Biomedical subjects

David Bello

Publications and source records attributed to David Bello.

5 recordsLinked to original sources

PubMed2005

Infarct morphology identifies patients with substrate for sustained ventricular tachycardia.

OBJECTIVES: We sought to evaluate whether infarct size characterization by cardiac magnetic resonance imaging (MRI) is a better predictor of inducible ventricular tachycardia (VT) than left ventricular ejection fraction (LVEF). BACKGROUND: Inducibility of VT at electrophysiologic study (EPS) and low LVEF can identify patients with a substrate for VT. Magnetic resonance imaging has been shown to identify, with high precision, areas of myocardial infarction and may therefore be a better tool to evaluate for a substrate for VT. METHODS: We studied 48 patients with known coronary artery disease who were referred for EPS using cine and gadolinium-enhanced MRI. Wall motion and infarct characteristics were determined blindly and compared among patients with no inducible ventricular arrhythmias (n = 21), those with inducible monomorphic VT (MVT, n = 18), and those with either inducible polymorphic VT or ventricular fibrillation (n = 9). RESULTS: Patients with MVT had larger infarcts than patients who did not have inducible arrhythmias (mass: 49 +/- 5 g [SE] vs. 28 +/- 5 g, p < 0.005; surface area: 172 +/- 15 cm(2) vs. 93 +/- 14 cm(2), p < 0.0005). Patients with polymorphic VT/fibrillation had intermediate values (mass: 36 +/- 7 g; surface area: 115 +/- 22 cm(2)). Ejection fraction was inversely related to infarct mass and surface area, with R(2) values ranging from 0.21 to 0.27. Logistic regression and receiver-operating characteristic analysis demonstrated that infarct mass and surface area were better predictors of inducibility of MVT than LVEF. CONCLUSIONS: Infarct surface area and mass, as measured by cardiac MRI, are better identifiers of patients who have a substrate for MVT than LVEF. Further evaluation of infarct size characterization by cardiac MRI as a predictor of sudden cardiac death is warranted.

Female↗

PubMed2004

Relation between contractile reserve and improvement in left ventricular function with beta-blocker therapy in patients with heart failure secondary to ischemic or idiopathic dilated cardiomyopathy.

Beta blockers improve left ventricular (LV) ejection fraction but patient responses are heterogenous. We investigated the role of contractile reserve (CR) in predicting beta-blocker response in ischemic and nonischemic cardiomyopathy. Resting and low-dose dobutamine echocardiograms were recorded in 32 patients with heart failure (LV ejection fraction <or=35%), 18 with ischemic cardiomyopathy (IC), and 14 with idiopathic dilated cardiomyopathy (IDC). A segment was defined as CR positive (CR+) or negative (CR-) based on response to dobutamine. Patients were then classified as CR+ or CR- based on number of improved segments (IC group) or ejection fraction improvement (IDC group) in response to dobutamine. During follow-up (2, 6, and 14 months after beta-blocker initiation), response was measured by the percent of segments showing improved contractility from baseline, ejection fraction, and wall motion score index. In the IC group, the percent of improved segments was greater at 2 and 6 months in CR+ versus CR- (70% vs 15% and 39% vs 17%, p <0.05), whereas it was greater at all periods in the patients with IDC (36% vs 9% at 2 months, 50% vs 19% at 6 months, and 63% vs 42% at 14 months, p <0.05). Findings for ejection fraction and wall motion score index were similar. Therefore, time course and magnitude of improvement in LV function in patients with heart failure receiving beta blockers are related to CR status. CR predicts a greater early response in IC, whereas it predicts a greater response at all time periods in IDC. However, even patients without CR showed improvement in LV function at 14 months.

Adrenergic beta-Antagonists↗

PubMed2004

Catheter ablation of ventricular tachycardia guided by contrast-enhanced cardiac computed tomography.

We describe catheter ablation of recurrent ventricular tachycardia using high-resolution definition of a myocardial infarct scar by contrast-enhanced cardiac computed tomography (CT). Positron emission tomography scanning as well as three-dimensional electroanatomic mapping confirmed the extent of scar prior to ablation. Catheter ablation based on substrate mapping was successful in eliminating the ventricular tachycardia. Detection of scar by cardiac CT has the potential to abbreviate voltage/substrate mapping in the electrophysiology laboratory. To our knowledge, this is the first time myocardial scar was defined by cardiac CT and utilized for defining an ablation strategy for ventricular tachycardia.

Aged↗

PubMed2003

Gadolinium cardiovascular magnetic resonance predicts reversible myocardial dysfunction and remodeling in patients with heart failure undergoing beta-blocker therapy.

BACKGROUND: In some patients with heart failure, beta-blockers can improve left ventricular (LV) function and reduce morbidity and mortality. We hypothesized that gadolinium-enhanced cardiovascular magnetic resonance imaging (CMR) can predict reversible myocardial dysfunction and remodeling in heart failure patients treated with beta-blockers. METHODS AND RESULTS: Forty-five patients with chronic heart failure underwent CMR. Contrast imaging using gadolinium was performed to obtain high-resolution spatial maps of myocardial scarring and viability. Cine imaging was performed to assess LV function and morphology and was repeated in 35 patients after 6 months of beta-blockade. Gadolinium CMR demonstrated scarring in 30 of 45 patients (67%). Scarring was found in 100% of patients with ischemic cardiomyopathy (28 of 28) but in only 12% with nonischemic cardiomyopathy (2 of 17). In the 35 patients who were maintained on beta-blockers and had a second study, there was an inverse relation between the extent of scarring at baseline and the likelihood of contractile improvement 6 months later (P<0.001). For instance, contractility improved in 56% (674 of 1207) of regions with no scarring but in only 3% with >75% scarring (8 of 232). Multivariate analysis showed that the amount of dysfunctional but viable myocardium by CMR was an independent predictor of the change in ejection fraction (P=0.01), mean wall motion score (P=0.0007), LV end-diastolic volume index (P=0.007), and LV end-systolic volume index (P< or =0.0001). CONCLUSIONS: For heart failure patients treated with beta-blockers, gadolinium-enhanced CMR predicts the response in LV function and remodeling.

Adrenergic beta-Antagonists↗

PubMed2003

Cardiology participation improves outcomes in patients with new-onset heart failure in the outpatient setting.

OBJECTIVES: This study examined the outcomes of new-onset heart failure (HF) outpatients managed by cardiologists and primary care (PC) physicians. BACKGROUND: Several studies have sought differences in outcomes between patients with HF managed by cardiologists and PC physicians, but most focused on inpatients, who often represent later stages of HF, whereas many treatments have their impact by delaying disease progression. METHODS: This was a retrospective cohort study of incident HF identified between 1996 and 1997 in a staff model health maintenance organization. Cardiology care was defined as >/=2 visits or >/=25% of total medical outpatient visits to cardiology. Records from a cohort of 403 patients with new-onset outpatient HF were reviewed. The main outcome measure was a combination of death and/or cardiovascular hospitalization at 24 months. RESULTS: Cardiologists' patients (n = 198) were younger (66 vs. 71 years, p = 0.001), were more likely men (54% vs. 46%, p = 0.01), had coronary artery disease (64% vs. 42%, p = 0.001), and had a low (</=45%) ejection fraction (EF) (66% vs. 44%, p < 0.001) compared with PC physicians' patients. More cardiologists' patients received an EF assessment (94% vs. 74%, p < 0.001), angiotensin-converting enzyme inhibitors (83% vs. 68%, p < 0.001), and beta-blockers (38% vs. 22%, p < 0.001). In multivariate proportional hazards modeling that included variables that differed between providers and univariate predictors of outcomes, cardiology care was an independent predictor of a lower risk for the combined outcome (hazard ratio 0.62, confidence interval 0.42 to 0.93, p = 0.02). CONCLUSIONS: Cardiology care at this early stage of HF is associated with improved guideline adherence and a reduced risk of the composite outcome of death plus cardiovascular hospitalization.

Aged↗