Mid-term outcomes of delivery catheter-based and stylet-based right ventricular septal pacing: Follow-up results from a multicenter, prospective, randomized study.

Background: The Mt FUJI study was a multicenter, prospective, randomized, single-blind, controlled trial comparing delivery catheter-based and stylet-based right ventricular (RV) lead placement at the RV septum. This study extended the follow-up duration to 1 year after implantation. Methods: Seventy patients with pacemaker indications for atrioventricular block were randomly assigned to the delivery catheter and stylet groups. We compared the mid-term efficacy and safety between the two groups at 1 year after implantation. The primary outcome was the change in the left ventricular ejection fraction (LVEF), and the secondary outcomes were changes in brain natriuretic peptide (BNP) levels, lead parameters, paced QRS duration, and the incidence of adverse events. Results: At the 1-year follow-up, no significant differences were observed in the changes in the LVEF (+1.0% ± 8.6% vs. +3.1% ± 8.1%, p = .332), BNP levels (+8.0 [-11.1, 26.5] pg/mL vs. -8.7 [-15.3, 13.2] pg/mL, p = .193), or lead performance between the delivery catheter and stylet groups. The QRS duration was significantly shorter in the delivery catheter group than in the stylet group (128 ± 23 ms vs. 146 ± 17 ms, p < .001). All-cause death, hospitalization for heart failure, new development of atrial fibrillation, and pacing-induced cardiomyopathy occurred in seven patients in the delivery catheter group and five in the stylet group. Conclusion: The delivery catheter system was similarly useful and safe compared to the stylet system in the mid-term follow-up from the Mt FUJI trial. Further long-term evaluations are warranted.

Delivery catheter system carries more physiological right ventricular septal pacing than stylet system.

INTRODUCTION: The Mt. FUJI multicenter trial demonstrated that a delivery catheter system had a higher rate of successful right ventricular (RV) lead deployment on the RV septum (RVS) than a conventional stylet system. In this subanalysis of the Mt. FUJI trial, we assessed the differences in electrocardiogram (ECG) parameters during RV pacing between a delivery catheter system and a stylet system and their associations with the lead tip positions. METHODS: Among 70 patients enrolled in the Mt FUJI trial, ECG parameters, RV lead tip positions, and lead depth inside the septum assessed by computed tomography were compared between the catheter group (n = 36) and stylet group (n = 34). RESULTS: The paced QRS duration (QRS-d), corrected paced QT (QTc), and JT interval (JTc) were significantly shorter in the catheter group than in the stylet group (QRS-d: 130 ± 19 vs. 142 ± 15 ms, p = .004; QTc: 476 ± 25 vs. 514 ± 20 ms, p < .001; JTc: 347 ± 24 vs. 372 ± 17 ms, p < .001). This superiority of the catheter group was maintained in a subgroup analysis of patients with an RV lead tip position at the septum. The lead depth inside the septum was greater in the catheter group than in the stylet group, and there was a significant negative correlation between the paced QRS-d and the lead depth. CONCLUSION: Using a delivery catheter system carries more physiological depolarization and repolarization during RVS pacing and deeper screw penetration in the septum in comparison to conventional stylet system. The lead depth could have a more impact on the ECG parameters rather than the type of pacing lead.

Takotsubo Cardiomyopathy Presenting with QT Prolongation and Torsade de Pointes in a Patient with Coronavirus Disease 2019.

Coronavirus disease 2019 (COVID-19) is associated with cardiovascular complications; however, Takotsubo cardiomyopathy (TCM) with QT prolongation and Torsade de pointes has been reported only rarely. We present a case of TCM after QT prolongation and Torsade de pointes. A 58-year-old woman was admitted because of COVID-19-related pneumonia. Seven days after admission, she developed sudden loss of consciousness without any indication of cardiovascular disease. A monitoring electrocardiogram indicated Torsade de pointes and a prolonged QT interval. Emergency cardiac catheterization revealed TCM. She was treated with favipiravir and steroids, followed by rehabilitation, and her condition improved. To detect asymptomatic TCM, routine electrocardiography screening should be considered for patients with COVID-19.

