Impaired coordination between the ventricles or uncoordinated contraction of individual ventricular walls against each other (dyssynchrony) contribute to further heart failure progression in some patients. Reduction or elimination of dyssynchrony through cardiac resynchronization therapy (CRT) is able to slow or even stop pathologic remodeling, improve heart failure symptoms and induce reverse remodeling leading to decreased hospitalization rate and mortality. However, our abilities to identify presence and type of dyssynchrony are still limited and although the primary goal of CRT is to restore normal ventricular contraction sequence (i.e. to eliminate mechanical dyssynchrony), our current CRT indication criteria are based solely on an electrical dyssynchrony, specifically on assumption that it is present based on 12-lead ECG. Therefore, the aim of this study is to assess relationship between electrical and mechanical dyssynchrony, their contribution to ventricular contraction inefficiency and to identify relevant markers of the presence and extent of mechanical dyssynchrony.

Porucha koordinované činnosti obou srdečních komor i jejich jednotlivých srdečních stěn vůči sobě navzájem (dyssynchronie) se u části nemocných se symptomatickým srdečním selháním podílí na další progresi onemocnění. Zmírnění nebo odstranění dyssynchronie pomocí srdeční resynchronizační terapie (CRT) je schopno zpomalit až zastavit proces patologické remodelace srdce, zlepšit symptomy srdečního selhání a navodit reverzní remodelaci vedoucí k poklesu počtu hospitalizací a mortality. Nicméně naše možnosti jak stanovit přítomnost a charakter dyssynchronie jsou dosud stále omezené a i když je primárním cílem CRT obnovit především normální kontrakční sekvenci komor (tedy eliminovat mechanickou dyssynchronii), jsou současná indikační kritéria CRT založena výhradně na dyssynchronii elektrické, resp. na usuzování, že je přítomna, podle 12-svodového EKG. Cílem studie je proto stanovit vazbu mezi elektrickou a mechanickou dyssynchronií, jejich podíl na neefektivitě komorové kontrakce a nalézt markery přítomnosti a rozsahu mechanické dyssynchronie, které budou použitelné v klinické praxi.

• MeSH
• biologické markery MeSH
• elektrokardiografie MeSH
• komorová dysfunkce patofyziologie   terapie   MeSH
• lidé MeSH
• magnetická rezonanční tomografie MeSH
• srdeční resynchronizační terapie metody   MeSH
• srdeční selhání terapie   MeSH
• výsledek terapie MeSH
• Check Tag
• lidé MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• kardiologie
• NLK Publikační typ
• závěrečné zprávy o řešení grantu AZV MZ ČR

Atrial fibrillation is the most common arrhythmia in the adult population, and its incidence and prevalence are still rising. Cardiac devices are widely used in clinical practice in the management of various rhythm disturbances and heart failure treatment. Many patients who receive a pacemaker, implantable cardioverter-defibrillator, or cardiac resynchronization therapy also experience atrial fibrillation in the course of their life. Therefore, this review aims to describe the role of these devices in the treatment and prevention of atrial fibrillation in the device recipients. In addition, all these implantable devices also serve as permanent ECG (electrocardiogram) monitors, thus providing important information about the presence and characteristics of atrial fibrillation that may or may not be detected by the patient but can modify our therapeutical approach with regard to the stroke prevention.

