BACKGROUND AND OBJECTIVES: Catheter ablation of ventricular tachycardia (VT) may include induction of VT and localization of VT-exit site. Our aim was to assess localization performance of a novel statistical pace-mapping method and compare it with performance of an electrocardiographic inverse solution. METHODS: Seven patients undergoing ablation of VT (4 with epicardial, 3 with endocardial exit) aided by electroanatomic mapping underwent intraprocedural 120-lead body-surface potential mapping (BSPM). Two approaches to localization of activation origin were tested: (1) A statistical method, based on multiple linear regression (MLR), which required only the conventional 12-lead ECG for a sufficient number of pacing sites with known origin together with patient-specific geometry of the endocardial/epicardial surface obtained by electroanatomic mapping; and (2) a classical deterministic inverse solution for recovering heart-surface potentials, which required BSPM and patient-specific geometry of the heart and torso obtained via computed tomography (CT). RESULTS: For the MLR method, at least 10-15 pacing sites with known coordinates, together with their corresponding 12-lead ECGs, were required to derive reliable patient-specific regression equations, which then enabled accurate localization of ventricular activation with unknown origin. For 4 patients who underwent epicardial mapping, the median of localization error for the MLR was significantly lower than that for the inverse solution (10.6 vs. 27.3 mm, P = 0.034); a similar result held for 3 patients who underwent endocardial mapping (7.7 vs. 17.1 mm, P = 0.017). The pooled localization error for all epicardial and endocardial sites was also significantly smaller for the MLR compared with the inverse solution (P = 0.005). CONCLUSIONS: The novel pace-mapping approach to localizing the origin of ventricular activation offers an easily implementable supplement and/or alternative to the preprocedure inverse solution; its simplicity makes it suitable for real-time applications during clinical catheter-ablation procedures.

• Klíčová slova
• 12-lead ECG, body surface potential mapping, catheter ablation, pace-mapping, ventricular tachycardia,
• MeSH
• anatomické modely MeSH
• katetrizační ablace metody   MeSH
• komorová tachykardie diagnostické zobrazování   patofyziologie   chirurgie   MeSH
• lidé MeSH
• mapování potenciálů tělesného povrchu přístrojové vybavení   metody   MeSH
• modely kardiovaskulární * MeSH
• zobrazování trojrozměrné přístrojové vybavení   metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Cardiac resynchronization therapy (CRT) has become standard therapy for selected patients with congestive heart failure and dyssynchrony of cardiac contraction that is a consequence of electrical dyssynchrony. Intracardiac mapping enables detailed analysis of electrical activation sequences far beyond the standard ECG and allows description of specific activation associated with the benefit of CRT. Intracardiac mapping can also localize the region of the latest ventricular activation and areas of slow conduction, and thus potentially assist in selection of optimal pacing site for CRT. Precise description of electrical activation sequences, and correlation with parameters of mechanical dyssynchrony, may contribute to understanding the principles and mechanisms underlying the effect of CRT.

• MeSH
• diagnostické zobrazování metody   MeSH
• kardiostimulace umělá metody   MeSH
• lidé MeSH
• mapování potenciálů tělesného povrchu metody   MeSH
• srdeční selhání diagnóza   prevence a kontrola   MeSH
• výběr pacientů * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

BACKGROUND: Biventricular pacing (BiV) is employed as the current standard for cardiac resynchronisation therapy. Other pacing modalities have been proposed as alternatives; however, data on changes in electrical activation sequence caused by pacing from various sites are limited. AIM: To describe changes in activation patterns during different ventricular pacing modes in patients with chronic heart failure. METHODS: A total number of 20 patients (mean age 59.6+/-8 years) with chronic heart failure, intraventricular conduction abnormality (QRS >130 ms) or complete AV block were studied. Endocardial activation maps of both ventricles (CARTOTM, Biosense-Webster) were obtained during spontaneous rhythm and biventricular (BiV, n=9), right ventricular bifocal (BiF, n=7) and single-site left ventricular (LV, n=4) pacing. The following parameters were assessed: activation pattern, total LV endocardial activation time (LVAT) and electrical interventricular delay (IVD). RESULTS: Right ventricular apical pacing was associated with the longest LVAT (145+/-24 ms). On the contrary, both BiV and BiF pacing shortened LVAT with BiV being superior in the degree of LVAT reduction (89+/-13 vs 103+/-10 ms, p<0.05). BiV pacing also significantly shortened IVD and modified the LV activation sequence in a complex manner. Such changes were not observed during BiF pacing. In the presence of fusion with spontaneous activation, single-site LV pacing was comparable to BiV pacing. CONCLUSIONS: Among the different pacing modes, BiV pacing and single-site LV pacing with fusion resulted in the most pronounced changes in ventricular activation that appear to be a prerequisite for successful resynchronization of both ventricles.

