Absence Of Prior Myocardial Infarction Research Articles

Impact of Positron Emission Tomographic Myocardial Perfusion Imaging on Patient Selection for Revascularization

BackgroundPositron emission tomography (PET) myocardial perfusion imaging (MPI) quantifies left ventricular ejection fraction (LVEF) at peak stress. PET LVEF reserve (LVEF-R = stress LVEF − rest LVEF) offers diagnostic and prognostic value. ObjectivesThe purpose of this study was to determine if PET LVEF-R identifies patients with survival benefit postrevascularization. MethodsWe followed 14,649 unique consecutive patients undergoing 82Rb rest/stress PET MPI from January 2010 to January 2016 (excluding known cardiomyopathy). Adjusted Cox models were built to predict all-cause death, and the 3-way interaction of known coronary artery disease (CAD) (prior myocardial infarction/revascularization), LVEF-R, and 90-day revascularization was tested. ResultsKnown CAD was present in 4,982 (34.0%). Ischemia was detected in 5,396 (36.8%; ≥10% in 1,909 [13%]). Mean LVEF-R was 4.2% ± 5.7%, and was ≤0, 1 to 5, and >5 in 3,349 (22.9%), 5,266 (35.9%), and 6,034 (41.2%). Over median follow-up of 3.4 years (IQR: 1.9-5.2 years), 1,324 (8.1%) had 90-day revascularization, and there were 2,192 (15.0%) deaths. In multivariable modeling, there was a significant 3-way interaction among known CAD, LVEF-R, and 90-day revascularization (P = 0.025), such that LVEF-R ≤0 identified patients with survival benefit with 90-day revascularization in those without prior CAD (interaction P = 0.005), independently beyond percent ischemia and myocardial flow reserve. Among patients with known CAD, LVEF-R was not prognostic of death (HR: 0.99; 95% CI: 0.98-1.02; P = 0.98). ConclusionsA lack of augmentation or drop in LVEF with vasodilator stress on PET MPI independently identifies patients who have better survival with revascularization within 90 days post-MPI compared with medical therapy, in absence of prior myocardial infarction or revascularization. Multiparametric assessment of ischemia with PET can optimize post-test management.

Predictors of Left Main Coronary Artery Disease in the ISCHEMIA Trial

BackgroundDetection of ≥50% diameter stenosis left main coronary artery disease (LMD) has prognostic and therapeutic implications. Noninvasive stress imaging or an exercise tolerance test (ETT) are the most common methods to detect obstructive coronary artery disease, though stress test markers of LMD remain ill-defined. ObjectivesThe authors sought to identify markers of LMD as detected on coronary computed tomography angiography (CTA), using clinical and stress testing parameters. MethodsThis was a post hoc analysis of ISCHEMIA (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches), including randomized and nonrandomized participants who had locally determined moderate or severe ischemia on nonimaging ETT, stress nuclear myocardial perfusion imaging, or stress echocardiography followed by CTA to exclude LMD. Stress tests were read by core laboratories. Prior coronary artery bypass grafting was an exclusion. In a stepped multivariate model, the authors identified predictors of LMD, first without and then with stress testing parameters. ResultsAmong 5,146 participants (mean age 63 years, 74% male), 414 (8%) had LMD. Predictors of LMD were older age (P < 0.001), male sex (P < 0.01), absence of prior myocardial infarction (P < 0.009), transient ischemic dilation of the left ventricle on stress echocardiography (P = 0.05), magnitude of ST-segment depression on ETT (P = 0.004), and peak metabolic equivalents achieved on ETT (P = 0.001). The models were weakly predictive of LMD (C-index 0.643 and 0.684). ConclusionsIn patients with moderate or severe ischemia, clinical and stress testing parameters were weakly predictive of LMD on CTA. For most patients with moderate or severe ischemia, anatomical imaging is needed to rule out LMD. (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches [ISCHEMIA]; NCT01471522)

Abstract 9985: Comprehensive Cardiac Magnetic Resonance Imaging Study for Characterising Remote Myocardial Zone Contractile Function, Perfusion and Fibrosis in Type 2 Diabetes Patients with Prior Myocardial Infarction

