1,720,996 research outputs found
[ST-elevation myocardial infarction: reperfusion strategy based on the results from large clinical trials].
No full textThe efficacy of reperfusion therapy, both pharmacological and mechanical, in patients with ST-elevation myocardial infarction (STEMI) is time-dependent. The relation is closer the earlier we are from symptom onset and is valid for thrombolysis within 6h and for primary angioplasty till to at least the twelfth hour. Benefits of reperfusion bring to an advantage both in terms of myocardial salvage and left ventricular systolic function and in terms of quality of life and long-term survival. Although mortality and morbidity of STEMI patients have been greatly reduced in the last 20 years, the need for guideline revision and implementation remains urgent, mostly because mortality of real-world STEMI patients keeps to be always much higher compared to what reported in big randomized controlled trials. The most important indications from big trials and guidelines regarding both pharmacological and non-pharmacological reperfusion strategy in STEMI patients are discussed
Can IVUS-virtual histology improve outcomes of percutaneous carotid treatment?
No full textSeveral previous studies focusing on comparison between outcomes of carotid artery stenting (CAS) and carotid endoarterectomy (CEA) have put forward conflicting results about the non-inferiority of CAS compared to CEA. Likely outcomes after CAS have been greatly limited by incomplete knowledge of atherosclerotic carotid pathology and probably inappropriate patient selection criteria. In the current practice, only the degree of lumen obstruction is indication to an invasive treatment (CEA or CAS) in symptomatic or asymptomatic patients, but it has been recently demonstrated that histology of carotid plaques also plays a major role. Indeed, plaque morphology and composition seem to influence more importantly outcomes of CAS than those of CEA. Angiography is a poor diagnostic tool to detect the severity and composition of atherosclerotic lesions. Virtual histology (VH) is a new technology incorporated in the latest intravascular ultrasound (IVUS) equipment that allows a validated histological characterization of plaques by performing a spectral, objective and highly-reproducible analysis of the radiofrequency and amplitude data of the ultrasound waves that cross different tissues. This manuscript reports authors' experience with the use of IVUS-VH during CAS. This new technology, by characterizing morphology, extension and histology of carotid plaque, seems to provide important information for confirming percentage of carotid stenosis and judging its embolic potential, tailoring the procedure and guiding the choice of stent and finally for checking stent apposition and complete covering of vulnerable plaques. According to authors' opinion IVUS-VH has the potential to optimize patients' and lesions' selection criteria for CAS in order to improve its outcomes
Cardiac resynchronization therapy in heart failure.
No full textCardiac resynchronization therapy (CRT) is a new therapeutic approach for a selected group of patients with symptomatic heart failure (NYHA functional class III-IV) despite optimal medical therapy, due to dilated cardiomyopathy of any etiology (left ventricular ejection fraction or = 55 mm), who present with electromechanical dyssynchrony (QRS > or = 130 ms). Safety and effectiveness of CRT have been demonstrated by several clinical trials, with patients achieving significant improvement in both clinical symptoms as well as functional status and exercise capacity. Furthermore, CRT has reduced morbidity of heart failure patients, while its impact in improving survival still remains to be clarified. Whether or not heart failure patients candidate to CRT should receive a defibrillator back-up remains debatable, although growing evidence is pointing to extensive use of a defibrillator in such a population
Right heart failure due to loss of right ventricular capture in a patient with atrioventricular junction ablation and biventricular pacing.
No full textWe describe the case of a patient with atrioventricular (AV) junction ablation and chronic biventricular pacing in which intermittent dysfunction of the right ventricular (RV) lead resulted in left ventricular (LV) stimulation alone and onset of severe right heart failure. Restoration of biventricular pacing by increasing device output and then performing lead revision resolved the issue. This case provides evidence that LV pacing alone in patients with AV junction ablation may lead to severe right heart failure, most likely as a result of iatrogenic mechanical dyssynchrony within the RV. Thus, probably this pacing mode should be avoided in pacemaker-dependent patients with heart failure
Stent-graft treatment of late stenosis of the left common carotid artery following thoracic graft placement.
No full textWe report the case of a patient with subtotal occlusion of the origin of the left common carotid artery (CCA) following thoracic graft placement. Retrograde endovascular placement of a stent-graft by minimal cervical access was undertaken to repair the occlusive lesion of the left CCA and prevent future complications of endoluminal thoracic reconstruction. The retrograde endovascular repair of CCA lesions, as other authors have already suggested, may be the treatment of choice in "high-surgical-risk" patients. In these cases where the ostium of supra-aortic trunks is compromised following thoracic aorta stent-graft migration, endoluminal placement of a stent-graft in the CCA can guarantee both maintenance of carotid flow and thoracic stent-graft fixation
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Volume measurement by CARTO compared with cardiac magnetic resonance.
No full textAIMS: The CARTO electrophysiological mapping system has demonstrated accurate results for end-diastolic ventricular volumes in casts and animals. However, in humans, a comparison with cardiac magnetic resonance (CMR), the non-invasive gold standard for volumetric analysis, has not yet been performed.
METHODS AND RESULTS:
A total of 34 (29 male) heart failure patients (NYHA class III/IV) underwent an electrophysiological mapping procedure with the CARTO system in the left ventricle (LV) (n = 34) and right ventricle (RV) (n = 12) and CMR for RV and LV end-diastolic volume (RVEDV and LVEDV) measurements another day. Mean LVEDV was comparable between CMR and CARTO (328 +/- 95 and 320 +/- 92 mL, respectively; P = NS), whereas RV volumes measured by CARTO were larger (CMR 140 +/- 48 vs. CARTO 176 +/- 47 mL; P < 0.01). Overall, we found a good correlation between CMR and CARTO measurements for both chambers; however, the Bland-Altman analysis showed a non-interchangeability of these methods. Measurement differences were independent of chamber size, but significantly affected by the number of acquired mapping points.
CONCLUSION:
Although CMR and CARTO showed a good correlation in the measurement of RVEDV and LVEDV in a group of heart failure patients, the clinical interchangeability of the two methods may be questioned
Arrhythmic risk evaluation during exercise at high altitude in healthy subjects: role of microvolt T-wave alternans.
No full textBACKGROUND: Altitude-induced sympathetic hyperactivity can elicit rhythm disturbances in healthy subjects, in particular during exercise.
AIM: To asses the real susceptibility of healthy myocardium to malignant ventricular arrhythmias during exercise at high altitude using microvolt T-wave alternans (MTWA).
METHODS: We evaluated eight healthy trained participants (one female, 42 +/- 9 years) during a mountain climbing expedition on Gashembrum II (Pakistan, 8,150 m). MTWA and heart rate variability (HRV) were measured in each subject at sea level and at high altitude, both under rest conditions and during exercise. MTWA was determined with the modified moving average method. HRV was expressed as root mean square of successive differences.
RESULTS: Rest HRV at high altitude was significantly lower compared to rest HRV at sea level (36 +/- 5 vs 56 +/- 9 ms, P = 0.003). HRV during exercise was significantly lower with respect to rest condition both in normoxia (46 +/- 7 vs 56 +/- 9 ms, P = 0.0001) and hypoxia (27 +/- 4 vs 36 +/- 5 ms, P = 0.005). Moreover, HRV was significantly lower during exercise at high altitude compared to exercise at sea level (27 +/- 4 vs 46 +/- 7 ms, P = 0.0002) and arrhythmias were more frequent during exercise in hypoxia. Nevertheless, MTWA was absent under rest conditions both at sea level and at high altitude and minimally evoked during exercise in both conditions (22 +/- 3 microV and 23 +/- 3 microV, respectively, P = 0.2).
CONCLUSIONS: In spite of an enhanced sympathetic activity, MTWA testing during exercise at high altitude was negative in all participants. Healthy trained subjects during exercise under hypoxia seem to be at low risk for dangerous arrhythmias
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