Red cell distribution width predicts death and appropriate therapy in patients with implantable cardioverter defibrillator: A simple measurement with prognostic value in a variety of diseases, may help in better selection of patients who will benefit the most from this device.

BACKGROUND: Red cell distribution width (RDW) is a measure of the size variation of erythrocytes. Its prognostic value has been described in a variety of cardiac and noncardiac diseases. Implantable cardioverter defibrillator (ICD) is useful in preventing sudden cardiac death in high-risk patients, but many of these patients continue to survive without needing ICD therapy. We sought to examine whether RDW, with its prognostic values, can benefit in risk stratification of patients with ICD by predicting death and ICD therapy, and thus help in the selection of patients who will benefit the most from ICD, and minimizing its implantation in others at low risk of death and arrhythmias. METHODS: In a retrospective study, we enrolled patients with ICD implanted for both primary and secondary prevention of sudden cardiac death. Baseline RDW values, demographics, and clinical characteristics, as well as the occurrence of death or first appropriate ICD therapy in postimplantation follow-up were collected. We examined whether RDW can predict higher-risk ICD-implanted patients prone to death and first appropriate ICD therapy (the combined outcome). RESULTS: Final population included 432 patients. Compared to others, patients in the upper RDW tertile were older and had more comorbidities and outcomes. In multivariate analysis including RDW, age, gender, and ejection fraction, RDW was the only predictor of the combined outcome. CONCLUSION: RDW may be useful in risk stratification of patients selected for ICD implantation. But larger prospective randomized trials are needed.

Restrictive left ventricular filling pattern and risk of new-onset atrial fibrillation after acute myocardial infarction.

Mechanisms for atrial arrhythmias that occur in the context of acute myocardial infarction (AMI) have not been well characterized. AMI often leads to alterations in left ventricular (LV) filling dynamics, which may result in advanced diastolic dysfunction. Diastolic dysfunction may produce increased left atrial (LA) pressure and initiate LA remodeling, promoting the progression to atrial fibrillation (AF). We studied 1,169 patients admitted with AMI. Advanced diastolic dysfunction was defined as a restrictive filling pattern (RFP), defined as ratio of early to late transmitral velocity of mitral inflow >1.5 or deceleration time <130 ms. The relation between RFP and the primary end point of new-onset AF occurring within 6 months was analyzed using multivariable Cox models. Of 1,169 patients (70% men, mean ± SD 64 ± 10 years of age), 110 (9.4%) developed new-onset AF (19.6% and 7.5% in patients with and without RFP, respectively, p <0.0001). RFP was associated with a hazard ratio of 2.72 for AF (95% confidence interval 1.83 to 4.05, p <0.0001). After multivariable adjustments for clinical variables, LV ejection fraction (EF) and LA size, RFP remained an independent predictor of AF (hazard ratio 2.17, 95% confidence interval 1.42 to 3.32, p <0.0001). Risk of AF was higher in patients with RFP for preserved (≥45%, hazard ratio 2.14, 95% confidence interval 1.09 to 4.20, p = 0.03) or decreased (hazard ratio 2.80, 95% confidence interval 1.63 to 4.82, p <0.0001) LVEF. In contrast, decreased LVEF in the absence of RFP was similar to that of patients with preserved LVEF and without RFP. In conclusion, in patients with AMI, presence of advanced diastolic dysfunction was independently associated with new-onset AF, suggesting that increased filling pressures may contribute to the development of AF after AMI.

Relationship of functional mitral regurgitation to new-onset atrial fibrillation in acute myocardial infarction.

BACKGROUND/OBJECTIVE: The role of factors that increase left atrial pressure or cause acute left atrial dilatation is frequently emphasised in the pathogenesis of atrial fibrillation (AF) in patients with acute myocardial infarction (AMI). This study was designed to test the hypothesis that functional mitral regurgitation (FMR) occurring after AMI may promote AF by producing left atrial volume overload. SETTING: Intensive care unit of a tertiary care hospital. PATIENTS AND METHODS: 1920 patients admitted with AMI were studied. Patients with known AF were excluded. FMR was classified using echocardiography into three groups: none; mild FMR and moderate or severe FMR. The relationship between FMR and AF occurring at any time during the hospital course was examined using multivariable logistic regression. RESULTS: Mild FMR was present in 744 patients (38.8%) and moderate or severe FMR was present in 150 patients (7.8%). AF developed in 51 (5.0%), 83 (11.2%) and 28 (18.7%) patients with no FMR, mild FMR and moderate or severe FMR, respectively (p trend <0.001). In multivariable logistic regression, both mild (odds ratio (OR) 1.6; 95% CI 1.1 to 2.3, p=0.02) and moderate or severe FMR (OR 2.1; 95% CI 1.2 to 3.6, p=0.007) were independent predictors of AF. There was a significant interaction between the left ventricular ejection fraction and FMR (p=0.003) such that mild FMR was predictive of AF only in patients with a reduced (<45%) ejection fraction. CONCLUSIONS: There is a graded independent association between the severity of FMR and the new onset of AF in patients with AMI.

Relation between red cell distribution width and clinical outcomes after acute myocardial infarction.

Increased red blood cell distribution width (RDW) has been associated with adverse outcomes in heart failure and stable coronary disease. We studied the association between baseline RDW and changes in RDW during hospital course with clinical outcomes in patients with acute myocardial infarction (AMI). Baseline RDW and RDW change during hospital course were determined in 1,709 patients with AMI who were followed for a median of 27 months (range 6 to 48). The relation between RDW and clinical outcomes after hospital discharge were tested using Cox regression models, adjusting for clinical variables, baseline hemoglobin, mean corpuscular volume, and left ventricular ejection fraction. Compared to patients in the first RDW quintile, the adjusted hazard ratios for death progressively increased with higher quintiles of RDW (second quintile 1.1, 95% confidence interval [CI] 0.6 to 2.1; third quintile 1.8, 95% CI 1.0 to 3.2; fourth quintile 2.0, 95% CI 1.1 to 3.4; fifth quintile 2.8, 95% CI 1.6 to 4.7, p for trend <0.0001). An increase in RDW during hospital course was also associated with subsequent mortality (adjusted hazard ratio 1.13 for 1-SD increase in RDW, 95% CI 1.02 to 1.25). Similar results were obtained for the end point of heart failure. The association between increased RDW and worse outcome was evident in patients with and without anemia. In conclusion, there is a graded, independent association between increased RDW and mortality after AMI. An increase in RDW during hospitalization also portends adverse clinical outcome.

Impact of diastolic dysfunction on the development of heart failure in diabetic patients after acute myocardial infarction.

BACKGROUND: Diabetes is often associated with an abnormal diastolic function. However, there are no data regarding the contribution of diastolic dysfunction to the development of heart failure (HF) in diabetic patients after acute myocardial infarction. METHODS AND RESULTS: A total of 1513 patients with acute myocardial infarction (417 diabetic) underwent echocardiographic examination during the index hospitalization. Severe diastolic dysfunction was defined as a restrictive filling pattern (RFP) based on E/A ratio >1.5 or deceleration time <130 ms. The primary end points of the study were readmission for HF and all-cause mortality. The frequency of RFP was higher in patients with diabetes (20 versus 14%; P=0.005). During a median follow-up of 17 months (range, 8 to 39 months), 52 (12.5%) and 62 (5.7%) HF events occurred in patients with and without diabetes, respectively (P<0.001). There was a significant interaction between diabetes and RFP (P=0.04) such that HF events among diabetic patients occurred mainly in those with RFP. The adjusted hazard ratio for HF was 2.77 (95%, CI 1.41 to 5.46) in diabetic patients with RFP and 1.21 (95% CI, 0.75 to 1.55) in diabetic patients without RFP. A borderline interaction (P=0.059) was present with regard to mortality (adjusted hazard ratio, 3.39 [95% CI, 1.57 to 7.34] versus 1.61 [95% CI, 1.04 to 2.51] in diabetic patients with and without RFP, respectively). CONCLUSIONS: Severe diastolic dysfunction is more common among diabetic patients after acute myocardial infarction and portends adverse outcome. HF and mortality in diabetic patients occur predominantly in those with concomitant RFP.