Background: Type 2 diabetes (T2D) is associated with accelerated increased risk of myocardial infarction (MI). However, ventricular dysfunction has been identified also in T2D patients without prior MI. Objectives: Using cardiac magnetic resonance (CMR), we assessed the effect of established MI on the non-infarcted myocardium’s contractile function, rest and stress myocardial blood flow (MBF) and extra cellular volume fraction (ECV) by comparing remote zone assessments in T2D patients with prior MI (priorMI-DM) to the global assessments in T2D patients with no MI (noMI-DM) and in controls. We also aimed to extrapolate the contributions of infarct size and glycemic control (HBA1c) to cardiac functional changes (global longitudinal strain [GLS] and left ventricular ejection fraction [LVEF]) in T2D. Methods: Age and sex matched 42 priorMI-DM, 47 noMI-DM, and 22 controls underwent CMR (3T). Results: Table-1 shows clinical and CMR data. Both T2D groups showed significant reductions in LVEF and GLS. PriorMI-DM remote zone stress MBF was decreased compared to stress MBF in noMI-DM and controls (remote zone priorMI-DM 1.6±0.6ml/g/min vs global noMI-DM 1.8±0.4ml/g/min vs global control 1.9±0.4ml/g/min, p=0.01). Remote ECV and global ECV were similar in priorMI-DM and were increased compared to noMI-DM and controls. Remote ECV correlated with infarct size (r=0.66, p=0.001). In priorMI-DM, infarct size correlated with GLS (r=0.4, p=0.005) and with LVEF (r=0.2, p=0.03) but not HBA1c. In noMI-DM, there was a significant correlation between HBA1c and GLS (r=0.3, p=0.03). Conclusions: T2D patients exhibit reductions in LVEF and GLS even in the absence of prior MI, suggesting that metabolic factors beyond high prevalence of MI contribute to the cardiac dysfunction in T2D. T2D patients with prior MI show significant increases in ECV in the remote zone, accompanied by reductions in stress MBF, while remote zone contractile function remains preserved.

Decade Long Temporal Trends in Revascularization for Patients With Diabetes Mellitus (From the Northern New England Cardiovascular Disease Study Group)

The FREEDOM trial demonstrated superiority of coronary artery bypass grafting (CABG) for patients with diabetes mellitus (DM) and multivessel coronary artery disease (MV CAD) as compared to percutaneous coronary intervention (PCI) with drug eluting stent (PCI-DES). We sought to study the impact of the FREEDOM trial on clinical practice. We studied trends in the use of CABG vs. PCI and factors associated with revascularization strategy among 6,985 patients with concomitant CAD and MV CAD at 7 centers pre- and post-trial (2008-2012 vs. 2013-2017) as well as hospital outcomes. Multivariable mixed effects logistic regression was performed to identify risk factors associated with choice of revascularization strategy among the patients with 3-vessel CAD (3V CAD). 41% of patients had 3V CAD and 18% were ≥75 years of age. While PCI-DES was the preferred strategy in 2-vessel CAD (2V CAD), 72% of patients with 3V CAD underwent CABG. For patients with 3V CAD, the ratio of CABG to PCI-DES procedures was 2.47 over the decade and did not differ pre- and post-trial (adjusted odds ratio (OR) for CABG (vs. PCI) 1.01, 95% confidence interval (CI) 0.84-1.20). Independent risk factors of CABG among patients with DM and 3V CAD included peripheral arterial disease and absence of prior myocardial infarction and prior PCI. The risk factors for PCI were female sex (OR 0.60, 95% CI 0.50-0.73, p<0.001) and age ≥75 (OR 0.50, 95% CI 0.35-0.72, p<0.001). Center based variability was observed for CABG vs. PCI (center effect, rho=14%, p<0.001). In conclusion, PCI-DES is the preferred strategy for DM patients with MV CAD. Yet, among those with 3V CAD, CABG was chosen in ¾ of patients with no change in clinical practice related to the publication of the FREEDOM trial.