• Publikační typ
• časopisecké články MeSH

BACKGROUND: The presence and extent of ventricular dyssynchrony are currently assessed from the QRS complex morphology and width. However, similar electrocardiography (ECG) pattern may be caused by variable ventricular activation sequence. This may then contribute to interindividually different response to cardiac resynchronization therapy (CRT). METHODS: Electroanatomical mapping and magnetic resonance imaging scan were performed in 11 patients with left bundle branch block (LBBB, QRS 170 ± 14 ms) and heart failure of ischemic (coronary artery disease (CAD), n = 2) and nonischemic (dilated cardiomyopathy (DCM), n = 9) etiology. Ventricular activation sequence was studied during LBBB and final CRT programming. Presence and extent of scarring were analyzed in the 17-segment left-ventricular (LV) model. RESULTS: Regardless of etiology, presence of typical LBBB was associated with diffuse prolongation of impulse conduction with right-to-left activation sequence. Basal lateral wall was constant site of late activation. This activation pattern was present in "true LBBB," but also in LBBB-like pattern (persistent S wave in V5-6) and left axis deviation. Activation started in right vetricular (RV) apex in patients with left axis deviation at RV free wall in normal axis. Individuals with CAD and DCM patient displayed focal scar. Despite that they exhibited typical LBBB and activation sequence mirrored findings in other LBBB individuals. Reverse remodeling (∆LVESV > 15% after 6 months) was evident in 10 patients. CONCLUSIONS: Both typical LBBB and LBBB-like pattern might be associated with constant activation sequence regardless of etiology and scar localization. Activation initiation in RV apex, not LV activation sequence can be surrogate for left axis deviation. CRT caused inter- and intraventricular LV resynchronization without significantly changed RV activation sequence and duration.

• MeSH
• blokáda Tawarova raménka diagnostické zobrazování   patofyziologie   terapie   MeSH
• elektrokardiografie * MeSH
• epikardiální mapování MeSH
• lidé středního věku MeSH
• lidé MeSH
• magnetická rezonanční tomografie MeSH
• senioři MeSH
• srdeční komory diagnostické zobrazování   patofyziologie   MeSH
• srdeční resynchronizační terapie metody   MeSH
• srdeční selhání diagnostické zobrazování   patofyziologie   terapie   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské 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

Cardiac resynchronization therapy (CRT) has proven efficacious in reducing or even eliminating cardiac dyssynchrony and thus improving heart failure symptoms. However, quantification of mechanical dyssynchrony is still difficult and identification of CRT candidates is currently based just on the morphology and width of the QRS complex. As standard 12-lead ECG brings only limited information about the pattern of ventricular activation, we aimed to study changes produced by different pacing modes on the body surface potential maps (BSPM). Total of 12 CRT recipients with symptomatic heart failure (NYHA II-IV), sinus rhythm and QRS width >/=120 ms and 12 healthy controls were studied. Mapping system Biosemi (123 unipolar electrodes) was used for BSPM acquisition. Maximum QRS duration, longest and shortest activation times (ATmax and ATmin) and dispersion of QT interval (QTd) were measured and/or calculated during spontaneous rhythm, single-site right- and left-ventricular pacing and biventricular pacing with ECHO-optimized AV delay. Moreover we studied the impact of CRT on the locations of the early and late activated regions of the heart. The average values during the spontaneous rhythm in the group of patients with dyssynchrony (QRS 140.5+/-10.6 ms, ATmax 128.1+/-10.1 ms, ATmin 31.8+/-6.7 ms and QTd 104.3+/-24.7 ms) significantly differed from those measured in the control group (QRS 93.0+/-10.0 ms, ATmax 79.1+/-3.2 ms, ATmin 24.4+/-1.6 ms and QTd 43.6+/-10.7 ms). Right ventricular pacing (RVP) improved significantly only ATmax [111.2+/-10.6 ms (p<0.05)] but no other measured parameters. Left ventricular pacing (LVP) succeeded in improvement of all parameters [QRS 105.1+/-8.0 ms (p<0.01), ATmax 103.7+/-7.1 ms (p<0.01), ATmin 20.2+/-3.7 ms (p<0.01) and QTd 52.0+/-9.4 ms (p<0.01)]. Biventricular pacing (BVP) showed also a beneficial effect in all parameters [QRS 121.3+/-8.9 ms (p<0.05), ATmax 114.3+/-8.2 ms (p<0.05), ATmin 22.0+/-4.1 ms (p<0.01) and QTd 49.8+/-10.0 ms (p<0.01)]. Our results proved beneficial outcome of LVP and BVP in evaluated parameters (what seems to be important particularly in the case of activation times) and revealed a complete return of activation times to normal distribution when using these CRT modalities.

• MeSH
• elektrokardiografie metody   trendy   MeSH
• lidé středního věku MeSH
• lidé MeSH
• senioři MeSH
• srdeční resynchronizační terapie metody   trendy   MeSH
• srdeční selhání diagnóza   patofyziologie   terapie   MeSH
• výsledek terapie MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH