Length of stay in myocardial infarction.

OBJECTIVE: We evaluated the association between length of hospital stay (LOS) and clinical factors, treatment intensity, and use of percutaneous coronary revascularization from 1988 to 1997. BACKGROUND: Multiple factors contribute to the observed reduction in LOS for patients with myocardial infarction. METHODS: We studied a series of 849 consecutive patients admitted with acute myocardial infarction to the Mayo Clinic Coronary Care Unit within three time periods: period I (1988-1990), period II (1991-1993), and period III (1994-1997). RESULTS: Median LOS decreased significantly between 1988 and 1997 (9 days to 5 days, 36% reduction, p < 0.0001), with significant reductions (p < 0.001) associated with certain therapies: primary reperfusion (6 days vs 7 days), b-blockers (6 days vs 8 days), and aspirin (6 days vs 8 days). Hospitalizations were lengthened by coronary artery bypass grafting (12 vs 6 days) and by serious complications (10 vs 6 days). The era of the admission (period I vs II vs III) is a significant, powerful predictor of LOS, even after adjustment for other key variables. CONCLUSION: The 36% reduction in LOS for acute myocardial infarction between 1988 and 1997 is related both to therapeutic modalities and temporal trends. Further study is needed to clarify whether the trend for decreasing LOS persists and influences outcome and health care quality variables.

[New methods of coronary imaging II. Intracoronary ultrasonography in clinical practice]. / Nuove modalità di imaging coronarico II. Ultrasonografia intracoronarica nella pratica clinica.

Coronary angiography remains the standard technique for the assessment and therapy of coronary artery disease. Recently, intravascular ultrasound (IVUS) has emerged as a new adjunctive invasive tool which allows the acquisition of direct images of the atherosclerotic plaque in the cardiac catheterization laboratory; however it cannot be considered as an alternative to angiography. The aim of this article was to describe the indications, technique, and interpretation of IVUS imaging and its diagnostic and therapeutic applications, to review the pertaining literature and report the experience from our catheterization lab group. Ultrasound provides a unique method to study the regression or progression of atherosclerotic lesions in vivo. Lipid-laden lesions appear hypoechoic, fibromuscular lesions generate low-intensity or "soft echos" while the fibrous and calcified tissue impedes ultrasound penetration, obscuring the underlying vessel wall (acoustic shadowing). IVUS has been used to evaluate arterial remodeling: positive remodeling is the increase in arterial size to compensate for plaque accumulation and represents a compensatory mechanism to preserve lumen size; negative remodeling is vessel shrinkage and has been implicated in restenosis after balloon angioplasty. Positive remodeling seems to be significantly more frequent in myocardial infarction and unstable angina, negative remodeling occurs more often in stable coronary syndromes and is the main mechanism of restenosis after balloon angioplasty. In ostial and bifurcation lesion, the stenosis may be obscured by overlapping contrast-filled structures. Intermediate stenoses are particularly problematic in patients whose symptomatic status is difficult to assess. In these ambiguous situations, ultrasound provides a tomographic perspective, independent of the radiographic projection, which often allows precise lesion quantification. IVUS has emerged as the optimal method for the detection of diffuse post-transplant vasculopathy. Rapidly progressive intimal thickening (> 0.5 mm increase) in the first year after transplantation has major negative prognostic significance. The safety of IVUS is well documented, with studies reporting complication rates varying from 1 to 3%; the complications most frequently reported is transient spasm. Ultrasound allows us to evaluate plaque morphology, plaque eccentricity and lesion length, often helping in procedural decision-making. IVUS demonstrates plaque fracture and arterial wall dissection more often than angiography. Coronary angiograms frequently underestimate disease burden, whereas IVUS identifies residual plaque burden and minimal lumen diameter as the most powerful predictor of clinical outcome (restenosis). Several IVUS studies of directional atherectomy have addressed the issue of more aggressive plaque removal possibly resulting in decreased angiographic restenosis rate. IVUS imaging has played a pivotal role in the optimization of stent therapy. The concept of high-pressure stent implantation disseminated quickly, and larger trials demonstrated the safety of stent implantation using high pressures. IVUS has shown that in-stent restenosis is determined by the degree of intimal hyperplasia within the stent or in the stent border. In conclusion, the use of IVUS in the world is slowly increasing. Ultrasound commonly detects occult disease in patients with coronary artery disease. However, no short- or long-term studies have determined whether disease detected exclusively by ultrasound portends a worse prognosis as compared with "true normal" angiography.

Characteristics of presenting electrocardiograms of acute myocardial infarction from a community-based population predict short- and long-term mortality.

To investigate the relevance of presenting electrocardiographic (ECG) patterns to short- and long-term mortality in nonreferral patients with acute myocardial infarction (AMI), 6 ECG patterns were analyzed. A consecutive series of 907 patients from Olmsted County, Minnesota, admitted to the Mayo Clinic Cardiac Care Unit from January 1, 1988 to March 31, 1998 for acute myocardial infarction comprised the study population. ECG patterns and distribution in the population were: (1) ST elevation alone (20.8%), (2) ST elevation with ST depression (35.2%), (3) normal or nondiagnostic electrocardiograms (18.5%), (4) ST depression alone (11.8%), (5) T-wave inversion only (10.7%), and (6) new left bundle branch block (LBBB) (3.0%). Seven- and 28-day mortalities varied significantly (p <0.01) among the 6 ECG groups. Respective mortalities were 3.0% and 6.0% for patients with normal or nondiagnostic electrocardiograms, 3.1% and 5.2% for T-wave inversion only, 7.4% and 10.6% for ST elevation alone, 9.4% and 13.1% for ST depression alone, 10.3% and 13.8% for ST elevation with ST depression, and 18.5% and 22.2% for new LBBB. Length of hospital stay (LOS) also varied among the ECG pattern groups (p <0.001) with the longest average LOS being in the new LBBB group (12.5 days). Long-term survival was similar among 5 ECG pattern groups (45% to 55% at 8 years from discharge) with the exception of LBBB (20% at 8 years). Among non-LBBB groups, ST-segment depression with or without ST elevation was associated with increased short-term mortality. Also, in this community-based population, 18.5% of patients had normal or nondiagnostic electrocardiograms.

Prevalence of atrial fibrillation and stroke in paced patients without prior atrial fibrillation: a prospective study.

BACKGROUND: Several reports suggest that the incidence of stroke and atrial fibrillation is reduced in patients receiving physiologic pacemakers, compared with patients receiving a ventricular pacemaker. HYPOTHESIS: The study was undertaken to address the impact of different pacing modalities on the incidence of stroke and atrial fibrillation. METHODS: We prospectively analyzed 210 consecutive patients. Those with previous episodes of cerebral ischemia and/or atrial fibrillation were excluded from the study. The study population included 100 patients paced for total atrioventricular (AV) block or second-degree AV block (type II Mobitz) and 110 patients paced for sick sinus syndrome (SSS). The pacing mode was randomized. All patients underwent a brain computed tomography (CT) scan at the date of enrollment and after 1 and 2 years. Patients were followed for 2 years, and the incidence of atrial fibrillation and stroke was evaluated. RESULTS: The incidence of atrial fibrillation was 10% at 1 year and 11% at 2 years. Comparing the different pacing modalities, we reported an increase in the incidence of atrial fibrillation in patients receiving ventricular pacing (p < 0.05). On the other hand, no difference was found between patients paced for AV block and those paced for SSS. At the end of follow-up, we reported 29 cases of cerebral ischemia: 9 patients had AV block while 20 had SSS (p < 0.05). Comparing the different pacing modalities, there was an increase in the incidence of stroke in patients receiving ventricular pacing (p < 0.05). CONCLUSION: There was an increase in the incidence of stroke and atrial fibrillation in patients with ventricular pacing.

Short atrioventricular delay reduces the degree of mitral regurgitation in patients with a sequential dual-chamber pacemaker.

This study was performed in a population of sequential dual-chamber pacemaker-patients with isolated mitral regurgitation (MR) to identify the "ideal atrioventricular (AV) delay" and to determine the effect of sequential pacing with the ideal AV delay on MR degree. Twenty consecutive patients (age 69 +/- 7 years; 45% men) hospitalized at our institution for symptomatic III degree AV block and isolated MR were studied. All received a dual-chamber pacemaker programmed in DDD at a rate of 70 pulses/minute. The ideal AV delay was selected using echo-color Doppler parameters; it was defined as that resulting in a lower degree of MR and in the highest cardiac output. The mean "optimal short" AV delay resulted in 98 +/- 7 ms. At short AV delay we observed a significant reduction in MR severity (regurgitant fraction from 48 +/- 12% to 25 +/- 10% and jet area from 15 +/- 2 to 9 +/- 2 cm2; p <0.0001) together with an increase in stroke volume (68 +/- 16 vs 88 +/- 15 ml; p = 0.007) and mitral early-to-late peak velocity ratio (0.79 +/- 0.33 vs 1.38 +/- 0.37; p <0.0001). In conclusion, a short AV delay may be used to improve cardiac output in sequential paced patients with pure, isolated MR.