Elective Coronary Revascularization Procedures in Patients With Stable Coronary Artery Disease: Incidence, Determinants, and Outcome (From the CORONOR Study)

ObjectivesThe authors sought to describe the incidence, determinants, and outcome of elective coronary revascularization (ECR) in patients with stable coronary artery disease (CAD). BackgroundObservational data are lacking regarding the practice of ECR in patients with stable CAD receiving modern secondary prevention. MethodsThe authors analyzed coronary revascularization procedures performed during a 5-year follow-up in 4,094 stable CAD outpatients included in the prospective multicenter CORONOR (Suivi d'une cohorte de patients COROnariens stables en région NORd-Pas-de-Calais) registry. ResultsSecondary prevention medications were widely prescribed at inclusion (antiplatelet agents 96.4%, statins 92.2%, renin-angiotensin system antagonists 81.8%). A total of 481 patients underwent ≥1 coronary revascularization procedure (5-year cumulative incidences of 3.6% [0.7% per year] for acute revascularizations and 8.9% [1.8% per year] for ECR); there were 677 deaths during the same period. Seven baseline variables were independently associated with ECR: prior coronary stent implantation (p < 0.0001), absence of prior myocardial infarction (p < 0.0001), higher low-density lipoprotein cholesterol (p < 0.0001), lower age (p < 0.0001), multivessel CAD (p = 0.003), diabetes mellitus (p = 0.005), and absence of treatment with renin-angiotensin system antagonists (p = 0.020). Main indications for ECR were angina associated with a positive stress test (31%), silent ischemia (31%), and angina alone (25%). The use of ECR had no impact on the subsequent risk of death, myocardial infarction, or ischemic stroke (hazard ratio: 1.04; 95% confidence interval: 0.76 to 1.41). ConclusionsThese real-life data show that ECR is performed at a rate of 1.8% per year in stable CAD patients widely treated by secondary medical prevention. ECR procedures performed in patients without noninvasive stress tests are not rare. Having an ECR was not associated with the risk of ischemic adverse events.

Impact of chronic kidney disease on mortality in adults undergoing balloon aortic valvuloplasty.

Balloon aortic valvuloplasty (BAV) is often utilized as a bridge prior to surgical or transcatheter aortic valve replacement. Chronic kidney disease (CKD) is commonly present in patients with aortic stenosis, however, its association with outcomes following BAV has not been well studied. Accordingly, we sought to assess the impact of CKD on mortality in adults undergoing BAV. The Nationwide Inpatient Sample was screened for hospitalizations involving adults undergoing BAV from 2006 to 2012. Demographic data and clinical history were recorded. Patients were divided into those with and without CKD as a documented comorbidity and were compared for adjusted in-hospital mortality risk. Among a national cohort of 10,845 adults undergoing BAV, 3842 (35.4%) adults had CKD while 7003 (64.6%) did not. Patients with CKD were older, more often male, and had higher rates of coronary disease, heart failure, diabetes mellitus, hypertension, peripheral artery disease, obesity, obstructive sleep apnea, and atrial fibrillation. Adults with CKD undergoing BAV had significantly higher in-hospital mortality rates (10.2% vs 6.3%, p=0.0005). In multivariable analysis, CKD was independently associated with a nearly 2-fold higher odds of in-hospital mortality (odds ratio 1.98, 95% confidence interval 1.45-2.70, p<0.0001). Other predictors of mortality included presence of atrial fibrillation and absence of prior myocardial infarction, hypertension, peripheral arterial disease, and smoking. CKD was independently associated with a nearly 2-fold higher odds of in-hospital mortality in adults undergoing BAV. Further studies are warranted to determine whether preventive interventions can improve outcomes in this high-risk population.

Angiotensin II receptor blockers versus angiotensin-converting enzyme inhibitors in patients with stable coronary artery disease: Prevalence, correlates, and prognostic impact (from the CORONOR study)

BackgroundIn international guidelines for patients with stable coronary artery disease (CAD), angiotensin-converting enzyme inhibitors (ACE-I) are recommended while angiotensin II receptor blockers (ARB) are proposed as an alternative in case of intolerance. There are no real-life data on the frequency and correlates of ARB use in this setting. MethodsWe studied 3363 outpatients included in a prospective registry on stable CAD (the CORONOR study) and receiving an ARB or an ACE-I at inclusion. ResultsAltogether, 944 patients received an ARB (28.1%). Factors positively and independently associated with ARB use versus ACE-I use were a history of hypertension, the absence of prior myocardial infarction, age, female gender, estimated glomerular filtration rate <60ml/min/m2, and left ventricular ejection fraction ≥40%. In the whole study population, the hazard ratio (HR) for the combined endpoint (cardiovascular death, myocardial infarction, stroke) of patients with ARB use was 0.95 (0.69–1.31) (p=0.765) (patients with ACE-I use as reference). Similar results were observed when the analysis was restricted to a propensity-matched cohort: HR=0.91 (0.62–1.34) (p=0.632). ConclusionsOur study shows that a significant proportion of stable CAD patients are treated with ARB rather than with ACE-I in modern practice. Several correlates of ARB prescription were identified. Our results suggest that patients receiving ARB have similar outcome than patients receiving ACE-I.

