Serial assessment of thrombogenicity and hemodynamics in patients with type II diabetes in a clinical research unit: Evidence for circadian variations in clot formation.

BACKGROUND: Circadian fluctuations in thrombogenicity and hemostasis play a role in acute cardiovascular thrombotic events occurring in the early morning hours. There is a lack of data assessing thrombogenicity, platelet function, and hemodynamics to investigate diurnal variations in a high cardiovascular risk population. METHODS: This was an exploratory, single-center study conducted in aspirin-treated patients with Type II Diabetes Mellitus (T2DM) (n = 37) with documented vascular disease and/or multiple cardiovascular risk factors. Hemodynamic monitoring and blood sample collection for thromboelastography (TEG) and platelet function testing were done serially at 7-9 AM (morning), 7-9 PM (evening), 11 PM-1 AM (night), and at 5-7 AM (awakening). RESULTS: R-value measured by TEG was shorter during awakening hours than during the night and day hours (p < 0.05). There were no changes in platelet reactivity in response to arachidonic acid, adenosine diphosphate, and collagen between time points. Pulse pressure (PP) was highest during awakening hours (p < 0.05). CONCLUSION: Study findings provide a mechanistic explanation for increased thrombotic events observed in the early waking hours among diabetics with multiple cardiovascular risk factors. The role of chronotherapy in reducing coagulability and PP to improve clinical outcomes should be explored.

Adenocarcinoma mimicking appendicular lump: a diagnostic dilemma-a case report.

BACKGROUND: Primary appendiceal adenocarcinoma is a rare tumor, mucinous variety being common. This case is reported to highlight the unusual presentation and diagnostic difficulty of appendiceal adenocarcinoma. CASE PRESENTATION: Patient presented with acute appendicitis with ill-defined tender lump which responded to conservative management. CONCLUSIONS: High index of suspicion should be kept in mind for elderly patients presenting with appendicular lump. Every effort should be made during elective appendectomy to remove stump in case of sloughed out appendix.

Risk factors associated with plasma omega-3 fatty acid levels in patients with suspected coronary artery disease.

INTRODUCTION: We sought to determine the associations between plasma eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels and various cardiovascular risk factors and with the use of fish oil supplements (FOS). PATIENTS AND METHODS: Patients with suspected coronary artery disease (CAD) undergoing cardiac catheterization (n=433) were studied. Serum fatty acid (FA) composition, the concentrations of lipids and biomarkers of oxidative stress, and dietary/lifestyle factors were measured. RESULTS: FOS use was associated with a higher plasma EPA+DHA levels (3.7±1.5 vs. 2.6±1.1%, p<0.0001). However, there was no relationship between FOS dose (mg/day) and EPA+DHA levels in 76 patients reporting FOS use (r=-0.21, p=0.07). Lower levels were inversely associated with risk factor profiles including lower ApoB100/ApoA1 ratios (p<0.001). DISCUSSION AND CONCLUSIONS: Higher EPA+DHA levels characterized patients with lower CAD risk. The lack of relations between FOS dose and plasma EPA+DHA levels likely reflects uncaptured variability in EPA+DHA content of supplements.

Relationship between catheter contact force and radiofrequency lesion size and incidence of steam pop in the beating canine heart: electrogram amplitude, impedance, and electrode temperature are poor predictors of electrode-tissue contact force and lesion size.

BACKGROUND: Electrode-tissue contact force (CF) is believed to be a major factor in radiofrequency lesion size. The purpose of this study was to determine, in the beating canine heart, the relationship between CF and radiofrequency lesion size and the accuracy of predicting CF and lesion size by measuring electrogram amplitude, impedance, and electrode temperature. METHODS AND RESULTS: Eight dogs were studied closed chest. Using a 7F catheter with a 3.5 mm irrigated electrode and CF sensor (TactiCath, St. Jude Medical), radiofrequency applications were delivered to 3 separate sites in the right ventricle (30 W, 60 seconds, 17 mL/min irrigation) and 3 sites in the left ventricle (40 W, 60 seconds, 30 mL/min irrigation) at (1) low CF (median 8 g); (2) moderate CF (median 21 g); and (3) high CF (median 60 g). Dogs were euthanized and lesion size was measured. At constant radiofrequency and time, lesion size increased significantly with increasing CF (P<0.01). The incidence of a steam pop increased with both increasing CF and higher power. Peak electrode temperature correlated poorly with lesion size. The decrease in impedance during the radiofrequency application correlated well with lesion size for lesions in the left ventricle but less well for lesions in the right ventricle. There was a poor relationship between CF and the amplitude of the bipolar or unipolar ventricular electrogram, unipolar injury current, and impedance. CONCLUSIONS: Radiofrequencylesion size and the incidence of steam pop increase strikingly with increasing CF. Electrogram parameters and initial impedance are poor predictors of CF for radiofrequency ablation.

Rapid high resolution electroanatomical mapping: evaluation of a new system in a canine atrial linear lesion model.

BACKGROUND: A canine right atrial (RA) linear lesion model was used to produce a complex pattern of RA activation to evaluate a novel mapping system for rapid, high resolution (HR) electroanatomical mapping. METHODS AND RESULTS: The mapping system (Rhythmia Medical, Incorporated) uses an 8F deflectable catheter with a minibasket (1.8 cm diameter), containing 8 splines of 8 electrodes (total 64 electrodes, 2.5 mm spacing). The system automatically acquires electrograms and location information based on electrogram stability and respiration phase. In 10 anesthetized dogs, HR-RA map was obtained by maneuvering the minibasket catheter during sinus rhythm and coronary sinus pacing. A right thoracotomy was performed, and either 1 or 2 (to create a gap) epicardial linear lesions were created on the RA free wall (surgical incision or epicardial radiofrequency lesions). RA maps during RA pacing close to the linear lesions were obtained. A total of 73 maps were created, with 44 to 729 (median 237) beats and 833 to 12 412 (median 3589) electrograms (≤2 to ≤5 mm from surface geometry), resolution 1.8 to 5.3 (median 2.7) mm, and 2.6 to 26.3 (median 7.3) minutes mapping time. Without manual annotation, the system accurately created RA geometry and demonstrated RA activation, identifying the location of lines of block and presence or absence of a gap in all 10 dogs. Endocardial radiofrequency catheter ablation of a gap (guided by activation map) produced complete block across the gap in all 3 dogs tested. CONCLUSIONS: The new HR mapping system accurately and quickly identifies geometry and complex patterns of activation in the canine RA, with little or no manual annotation of activation time.

Interactions between atrial electrical remodeling and autonomic remodeling: how to break the vicious cycle.

BACKGROUND: The mechanism(s) underlying the maintenance of atrial fibrillation (AF) during the first few hours after AF was initiated remains poorly understood. OBJECTIVE: To investigate the roles of the intrinsic cardiac autonomic nervous system in the maintenance of AF at the early stage. METHODS: In 10 anesthetized dogs, we attached multielectrode catheters on atria and pulmonary veins. Microelectrodes inserted into the anterior right ganglionated plexi recorded neural activity. At baseline, programmed stimulation determined the effective refractory period (ERP) and window of vulnerability (WOV), a measure of AF inducibility. For the next 6 hours, AF was simulated by rapid atrial pacing (RAP) and the same parameters were measured hourly during sinus rhythm. A circular catheter was positioned in the superior vena cava for high-frequency stimulation (20 Hz) of the adjacent vagal preganglionics. During 4-6 hours of RAP, we delivered low-level vagal stimulation in the superior vena cava (LL-SVCS), 50% below that which induced slowing of the sinus rate. RESULTS: During the 6-hour RAP, there was a progressive decrease in the ERP and an increase in ERP dispersion, WOV, and neural activity. With LL-SVCS during 4-6-hour RAP, ERP, WOV, and neural activity returned toward baseline levels (all P <.05, compared with the third-hour RAP values). CONCLUSIONS: RAP not only induces atrial electrical remodeling but also promotes autonomic remodeling. These 2 remodeling processes may form a vicious cycle and each may perpetuate the other. These findings may help to explain how AF maintains itself in its very early stage. LL-SVCS both reversed remodeling processes and can potentially break the vicious cycle of "AF begets AF" in the first few hours of AF.