Angiographic Quantification of Thrombus in ST-Elevation Acute Myocardial Infarction Presenting with an Occluded Infarct-Related Artery and Its Relationship with Results of Percutaneous Intervention

Introduction: Routine thrombectomy has been advocated for ST-segment-elevation myocardial infarction (STEMI), but it is unknown how many patients present with a large thrombus. We aimed to quantify the intracoronary thrombus in STEMI and to correlate it with procedure results.
Methods: In 98 patients with STEMI and TIMI flow grades 0–2 in the infarct-related artery, thrombus was qualified as small (ST) when its maximal dimension was <2 vessel diameters and large (LT) when ≥2. Main outcome measures were TIMI flow, myocardial blush grade (MBG), corrected TIMI frame count (cTFC), and ST-segment elevation resolution (STSER).
Results: Only a third of the patients presented with an LT. Thrombus grade was independent of the initial vessel patency. Diabetes (OR 3.1, 95% CI 1.20–8.02, P = 0.027) and pretreatment with clopidogrel (OR 0.27, 95% CI 0.08–0.86, P = 0.034) were independent predictors of LT. LT was an independent predictor of unfavorable results: <3 TIMI flow (OR 2.87, 95% CI 1.04–8.00, P = 0.043), MBG 0–1 (OR 3.36, 95% CI 1.10–10.26, P = 0.033), cTFC > 21 (OR 2.86, 95% CI 1.09–7.49, P = 0.033) and <50% STSER (OR 3.19, 95% CI 1.06–9.63, P = 0.039).
Conclusion: Only a third of STEMI patients present with an LT, being diabetes and lack of clopidogrel pretreatment independent predictors. An LT is strongly associated with worse PCI results.     

Limitations and Potentialities of Doppler Echocardiography in the Evaluation of Mitral Flow

Doppler ultrasound has improved the evaluation of mitral valve diseases. There are, however, some limitations to its use. We describe a case of mitral valve disease in which an unusual concomitant rhythm disturbance highlights the limitations of the Doppler-derived pressure half-time method in evaluating the valve area, and the different behavior of the diastolic regurgitation across the two atrioventricular valves.     

RELATIONSHIP BETWEEN ETHANOL-RELATED DISEASES AND NUTRITIONAL STATUS IN CHRONICALLY ALCOHOLIC MEN

Two-hundred and fifty chronically alcoholic men (mean age, 41± 11 years) entering an alcoholism treatment programwere studied. Detailed clinical history, nutritional assessmentand measurement of muscle strength by electronic myometer wereperformed in each case. In addition, hepatic ultrasonographyand liver biopsy, echocardiography and radionuclide cardiacscanning, and electrophysiological testing of peripheral nerveswere performed when there was clinical evidence of liver disease,cardiomyopathy or neuropathy, respectively. Alcoholic cirrhosiswas diagnosed in 20 cases, skeletal myopathy in 117, dilatedcardiomyopathy in 20 and peripheral neuropathy in 41 cases.No patients with chronic myopathy or cardiomyopathy showed eitherclinical or laboratory evidence of malnutrition. Patients withcirrhosis showed a significantly lower lean body mass than controls(P = 0.03) and significantly lower nutritional protein levelsthan those alcoholics without cirrhosis. Alcoholics with peripheralneuropathy had significantly lower anthropometric parametersand nutrition protein levels than their counter parts (P <0.001). However, in the multivariate analysis, the only independentfactor for developing these complications of alcoholism wasthe total lifetime dose of ethanol (P < 0.001). We concludethat alcohol-related diseases are common in asymptomatic alcoholicmen and these diseases appear to be due to an accumulative toxiceffect of ethanol. Age and nutritional status do not seem toplay a part in the development of such diseases.     

Hyalocyte-Like Cells are more Numerous in the Posterior Chamber than they are in the Vitreous of the Rabbit Eye

The distribution and concentration of free cells inside the eye chambers of rabbits were investigated using semi-quantitative analysis of histological paraffin sections. Studies using light (methacrylate sections) as well as transmission and scanning electron microscopy were undertaken for the morphological characterization of the free cells. Immunocytochemistry and autoradiography were employed in an attempt to find out their nature and their origin, respectively. It was observed that cells morphologically similar to the vitreous hyalocytes were more numerous inside the posterior chamber than were the hyalocytes in the cortical vitreous. Neither the hyalocytes nor the posterior-chamber cells reacted with an antibody to rabbit macrophages. The finding of labeled free cells after an intravitreal injection of³H-thymidine indicates that these cells can renew themselves and that their number does not depend exclusively on monocytes migrating from the blood stream to the eye chambers, as is believed to occur. In conclusion, hyalocytes or hyalocyte-like cells are more concentrated in the posterior chamber than they are in the vitreous. Both the hyalocytes and the posterior-chamber cells could not be characterized as fully developed macrophages.     

Improved Spatial Resolution for Cardiac Mapping Using Current Source Density-Based Electrode Arrays

The time of the minimum slope (i.e., the fastest negative deflection) in monopolar (MP) electrograms from normal hearts compares closely with time of phase 0 of the action potential in cells underlying the electrode, but poor rejection of far-field activity may limit the utility ofMP electrode technology in dense arrays used for the study of ventricular tachycardia and fibrillation. The purpose of this study is to evaluate more myopic discrete bipolar (BP) and nondirectional, two-dimensional current source density (CSD) based arrays for rejection of far-field potentials and precision of activation time determination. Simultaneous recordings of the CSD, MP, and multiple BP electrograms were performed on normal dog epicardium. The time of the minimum slope in MP electrograms was compared to activation times in CSD and BP derivations using: (1) peak; (2) steepest slope; (3) zero crossing of the steepest sloping segment in either direction; and (4) waveform morphology. In vivo, CSD amplitude was reduced significantly more than MP and BP amplitudes by insertion of inert media between the heart and the electrodes. The time of the steepest slope in CSD electrograms designated activation times closest to the time of the minimum slope in MP electrograms (0.9 ± 1.3 msec). We conclude that CSD provides a nondirectional electrode system that accurately defines the time of local activation and possesses better spatial specificity than MP electrode systems and BP electrode systems having the same interelectrode distances.     

The Epicardial Field Potential in Dog: Implications for Recording Site Density During Epicardial Mapping

Investigations into mechanisms and successful surgical therapy of ventricular tachycardia (VT) depend upon accurate endocardial/epicardial mapping. Deduction of local activation is based upon parameters derived from the field potentiai (FP) (monopolar recording) or its first spatial derivative (bipolar recording). Adequate electrode spacing is an assumption fundamental to the mapping process, but the electrode spacing required for accurate representation of the FP is unknown. The purpose of this work is to derive the electrode spacing necessary to accurately describe the FP on the epicardium. In 11 dogs, electrograms from vertical (V) (base to apex h) bands having 40 electrodes and horizontal (H) bands having 40 to 80 electrodes were sampled at I kHz. The spatial handwidths (BW) were computed according lo two criteria: (1) the frequency yielding 2% mean squared error (MSE) computed at the time of the greatest integrated magnitudes of the Fourier transform; and (2) the highest frequency bounding 95% power computed at each msec throughout the beat. Implied electrode spacings were defined according to the sampling theorem. The 5th percentiles of the implied electrode spacing distributions were used to define the widest interelectrode distance required to prevent spatial aliasing. H-5th percentile and V-5th percentile were, respectively; 2% MSE (3.5 mm, 2.3 mm); 95% power (3.6 mm, 2.3 mm). Thus, a typical 20-kg dog requires more than 250 recording sites for accurate epicardial mapping. Extrapolating to man, these results suggest inadequate electrode density may partially be responsible for incomplete and ambiguous reentry patterns often observed during intraoperutive mapping.     

Treatment Strategies for Long and Calcified Lesions

This study discusses the treatment strategies used to approach long lesions, lesions in small vessels, and calcified lesions. Traditional treatment strategies for these lesion subtypes have yielded high acute complication rates and poor long-term outcome. A prospective analysis of 160 lesions was performed using intravascular ultrasound (IVUS) guided PTCA for the treatment of long lesions and lesions in small vessels, while a retrospective analysis of 106 calcified lesions was performed that were treated with the combination of rotablation and stenting. Acute and short-term results of TVUS guided PTCA with spot stenting show a 30-day major adverse cardiac event rate (MACE) of 5% with a high procedural success rate (96%), while the long-term outcome resulted in an agiographic restenosis rate of 17.4% and a target lesion revascularization rate of 13%. The combination of rotablation and stenting also rendered results in calcified lesions of a 93% angiographic success rate and a long-term outcome of restenosis of 22.5%. Optimal coronary stenting after rotational atherectomy in calcified lesions can be performed with a high success rate, an acceptable rate of procedural complications, and a low rate of stent thrombosis. This approach was associated with a low incidence of angiographic restenosis compared with results obtained with other interventional approaches. IVUS guided PTCA with spot stenting allows safe treatment of long lesions and lesions in small vessels. Short-term and long-term outcomes including 6-month MACE and angiographic restenosis appear to be better than results achieved in historical controls that utilize balloon angioplasty alone or stents in a manner where the lesion is covered from the proximal normal segment to the distal normal segment.