24-HOUR ARTERIAL STIFFNESS PROFILE IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE AND CHRONIC HEART FAILURE

Objective: to study the specific features of arterial stiffness (AS) in patients with chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF) as evidenced by 24­hour monitoring. Subjects and methods . A total of 111 patients with COPD, including 76 with signs of CHF, were examined. The patients with COPD and CHF were divided into 2 groups according to the presence or absence of prior myocardial infarction (MI). A BPLab МнСДП­2 apparatus was used to study 24­hour AS monitoring readings. Results. The patients with COPD and CHF were noted to have higher values of AS index (ASI) (during a day, daytime) and pulse wave propa­ gation velocity (during a day, daytime, nighttime) than those with COPD without CHF. There was an association between ASI and major car­ diovascular risk factors (hypertension, age, body mass index). The patients with COPD, CHF, and prior MI, unlike those without the latter, were found to have an increased augmentation index throughout the follow­up (during both daytime and nighttime). In the patients with CHF without prior MI, the diurnal ASI was considerably greater than that in both the COPD patients without CHF and those with CHF and prior MI. Conclusion. Increased vascular wall stiffness was detected in the patients with COPD and CHF. By taking into account pronounced AS changes not only during daytime and nighttime hours, it is reasonable to perform 24­hour AS monitoring in patients with comorbidities in order to obtain more objective results.

Impact of severity of renal dysfunction on determinants of in‐hospital mortality among patients undergoing percutaneous coronary intervention

Chronic kidney disease (CKD) is a known prognostic indicator of poor outcomes following percutaneous coronary intervention (PCI) for coronary artery disease. However, it is unclear whether other predictors of mortality differ among patients with varying degrees of renal impairment. Thus, we aimed to identify determinants of in-hospital mortality which are specific to patients with preserved renal function, moderate CKD, or end stage renal disease (ESRD) on dialysis, undergoing PCI. The study population included 25,018 patients who underwent PCI between January 1, 2004, and December 31, 2007, at four New York State hospitals. The primary endpoint of the study was in-hospital mortality. A total of 474 (1.9%) patients had ESRD on dialysis, 6,596 (26.4%) had moderate CKD (GFR<60 ml/min/1.73 m(2) ), and 17,948 (71.7%) had preserved renal function (GFR>60 ml/min/1.73 m(2) ). Patients with ESRD and moderate CKD were older, more often male, and had higher rates of prior coronary revascularization, peripheral vascular disease, congestive heart failure, prior stroke, and diabetes than those with preserved function. All-cause in-hospital mortality rates were significantly higher in patients with ESRD and moderate CKD compared to patients with GFR >60 ml/min/1.73 m(2) (2.1% and 1.3%, respectively vs. 0.3%, p < 0.001). In multivariable analysis, ESRD (OR: 3.68, 95% CI 1.62-8.36) and moderate CKD (OR: 2.92, 95% CI 1.91-4.46) were independently associated with higher rates of in-hospital mortality. Independent predictors of mortality were markedly distinct in each group and included female gender and myocardial infarction within the past 72 hr in the ESRD group, versus left ventricular ejection fraction, peripheral vascular disease, congestive heart failure, emergency PCI, and absence of prior PCI in the moderate CKD group and age, prior bypass graft surgery, congestive heart failure, emergency PCI, and absence of prior myocardial infarction in patients with preserved renal function. Patients with moderate CKD or ESRD undergoing PCI have an approximately threefold increase in the risk of in-hospital mortality compared with patients with preserved renal function, with radically different mortality predictors existing for varying levels of renal function.

Effect of cardiac disease history on gated blood pool SPECT LV measurement accuracy

Background: Recently software has become available for the routine analysis of left ventricular (LV) end-diastolic volume (EDV) and ejection fraction (EF) from gated blood pool SPECT (GBPS) data. This investigation examined whether accuracy of GBPS measurements, using cardiac magnetic resonance (CMR) imaging as the standard, are influenced by unusual LV shapes, as would be expected for patients with prior MI. Methods: LV functional parameters were measured for 28 subjects (age=58±12 years; 85% male, 13 with prior MI (MI) and 15 with non-ischemic cardiomyopathy (CM) by GBPS, planar-GBP and by true-FISP CMR. GBPS calculations from a count-threshold algorithm (BP-SPECT, Columbia University, New York, NY), and a surface gradient algorithm (QBS, Cedars-Sinai Medical Center, Los Angeles, CA) were evaluated. Results: By linear regression analysis BP-SPECT, QBS and planar-GBP EF's correlated similarly with CMR (r=0.92, 0.88 and 0.90, respectively) and both GBPS methods correlated similarly versus CMR for EDV (r=0.88 and 0.89, respectively). By the paired t-test, CMR EF's (38%±17%) were not different from BP-SPECT, QBS or planar-GBP (44%±18%, 36%±19%, and 38%±16%, respectively) for MI and CM patients. BP-SPECT and QBS EDV's were found to be significantly lower than CMR for MI patients (159±51 ml and 140±69 ml versus 207±70 ml) but not for CM patients (223±108 ml and 206±111 ml versus 274±109 ml). Conclusion: GBPS LV function measurements closely parallel those of CMR and planar-GBP, but volume accuracy is influenced by presence or absence of prior myocardial infarction.

Optimal final lumen area and predictors of target lesion revascularization after stent implantation in small coronary arteries

Despite similar early clinical events, patients who undergo treatment of small vessels are at an increased risk for target lesion revascularization (TLR) after coronary artery stenting. We sought to determine predictors of TLR after stent implantation in small coronary arteries. We identified 423 consecutive patients who underwent intravascular ultrasound (IVUS)-guided small vessel stenting procedures in 465 coronary lesions with an angiographic reference vessel diameter of <2.75 mm. Patients were divided into 2 groups based on a final IVUS lumen area of ≤6.0 mm 2 (n = 345 lesions, group I) and >6.0 mm 2 (n = 115, group II). Baseline patient characteristics and in-hospital outcomes were similar between the 2 groups, except for a higher rate of restenotic lesions in group I and bifurcation lesions in group II. Group I had higher TLR rates at 1 year compared with group II patients (39% vs 26%, p = 0.02). The TLR rate appeared to decrease with greater stent expansion, especially at >90% of the reference vessel area, as assessed by IVUS. By multivariate analysis, an IVUS final stent area of ≤6 mm 2, diabetes, absence of prior myocardial infarction, and history of intervention were independent predictors of 1-year TLR in this population. Final stent area of >6.0 mm 2 and greater stent expansion were associated with a decrease in TLR. Therefore, there does not appear to be any “downside” to aggressive stent implantation strategies in small vessels. In contrast, IVUS allows maximization of final lumen dimensions to minimize clinical restenosis.

Atypical presentations among medicare beneficiaries with unstable angina pectoris

Chest pain is a hallmark symptom in patients with unstable angina pectoris (UAP). However, little is known regarding the prevalence of an atypical presentation among these patients and its relation to subsequent care. We examined the medical records of 4,167 randomly sampled Medicare patients hospitalized with unstable angina at 22 Alabama hospitals between 1993 and 1999. We defined typical presentation as (1) chest pain located substernally in the left or right chest, or (2) chest pain characterized as squeezing, tightness, aching, crushing, arm discomfort, dullness, fullness, heaviness, pressure, or pain aggravated by exercise or relieved with rest or nitroglycerin. Atypical presentation was defined as confirmed UAP without typical presentation. Among patients with confirmed UAP, 51.7% had atypical presentations. The most frequent symptoms associated with atypical presentation were dyspnea (69.4%), nausea (37.7%), diaphoresis (25.2%), syncope (10.6%), or pain in the arms (11.5%), epigastrium (8.1%), shoulder (7.4%), or neck (5.9%). Independent predictors of atypical presentation for patients with UAP were older age (odds ratio 1.09, 95% confidence interval 1.01 to 1.17/decade), history of dementia (odds ratio 1.49, 95% confidence interval 1.10 to 2.03), and absence of prior myocardial infarction, hypercholesterolemia, or family history of heart disease. Patients with atypical presentation received aspirin, heparin, and β-blocker therapy less aggressively, but there was no difference in mortality. Thus, over half of Medicare patients with confirmed UAP had “atypical” presentations. National educational initiatives may need to redefine the classic presentation of UAP to include atypical presentations to ensure appropriate quality of care.

Angioplasty decreases prolonged QT dispersion in patients with angina pectoris but not in patients with prior myocardial infarction.

Prolonged QT dispersion (QTd) is shortened by successful percutaneous transluminal coronary angioplasty (PTCA) in patients with ischemic heart disease. Particularly, QTd plays an important role in the prognostication in patients with prior myocardial infarction (MI). However, whether the effect of PTCA on QTd differs in patients with and without prior MI is not clear, and this study sought to clarify this question. In 41 consecutive patients with ischemic heart disease, we measured QTd from a routine 12-lead electrocardiogram taken at 72 h before and after successful PTCA. Patients were divided into two groups based on the presence or absence of prior MI: Group 1 consisted of 24 patients with angina (61 +/- 11 years old) without prior MI and Group 2 was comprised of 17 patients (69 +/- 10 years old) with prior MI. QTd was calculated as the difference between the maximum and minimum QT and QT corrected for heart rate (QTc), using Bazett's formula for calculating QTcd. All measurements were obtained manually and blindly. In Group 1, 15 of 24 patients (63%) demonstrated multivessel disease and 16 of 24 (67%) patients had high QTd > 60 ms. Percutaneous transluminal coronary angioplasty decreased QTd and QTcd in Group 1 (QTd, from 83 +/- 35 to 57 +/- 19 ms, p < 0.05 ; QTcd, from 89 +/- 37 to 63 +/- 33 ms, p < 0.05), whereas no changes were observed in Group 2 (QTd, from 73 +/- 25 to 69 +/- 22 ms, NS; QTcd, from 80 +/- 30 to 79 +/- 28 ms, NS). QTd is more sensitive to decrease by successful PTCA in patients with angina than in patients with prior MI. The effect of successful PTCA on inhomogeneity of ventricular repolarization reflected by QTd in patients with prior MI is different from that in patients without prior MI.

'ACE inhibitors are better than AT(1) receptor blockers (ARBs)' - controversies in heart failure.

'ACE inhibitors are better than AT(1) receptor blockers (ARBs)' - controversies in heart failure.

Previous Angina Reduces In-Hospital Death in Patients With Acute Myocardial Infarction

There is little information on how previous angina influences in-hospital deaths secondary to acute myocardial infarction (MI). This study evaluated the causes of in-hospital deaths in MI patients with and without previous angina. A total of 2,264 consecutive patients were admitted to our hospital due to acute MI. These patients were divided into 2 groups according to the presence or absence of prior MI. Both groups were further divided according to the presence or absence of previous angina. The causes of in-hospital deaths were classified into 4 categories: (1) cardiogenic shock or congestive heart failure, (2) cardiac rupture, (3) arrhythmia, and (4) other causes. In patients with a first MI, the in-hospital mortality rate was lower in patients with previous angina than those without (6.9% vs 11.4%, p <0.01). There was no significant difference between these patients with and without previous angina in in-hospital deaths due to cardiogenic shock or congestive heart failure, arrhythmia, or other causes. Death due to cardiac rupture was less frequent in patients with previous angina (1.4% vs 5.0%, p <0.01). In patients with prior MI, the in-hospital mortality rate was lower in patients with than without previous angina (17.7% vs 25.3%, p <0.05). In contrast to patients with their first MI, there was a trend toward a lower incidence of in-hospital death due to cardiogenic shock or congestive heart failure in patients with previous angina (12.8% vs 19.0%, p = 0.05). There were no significant differences in in-hospital deaths due to cardiac rupture, arrhythmia, and other causes between the 2 subgroups. In multivariate analysis, previous angina was an independent predictor of in-hospital death. Thus, in-hospital deaths after acute MI in patients with previous angina were less because of less cardiac rupture in patients with a first MI and less cardiogenic shock or congestive heart failure in patients with prior MI.