Preferred left ventricular lead position for upgrade from right ventricular pacing to cardiac resynchronization therapy.

INTRODUCTION: Cardiac resynchronization therapy (CRT) is well-established for treating symptomatic heart failure with electrical dyssynchrony. The left ventricular (LV) lead position is recommended at LV posterolateral to lateral sites in patients with left bundle branch block; however, its preferred region remains unclear in patients being upgraded from right ventricular (RV) apical pacing to CRT. This study aimed to identify the preferred LV lead position for upgrading conventional RV apical pacing to CRT. METHODS: We used electrode catheters positioned at the RV apex and LV anterolateral and posterolateral sites via the coronary sinus (CS) branches to measure the ratio of activation time to QRS duration from the RV apex to the LV anterolateral and posterolateral sites during RV apical pacing. Simultaneous biventricular pacing was performed at the RV apex and each LV site, and the differences in QRS duration and LV dP/dtmax from those of RV apical pacing were measured. RESULTS: Thirty-seven patients with anterolateral and posterolateral LV CS branches were included. During RV apical pacing, the average ratio of activation time to QRS duration was higher at the LV anterolateral site than at the LV posterolateral site (0.90 ± 0.06 vs. 0.71 ± 0.11, p < .001). The decreasing ratio of QRS duration and the increasing ratio of LV dP/dtmax were higher at the LV anterolateral site than at the posterolateral site (45.7 ± 18.0% vs. 32.0 ± 17.6%, p < .001; 12.7 ± 2.9% vs. 3.7 ± 8.2%, p < .001, respectively) during biventricular pacing compared with RV apical pacing. CONCLUSION: The LV anterolateral site is the preferred LV lead position in patients being upgraded from conventional RV apical pacing to CRT.

Usefulness of delivery catheter on accurate right ventricular septal pacing: Mt FUJI trial.

AIMS: Although the delivery catheter system for pacemaker-lead implantation is a new alternative to the stylet system, no randomized controlled trial has addressed the difference in right ventricular (RV) lead placement accuracy to the septum between the stylet and the delivery catheter systems. This multicentre prospective randomized controlled trial aimed to prove the efficacy of the delivery catheter system for accurate delivery of RV lead to the septum. METHODS AND RESULTS: In this trial, 70 patients (mean age 78 ± 11 years; 30 men) with pacemaker indications of atrioventricular block were randomized to the delivery catheter or the stylet groups. Right ventricular lead tip positions were assessed using cardiac computed tomography within 4 weeks of pacemaker implantation. Lead tip positions were classified into RV septum, anterior/posterior edge of the RV septal wall, and RV free wall. The primary endpoint was the success rate of RV lead tip placement to the RV septum. RESULTS: Right ventricular leads were implanted as per allocation in all patients. The delivery catheter group had higher success rate of RV lead deployment to the septum (78 vs. 50%; P = 0.024) and narrower paced QRS width (130 ± 19 vs. 142 ± 15 ms P = 0.004) than those in the stylet group. However, there was no significant difference in procedure time [91 (IQR 68-119) vs. 85 (59-118) min; P = 0.488] or the incidence of RV lead dislodgment (0 vs. 3%; P = 0.486). CONCLUSION: The delivery catheter system can achieve a higher success rate of RV lead placement to the RV septum and narrower paced QRS width than the stylet system. TRIAL REGISTRATION NUMBER: jRCTs042200014 (https://jrct.niph.go.jp/en-latest-detail/jRCTs042200014).

Improvement in Quality of Life via Catheter Ablation for Atrial Fibrillation in Patients Undergoing Hemodialysis Therapy.

Background: Atrial fibrillation (AF) is the most common arrhythmia in patients undergoing hemodialysis (HD); AF lowers quality of life (QoL) and increases the risk of dialysis-related complications. The present study aimed to evaluate the effectiveness of AF ablation on the QoL in patients undergoing HD. Methods: Nineteen patients undergoing HD (14 men, age 68 ± 8 years; 15 with paroxysmal AF) who underwent catheter ablation (CA) of AF were enrolled in the study. The Kidney Disease Quality of Life Short Form (KDQOL-SF) was assessed to evaluate the QoL of the HD patients at baseline and 6 months after the ablation. Ablation outcomes and procedural complications were evaluated and compared to those of 1053 consecutive non-HD patients who underwent AF ablation. Results: The KDQOL-SF of the HD patients 6 months after the ablation showed an improvement in physical functioning (54 ± 23 to 68 ± 28, P < 0.01), general health perceptions (38 ± 17 to 48 ± 15, P < 0.01), and symptoms/problems (75 ± 21 to 84 ± 13, P = 0.02), compared to baseline. For intradialytic symptoms, dyspnea during HD significantly improved after the CA in the HD patients without AF recurrence (43% to 7%, P = 0.04), whereas the atrial tachyarrhythmias and hypotension during HD remained unchanged. During the follow-up period of 17 ± 13 months after the last procedure, the incidence of being arrhythmia-free was similar (HD patients, 79% vs non-HD patients, 86%, log-rank P = 0.82). No life-threatening complications occurred in any of the patients. Conclusions: CA of AF improves QoL in patients undergoing chronic HD therapy.

Contexte: La fibrillation auriculaire (FA), la forme d'arythmie la plus fréquente chez les patients sous hémodialyse (HD), entraîne une diminution de la qualité de vie (QdV) et une augmentation des risques de complications liées à la dialyse. La présente étude visait à évaluer l'effet de l'ablation de la FA sur la QdV des patients sous HD. Méthodologie: Dix-neuf patients sous HD (âgés de 68 ± 8 ans, dont 14 étaient des hommes et 15 étaient atteints de FA paroxystique) ayant subi une ablation par cathéter de la FA ont été admis dans l'étude. Le questionnaire KDQOL-SF (Kidney Disease Quality of Life Short Form) a été utilisé pour évaluer la QdV des patients sous HD avant l'intervention et six mois après l'ablation. L'issue de l'ablation et les complications liées à l'intervention ont été évaluées et comparées à celles de 1 053 patients consécutifs n'étant pas hémodialysés et ayant subi une ablation de la FA. Résultats: La comparaison des résultats initiaux au KDQOL-SF des patients hémodialysés avec les résultats obtenus six mois après l'ablation a montré des améliorations de la fonction physique (de 54 ± 23 à 68 ± 28, p < 0,01), de la perception de l'état de santé global (de 38 ± 17 à 48 ± 15, p < 0,01), et des symptômes/problèmes de santé (de 75 ± 21 à 84 ± 13, p = 0,02). En ce qui concerne les symptômes survenant lors des séances d'HD, une amélioration significative de la dyspnée a été observée après l'ablation par cathéter chez les patients sous HD sans récurrence de la FA (de 43 % à 7 %, p = 0,04), alors qu'aucun changement n'a été constaté pour les tachyarythmies auriculaires et l'hypotension. Durant la période de suivi de 17 ± 13 mois après la dernière intervention, le nombre de patients sans arythmie était comparable dans les deux groupes (79 % chez les patients hémodialysés et 86 % chez les patients non hémodialysés, test du log-rank = 0,82). Aucun patient n'a subi de complication menaçant le pronostic vital. Conclusions: L'ablation par cathéter de la FA permet d'améliorer la QdV des patients qui subissent un traitement par HD de longue durée.

Comparison of delivery catheter-based and stylet-based right ventricular lead placement at the right ventricular septum under fluoroscopic guidance judged by cardiac CT (Mt. FUJI): a study protocol for the Mt. FUJI randomised controlled trial.

INTRODUCTION: Pacing-induced cardiomyopathy occasionally occurs in patients undergoing pacemaker implantation. Although compared with right ventricular (RV) apical pacing, RV septal pacing can attenuate left ventricular dyssynchrony; the success rate of lead placement on the RV septum using the stylet system is low. Additionally, no randomised controlled trial has addressed the issue regarding the accuracy of RV lead placement on the RV septum using the stylet and delivery catheter systems. This study hypothesises that a newly available delivery catheter system can improve the accuracy of RV lead placement on the RV septum. METHODS AND ANALYSIS: In a multicentre, prospective, randomised, single-blind, controlled trial, 70 patients with pacemaker indication owing to atrioventricular block will be randomised to either the delivery catheter or stylet group before the pacemaker implantation procedure. The position of the RV lead tip will be assessed using ECG-gated cardiac CT in all patients within 4 weeks after pacemaker implantation. Lead tip positions are classified into three groups: (1) RV septum, (2) anterior/posterior edge of the RV septal wall and (3) RV free wall. The primary endpoint will be the success rate of RV lead tip placement on the RV septum, which will be evaluated using cardiac CT. ETHICS AND DISSEMINATION: This study will be conducted according to the stipulations of the Helsinki Declaration and the institutional review board of Hamamatsu University School of Medicine. The results of the study will be disseminated at several research conferences and will be published in peer-reviewed journals. TRIAL REGISTRATION NUMBER: jRCTs042200014; Pre-results.

Structural heart disease, not the right ventricular pacing site, determines the QRS duration during right ventricular pacing.

Right ventricular (RV) pacing causes changes in the heart's electrical and mechanical activation patterns. The QRS duration is a useful surrogate marker of electrical dyssynchrony; a longer QRS duration during RV pacing indicates poor prognosis. However, the mechanisms underlying a longer QRS duration during RV pacing remain unclear; hence, we investigated factors predicting QRS prolongation during RV pacing. We enrolled 211 patients who underwent catheter ablation for supraventricular tachyarrhythmia and showed no bundle branch block. Three-dimensional mapping for the QRS duration during RV pacing from the RV outflow to RV apex was performed, and differences in the QRS duration were analyzed. The predisposing factors causing QRS > 160 ms during RV apical pacing were also analyzed. The QRS durations at baseline and during RV pacing from the RV outflow and at the RV apex were 85.0 ± 7.5 ms, 163.7 ± 17.1 ms, and 156.2 ± 16.1 ms, respectively. With respect to the QRS duration, there was a significant correlation between RV outflow and RV apical pacing (r = 0.658, p < 0.001). Difference in the QRS duration between the RV outflow and RV apex in each patient was only 12.5 ± 10.4 ms. Logistic multivariable regression analysis identified baseline QRS duration [odds ratio (OR) 1.24, 95% confidence interval (CI) 1.15-1.33, p < 0.01], interventricular septum thickness (OR 1.20, 95% CI 1.02-1.40, p = 0.025), left atrial diameter (OR 1.08, 95% CI 1.01-1.16, p = 0.024), and E/e' (OR 1.23, 95% CI 1.12-1.35, p < 0.01) as significant predictors of QRS prolongation during RV apical pacing. The QRS duration during RV pacing largely depends not on the pacing site, but on the underlying structural heart diseases.

Effects of empagliflozin versus placebo on cardiac sympathetic activity in acute myocardial infarction patients with type 2 diabetes mellitus: the EMBODY trial.

BACKGROUND: Protection from lethal ventricular arrhythmias leading to sudden cardiac death (SCD) is a crucial challenge after acute myocardial infarction (AMI). Cardiac sympathetic and parasympathetic activity can be noninvasively assessed using heart rate variability (HRV) and heart rate turbulence (HRT). The EMBODY trial was designed to determine whether the Sodium-glucose cotransporter 2 (SGLT2) inhibitor improves cardiac nerve activity. METHODS: This prospective, multicenter, randomized, double-blind, placebo-controlled trial included patients with AMI and type 2 diabetes mellitus (T2DM) in Japan; 105 patients were randomized (1:1) to receive once-daily 10-mg empagliflozin or placebo. The primary endpoints were changes in HRV, e.g., the standard deviation of all 5-min mean normal RR intervals (SDANN) and the low-frequency-to-high-frequency (LF/HF) ratio from baseline to 24 weeks. Secondary endpoints were changes in other sudden cardiac death (SCD) surrogate markers such as HRT. RESULTS: Overall, 96 patients were included (46, empagliflozin group; 50, placebo group). The changes in SDANN were + 11.6 and + 9.1 ms in the empagliflozin (P = 0.02) and placebo groups (P = 0.06), respectively. Change in LF/HF ratio was - 0.57 and - 0.17 in the empagliflozin (P = 0.01) and placebo groups (P = 0.43), respectively. Significant improvement was noted in HRT only in the empagliflozin group (P = 0.01). Whereas intergroup comparison on HRV and HRT showed no significant difference between the empagliflozin and placebo groups. Compared with the placebo group, the empagliflozin group showed significant decreases in body weight, systolic blood pressure, and uric acid. In the empagliflozin group, no adverse events were observed. CONCLUSIONS: This is the first randomized clinical data to evaluate the effect of empagliflozin on cardiac sympathetic and parasympathetic activity in patients with T2DM and AMI. Early SGLT2 inhibitor administration in AMI patients with T2DM might be effective in improving cardiac nerve activity without any adverse events. TRIAL REGISTRATION: The EMBODY trial was registered by the UMIN in November 2017 (ID: 000030158). UMIN000030158; https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000034442 .

Exercise-based cardiac rehabilitation for patients with catheter ablation for persistent atrial fibrillation: A randomized controlled clinical trial.

AIMS: The efficacy and safety of cardiac rehabilitation for patients with persistent atrial fibrillation who restored sinus rhythm after catheter ablation remains unclear. The aim of the present study was to evaluate the effects of cardiac rehabilitation on exercise capacity, inflammatory status, cardiac function, and safety in patients with persistent atrial fibrillation who had catheter ablation. METHODS: In this randomized controlled study, 61 patients treated with catheter ablation for persistent atrial fibrillation (male, 80%; mean age, 66 ± 9 years) were analyzed. Thirty patients underwent cardiac rehabilitation (rehabilitation group), whereas the remaining 31 patients received usual care (usual care group). The rehabilitation group underwent endurance and resistance training with moderate intensity, at least three times per week for six months. Six-minute walk distance, muscle strength, serum high-sensitivity C-reactive protein, plasma pentraxin 3, left ventricular ejection fraction and atrial fibrillation recurrence were assessed at baseline and at six-month follow-up. RESULTS: In the rehabilitation group, significant increases in the six-minute walk distance, handgrip strength, leg strength and left ventricular ejection fraction and significant decreases in high-sensitivity C-reactive protein and plasma pentraxin 3 concentrations were observed at six-month follow-up compared with baseline (all p < 0.05). No significant changes were observed in the usual care group. During the six-month follow-up period, the number of patients with atrial fibrillation recurrence was six (21.4%) in the rehabilitation group and eight (25.8%) in the usual care group (risk ratio, 0.83; 95% confidence interval, 0.33 to 2.10). CONCLUSIONS: Cardiac rehabilitation improved exercise capacity without increasing the risk for atrial fibrillation recurrence. It may also be effective in managing systemic inflammatory status and systolic left ventricular function in patients with persistent atrial fibrillation treated with catheter ablation.

Mid-term feasibility and safety of downgrade procedure from defibrillator to pacemaker with cardiac resynchronization therapy.

BACKGROUNDS: Some patients who undergo implantation of cardiac resynchronization therapy with defibrillator (CRT-D) survive long enough, thus requiring CRT-D battery replacement. Defibrillator therapy might become unnecessary in patients who have had significant clinical improvement and recovery of left ventricular ejection fraction (LVEF) after CRT-D implantation. METHODS: Forty-nine patients who needed replacement of a CRT-D battery were considered for exchange of CRT-D for cardiac resynchronization therapy with pacemaker (CRT-P) if they met the following criteria: LVEF >45%; the indication for an implantable cardioverter defibrillator was primary prevention at initial implantation and no appropriate implantable cardioverter defibrillator therapy was documented after initial implantation of the CRT-D. RESULTS: Seven patients (14.2%) were undergone a downgrade from CRT-D to CRT-P without any complications. No ventricular tachyarrhythmic events were observed during a mean follow-up of 39.7 ±â€¯21.1 months and there was no significant change in LVEF between before and 1 year after device replacement (53.5% ±â€¯6.2% vs. 56.4% ±â€¯7.3%, P = 0.197). CONCLUSIONS: This study confirmed mid-term feasibility and safety of downgrade from CRT-D to CRT-P alternative to conventional replacement with CRT-D.

Effects of exercise training on exercise capacity, cardiac function, BMI, and quality of life in patients with atrial fibrillation: a meta-analysis of randomized-controlled trials.

Exercise training has become part of the standard care for patients with cardiovascular disease. We investigated the effects of exercise training on exercise capacity, cardiac function, BMI, and quality of life in patients with atrial fibrillation (AF). We searched for randomized-controlled trials of supervised exercise training versus care without exercise training (the control) in patients with permanent or nonpermanent AF published up to November 2016. Standard mean differences (SMD) or mean differences (MD), and 95% confidence intervals (CIs) were calculated using random-effect models. We identified 259 trials, and after an assessment of relevance, five trials with a combined total of 379 participants were analyzed. In AF patients, exercise training significantly improved exercise capacity and left ventricular ejection fraction compared with the control (SMD: 0.91, 95% CI: 0.70 to 1.12; MD: 4.8%, 95% CIs: 1.56 to 8.03, respectively). Compared with the control, exercise training also significantly reduced BMI (MD: -0.47 kg/m, 95% CIs: -0.89 to -0.06) and significantly improved scores in the 'general health' and 'vitality' sections of the 36-item Short Form Health Status Survey (SMD: 0.71, 95% CIs: 0.30 to 1.12; SMD: 0.81, 95% CIs: 0.40 to 1.23, respectively). Exercise training improved exercise capacity, left ventricular ejection fraction, and some the 36-item Short Form Health Status Survey scores, and reduced BMI in AF patients.

Stretching Exercises Improve Vascular Endothelial Dysfunction Through Attenuation of Oxidative Stress in Chronic Heart Failure Patients With an Implantable Cardioverter Defibrillator.

PURPOSE: Endurance training improves oxidative stress and vascular endothelial dysfunction in patients with chronic heart failure (CHF). However, patients with CHF and an implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy-defibrillator (CRT-D) often avoid endurance training for fear of ICD shock. Recent studies have reported that stretching exercises enhance antioxidant activity and improve vascular responses. Therefore, we aimed to assess the effects of 4 weeks of stretching exercises on oxidative stress and vascular endothelial function in patients with CHF with an ICD or CRT-D. METHODS: Fifty sedentary patients with CHF (78% males; mean age = 70 ± 9 years; left ventricular ejection fraction = 26% ± 8%) with an ICD or CRT-D were randomly divided into a group that performed 4 weeks of stretching exercises (stretching group) and a group that continued a sedentary lifestyle (control group). We compared the reactive hyperemia peripheral arterial tonometry (RH-PAT) index and blood parameters, such as von Willebrand factor (vWF), malondialdehyde-modified low-density lipoprotein cholesterol (MDA-LDL), reactive oxygen species (ROS), high-sensitivity C-reactive protein, pentraxin 3, and fibrinogen between the 2 groups before and after the 4-week study period. RESULTS: In the stretching group, a significant increase in the RH-PAT index and significant decreases in vWF, MDA-LDL, ROS, and fibrinogen concentrations were observed after the study compared with before (all P < .05). No significant changes were observed in the control group. CONCLUSION: Four weeks of stretching exercises improved vascular endothelial dysfunction through attenuation of oxidative stress in sedentary patients with CHF with an ICD or CRT-D.

