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- Liuba, Ioan, et al.
(författare)
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Scar progression in patients with nonischemic cardiomyopathy and ventricular arrhythmias
- 2014
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Ingår i: Heart Rhythm. - : Elsevier. - 1547-5271 .- 1556-3871. ; 11:5, s. 755-762
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND Disease progression in patients with nonischemic cardiomyopathy (NICM) is poorly understood. OBJECTIVE To assess left ventricular(LV) scar progression and dilatation by using endocardial electroanatomic mapping. METHODS We studied 13 patients with NICM and recurrent ventricular tachycardia. Two detailed sinus rhythm endocardial voltage maps(265 +/- 122 points/map) were obtained after a mean of 32 months(range 9-77 months). The scar area, defined by low bipolar (BI; less than 1.5 mV) and unipolar(UNI; less than 8.3 mV) endocardial voltage, and the LV volume were measured and compared. A scar difference of greater than 6% of the LV surface and an increase in LV volume of greater than= 20 mL were considered beyond measurement error. RESULTS Six (46%) patients had an increase in scar area beyond boundaries of prior ablation. Five patients had an increase in UNI and 1 patient had an increase in both BI and UNI areas. The increase in BI area represented 16% and the increase in UNI area represented 6.5%-46.2% of the LV surface. A significant decrease in LV ejection fraction was found only in patients with scar progression (from 39% +/- 8%:p = .0003) (LV volume increase ranging between 9% and 23%) was noted in 3 patients, all of whom had scar progression. CONCLUSIONS Progressive scarring with an increase in the area of UNI and less commonly BI electrogram abnormality is seen in 46% of the patients with NICM and ventricular tachycardia and is associated with LV dilatation and decrease in LV ejection fraction. The prominent UNI abnormality suggests predominantly midmyo-cardial or epicardial scarring.
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- Odenstedt, Jacob, 1968, et al.
(författare)
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Spinal cord stimulation effects on myocardial ischemia, infarct size, ventricular arrhythmia, and noninvasive electrophysiology in a porcine ischemia-reperfusion model.
- 2011
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Ingår i: Heart Rhythm. - : Elsevier BV. - 1556-3871 .- 1547-5271. ; Jan:18
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Susceptibility to ventricular arrhythmias and sudden cardiac death can be reduced by modulation of autonomic tone. Spinal cord stimulation (SCS) presumably affects autonomic tone and reduces myocardial ischemia. OBJECTIVE: The purpose of this study was to investigate whether SCS could reduce myocardial ischemia, infarct size, and ventricular arrhythmias as well as repolarization alterations in a porcine ischemia-reperfusion model. METHODS: Anesthetized common Landrace pigs were randomized to SCS (n = 10) or sham treatment (n = 10) before, during, and after 45 minutes of coronary occlusion. Area at risk, infarct size, and spontaneous ventricular arrhythmias were analyzed. Continuous three-dimensional vectorcardiograms was recorded and analyzed with respect to ECG intervals, ST-segment, and T-vector and T-vector-loop morphology. RESULTS: SCS was associated with significantly (P <.04) fewer episodes of nonsustained ventricular tachycardia (NSVT) and sustained ventricular tachycardia (SVT), particularly during mid-left anterior descending artery (LAD) occlusion (SCS vs non-SCS; NSVT, mid- and proximal LAD: 0 vs 22 and 45 vs 72; SVT, mid- and proximal LAD: 3 vs 15 and 5 vs 5). No difference in ventricular fibrillation episodes was observed. The SCS group had significantly less ST elevation (P <.03) but similar area at risk, infarct size, and ratio of infarct size/area at risk. Ischemia induced increases of T(amplitude) and T(area) suggesting increased repolarization gradients, which were significantly reduced by SCS (P <.01 for both). CONCLUSION: SCS appears to have an antiarrhythmic effect on spontaneous NSVT and SVT during ischemia-reperfusion in association with a reduction of repolarization alterations. Vectorcardiography signs of myocardial ischemia were reduced by SCS, but this intervention was not accompanied by any effect on infarct size.
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- Vahedi, Farzad, et al.
(författare)
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Instability of repolarization in LQTS mutation carriers compared to healthy control subjects assessed by vectorcardiography
- 2013
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Ingår i: Heart Rhythm. - : Elsevier BV. - 1547-5271 .- 1556-3871. ; 10:8, s. 1169-1175
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND Potassium channel dysfunction in congenital and acquired forms of long QT syndrome types 1 and 2 (LQT1 and LQT2) increases the beat-to-beat variability of the (IT interval. OBJECTIVE To study about the little known variability (instability) of other aspects of ventricular repolarization (VR) in humans by using vectorcardiography. METHODS Beat-to-beat analysis was performed regarding vectorcardiography derived RR, QRS, and QT intervals, as well as T vector- and T vector loop-based parameters during 1-minute recordings of uninterrupted sinus rhythm at rest in 41 adult LQT1 (n = 31) and LQT2 (n = 10) mutation carriers and 41 age- and sex-matched control subjects. The short-term variability for each parameter, describing the mean orthogonal distance to the line of identity on the Poincare plot, was calculated. RESULTS Mutation carriers showed significantly larger (by a factor 2) instability in most VR parameters compared to controls despite higher instantaneous heart rate variability (STVRR) in the control group. The longer the (IT interval, the greater was its instability, and the instability of VR dispersion measures. CONCLUSIONS A greater instability of most aspects of VR already at rest seems to be a salient feature in both LQT1 and LQT2, which might pave the way for early afterdepolarizations and torsades de pointes ventricular tachycardia. In contrast, no signs of increased VR dispersion per se were observed in mutation carriers.
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