Excimer Laser Coronary Angioplasty: The New Approaches to Coronary Intervention (NACI) Experience

In the New Approaches to Coronary Intervention (NACI) registry, 887 patients were electively treated with excimer laser coronary angioplasty (ELCA) for coronary artery disease. The Advanced Interventional System (AIS) system was used in 487 cases; the Spectranetics system, in 400. The mean age was 63.4 years. Most patients had unstable angina (60.3%); 43.7% had a prior myocardial infarction; and 18.6% were high risk or inoperable patients. Mean ejection fraction was 55.4%. A total of 1,000 lesions were treated in the 887 patients. Of the 1,000 lesions treated with ELCA in the 887 patients, 36% were in the right coronary artery; 33%, left anterior descending; 13%, circumflex; 3%, left main; and 16.6%, vein graft. By angiographic core laboratory analysis available for 752 (85%) patients with 839 lesions, lesions were 12.76 mm long. The minimum lumen diameter increased to 1.29 mm after the laser and finally to 1.95 mm after adjunctive percutaneous transluminal coronary angioplasty (PTCA) (which was performed in 93% of all lesions), with a final residual stenosis of 32.1% and Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow in 95%. Dissections of grades B, C, or D were seen after 22.0% of initial laser attempts, and postlaser perforations were noted in 2.6%. Additional such dissections accumulated after adjunctive PTCA but the perforation rate remained low. Procedural success was achieved in 84% of patients, but 1.2% died, 0.7% experienced Q-wave myocardial infarction (MI), and 2.7% required emergency bypass surgery. Multiple logistic regression analysis could not identify any independent predictors of these in-hospital complications. One-year mortality was 5.7% and the cumulative incidence of Q-wave MI was 1.5%. Coronary artery bypass graft (CABG) surgery was performed in 15.0% of patients whereas 25.5% required repeat percutaneous intervention with a target lesion revascularization rate of 31%. Independent predictors of death, Q-wave MI, or target lesion revascularization (which, combined, occurred in 35.6% of patients) were the absence of prior MI, ELCA in the circumflex, perforation after the procedure, and small (<2 mm) final minimal lumen diameter. Considering the large number of patients with high-risk lesions, laser angioplasty was performed with excellent procedural success rates and a reasonable incidence of major complications.

Drug response at electropharmacologic study in patients with ventricular tachyarrhythmias: The importance of ventricular refractoriness

The clinical and electrophysiologic predictors of successful antiarrhythmic drug therapy for patients with inducible ventricular tachycardia were evaluated in 59 consecutive patients undergoing serial electropharmacologic trials. Structural heart disease was less frequently present in patients for whom effective therapy was found (p < 0.05). The presence of coronary artery disease and a history of prior myocardial infarction were significantly more frequently present in patients for whom antiarrhythmic drug therapy could not be found (p < 0.05). The corrected QT interval and ventricular effective refractory period measured at a pacing cycle length of 400 ms were significantly shorter in responders compared with nonresponders (QT interval 428 ± 52 versus 460 ± 59 ms; ventricular effective refractory period 237 ± 28 versus 254 ± 24 ms; (p < 0.05). In addition, the interelectrogram coupling interval of the ventricular extrastimulus initiating ventricular tachycardia was significantly shorter in responders compared with nonresponders (223 ± 37 versus 251 ± 33 ms; p = 0.003).Logistic regression analysis identified a short ventricular inter-electrogram coupling interval (p < 0.01) end absence of prior myocardial infarction (p < 0.05) as the only independent predictors of antiarrhythmic drug suppression of the induction of ventricular tachycardia. Greater drug-induced increments in the ventricular effective and functional refractory periods were observed in responders than in nonresponders as was the shortest ventricular interelectrogram coupling interval.Thus, baseline electrophysiologic measurements identify patients with inducible ventricular tachycardia who are likely to respond to antiarrhythmic drag therapy. Furthermore, these patients demonstrate greater drug-induced electrophysiologic changes.

Effects of exercise on the signal-averaged electrocardiogram in coronary artery disease

The effects of exercise on the signal-averaged electrocardiogram (SAECG) were investigated in 52 patients with stable coronary artery disease. The SAECG was recorded before and immediately after the exercise test and analyzed at 25 to 250 Hz and 40 to 250 Hz. All patients had SAECG with noise level ≤0.8 μV at 25 Hz and ≤0.6 μV at 40 Hz and with the difference in noise level between control SAECGs and SAECGs after exercise ≤0.2 to 0.3 μV. Twenty-eight patients developed ST changes consistent with transient subendocardial ischemia that persisted during the SAECG recording after exercise. There was no significant difference between control SAECGs and SAECGs after exercise in patients with or without a positive exercise test. The absence of significant change on the SAECG was not related to the presence or absence of prior myocardial infarction, site of infarction, development of exercise-induced ventricular arrhythmias or presence of an abnormal recording at baseline. These data suggest that exercise-induced electrophysiologic changes and ventricular arrhythmias may not be related to the anatomic-electrophysiologic substrate that underlies late potentials on the SAECG.

Relation of baseline characteristics to suppression of ventricular arrhythmias during placebo and active antiarrhythmic therapy in patients after myocardial infarction.

In the Cardiac Arrhythmia Pilot Study (CAPS), patients early (6-60 days) after acute myocardial infarction (MI) with ventricular premature complexes (VPCs) of over 10 per hour were randomized to receive, unaware, therapy with one of four antiarrhythmic drugs (n = 402) or placebo (n = 100). Treatment success was defined as 70% or more decrease in VPC rate and 90% or more decrease in VPC runs. If the first active drug was ineffective, a second drug was given. If placebo was ineffective, a second placebo was given. To determine whether or not baseline clinical characteristics predict the response to antiarrhythmic therapy, 10 baseline variables were selected for investigation: age, prior MI, time from CAPS MI to randomization, ejection fraction, baseline VPC frequency, presence of runs (greater than or equal to 3 consecutive VPCs, greater than or equal to 100 beats/min), beta-blocker therapy, digitalis therapy, MI transmurality, and MI location. At the end of the first drug treatment, apparent treatment success in patients receiving placebo was associated on univariate analysis with absence of prior MI, with trends for younger age and Q wave MI, whereas in patients receiving active therapies, higher ejection fraction and younger age were associated with better suppression. In the encainide and flecainide treatments, where the greatest response was observed, absence of prior MI, higher ejection fraction, and younger age were associated with more successful treatment. In a multivariate analysis with these variables, ejection fraction and age remained significant for all active therapies, absence of prior MI and ejection fraction remained significant in the encainide and flecainide treatments, and absence of prior MI in the placebo treatment. Few variables except ejection fraction were associated with VPC suppression during the 1-year follow-up, and only lower ejection fraction and older age related to loss of long-term suppression. Thus, there are only a few independent baseline clinical variables (notably, ejection fraction) that substantially affect antiarrhythmic drug efficacy in suppressing VPCs in patients early after MI. Some variables, however, may be associated with spontaneous arrhythmia variability, leading to an apparent (placebo) response. These findings will be helpful in designing and interpreting treatment studies in patients after MI.

Effects of the Mueller maneuver on global and regional left ventricular function in angina pectoris with or without previous myocardial infarction

In patients with coronary artery disease, left ventricular (LV) regional wall akinesia can develop during the Mueller maneuver. 15 The present study determines if the presence of myocardial ischemic disease with no infarction is a sufficient condition for this to occur, or if the presence of prior acute myocardial infarction (MI) is necessary. In men, first-pass radionuclide ventriculography was performed in the 30 ° left anterior oblique supine position to measure LV ejection fraction, end-diastolic and end-systolic volumes and heart rate, and to obtain an image of the LV cavitary perimeter. This procedure was performed in 4 subject groups: 13 normal volunteers, 25 patients with coronary artery disease but no prior MI, 13 patients with coronary artery disease and prior nontransmural MI, and 36 patients with coronary artery disease and prior transmural MI. All patients had angina and underwent routine contrast coronary angiography; 60 also underwent contrast LV angiography. Ejection fraction decreased during the Mueller maneuver in each of all the coronary artery disease groups (p < 0.01), but not in the normal subjects. Heart rate increased in groups 1, 2 and 4 (p < 0.01), and end-diastolic volume decreased in all 4 groups (p < 0.01), whereas end-systolic volume did not change. Only in group 4 did regional wall akinesia develop (17 patients) during the Mueller maneuver. Among patients who had akinesia during the Mueller maneuver and also underwent routine contrast ventriculography, half of the akinetic segments were not seen on routine contrast study, but were seen only on radionuclide ventriculography during the Mueller maneuver. Thus, the appearance of regional LV wall akinesia on the radionuclide ventriculogram during the Mueller maneuver signifies the presence of prior transmural MI. The Mueller maneuver enhances the sensitivity of the radionuclide ventriculogram for detecting poorly functioning or nonfunctioning myocardium. The decrease in ejection fraction occurring in the patient groups, even in the absence of prior MI, may indicate that subtle abnormalities are present, which are exaggerated and detected during the performance of the Mueller maneuver.