Cardiac resynchronization therapy (CRT) is a contemporary and established treatment for patients with symptomatic heart failure, severely impaired left ventricular (LV) systolic dysfunction and a wide (>150 ms) complex. As with any other treatment, the response to CRT is variable. The degree of preimplant scar burden and scar localization to the vicinity of the LV pacing stimulus are known to influence response and outcome. As well as providing measurements of global and segmental cardiac function, coronary venograghy, CMR also permits localization and quantification of myocardial perfusion and scars. This review explores on the role of CMR in the assessment of patients undergoing CRT, with emphasis on risk stratification and RV and LV leads deployment.

Purpose. To assess and to compare the ventricular myocardium activation patern obtained by non-invasive epi- and endocardial mapping (NIEEM), as well as electrocardiographic (ECG) variants of lef bundle branch block (LBBB) and to estimate the value of these data for the success of cardiac resynchronization therapy (CRT).Materials and methods. Te study included 23 patients (mean age 59,6±9,9 years) with LBBB, QRS duration ≥ 130 ms, lef ventricular ejection fraction (LVEF) ≤ 35%, heart failure (HF) NYHA II-IV despite optimal pharmacological therapy during 3 month. All patients had undergone CRT-D implantation. Depending on presence or absence of LBBB ECG-criteria, proposed by Strauss D.G. et. al, patients were divided into 2 groups: 1group - strict LBBB, proposed by Strauss D.G. et. al. (n=14) and 2 group – other ECG morphologies of LBBB (n=9). NIEEM by the Amycard 01C system with an analysis of epi- and endocardial ventricular electrical activation was performed in all patients and 5 healthy volunteers (mean age 29±1,0years). Response to CRT was estimated by echo and was defned as decrease in lef ventricular (LV) end-systolic volume by > 15% afer 6 months of follow-up.Results. LBBB ECG-criteria, proposed by Strauss D.G. et. al, was detected in 14 patients (61% of all included). According to the results of NIEEM, these patients had more pronounced ventricular electrical uncoupling (VEU) (р=0,002). Most ofen the line of block was detected in the anteroseptal or posterolateral region of the LV. Te zone of late LV activation, which is the most optimal position for the LV pacing electrode, was located in the basal and middle segments of the lateral and posterior walls. Afer 6 months of CRT 15 patients (65%) were included in the "response" group, the remaining 8 patients (35%) formed the "non-response" group according to echo criteria. In the "response" group the morphology of the QRS complex more frequently met the criteria, proposed by Strauss D.G. et al, than other ECG variants of LBBB (12 vs. 3 respectively, p = 0.023). Initially, VEU was more pronounced in the "response" group (VEU 55 [51, 64] ms in the "response" group vs 22 [8, 38] ms in the "non-response" group).Сonclusions. LBBB ECG criteria, proposed by Strauss D.G., identify patients with delayed transseptal interventricular conduction due to complete LBBB, what is a good target for CPT. Identifcation of individual ventricular activation properties may help to reveal responders to CRT in patients with LBBB.

Introduction. As a significant number of patients with heart failure (HF) does not respond to cardiac resynchronization therapy (CRT), a lot of research has deservedly focused on optimization, and better patient selection. The ideal resynchronization depends on different factors, from device programming to heart features and left ventricle (LV) lead position. Analysis of the 12-lead electrocardiogram (ECG) is the most simple method which can provide important information on LV lead location, presence of scar at LV pacing site, and fusion of intrinsic activation or RV pacing with LV pacing.Purpose. To analyze the electrophysiological and structural heart features and their correlation with the ECG pattern during biventricular (BV) pacing in patients with HF and CRT devices.Methods. The study included 47 patients (mean age 62.3±8.9 years) with LBBB, QRS duration ≥ 130 ms, left ventricular ejection fraction (LVEF) ≤ 35%, heart failure (HF) NYHA II-IV despite optimal pharmacological therapy during months. All patients had undergone CRT-D implantation. Late-gadolinium enhancement-cardiovascular magnetic resonance (LGE-CMR), 12-lead ECG, non-invasive cardiac mapping (NICM) (with obtaining the zone of late LV activation (ZLA)) were undertaken prior to CRT devices implantation. NICM with cardiac CT and evaluation of LV lead position, ECG pattern during BV pacing (#1 - fusion complex with increased or dominant R wave, independent of QRS duration, #2- QS pattern with QRS duration normalization, and #3- QS pattern with increased QRS duration) were undertaken after CRT devices implantation. Response to CRT was estimated by echo and was defined as decrease in LV end-systolic volume by > 15% after 6 months of follow-up.Results. CRT was effective in 28 patients (59.5%). According to the results of NICM, zone of late LV activation more often was located at 5,6,11,12 segments, and LV pacing site - at 6,7,12 segments of LV. In the “response” group overlap of scar zone and zone of late LV activation was observed (p=0.005). The presence of scar tissue in the LV pacing site was associated with CRT non-response (p<0.001), and the pacing zone of late LV activation resulted in the best CRT response (p<0.001). The distance from the LV electrode to the zone of late LV activation was less in the “CRT response” group (33 [20;42] mm vs 83 [55;100] mm, p<0.001). The most beneficial ECG pattern during BV pacing was #2, and #3 was more often observed in the group “CRT non-response”; configuration #1 was intermediate between ECG patterns #2 and #3.Conclusions. A comprehensive examination, including the study of the structural and electrophysiological heart features is important for the optimal positioning the LV lead and subsequent CRT device programming. The simple analysis of the QRS pattern during BV pacing can show whether biventricular pacing is adequately performed and can reveal inadequate CRT programming and LV lead positioning.

У пациентов с дилатационной кардиомиопатией (ДКМП) часто развиваются нарушения внутрижелудочковой проводимости, которые способствуют усугублению клинического течения сердечной недостаточности, в большинстве случаев имеют прогрессирующее течение, и могут определять прогноз заболевания. Пароксизмальные суправентрикулярные аритмии у таких больных протекают с тяжелыми клиническими проявлениями, нередко сопровождаются гемодинамической нестабильностью и синкопальными состояниями.Представлен клинический случай пациентки К., 59 лет с ДКМП, сниженной фракцией выброса левого желудочка (35-37%), блокадой левой ножки пучка Гиса и пароксизмальной ортодромной реципрокной тахикардией. При постановке диагностического электрода в верхушку правого желудочка в ходе процедуры радиочастотной аблации добавочного пути проведения у пациентки было отмечено возникновение полной поперечной блокады.Сохранение полной поперечной блокады в течение операции, ее рецидивы при попытках удаления электрода из верхушки правого желудочка потребовали обеспечения временной, а затем постоянной электрокардиостимуляции. Учитывая ДКМП, со снижением фракции выброса левого желудочка, наличие блокады левой ножки пучка Гиса и высокий ожидаемый процент стимуляции правого желудочка, принято решение об имплантации сердечного ресинхронизирующего устройства с функцией дефибриллятора. В обзоре литературы рассмотрены факторы риска развития полной поперечной блокады в ходе катетеризации сердца, возможности профилактики этого опасного осложнения, обсуждены прогностическая значимость катетер-индуцированных нарушений проводимости, показания к временной и постоянной электрокардиостимуляции.

Aim. To assess the value of the complex analysis of electrocardiographic (ECG) variants and echocardiographic (echo) manifestation of left bundle branch block (LBBB) in predicting the success of cardiac resynchronization therapy (CRT). Materials and methods. The study included 39 patients (mean age 61.49±9.0 years) on sinus rhythm with LBBB, QRS duration ≥130 ms, left ventricular ejection fraction (LVEF) ≤35%, heart failure (HF) NYHA II-IV despite optimal pharmacological therapy during 3 month. All patients had undergone CRT-D implantation. Depending on presence or absence of ECG-criteria, proposed by D.G. Strauss et al., patients were divided into 2 groups: 1 group - strict LBBB, proposed by D.G. Strauss et al. (n=29) and 2 group - other patients (n=10). In addition to standard echocardiography, global longitudinal 2-dimensional strain (GLS) and LBBB contraction pattern have been performed initially and in 6 months after implantation. Response to CRT was defined as decrease in LV end-systolic volume by >15% after 6 months of follow-up. Results and discussion. Typical LBBB echo contraction pattern was detected in 25 patients (64% of all included). These patients had more pronounced longitudinal dissynchrony and a more expressed global longitudinal strain before CPT-D implantation (p