BACKGROUND AND AIMS: Right bundle branch block (RBBB) and resulting right ventricular (RV) electromechanical discoordination are thought to play a role in the disease process of subpulmonary RV dysfunction that frequently occur post-repair tetralogy of Fallot (ToF). We sought to describe this disease entity, the role of pulmonary re-valvulation, and the potential added value of RV cardiac resynchronization therapy (RV-CRT). METHODS: Two patients with repaired ToF, complete RBBB, pulmonary regurgitation, and significantly decreased RV function underwent echocardiography, cardiac magnetic resonance, and an invasive study to evaluate the potential for RV-CRT as part of the management strategy. The data were used to personalize the CircAdapt model of the human heart and circulation. Resulting Digital Twins were analysed to quantify the relative effects of RV pressure and volume overload and to predict the effect of RV-CRT. RESULTS: Echocardiography showed components of a classic RV dyssynchrony pattern which could be reversed by RV-CRT during invasive study and resulted in acute improvement in RV systolic function. The Digital Twins confirmed a contribution of electromechanical RV dyssynchrony to RV dysfunction and suggested improvement of RV contraction efficiency after RV-CRT. The one patient who underwent successful permanent RV-CRT as part of the pulmonary re-valvulation procedure carried improvements that were in line with the predictions based on his Digital Twin. CONCLUSION: An integrative diagnostic approach to RV dysfunction, including the construction of Digital Twins may help to identify candidates for RV-CRT as part of the lifetime management of ToF and similar congenital heart lesions.

• MeSH
• blokáda Tawarova raménka diagnostické zobrazování   etiologie   terapie   MeSH
• dysfunkce pravé srdeční komory * diagnostické zobrazování   etiologie   terapie   MeSH
• echokardiografie MeSH
• Fallotova tetralogie * diagnostické zobrazování   chirurgie   MeSH
• lidé MeSH
• počítačová simulace MeSH
• srdeční komory MeSH
• srdeční resynchronizační terapie * škodlivé účinky   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

The goal of the study was to design a model of cardiac ventricles with realistic geometry that enables simulation of the ventricular activation with normal conduction system functions, as well as with bundle branch blocks. In ventricles, electrical activation propagates from the His bundle to the left and right bundle branches and continues to the fascicles and branching fibers of the Purkinje system. The role of these parts of the conduction system is to lead the activation rapidly and synchronously to the left and right ventricle. The velocity of propagation in the conduction system is several times higher than in the surrounding ventricular myocardium. If the conduction system works normally, QRS duration representing the total activation time of the ventricles lies in the physiological range of about 80 to 120 ms but it is more than 120 ms in the case of bundle branch blocks. In our study, the realistic geometry of the ventricles was constructed on the base of a patient CT scan, defining epicardial and endocardial surfaces. The first part of the conduction system (fast-conducting bundle branches, fascicles in the left ventricle and initial parts of the Purkinje fibers) was modeled as polyline pathways isolated from the surrounding ventricular tissue. The remaining part of the Purkinje system was modeled as an endocardial layer with higher conduction velocity. The propagation of the electrical activation in the ventricular model was modeled using reaction-diffusion (RD) equations, except for the first part of the conduction system, where the activation times were evaluated algebraically with respect to predefined velocity of propagation and estimated distance between the His bundle and particular entry point to the layer with higher conduction velocity. Propagation of activation in cardiac ventricles was numerically solved in Comsol Multiphysics environment. Several configurations of the first part of the conduction system with different number of polyline pathways and entry points were proposed and tested to achieve realistic activation propagation. For the model with 9 starting points, realistic total activation time (TAT) of the whole ventricles of about 108 ms was obtained for the model with normal conduction system, and realistic TAT of 126 ms and 149 ms were obtained for the right and left bundle branch block (RBBB, LBBB), respectively. Very similar TAT was found also for the model with 7 starting points, but unrealistically long TAT was obtained in LBBB simulation for the model with only 5 starting points.

• MeSH
• anatomické modely MeSH
• biomedicínské technologie metody   MeSH
• biomedicínský výzkum přístrojové vybavení   trendy   MeSH
• blokáda Tawarova raménka * diagnostické zobrazování   patofyziologie   MeSH
• lidé MeSH
• modely kardiovaskulární MeSH
• počítačová simulace klasifikace   MeSH
• srdeční komory anatomie a histologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH
• přehledy 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

Left bundle branch block increases the risk of death in patients with chronic heart failure. We herein report four clinical cases of patients with chronic heart failure caused by nonischemic cardiomyopathy with left bundle branch block that occurred when adding ivabradine to optimal medical therapy, resulting in reverse electrical and mechanical remodeling. This phenomenon might be explained by the effect of ivabradine on reverse remodeling of the left ventricle with improvement of intraventricular conduction.

