Raja Kannan Mutharasan

Computer three-dimensional reconstruction of the atrioventricular conduction system.

The human atrioventricular conduction system (AVCS), which includes the AV node and its approaches, AV bundle (penetrating, branching, and bifurcating parts), and the bundle branches, is a curved complex structure that has not been reconstructed in three dimensions using computer technology. Microscopic slides of every 40th serial section (cut at 7 micron level) of the AVCS were digitized into 600 dots/inch color images. External outlines of each section were manually segmented using commercially available three‐dimensional rendering software (Rhinoceros). The AVCS was traced from light microscopy and superimposed onto the external outlines. To account for inherent errors in histological slide preparation, an optimization procedure was used to align external outlines of all sections. The optimal rotation and translation of each section was established by maximizing area of overlap between adjacent sections. A sequential one‐dimensional minimization algorithm was used for optimization. Rotation and translation values were then used to align external outlines and the superimposed conduction system, reconstructing the AVCS in three‐dimensions. To validate the method, the algorithm was applied to a digitized image transformed with known translations and rotations. The validation procedure demonstrated that each test image aligned in translations and to within 0.01 degree in rotations. Spatial error determined by resolution of the digitized images was ±0.5/600 inch (±21 microns). Three‐dimensional reconstruction of every 40th serial section clearly demonstrated the complex curved shape of the AVCS. Three‐dimensional reconstruction of the human and canine AVCS permits accurate pathological and electrophysiological correlation of the conduction system. (PACE 2004; 27[Pt. I]:740–748)

CARDIAC MRI IN DIAGNOSING AND TREATING PERICARDIAL DISEASE: A CASE OF EFFUSIVE CONSTRICTIVE PERICARDITIS WITH RECURRENT CARDIOGENIC SHOCK

Effusive constrictive pericarditis is a rare but important cause of pericardial effusion and cardiogenic shock. A 79-year-old woman with a history of a pituitary macroadenoma with recent transphenoidal resection presented to the emergency department with dyspnea and hypotension. The patient had two

A Prospective Pilot Study of Pocket-Carried Ultrasound Pre- and Postdischarge Inferior Vena Cava Assessment for Prediction of Heart Failure Rehospitalization

BACKGROUND Rehospitalization for heart failure (HF) is common, and subclinical congestion may be present at discharge. Larger inferior vena cava (IVC) size and lower collapsibility at discharge assessed via bedside ultrasound are predictive of rehospitalization; however, the utility of IVC assessment with the use of pocket-carried ultrasound (PCUS) during the transition from discharge to the posthospitalization follow-up visit (FU) has not been investigated. METHODS AND RESULTS IVCmax and IVCmin were measured with the use of PCUS, and the collapsibility index (IVCCI = [IVCmax - IVCmin]/IVCmax) was determined. The primary outcome was 90-day rehospitalization or death. We prospectively enrolled 49 adults (71 ± 13 years of age, 51% male, 47% black, 43% preserved ejection fraction) hospitalized for HF. Nineteen patients (39%) experienced the outcome. Within the rehospitalized group, discharge and FU mean IVCmax were both >2.1 cm (2.2 ± 0.5 and 2.2 ± 0.7) and IVCCIs <50% (44 ± 20% and 45 ± 24%). Within those not rehospitalized, FU IVCmax was ≤2.1 cm (2.1 ± 0.6 and 1.9 ± 0.6; P = .038) and IVCCI >50% at both time points (55 ± 25% and 62 ± 19%; P = NS). FU IVCCI below an optimal cutoff of 42% had modest discrimination alone (c-statistic = 0.73). FU IVCCI <42% was associated with a greater hazard of the outcome independent of admission log B-type natriuretic peptide (adjusted hazard ratio = 6.8; 95% confidence interval 2.4-19.0; P < .001). CONCLUSIONS Posthospitalization IVCCI assessment with PCUS predicts HF rehospitalization and may identify patients in need of intervention.

Reducing Readmissions in Patients With Both Heart Failure and COPD

&NA; Patients with both COPD and heart failure (HF) pose particularly high costs to the health‐care system. These diseases arise from similar root causes, have overlapping symptoms, and share similar clinical courses. Because of these strong parallels, strategies to reduce readmissions in patients with both conditions share synergies. Here we present 10 practical tips to reduce readmissions in this challenging population: (1) diagnose the population accurately, (2) detect admissions for exacerbations early and consider risk stratification, (3) use specialist management in hospital, (4) modify the underlying disease substrate, (5) apply and intensify evidence‐based therapies, (6) activate the patient and develop critical health behaviors, (7) setup feedback loops, (8) arrange an early follow‐up appointment prior to discharge, (9) consider and address other comorbidities, and (10) consider ancillary support services at home. The multidisciplinary care teams needed to support these care models pose expense to the health‐care system. Although these costs may more easily be recouped under financial models such as accountable care organizations and bundled payments, the opportunity cost of an admission for COPD or HF may represent an underrecognized financial lever.

POSITIVE PREDICTIVE VALUE OF ECG SCREENING BY SEATTLE CRITERIA IN COLLEGIATE ATHLETES

Pre-participation electrocardiographic (ECG) screening is a very sensitive approach to detecting abnormalities conferring risk for sudden cardiac death. Because training alters the ECG, athlete-specific criteria such as the Seattle criteria have been developed to reduce the false discovery rate.