Septal-to-posterior Wall Motion Delay Research Articles

Comparison between left bundle branch area pacing and right ventricular pacing: ventricular electromechanical synchrony and risk of atrial high-rate episodes.

The electromechanical dyssynchrony associated with right ventricular pacing (RVP) has been found to have adverse impact on clinical outcomes. Several studies have shown that left bundle branch area pacing (LBBAP) has superior pacing parameters compared with RVP. We aimed to assess the difference in ventricular electromechanical synchrony and investigate the risk of atrial high-rate episodes (AHREs) in patients with LBBAP and RVP. We consecutively identified 40 patients with atrioventricular block and no prior atrial fibrillation. They were divided according to the ventricular pacing sites: the LBBAP group and the RVP group (including the right ventricular apical pacing (RVA) group and the right side ventricular septal pacing (RVS) group). Evaluation of ventricular electromechanical synchrony was implemented using electrocardiogram and two-dimensional speckle tracking echocardiography (2D-STE). AHRE was defined as event with an atrial frequency of ≥176 bpm lasting for ≥6 min recorded by pacemakers during follow-up. The paced QRS duration of the LBBAP group was significantly shorter than that of the other two groups: LBBAP 113.56 ± 9.66 ms vs. RVA 164.73 ± 14.49 ms, p < 0.001; LBBAP 113.56 ± 9.66 ms vs. RVS 148.23 ± 17.3 ms, p < 0.001. The LBBAP group showed shorter maximum difference (TDmax), and standard deviation (SD) of the time to peak systolic strain among the 18 left ventricular segments, and time of septal-to-posterior wall motion delay (SPWMD) compared with the RVA group (TDmax, 87.56 ± 56.01 ms vs. 189.85 ± 91.88 ms, p = 0.001; SD, 25.40 ± 14.61 ms vs. 67.13 ± 27.40 ms, p < 0.001; SPWMD, 28.75 ± 21.89 ms vs. 99.09 ± 46.56 ms, p < 0.001) and the RVS group (TDmax, 87.56 ± 56.01 ms vs. 156.46 ± 55.54 ms, p = 0.003; SD, 25.40 ± 14.61 ms vs. 49.02 ± 17.85 ms, p = 0.001; SPWMD, 28.75 ± 21.89 ms vs. 91.54 ± 26.67 ms, p < 0.001). The interventricular mechanical delay (IVMD) was shorter in the LBBAP group compared with the RVA group (-5.38 ± 9.31 ms vs. 44.82 ± 16.42 ms, p < 0.001) and the RVS group (-5.38 ± 9.31 ms vs. 25.31 ± 21.36 ms, p < 0.001). Comparing the RVA group and the RVS group, the paced QRS duration and IVMD were significantly shorter in the RVS group (QRS duration, 164.73 ± 14.49 ms vs. 148.23 ± 17.3 ms, p = 0.02; IVMD, 44.82 ± 16.42 ms vs. 25.31 ± 21.36 ms, p = 0.022). During follow-up, 2/16 (12.5%) LBBAP patients, 4/11 (36.4%) RVA patients, and 8/13 (61.5%) RVS patients had recorded novel AHREs. LBBAP was proven to be independently associated with decreased risk of AHREs than RVP (log-rank p = 0.043). LBBAP generates narrower paced QRS and better intro-left ventricular and biventricular contraction synchronization compared with traditional RVP. LBBAP was associated with a decreased risk of AHREs compared with RVP.

The relationship between mechanical dyssynchrony of the left ventricular myocardium and the degree of coronary artery occlusion in patients with coronary artery disease

Background. The prevalence of chronic heart failure in the world is increasing; however, it is stabilizing in developed countries. One of the reasons for this stabilization is an improvement of acute coronary syndrome treatment and revascularization. Revascularization in patients with chronic coronary syndromes without signs of the left ventricular dysfunction is less effective. One of the promising methods for assessing left ventricular dysfunction is the detection of electrical and mechanical dyssynchrony of the myocardium (DM). However, mechanical dyssynchrony of the myocardium has not been sufficiently studied in patients with coronary artery (CA) disease. The purpose was to assess the relationship between mechanical myocardial dyssynchrony and the degree of coronary artery occlusion in patients with coronary artery disease who underwent revascularization. Materials and methods. One hundred and thirty-four patients with coronary artery disease (35 with myocardial infarction and 99 with chronic coronary syndromes) who underwent coronary angiography and revascularization of coronary arteries were included in the study. According to the results of coronary angiography, patients were divided into 3 groups: 12 had unchanged CA (group 1), 17 had atherosclerotic lesions of CA without signs of occlusion (group 2), and 105 patients were with CA occlusion. Among those with CA occlusion, 10 people had an occlusion of less than 50 %, 26 patients had occlusion from 50 to 80 %, 36 had more than 80 %, and 33 patients had complete occlusion of at least one coronary artery. In all patients, parameters of mechanical DM were determined by ultrasound method. Results. In the first group, 3 patients (25 %) had mechanical DM, in the second — 4 patients (23.5 %), in the group with coronary artery occlusion, 42 patients (40 %) had mechanical DM. In the group with complete CA occlusion, mechanical DM was detected in 18 (53 %) cases. Septal to posterior wall motion delay (SPWMD) did not differ significantly in the comparison groups; however, it increased significantly to 64.8 ± 43.2 ms in patients with complete CA occlusion compared with 40.8 ± 13.1 ms in the group with unchanged CA (p &lt; 0.05). SPWMD had a significant correlation with the degree of CA occlusion (r = 0.254, p = 0.009). The interventricular mechanical delay increased significantly, to 61.3 ± 40.5 ms compared with 33.4 ± 3.4 ms in patients with unchanged CA (p &lt; 0.05). Left ventricular filling time was significantly shorter in the group with complete CA occlusion compared to the patients with incomplete CA occlusion and those with unchanged CA (47.3 ± 10.4 ms vs. 54.2 ± 5.7 ms, respectively; p &lt; 0.05). Left ventricular ejection time was not significantly different between comparison groups, but correlated significantly with the degree of CA occlusion (r = 0.241, p = 0.013). The early ventricular time deceleration, the time from the beginning of the QRS complex to the beginning of the peak systolic velocity did not differ significantly. The time to the peak systolic velocity was significantly longer in the group with complete CA occlusion (32.6 ± 8.5 ms), and had a significant correlation with the degree of CA occlusion (r = 0.26, p = 0.007). Conclusions. A third of patients with chronic coronary syndrome included in the study had DM. In the group with complete CA occlusion, the frequency of DM detection increased significantly and was diagnosed in half of cases. In patients with complete CA occlusion, DM manifested itself in a significant SPWMD, an increase in the period of pre-ejection into the aorta and, as a result, a significant increase in the interventricular mechanical delay. An increase in the time to peak systolic velocity was also found in the group of patients with complete CA occlusion. DM associated with left ventricular diastolic dysfunction was detected in a group of patients with complete CA occlusion and manifested itself in a reduced left ventricular filling time.

Can echocardiography facilitate decision-making to CRT?

Abstract Introduction Cardiac resynchronization therapy (CRT) remains underused despite its well-established therapeutic effect and clear guidelines. Among various reasons are the lack of referral, the fear of complications and the high therapy cost. The assessment of mechanical dyssynchrony (MD) on echocardiography has been suggested to aid patient selection. In the past, however, several studies have used old markers of MD producing disappointing results and the use of echocardiography for patient selection became discredited. Promising new markers have been developed since and could aid clinical decision-making for CRT. These should, however, first be thoroughly tested and compared to the old markers. Purpose (I) To confirm the relevance of the new markers of MD for survival free of cardiac death and (II) to compare old and new markers of MD for predicting cardiac death within 5 years post-CRT in patients eligible for CRT according the 2021 ESC guidelines. Methods 222 CRT-patients were analysed retrospectively in a multicentre setting. MD was assessed using three old markers: septal-to-posterior wall-motion-delay (SPWMD), left-ventricular-filling-time/cardiac-cycle ratio (LVFT/RR), and intraventricular mechanical delay (IVMD); and three new markers: systolic stretch index (SSI), myocardial work index (MWI), and visual presence of septal flash or apical rocking (SFoAR). For each marker, patients were categorized using previously published cut-offs as “MD present” (Yes) or “MD not present” (No). Log rank tests were performed on Kaplan-Meier curves for survival free of cardiac death. Cox proportional hazards regressions were used to compute the hazard-ratio (HR) for cardiac death within 5 years after implantation. Results Cardiac death occurred in 37 patients (17%). Patients with MD before CRT according to IVMD (p=0.003), SSI (p&amp;lt;0.001), MWI (p&amp;lt;0.001) or SFoAR (p&amp;lt;0.001) had a significantly better survival. The hazard ratios were 0.34 (95% CI, 0.19–0.75) for IVMD, 0.30 (95% CI, 0.15–0.57) for SSI, 0.26 (95% CI, 0.12–0.54) for MWI and, 0.28 (95% CI, 0.14–0.53) for SFoAR. The other markers for MD were not significant for survival. Conclusion The new markers for dyssynchrony are better than the old. Patients with mechanical dyssynchrony on echocardiography before CRT according to SSI, MWI or SFoAR are 3 to 4 times less likely to die within 5 years after CRT implantation. The presence of one of these markers in patients with a broad QRS (≥130ms) and reduced LVEF (≤35%) should prompt clinicians to refer for or to proceed to CRT. Funding Acknowledgement Type of funding sources: None.

Echocardiographic assessment of mechanical dyssynchrony: are the new parameters better?

Abstract Funding Acknowledgements Type of funding sources: None. Introduction - The high cost and important non-response rate are preventing optimal use of cardiac resynchronization therapy (CRT). Assessing mechanical dyssynchrony on echocardiography in candidates for CRT could remove these barriers by improving patient selection. In 2008 the PROSPECT study compared several old parameters of dyssynchrony in search of a reproducible parameter capable of better predicting response to CRT. Unfortunately, the results were disappointing and the assessment of dyssynchrony became discredited. Promising new parameters have been developed but a comparison with the old parameters is currently missing. Purpose - To compare the old and new parameters of mechanical dyssynchrony for (1) their effect on response to CRT as additional selection criteria, (2) predicting favourable long-term outcome after CRT and (3) their reproducibility. Methods - 146 CRT patients were analysed retrospectively in a multicentre setting. Mechanical dyssynchrony was assessed using three old parameters: septal-to-posterior wall motion delay (SPWMD), left ventricular filling time/cardiac cycle ratio (LVFT/RR), and intraventricular mechanical delay (IVMD); and three new parameters: systolic stretch index (SSI), myocardial work index (MWI), and visual presence of septal flash or apical rocking (SFoAR). Response to CRT was defined as a ≥15% decrease in LV end-systolic volume 1 year after CRT. For each parameter patients were categorized using previously published cut-offs as ‘eligible’ or ‘non-eligible’. The ‘non-eligible’ were considered untreated. Results were compared to the guidelines (Fig. 1). The hazard ratio (HR) for cardiac death within 5 years after implantation was computed for all patients (Fig. 2), and intra- and interrater agreement was determined. Results - 73% (n= 107) of patients showed response to CRT. The old parameters maintained less than 75% of the original responders. SFoAR preserved the highest proportion of responders (93%), while reducing the number of non-responders by 39% (Fig. 1). The prediction of cardiac death was significant for SFoAR (HR = 0.29; 95% CI: 0.12-0.74; P = 0.009) and IVMD (HR = 0.32; 95% CI: 0.13-0.79; P = 0.014) (Fig. 2). Intra- and interrater agreement was best for SFoAR (κ = 0.89; 95% CI: 0.67-1.0 and κ = 0.78; 95% CI: 0.50-1.0 respectively). Interrater agreement was poor for all old parameters (κ &amp;lt; 0.6). Conclusion - The new parameters for dyssynchrony are performing better. The visual presence of apical rocking or septal flash provided the most responders to CRT, predicted favourable long-term outcome and was highly reproducible. Our results show that future research should focus on the new parameters. Abstract Figure. Abstract Figure.

The Effect of Accessory Pathway Location on Cardiac Function in Adult Patients with Wolff-Parkinson-White Syndrome.

Introduction The relationship between ventricular pre-excitation and left ventricular dysfunction has been described in the absence of sustained supraventricular tachycardia in a series of case reports. However, there have been no systematic studies about the effect of ventricular pre-excitation on cardiac function in adult patients with different accessory pathway locations. Methods and Results Patients were divided into four groups based on the type and location of their accessory pathway: septal, right free wall, left free wall, and concealed. N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels, electrocardiogram recordings, electrophysiological properties, and transthoracic echocardiographic data (septal-to-posterior wall motion delay (SPWMD) and interventricular mechanical delay (IVMD) indicating intraventricular and interventricular dyssynchrony) were compared before and after successful ablation. Before radiofrequency catheter ablation, left ventricular ejection fraction (LVEF) was significantly lower in patients with septal and right free wall accessory pathways. Within three months after radiofrequency catheter ablation, NT-proBNP levels decreased, left ventricular function improved, and intraventricular left ventricular dyssynchrony disappeared. There was a negative correlation between initial LVEF with initial QRS duration and initial SPWMD. Notably, SPWMD had a stronger correlation with LVEF than initial QRS duration. Conclusions Anterograde conduction with a septal or right free wall accessory pathway may cause left ventricular dyssynchrony and impair left ventricular function. Intraventricular left ventricular dyssynchrony seems to be responsible for the pathogenesis of left ventricular dysfunction. Radiofrequency catheter ablation results in decreased NT-proBNP levels, normalized QRS duration, mechanical resynchronization, and improved left ventricular function.

Assessment of cardiac dyssynchrony in Nigerian patients with dilated cardiomyopathy

Background: Interventricular, intraventricular, and atrioventricular dyssynchrony (AVD) have been reported in patients with dilated cardiomyopathy (DCM). However, the causes of DCM vary with the regional distribution in various etiologies, with expected differences in the pattern and frequency of cardiac dyssynchrony. Objective: The aim of this study was to evaluate cardiac dyssynchrony in patients with DCM by conventional echocardiographic assessment. Materials and Methods: Fifteen patients with DCM were studied. All patients underwent conventional Doppler echocardiographic evaluation including septal-to-posterior wall motion delay (SPWMD), interventricular motion delay (IVMD), and diastolic filling period. Results: Cardiac dyssynchrony was present in 13 of the 15 patients (86.7%). The overall frequencies of intra-left ventricular dyssynchrony (intra-LVD), interventricular dyssynchrony (inter-VD), and AVD are 38.5%, 30.8%, and 53.9%, respectively. Conclusion: The prevalence of dyssynchrony in our patients with DCM was significant. This raises the need for the development of local expertise in interventional cardiology including cardiac resynchronization therapy (CRT).

Novel dyssynchrony evaluation by M-mode imaging in left bundle branch block and the application to predict responses for cardiac resynchronization therapy

BackgroundTo determine an appropriate M-mode method in assessing left ventricular (LV) dyssynchrony in left bundle branch block (LBBB), and to assess feasibility of the method to predict cardiac resynchronization therapy (CRT) responses. Methods and resultsFifty-one patients with LBBB were enrolled. Among them 31 patients underwent CRT. In addition to original septal to posterior wall motion delay (SPWMD), first peak-SPWMD was proposed as time of difference between the first septal displacement and the maximum displacement of the posterior. If an early septal point was not present, anatomical M-mode was used to visualize an early septal displacement spreading scan-area until inferoseptal wall. CRT responders were defined as LV end-systolic volume reduction (>15%) at 6 months after CRT. Twenty patients (65%) were identified as CRT responders. First peak-SPWMD in responders was significantly higher than those in nonresponders, although SPWMD did not differ between groups. Strong predicting ability of first peak-SPWMD was revealed (first peak-SPWMD: 80/90/83%; SPWMD: 35/100/58%), and area under the curve in receiver operating characteristic analysis of first peak-SPWMD (0.88) was significantly higher than that of SPWMD (0.61) (p<0.05). ConclusionIn patients with LBBB, time differences between early septal and delayed displacement of posterolateral wall on M-mode images were the appropriate dyssynchrony parameter, and could improve the predictive ability for CRT responses.

Intraoperative characterization of interventricular mechanical dyssynchrony using electroanatomic mapping system—a feasibility study

Interventricular mechanical dyssynchrony (VVMD) is a strong predictor of cardiac resynchronization therapy (CRT) response. However, no simple and reliable clinical method of measuring VVMD during CRT implant is currently available. We tested the hypothesis that the EnSite™ NavX™ system (St. Jude Medical, St. Paul, MN, USA) can be used intraoperatively to determine VVMD, thereby facilitating CRT optimization. During CRT implant, the leads in the right atrium (RA), right ventricle (RV), and left ventricle (LV) were connected to the EnSite™ NavX™ system to record the real-time 3D motion of the lead electrodes. The distances from RA to RV lead electrodes (RA-RV) and RA to LV lead electrodes (RA-LV) were computed over ten cardiac cycles during each of RV pacing and biventricular (BiV) pacing, respectively. The degree of synchrony was computed from the distance waveforms between RA-RV and RA-LV by a cross-covariance method to characterize VVMD. Septal-to-posterior wall motion delay (SPWMD) from M-mode echocardiography (echo) was measured for reference at each pacing intervention. VVMD was present in all five patients undergoing CRT implant. Four of the five patients demonstrated clear improvement in EnSite™ NavX™-derived VVMD during BiV versus RV pacing, which corresponded to the SPWMD results by echo. It is feasible to characterize VVMD and resynchronization in CRT patients with the EnSite™ NavX™ system during implant, demonstrating its potential as a tool for intraoperative CRT optimization.

Pharmacologic Cardiac Resynchronization of a 1-Year-Old Boy With Severe Left Ventricular Dysfunction

Postero-septal accessory pathways (AP) are a rare cause of intraventricular dyssynchrony and severe LV dysfunction in children. Beside the common treatment with radiofrequency ablation of septal substrates we present the case of a successful pharmacologic resynchronization in a 13/12 years old male toddler with Wolff-Parkinson-White syndrome (WPW) and severe LV dysfunction (left ventricular biplane EF of 31 %) due to intraventricular dyssynchrony with septal to posterior wall motion delay (SPWMD) of 350 ms. Interventricular mechanical delay (IVMD) was 65 ms. Using propafenone, pharmacologic cardiac resynchronization could be achieved. Pharmacologic resynchronization should be considered as safe and effective alternative to catheter ablation in very young children.

CRT response score predicts the effects of cardiac resynchronisation therapy

Background and objectivesThe effectiveness of cardiac resynchronisation therapy (CRT) has been verified by large multi-centre studies, but non-response phenomenon occurs in about 30% of patients according to the indications of...

Cardiac Resynchronization Therapy

Cardiac Resynchronization Therapy

Prediction of CRT Responder in Non-Ischemic Cardiomyopathy Patients by CardioGRAF

Background: Cardiac resynchronization therapy (CRT) is effective for serious cardiac failure, but predictor of CRT responder is not established. CardioGRAF (cardio Gated single photon emission computed tomography Regional Assessment for left ventricular Function), has been developed to analyze regional left ventricular (LV) segmental time-volume and dyssynchrony. The aim of this study was to evaluate the usefulness of CardioGRAF for predicting a CRT responder. Methods: We retrospectively studied 32 non-ischemic cardiomyopathy (non-ICM) patients who had undergone CardioGRAF and 2D-echo at pre and post CRT. Responder was defined as improvement of NYHA and ejection fraction (EF). In CardioGRAF, dyssynchrony was evaluated by the new index, SD-12 which indicates standard deviation of time to end systole of 12 areas except apex. 2D-echo was performed and calculated septal to posterior wall motion delay (SPWMD) as an indicator of LV dyssynchrony. Results: 16 patients (50%) were identified responder. In pre CRT, SD-12 was significantly difference between responder (R, n=16) and non-responder (NR, n=16) (R: 108.65±91.1, NR: 48.3±47.8, p=0.02). SPWMD was no significantly different between responder and non-responder. Furthermore among responders, the number of patient, who improved SD12 after CRT was significantly more than that of SPWMD (87% vs. 50%, p=0.02). Conclusion: CardioGRAF is a useful modality for predicting CRT responder in patients with non-ICM, which should be considered in CRT implantation decision.

Effect of Medical Therapy on Left Ventricular Ejection Fraction in Patients With Systolic Heart Failure and Narrow QRS Duration With and Without Ischemic Heart Disease and Left Ventricular Mechanical Dyssynchrony

We studied 99 consecutive patients with class III-IV systolic heart failure with a left ventricular ejection fraction (LVEF) < or =35% and a QRS duration <120 milliseconds. Patients with cardiac resynchronization therapy were excluded. Echocardiography was performed in all patients before and after optimal standard heart failure therapy. The septal-to-posterior wall motion delay (SPWMD) > or =130 milliseconds on echocardiogram was defined as left ventricular mechanical dyssynchrony (LVMD). Sixty-nine of 99 patients (70%) had ischemic heart disease. During follow-up of 15.2 +/- 9.8 months, LVEF improvement > or =15% was greater patients in nonischemic group (50%, 15/30) than in ischemic group (9%, 6/69; P < 0.001). After adjustment for age, gender, and clinical and echocardiographic characteristics, ischemic heart disease and grade of coronary disease were persistently related to LVEF improvement > or =15% (P = 0.03 and 0.02, respectively). Twenty of 99 patients (20%) had SPWMD > or =130 milliseconds (LVMD group), and 79 of 99 patients (80%) had SPWMD <130 milliseconds (non-LVMD group). LVEF increased in both groups (P = 0.005) during follow-up, but the percentage of patients with LVEF improvement > or =15% in LVMD was greater compared with patients without LVMD (40% versus 16%, respectively, P = 0.03). In conclusion, the improvement of LVEF in patients with systolic heart failure and narrow QRS was greater in patients with nonischemic heart disease and LVMD compared with patients with ischemic heart disease and absence of LVMD during medical therapy without cardiac resynchronization therapy.

M-mode Echocardiography,pulsed-wave Doppler and tissue Doppler imaging failed to predict cardiac resynchronization therapy responders

Objective To assess whether echocardiographic parameters of M-mode,pulsed-wave Doppler and tissue Doppler imaging which were usually used for selecting cardiac resynchronization therapy (CRT) candidates could predict CRT responders.Methods Twenty-nine patients with NYHA class Ⅲ or Ⅳ heart failure,left ventricular ejection fraction(LVEF)≤35%,QRS≥130 ms were enrolled.All of them underwent biventricular pacemaker implantation.The septal-to-posterior wall motion delay(SPWMD) from M-mode recording,and the standard deviation of time to peak systolic velocity(Ts-SD) were used to evaluate intraventricular dyssynchrony.The interventricular mechanical delay (IVMD) by pulsed Doppler echocardiography was calculated by subtracting the right ventricular preejection intervals (RV-PEI:the onset of the QRS on the electrocardiogram to the onset of pulmonary outflow) from the left ventricular preejection intervals (LV-PEI:the onset of the QRS on the electrocardiogram to the onset of aortic outflow).At least 15 % reduction in left ventricular end-systolic volume(LVESV) at the 6-month after CRT was defined as responder.Results In the 29 patients,there were 20 (68.97%) responders.The area under the receiver operating curve(ROC) of SPWMD,Ts-SD,LV-PEI,RV-PEI and IVMD to predict CRT responders was 0.448 (95% CI 0.184-0.712,P＞0.05),0.557 (95% CI 0.317-0.798,P＞0.05),0.479 (95% CI 0.186-0.773,P＞0.05),0.568 (95 % CI 0.272-0.863,P＞0.05) and 0.411 (95% CI0.136-0.687,P＞0.05),respectively.Conclusions M-mode echocardiography,pulsed Doppler and tissue Doppler imaging failed to predict CRT responders.New echocardiographic techniques including threedimensional echocardiography and speckle tracking image will be investigated,and may improve the predictive power. Key words: Echocardiography; Ventricular function; left; Cardiac resynchronization therapy

Differential effects of the site of permanent epicardial pacing on left ventricular synchrony and function in the young: implications for lead placement

To analyse left ventricular (LV) synchrony and function with respect to the epicardial pacing site in the young. Left ventricular function and synchrony (M-mode, speckle tracking) were evaluated during mid-term follow-up in 32 children with complete non-surgical (n = 15) or surgical (n = 17) atrioventricular block (structural heart disease in 21/32) paced from LV apex (n = 19), right ventricular (RV) apex (n = 7), and RV free wall (n = 6), respectively. Data are in the following order: LV apical, RV apical, and RV free wall pacing. Septal to posterior wall motion delay (SPWMD) = median 0, 69, and 136 ms (P < 0.001), septal to lateral mechanical delay = 54 +/- 29, 73 +/- 24, and 129 +/- 70 ms (P = 0.001), apical to basal mechanical delay = 96 +/- 37, 106 +/- 50, and 79 +/- 18 ms (P NS), and LV ejection fraction (LVEF) = 57 +/- 9, 49 +/- 12, and 33 +/- 10% (P < 0.001), respectively. Left ventricular ejection fraction correlated negatively with SPWMD (R(2) = 0.454, P < 0.001) and septal to lateral mechanical delay (R(2) = 0.320, P < 0.001) but not with apical to basal mechanical delay. Right ventricular free wall pacing (P = 0.014) and SPWMD (P = 0.044) were negative multivariable predictors of LVEF. Compared with other sites, LV apical pacing preserves septal to lateral LV synchrony and systolic function and may be the preferred epicardial pacing site in the young.

Left ventricular dyssynchrony from right ventricular pacing depends on intraventricular conduction pattern in intrinsic rhythm

Right ventricular pacing (RVP) prolongs ventricular activation and may induce mechanical dyssynchrony. We hypothesized that the severity of RVP-associated ventricular mechanical dyssynchrony may depend on the intrinsic intraventricular conduction pattern. Sixty-five patients with a single- or dual-chamber RV pacemaker were included. Forty-seven patients with ejection fraction (EF) <or= 35%, 17 with no bundle branch block (BBB), 16 with right bundle branch block (RBBB), and 14 with left bundle branch block (LBBB). Eighteen patients with EF > 35% and no BBB served as a control group. Echocardiographic dyssynchrony parameters [aortic pre-ejection delay (AoPEP), interventricular mechanical delay, delayed posterior left ventricular wall motion, and septal-to-posterior wall motion delay (SPWMD)] were evaluated in all patients with and without RVP. No dyssynchrony was found in patients with no BBB, RBBB, and in the control group, whereas LBBB patients showed significant dyssynchrony in AoPEP and SPWMD. RVP had a significant negative impact on all dyssynchrony parameters in patients with no BBB or LBBB. RVP induced significantly less severe dyssynchrony in RBBB patients. With RVP 100, 94, 56 and 16% of patients with LBBB, without BBB, RBBB, and from the control group, respectively, fulfilled the CARE-HF criteria for ventricular dyssynchrony. RVP worsens mechanical ventricular dyssynchrony in patients with reduced EF. These effects are most pronounced in patients with either normal QRS width or LBBB during intrinsic rhythm. In contrast, patients with an RBBB during intrinsic rhythm without RVP evidenced a better preserved haemodynamic function and mechanical synchrony with RVP, despite a comparable extent of pacing-induced QRS prolongation.

DDDR pacing results in left ventricular asynchrony with preservation of ejection fraction and NT-proBNP: A prospective study in sick sinus syndrome and normal ventricular function

Desynchronization induced by right ventricular pacing may increase the risk for heart failure. We aimed to compare left ventricular (LV) function, synchrony and left atrial size along with NT-proBNP levels, in 2 different modes of pacing: AAIR versus DDDR. This was a prospective study of 60 patients with sick sinus syndrome, preserved LV function and normal atrioventricular conduction. Each pacing mode lasted at least 2months, in every patient, after which period every patient was switched to the alternate pacing mode. Intraventricular asychrony was assessed by: 1) M-Mode septal-to-posterior wall motion delay (SPWMD), and 2) Tissue Doppler imaging (TDI) septal to lateral delay. NT-proBNP was measured at the end of each pacing mode. LV ejection fraction and left atrial diameter were not different in the 2 pacing modes, although asynchrony was induced in the DDDR arm (p<0.001 for TDI). NT-proBNP was lower in the DDDR compared to the AAIR mode (p=0.003, F=9.64). The NT-proBNP was inversely correlated to LV ejection fraction in the DDDR mode (p=0.0001, R=-0.75), whilst it was significantly correlated to the TDI septal-lateral delay and SPWMD (p=0.007, R=0.4 and p=0.002, R=0.5) in the AAIR mode. In conclusion in sick sinus syndrome with preserved LV function the DDDR mode does not compromise LV systolic function although it causes asynchrony. The NT-proBNP is lower when the right ventricle is paced, is inversely related to LV function and it is related to the degree of LV synchronization in the AAIR mode.