Left atrial size is the major predictor of cardiac death and overall clinical outcome in patients with dilated cardiomyopathy: a long-term follow-up study.

HYPOTHESIS: This study was undertaken to determine whether echo-derived left atrial dimension and other echocardiographic, clinical, and hemodynamic parameters detected at the time of entry into the study may influence prognosis in patients with dilated cardiomyopathy during a long-term follow-up. METHODS: This was a prospective cohort analysis of 123 patients with dilated cardiomyopathy. Clinical evaluation, chest x-ray, M-mode and two-dimensional echocardiogram, exercise test, 72-h ambulatory electrocardiogram monitoring, and cardiac catheterization study were performed in all patients. The study was divided into two phases: in the first phase, patients were divided into two groups according to the left atrial size (> or = 45 mm; < 45 mm), with cardiac death as the end point. In the second phase, all patients were further divided into two groups according to their clinical course. A multivariate analysis was performed to determine independent correlated parameters of cardiac mortality and overall clinical outcome. RESULTS: Cardiac mortality rate was 47.9%: 29% in the group without left atrial dilation and 54.3% in the group with dilated left atrium. Multivariate analysis revealed that left atrium > or = 45 mm, New York Heart Association functional classes III/IV, and the presence of one or more episodes of ventricular tachycardia at Holter monitoring were independent predictors of cardiac mortality, while left atrium > or = 45 mm, left ventricular end-diastolic pressure > 17 mmHg, and exercise tolerance < or = 15 min were independent predictors of poor clinical outcome. CONCLUSIONS: Our results revealed that left atrial size is the principal independent predictor of prognosis in patients with dilated cardiomyopathy in that patients with left atrial dilation had an increase in mortality and a worse clinical outcome compared with those without left atrial dilation.

Early predictors of late dilation and remodeling after thrombolized anterior transmural myocardial infarction.

BACKGROUND AND HYPOTHESIS: Dilation of the left ventricle after myocardial infarction is associated with an adverse prognosis. There are no clinical studies on the role viable myocardium in the infarcted area assumes in relation to the development of late ventricular remodeling. The hypothesis of this study was to define the relation between remodeling and the presence of viable but akinetic myocardium in the infarct area and to identify early predictors of left ventricular (LV) dilation at 1 year. METHODS: In all, 92 consecutive patients with myocardial infarction were divided into two groups according to their ventricular volumes. Group I included 57 patients with normal volumes at discharge (9 +/- 3 days after acute infarction) and after 12 months or with LV dilation at discharge who had a normalization of their volumes over a 12-month period. Group II included 35 patients who, independent of their initial volumes, developed LV dilation during follow-up. Low-dose dobutamine infusion was utilized at discharge for echocardiographic evaluation of contractile recovery of viable myocardial segments. RESULTS: At the first control, patients in Group I presented an end-diastolic volume index (EDVI) of 100 +/- 7 ml/m2 which decreased to 68.8 +/- 6.5 ml/m2 12 months later (p < 0.0001), and an end-systolic volume index (ESVI) of 47.6 +/- 6.7 ml/m2 at the first control and 30.5 +/- 8.8 ml/m2 after 12 months (p < 0.001). Patients in Group II presented a mean EDVI of 116.2 +/- 8.1 ml/m2 at the first control and 138.8 +/- 8 ml/m2 12 months later (p < 0.001), and a mean ESVI of 68.8 +/- 6.5 ml/m2 at the first control and 79.5 +/- 5.4 after 12 months (p < 0.01). Ventricular mass index (VMI) in Group I increased from 106.4 +/- 11 to 122.3 +/- 15 g/m2 (p < 0.01), while in Group II it decreased from 101.1 +/- 10 to 98.7 +/- 8 g/m2 (p = NS). In Group I, mass-to-volume ratio was 1.15 +/- 0.1 g/ml at the first control and 1.67 +/- 0.1 g/ml 12 months later (p < 0.001), while in Group II it declined from 0.88 +/- 0.1 to 0.69 +/- 0.1 g/ml (p < 0.01). The multivariate analysis revealed that ejection fraction < or = 40%, restrictive filling pattern, wall motion score index > 2.5 in response to dobutamine infusion, and mass-to-volume ratio < or = 1 g/ml, all at discharge, as well as an occluded left anterior descending artery discriminate in favor of late LV dilation and remodeling. CONCLUSIONS: Correct use of noninvasive strategies should result in early identification of postinfarct patients who are at risk of developing LV remodeling.