• MeSH
• dospělí MeSH
• dysfunkce pravé srdeční komory komplikace   patofyziologie   MeSH
• kardiostimulace umělá metody   MeSH
• lidé středního věku MeSH
• lidé MeSH
• senioři MeSH
• srdeční komory anatomie a histologie   patofyziologie   MeSH
• srdeční selhání etiologie   chirurgie   MeSH
• srdeční septum patofyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

In order to diagnose myocardial ischaemia, the authors performed transoesophageal atrial pacing using commercially available electrodes and a pacing device of their own design. On assessing the 12-lead electrocardiogram, they compared the results of pacing and exercise testing in 204 subjects. They found full agreement in all controls and in most IHD patients. In 33 persons, atrial pacing was combined with assessment of the ST segment precordial mapping. On atrial pacing mapping, the authors found manifestations of ischaemia similar to those discovered during exercise testing. Both methods have proved useful in the detection of myocardial ischaemia and are recommended as alternative techniques to exercise testing, especially in cases when the latter technique is not feasible or cannot be interpreted.

• MeSH
• elektrokardiografie * MeSH
• kardiostimulace umělá metody   MeSH
• koronární angiografie MeSH
• koronární nemoc diagnóza   MeSH
• lidé středního věku MeSH
• lidé MeSH
• zátěžový test MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Cardiac resynchronization therapy (CRT) has proven efficacious in the treatment of patients with heart failure and dyssynchronous activation. Currently, we select suitable CRT candidates based on the QRS complex duration (QRSd) and morphology with left bundle branch block being the optimal substrate for resynchronization. To improve CRT response rates, recommendations emphasize attention to electrical parameters both before implant and after it. Therefore, we decided to study activation times before and after CRT on the body surface potential maps (BSPM) and to compare thus obtained results with data from electroanatomical mapping using the CARTO system. Total of 21 CRT recipients with symptomatic heart failure (NYHA II-IV), sinus rhythm, and QRSd >/=150 ms and 7 healthy controls were studied. The maximum QRSd and the longest and shortest activation times (ATmax and ATmin) were set in the BSPM maps and their locations on the chest were compared with CARTO derived time interval and site of the latest (LATmax) and earliest (LATmin) ventricular activation. In CRT patients, all these parameters were measured during both spontaneous rhythm and biventricular pacing (BVP) and compared with the findings during the spontaneous sinus rhythm in the healthy controls. QRSd was 169.7+/-12.1 ms during spontaneous rhythm in the CRT group and 104.3+/-10.2 ms after CRT (p<0.01). In the control group the QRSd was significantly shorter: 95.1+/-5.6 ms (p<0.01). There was a good correlation between LATmin(CARTO) and ATmin(BSPM). Both LATmin and ATmin were shorter in the control group (LATmin(CARTO) 24.8+/-7.1 ms and ATmin(BSPM) 29.6+/-11.3 ms, NS) than in CRT group (LATmin(CARTO) was 48.1+/-6.8 ms and ATmin(BSPM) 51.6+/-10.1 ms, NS). BVP produced shortening compared to the spontaneous rhythm of CRT recipients (LATmin(CARTO) 31.6+/-5.3 ms and ATmin(BSPM) 35.2+/-12.6 ms; p<0.01 spontaneous rhythm versus BVP). ATmax exhibited greater differences between both methods with higher values in BSPM: in the control group LATmax(CARTO) was 72.0+/-4.1 ms and ATmax (BSPM) 92.5+/-9.4 ms (p<0.01), in the CRT candidates LATmax(CARTO) reached only 106.1+/-6.8 ms whereas ATmax(BSPM) 146.0+/-12.1 ms (p<0.05), and BVP paced rhythm in CRT group produced improvement with LATmax(CARTO) 92.2+/-7.1 ms and ATmax(BSPM) 130.9+/-11.0 ms (p<0.01 before and during BVP). With regard to the propagation of ATmin and ATmax on the body surface, earliest activation projected most often frontally in all 3 groups, whereas projection of ATmax on the body surface was more variable. Our results suggest that compared to invasive electroanatomical mapping BSPM reflects well time of the earliest activation, however provides longer time-intervals for sites of late activation. Projection of both early and late activated regions of the heart on the body surface is more variable than expected, very likely due to changed LV geometry and interposed tissues between the heart and superficial ECG electrode.

• MeSH
• blokáda Tawarova raménka diagnóza   patofyziologie   terapie   MeSH
• dospělí MeSH
• elektrofyziologické jevy fyziologie   MeSH
• elektrokardiografie metody   trendy   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mapování potenciálů tělesného povrchu metody   trendy   MeSH
• převodní systém srdeční patofyziologie   MeSH
• senioři MeSH
• srdeční resynchronizační terapie metody   trendy   MeSH
• srdeční selhání diagnóza   patofyziologie   terapie   MeSH
• výsledek terapie MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: The left ventricular (LV) lead local electrogram (EGM) delay from the beginning of the QRS complex (QLV) is considered a strong predictor of response to cardiac resynchronization therapy. We have developed a method for fast epicardial QLV mapping during video-thoracoscopic surgery to guide LV lead placement. METHODS: A three-port, video-thoracoscopic approach was used for LV free wall epicardial mapping and lead implantation. A decapolar electrophysiological catheter was introduced through one port and systematically attached to multiple accessible LV sites. The pacing lead was targeted to the site with maximum QLV. The LV free wall activation pattern was analyzed in 16 pre-specified anatomical segments. RESULTS: We implanted LV leads in 13 patients with LBBB or IVCD. The procedural and mapping times were 142 ± 39 minutes and 20 ± 9 minutes, respectively. A total of 15.0 ± 2.2 LV segments were mappable with variable spatial distribution of QLV-optimum. The QLV ratio (QLV/QRSd) at the optimum segment was significantly higher (by 0.17 ± 0.08, p < 0.00001) as compared to an empirical midventricular lateral segment. The LV lead was implanted at the optimum segment in 11 patients (at an adjacent segment in 2 patients) achieving a QLV ratio of 0.82 ± 0.09 (range 0.63-0.93) and 99.5 ± 0.6% match with intraprocedural mapping. CONCLUSION: Video-thoracoscopic LV lead implantation can be effectively and safely guided by epicardial QLV mapping. This strategy was highly successful in targeting the selected LV segment and resulted in significantly higher QLV ratios compared to an empirical midventricular lateral segment.

• Klíčová slova
• cardiac resynchronization therapy, epicardial mapping, heart failure, implantable cardioverter defibrillator, left ventricular lead, thoracoscopic implantation, video,
• MeSH
• blokáda Tawarova raménka diagnóza   patofyziologie   terapie   MeSH
• časové faktory MeSH
• design vybavení MeSH
• epikardiální mapování * MeSH
• funkce levé komory srdeční MeSH
• hrudní chirurgie video-asistovaná * MeSH
• komorový tlak (srdce) MeSH
• lidé středního věku MeSH
• lidé MeSH
• perikard patofyziologie   MeSH
• prediktivní hodnota testů MeSH
• prostředky srdeční resynchronizační terapie * MeSH
• senioři MeSH
• srdeční komory patofyziologie   chirurgie   MeSH
• srdeční resynchronizační terapie * škodlivé účinky   MeSH
• studie proveditelnosti MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH

Hippocampal place cells represent different environments with distinct neural activity patterns. Following an abrupt switch between two familiar configurations of visual cues defining two environments, the hippocampal neural activity pattern switches almost immediately to the corresponding representation. Surprisingly, during a transient period following the switch to the new environment, occasional fast transitions between the two activity patterns (flickering) were observed (Jezek, Henriksen, Treves, Moser, & Moser, ). Here we show that an attractor neural network model of place cells with connections endowed with short-term synaptic plasticity can account for this phenomenon. A memory trace of the recent history of network activity is maintained in the state of the synapses, allowing the network to temporarily reactivate the representation of the previous environment in the absence of the corresponding sensory cues. The model predicts that the number of flickering events depends on the amplitude of the ongoing theta rhythm and the distance between the current position of the animal and its position at the time of cue switching. We test these predictions with new analysis of experimental data. These results suggest a potential role of short-term synaptic plasticity in recruiting the activity of different cell assemblies and in shaping hippocampal activity of behaving animals.

• Klíčová slova
• CA3, attractor neural network, hippocampus, memory, place cell, recurrent neural network, teleportation, theta,
• MeSH
• akční potenciály fyziologie   MeSH
• časové faktory MeSH
• elektroencefalografie MeSH
• hipokampus cytologie   MeSH
• krysa rodu Rattus MeSH
• mapování mozku MeSH
• modely neurologické * MeSH
• nervová síť fyziologie   MeSH
• neurony fyziologie   MeSH
• neuroplasticita fyziologie   MeSH
• podněty MeSH
• prostorová paměť fyziologie   MeSH
• světelná stimulace MeSH
• theta rytmus EEG fyziologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Although one-quarter of plant and vertebrate species are threatened with extinction, little is known about the potential effect of extinctions on the global diversity of ecological strategies. Using trait and phylogenetic information for more than 75,000 species of vascular plants, mammals, birds, reptiles, amphibians, and freshwater fish, we characterized the global functional spectra of each of these groups. Mapping extinction risk within these spectra showed that larger species with slower pace of life are universally threatened. Simulated extinction scenarios exposed extensive internal reorganizations in the global functional spectra, which were larger than expected by chance for all groups, and particularly severe for mammals and amphibians. Considering the disproportionate importance of the largest species for ecological processes, our results emphasize the importance of actions to prevent the extinction of the megabiota.

• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The EU Horizon 2020 Framework-funded Standardized Treatment and Outcome Platform for Stereotactic Therapy Of Re-entrant tachycardia by a Multidisciplinary (STOPSTORM) consortium has been established as a large research network for investigating STereotactic Arrhythmia Radioablation (STAR) for ventricular tachycardia (VT). The aim is to provide a pooled treatment database to evaluate patterns of practice and outcomes of STAR and finally to harmonize STAR within Europe. The consortium comprises 31 clinical and research institutions. The project is divided into nine work packages (WPs): (i) observational cohort; (ii) standardization and harmonization of target delineation; (iii) harmonized prospective cohort; (iv) quality assurance (QA); (v) analysis and evaluation; (vi, ix) ethics and regulations; and (vii, viii) project coordination and dissemination. To provide a review of current clinical STAR practice in Europe, a comprehensive questionnaire was performed at project start. The STOPSTORM Institutions' experience in VT catheter ablation (83% ≥ 20 ann.) and stereotactic body radiotherapy (59% > 200 ann.) was adequate, and 84 STAR treatments were performed until project launch, while 8/22 centres already recruited VT patients in national clinical trials. The majority currently base their target definition on mapping during VT (96%) and/or pace mapping (75%), reduced voltage areas (63%), or late ventricular potentials (75%) during sinus rhythm. The majority currently apply a single-fraction dose of 25 Gy while planning techniques and dose prescription methods vary greatly. The current clinical STAR practice in the STOPSTORM consortium highlights potential areas of optimization and harmonization for substrate mapping, target delineation, motion management, dosimetry, and QA, which will be addressed in the various WPs.

• Klíčová slova
• Cardiac arrhythmias, Consortium, EU Horizon 2020, Stereotactic arrhythmia radioablation, Stereotactic body radiotherapy, Ventricular tachycardia,
• MeSH
• katetrizační ablace * škodlivé účinky   metody   MeSH
• komorová tachykardie * MeSH
• lidé MeSH
• prospektivní studie MeSH
• srdeční arytmie MeSH
• srdeční komory MeSH
• výsledek terapie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

We present a 34-year-old woman with idiopathic ventricular tachycardia that resisted 2 previous attempts for catheter ablation and was successfully ablated in the myocardial extension within the noncoronary aortic cusp.

• MeSH
• akční potenciály MeSH
• aortální chlopeň patofyziologie   chirurgie   MeSH
• časové faktory MeSH
• dospělí MeSH
• elektrofyziologické techniky kardiologické MeSH
• elektrokardiografie MeSH
• kardiostimulace umělá MeSH
• katetrizační ablace * MeSH
• komorová tachykardie diagnóza   patofyziologie   chirurgie   MeSH
• lidé MeSH
• myokard MeSH
• reoperace MeSH
• srdeční komory patofyziologie   chirurgie   MeSH
• výsledek terapie MeSH
• zobrazování pomocí barviva citlivého na potenciál MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH