT; ventricular fibrillation, VF) occurred in 80 patients (3.3%). Receiver operating characteristic curves showed that QRSd discriminated patients with all types of AEs, but VRMS and LAS discriminated only VT patients; QRSd minus LAS also discriminated AE patients. Sex, age, and MI location significantly affected the SAECG; survivors without VT or VF were divided into subgroups (2 sex x 4 age x 2 MI), and QRSd values exceeding the 70th percentile in each subgroup predicted AEs with a sensitivity of 65.4%. An unadjusted QRSd criterion showed the same overall sensitivity and specificity but with less uniform values for each subgroup. A Cox model was constructed by use of multiple prognostic indicators, and in rank order, QRSd, previous MI, and Killip class were predictive of AEs. CONCLUSIONS SAECG adjustments for sex, age, and MI location did not improve sensitivity and specificity but produced a more uniform predictive performance. The proposed criteria are based only on QRSd, because late potentials (VRMS and LAS) did not discriminate patients with sudden death. Duration of high-level activity during QRS (QRSd-LAS) can predict AEs, suggesting that the arrhythmogenic substate involves a large mass of myocardium.

Sustained postoperative anaemia is associated with an impaired outcome after coronary artery bypass graft surgery: insights from the IMAGINE trial

Objective To investigate the association between sustained postoperative anaemia and outcome after coronary artery bypass graft (CABG) surgery. Design Retrospective analysis of the IMAGINE trial, which tested the effect of the ACE inhibitor quinapril on cardiovascular events after CABG. Setting Thoracic surgery clinic/outpatient department. Patients 2553 stable patients with left ventricular ejection fraction >40% 2–7 days after scheduled CABG. Interventions Randomisation to quinapril or placebo. Main outcome measures Cox regression analysis for the association between postoperative anaemia and cardiovascular events and the effect of quinapril on the incidence of anaemia. Results Postoperative anaemia was sustained for >50 days in 44% of patients. Sustained postoperative anaemia was associated with an increased incidence of cardiovascular events during the first 3 months (adjusted HR (adjHR) 1.77, 95% CI 1.10 to 2.85, p=0.012) and during the maximum follow-up of 43 months (adjHR 1.37, 95% CI 1.14 to 1.65, p=0.008). When haemoglobin (Hb) was considered as a continuous variable, every 1 mg/dl decrease in Hb was associated with a 13% increase in cardiovascular events (adjHR 0.87, 95% CI 0.81 to 0.95, p=0.003) and a 22% increase in all-cause mortality (adjHR 0.78, 95% CI 0.60 to 0.99, p=0.034). Quinapril was associated with a slower postoperative recovery of Hb levels and a higher incidence of cardiovascular events in patients with anaemia (adjHR 1.60, 95% CI 1.1 to 2.4, p=0.024). Conclusions Postoperative anaemia is common, frequently persists for months after CABG surgery and is associated with an impaired outcome. In patients with anaemia, ACE inhibitors slowed recovery from postoperative anaemia and increased the incidence of cardiovascular events after CABG.

Impact of previous percutaneous transluminal coronary angioplasty and/or stenting revascularization on outcomes after surgical revascularization : insights from the imagine study

AIM To determine the impact of previous coronary artery revascularization by percutaneous transluminal coronary angioplasty and/or stenting (PCI) on outcome after subsequent coronary artery bypass grafting (CABG). METHODS AND RESULTS The ischaemia management with Accupril post-bypass Graft via Inhibition of the coNverting Enzyme (IMAGINE) trial, conducted between November 1999 and September 2004, tested whether early initiation of an angiotensin-converting enzyme inhibitor post-CABG, in stable patients with LVEF >or=40%, would reduce cardiovascular events. Of the 2489 patients included in the IMAGINE trial, undergoing their first operation, 430 had a history of PCI prior to surgery (PCI group), and 2059 were referred to surgery without previous PCI (non-PCI group). There was a significant increase in the primary IMAGINE endpoint in the PCI group, HR = 1.53 [1.17-1.98], P = 0.0016. Coronary revascularization, HR = 1.80 [1.13-2.87], P = 0.014, unstable angina requiring hospitalization, HR = 2.43 [1.52-3.89], P = 0.0002, were the two individual components that significantly increased in the PCI group, even when adjusted for baseline characteristics (age, sex, history of myocardial infarction or stroke, diabetes, treatment group, or off-pump surgery). CONCLUSION Patients with left ventricular ejection fraction >or=40% having a history of PCI prior to surgery had a worse outcome post-CABG than those with no prior PCI. Further studies are needed to investigate whether these results apply for drug eluting stents.

Effect of diltiazem on symptomatic and asymptomatic episodes of ST segment depression occurring during daily life and during exercise.

BackgroundSilent myocardial ischemia is an adverse prognostic marker in patients with coronary disease; however, controlled data on the effect of treatment are sparse and contradictory, and the relations among the occurrence of ST segment depression, drug efficacy, and heart rate are unclear. Methods and ResultsSixty patients with stable coronary artery disease, a positive treadmill exercise test and asymptomatic ST segment depression on ambulatory electrocardiographic recording were assessed in a multicenter, double-blind, placebo-controlled, cross-over trial. Treadmill exercise tests and 72-hour electrocardiographic recordings were obtained at the end of two 2-week treatment periods with sustained-release diltiazem 180 mg b.i.d. or equivalent placebo. Episodes of asymptomatic ST depression decreased by 50% or more in 70% of the patients from a median number of 4.5 (range, 0-19) to 1.5 (range, 0-13) (p =0.0001); their cumulative duration also decreased from 78.5 (range, 0-60) to 24.5 (range, 0-411) minutes (p =0.001). No circadian variation was found in the efficacy of diltiazem. The occurrence of ischemic type ST segment depression was modulated by changes in heart rate rather than by absolute heart rate. Diltiazem also improved exercise test end points but to a lesser extent. Time to ST segment depression increased to 341 ± 148 from 296 ± 154 seconds (p =0.005). Although less frequent with diltiazem administration (45 versus 54 patients, p < 0.03), exercise-induced ST depression Was more often asymptomatic (98% versus 72% of patients, p < 0.0001). ConclusionsDiltiazem reduces the frequency and severity of ischemic type ST depression in patients with stable coronary artery disease. (Circulation 1991;84:15–22)

Usefulness of sustained-release diltiazem for stable angina pectoris

Sustained-release diltiazem, 120 and 180 mg twice daily, was assessed in a multicenter, double-blind, randomized, placebo-controlled trial in 65 stable angina patients with exercise-induced ST depression. Exercise testing was performed 12 +/- 1 hours after the last dose at the end of each of the 3 treatment weeks. Both dose levels of drug reduced spontaneous angina (p less than 0.001) and increased exercise duration (p less than 0.01) and time to 1-mm ST depression (p less than 0.001). No differences were noted between the 2 dose levels. Rate-pressure product at maximal exercise was similar for the 3 groups. Only 1 patient terminated the study because of adverse drug effects; severe adverse effects occurred in 1 placebo and 1 low-dose period. Sustained-release diltiazem is safe and efficacious monotherapy for patients with stable angina.

A model continuing medical education program on congestive heart failure: An analysis

&NA; Clinical practice guidelines have become an important focus for clinical care. This article describes a process undertaken to disseminate and evaluate an educational project designed to ensure that all physicians in a large geographic area received information about the guidelines for congestive heart failure and had an opportunity to work through them and begin the adoption process to improve the care of their patients. The educational strategy was based on a combination of predisposing, enabling, and reinforcing methods. The predisposing methods included printed materials, lectures, and rounds. A computer disk that allowed the physician to test his or her cognitive knowledge as well as work through patient cases comprised the enabling method. The program was reinforced by regular newsletter reminders of the project. The program was evaluated through a combination of telephone interviews and printed questionnaires. Despite the contemporary nature of the educational thought on which the program was designed, the adoption of the guidelines fell short of expectations. The disease proved to be more complex to manage than anticipated. Physicians appeared unwilling to spend as much time as the programs design required. Physicians were less computer literate than expected and found the Windows‐based computer‐assisted instruction difficult to use. Additional studies are needed to identify how best to implement a community‐wide strategy to promote guidelines.

Prediction of Cardiac Death in Patients with Bundle Branch Block After Myocardial Infarction

Left (LBBB) and right (RBBB) bundle branch block (BBB) patients have an increased incidence of cardiac death after myocardial infarction (Ml). The purpose of this study was to assess the value of the signal‐averaged electrocardiogram (SAECG) and other clinical variables for the prediction of cardiac death after MI in BBB patients.