Restoration of ventricular septal hypoperfusion by cardiac resynchronization therapy in patients with permanent right ventricular pacing.

BACKGROUND: Pacing from the right ventricular apex (RVA) is associated with cardiac dysfunction and shows electrophysiological features similar to left bundle branch block in which left ventricular (LV) mechanical dyssynchrony impairs septal coronary artery perfusion. METHODS: A total of 62 non-ischemic patients with an implanted pacemaker at the RVA with a pacing rate of >95% were studied. LV septal coronary perfusion as indicated by the LV septal perfusion index was measured by electrocardiography (ECG)-gated single-photon emission computed tomography for all patients at baseline and for patients who were upgraded to CRT at 6months after CRT. Relationships among LV septal perfusion index, QRS duration, and LV ejection fraction were analyzed. RESULTS: Among the patients with permanent RVA pacing, 28 of 62 (45%) had impaired septal perfusion (i.e., septal perfusion index <0.9). The LV septal perfusion index was significantly correlated with both QRS duration (r=-0.763, p<0.001) and LV ejection fraction (r=0.462, p=0.001). Eleven patients were upgraded to CRT. CRT significantly improved the LV septal perfusion index from 0.63 (SD=0.13) to 0.89 (SD=0.19) (p<0.001)and cardiac function: LV end-systolic volume from 102.3mL (SD=70.0) to 179.7mL (SD=118.4) (p=0.002) and LV ejection fraction from 22.5 (SD=8.9%) to 38.4% (SD=13.9%) (p=0.001). CONCLUSIONS: Nearly half of the non-ischemic patients with permanent RVA pacing presenting with prolonged QRS duration and LV dysfunction developed LV septal hypoperfusion. Both septal perfusion and LV function improved in patients who were upgraded to CRT.

Cardiac resynchronization therapy restored ventricular septal myocardial perfusion and enhanced ventricular remodeling in patients with nonischemic cardiomyopathy presenting with left bundle branch block.

BACKGROUND: Left bundle branch block (LBBB) causes intraventricular conductional delay, which results in left ventricle (LV) mechanical dyssynchrony. In the absence of coronary artery disease, patients with LBBB often have diminished accumulation of technetium-99m compounds at the myocardial septal area in electrocardiogram-gated single-photon emission computed tomography. OBJECTIVE: To investigate whether cardiac resynchronization therapy (CRT) could improve septal myocardial perfusion, leading to favorable reverse remodeling. METHODS: The study included all 26 patients with nonischemic cardiomyopathy eligible for CRT, who presented with LBBB, New York Heart Association class II-IV heart failure, and LV ejection fraction ≤35%. Single-photon emission computed tomography was performed at baseline and 6 months after CRT. Perfusion counts were measured at the ventricular septum and LV lateral free wall. Left ventricular end-systolic volume (LVESV) was measured by echocardiography to evaluate LV reverse remodeling by CRT. RESULTS: At baseline, a perfusion defect at the LV septal myocardial area was confirmed in 19 of 26 (73%) patients. In these patients, septal perfusion significantly increased 6 months after CRT (56.1% ± 22.8% vs 82.9% ± 21.2%; P < .001). LVESV reduction and improved septal perfusion index were positively correlated (r = .561; P = .012), whereas no correlation was found between LVESV reduction and the difference of QRS duration before and 6 months after CRT (r = .218; P = .371). The improvement in LV septal perfusion was associated with LV reverse remodeling. CONCLUSIONS: CRT could restore LV septal myocardial perfusion and ameliorate ventricular reverse remodeling in most patients with nonischemic cardiomyopathy and LBBB.