• MeSH
• blokáda Tawarova raménka komplikace   diagnostické zobrazování   farmakoterapie   patofyziologie   MeSH
• dospělí MeSH
• elektrokardiografie MeSH
• ivabradin farmakologie   terapeutické užití   MeSH
• kardiomyopatie komplikace   diagnostické zobrazování   farmakoterapie   patofyziologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• remodelace síní účinky léků   MeSH
• senioři MeSH
• srdeční frekvence účinky léků   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH

• MeSH
• blokáda Tawarova raménka diagnostické zobrazování   MeSH
• diabetes mellitus 1. typu patofyziologie   patologie   MeSH
• diabetes mellitus patofyziologie   patologie   MeSH
• elektrokardiografie metody   normy   MeSH
• hyperkalemie diagnostické zobrazování   MeSH
• hypertrofie levé komory srdeční diagnostické zobrazování   MeSH
• hypokalemie diagnostické zobrazování   MeSH
• komplikace diabetu diagnostické zobrazování   etiologie   MeSH
• lidé MeSH
• srdeční frekvence MeSH
• Check Tag
• lidé MeSH

BACKGROUND: Electromechanical discoordination may contribute to long-term pulmonary right ventricular (RV) dysfunction in patients after surgery for congenital heart disease. We sought to evaluate changes in RV function after temporary RV cardiac resynchronization therapy. METHODS AND RESULTS: Twenty-five patients aged median 12.0 years after repair of tetralogy of Fallot and similar lesions were studied echocardiographically (n=23) and by cardiac catheterization (n=5) after primary repair (n=4) or after surgical RV revalvulation for significant pulmonary regurgitation (n=21). Temporary RV cardiac resynchronization therapy was applied in the presence of complete right bundle branch block by atrial-synchronized RV free wall pacing in complete fusion with spontaneous ventricular depolarization using temporary electrodes. The q-RV interval at the RV free wall pacing site (mean 77.2% of baseline QRS duration) confirmed pacing from a late activated RV area. RV cardiac resynchronization therapy carried significant decrease in QRS duration (P<0.001) along with elimination of the right bundle branch block QRS morphology, increase in RV filling time (P=0.002), pulmonary artery velocity time integral (P=0.006), and RV maximum +dP/dt (P<0.001), and decrease in RV index of myocardial performance (P=0.006). RV mechanical synchrony improved: septal-to-lateral RV mechanical delay decreased (P<0.001) and signs of RV dyssynchrony pattern were significantly abolished. RV systolic stretch fraction reflecting the ratio of myocardial stretching and contraction during systole diminished (P=0.001). CONCLUSIONS: In patients with congenital heart disease and right bundle branch block, RV cardiac resynchronization therapy carried multiple positive effects on RV mechanics, synchrony, and contraction efficiency.

• MeSH
• biomechanika MeSH
• blokáda Tawarova raménka diagnostické zobrazování   etiologie   patofyziologie   terapie   MeSH
• časové faktory MeSH
• dítě MeSH
• dysfunkce pravé srdeční komory diagnostické zobrazování   etiologie   patofyziologie   MeSH
• elektrofyziologické techniky kardiologické MeSH
• elektrokardiografie MeSH
• Fallotova tetralogie komplikace   diagnostické zobrazování   patofyziologie   chirurgie   MeSH
• funkce pravé komory srdeční * MeSH
• hemodynamika MeSH
• kardiochirurgické výkony * MeSH
• kontrakce myokardu * MeSH
• lidé MeSH
• mladiství MeSH
• obnova funkce MeSH
• pulzní dopplerovská echokardiografie MeSH
• srdeční katetrizace MeSH
• srdeční resynchronizační terapie * MeSH
• výsledek terapie MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• blokáda Tawarova raménka diagnostické zobrazování   MeSH
• diagnostické techniky kardiovaskulární trendy   MeSH
• infarkt myokardu diagnostické zobrazování   MeSH
• ischemická choroba srdeční diagnostické zobrazování   prevence a kontrola   MeSH
• lidé MeSH
• radioisotopová angiografie * metody   trendy   MeSH
• radioisotopová scintigrafie * metody   trendy   MeSH
• radioizotopy sodíku MeSH
• radionuklidy * klasifikace   MeSH
• zátěžový test metody   normy   trendy   MeSH
• zobrazování myokardiální perfuze metody   trendy   MeSH
• Check Tag
• lidé MeSH