Color M‐Mode Echocardiography Is More Reproducible than Conventional M‐Mode Echocardiography for Septal‐to‐Posterior Wall Motion Delay Measurements

To compare the reproducibility of conventional gray-scale M-mode to color Doppler M-mode assessment of the septal-to-posterior wall motion delay (SPWMD) which is used as a marker of left ventricular mechanical dyssynchrony. Forty-two SPWMD datasets were interpreted by two experienced cardiologists and the inter- and intraobserver correlation coefficients were determined. Subgroup analysis was performed on patients with severe septal wall motion abnormalities. The correlation coefficients were significantly higher in color Doppler M-mode versus traditional M-mode in all subgroups analyzed. Our findings indicate that the color Doppler technique is more reproducible than conventional gray-scale M-mode technique to assess SPWMD. These findings suggest that the color Doppler M-mode may be a superior marker of the SPWMD measurement and predictor of left ventricular (LV) remodeling after cardiac resynchronization therapy.

Usefulness of Ventricular Dyssynchrony Measured Using M-Mode Echocardiography to Predict Response to Resynchronization Therapy

There are discordant data about the utility of septal-to-posterior wall motion delay (SPWMD) assessed using M-mode echocardiography to predict an improvement with cardiac resynchronization therapy (CRT). Baseline SPWMD was measured using M-mode in a parasternal short-axis view in a series of 67 patients undergoing CRT and followed up after 6 months. Heart failure was caused by coronary artery disease in 27 patients. Clinical responders were patients who were alive, had not undergone heart transplantation, and also increased the distance walked in 6 minutes by >10%. Baseline SPWMDs were mean 155 +/- 113 ms and median 135. Thirty-four patients (51%) had an SPWMD >130 ms. At 6-month follow-up, there were 17 nonresponders. At baseline, there were no significant differences between patients with SPWMD >130 or <130 ms in age, drug therapy, permanent atrial fibrillation, New York Heart Association functional class, underlying cause of cardiomyopathy, QRS duration, left ventricular (LV) ejection fraction, LV dimensions, or neurohormonal activation (norepinephrine and atrial and brain natriuretic peptide). At 6-month follow-up, baseline SPWMD was not associated with clinical response, New York Heart Association functional class, distance walked in 6 minutes, LV reverse remodeling, or neurohormonal activation. SPWMD >130 ms was also not a predictor. In conclusion, SPWMD is not a good predictor of response to CRT.

Evidence of left ventricular dyssynchrony resulting from right ventricular pacing in patients with severely depressed left ventricular ejection fraction

Cardiac resynchronization therapy (CRT) has recently emerged as an effective treatment for patients with moderate-to-severe systolic heart failure and left bundle branch block (LBBB). Right ventricular pacing (RVP) leads to an LBBB-like pattern in the electrocardiogram. The aim of this study was to evaluate the frequency of ventricular mechanical dyssynchrony in patients induced by RVP. The study included 33 patients with a conventional single or dual chamber pacemaker, 18 with ejection fraction (EF) > 35% and 15 with EF < or = 35%. In all patients, an intrinsic rhythm without intraventricular conduction delay (QRS < or = 120 ms) was present without RVP. Two-dimensional and Doppler echocardiographic criteria for mechanical dyssynchrony [aortic pre-ejection delay (APE), interventricular mechanical delay (IVMD), delayed activation of the posterior left ventricular wall (PD), septal-to-posterior wall motion delay (SPWMD)] were evaluated in all patients with and without RVP. QRS duration showed no difference between the two EF-groups without RVP (93 +/- 10 vs. 96 +/- 9 ms), but was significantly longer in patients with low EF with RVP (152 +/- 18 vs. 181 +/- 18 ms; P < 0.001). In patients with EF > 35%, only APE was slightly prolonged by RVP (111 +/- 20 vs. 129 +/- 17 ms; P = 0.03), whereas in patients with EF < or = 35% marked pathological differences in APE (118 +/- 29 vs. 169 +/- 24 ms; P < 0.001), IVMD (22 +/- 17 vs. 58 +/- 14 ms; P < 0.001), SPWMD (103 +/- 28 vs. 125 +/- 29 ms; P = 0.004), and PD (-21 +/- 25 vs. - 39 +/- 25 ms; P = 0.005) were found. A significant correlation between QRS duration and mechanical ventricular dyssynchrony was only found for two echocardiographic parameters (IVMD, APE) with RVP. In patients with a conventional pacemaker, mechanical dyssynchrony with RVP was shown exceptionally in patients with preserved or moderately depressed systolic left ventricular (LV) function, but in nearly all patients with severely depressed systolic LV function. These patients might benefit from CRT when frequent RVP is required.