Septal flash correction with His-Purkinje pacing predicts echocardiographic response in resynchronization therapy.

BACKGROUND: His-Purkinje conduction system pacing (HPCSP) has been proposed as an alternative to Cardiac Resynchronization Therapy (CRT); however, predictors of echocardiographic response have not been described in this population. Septal flash (SF), a fast contraction and relaxation of the septum, is a marker of intraventricular dyssynchrony. METHODS: The study aimed to analyze whether HPCSP corrects SF in patients with CRT indication, and if correction of SF predicts echocardiographic response. This retrospective analysis of prospectively collected data included 30 patients. Left ventricular ejection fraction (LVEF) was measured with echocardiography at baseline and at 6-month follow-up. Echocardiographic response was defined as increase in five points in LVEF. RESULTS: HPCSP shortened QRS duration by 48 ± 21 ms and SF was significantly decreased (baseline 3.6 ± 2.2 mm vs. HPCSP 1.5 ± 1.5 mm p < .0001). At 6-month follow-up, mean LVEF improvement was 8.6% ± 8.7% and 64% of patients were responders. There was a significant correlation between SF correction and increased LVEF (r = .61, p = .004). A correction of ≥1.5 mm (baseline SF - paced SF) had a sensitivity of 81% and 80% specificity to predict echocardiographic response (area under the curve 0.856, p = .019). CONCLUSION: HPCSP improves intraventricular dyssynchrony and results in 64% echocardiographic responders at 6-month follow-up. Dyssynchrony improvement with SF correction may predict echocardiographic response at 6-month follow-up.

The Ventricular Hypokinesis at the Apical Pacing Site due to the Early Shortening and Rebound Stretch in a Case with Fontan Procedure.

The left ventricular (LV) apex is recommended as the first choice for positioning the epicardial pacing. We encountered a patient with congenital heart disease (CHD) showing hypokinesis of the LV apical pacing site after implantation of a pacemaker with epicardial leads. This phenomenon was revealed by the early shortening and systolic rebound stretch of the same lesion on two-dimensional speckle tracking echocardiography, which developed in the intraventricular dyssynchrony between the LV apex and base. Cardiac resynchronization therapy provided an excellent result around the hypokinetic lesion. It is wise to arrange detailed evaluations in each patient with complicated CHD, aiming at a successful treatment to enable ventricular synchronicity.

Left ventricular mechanical dyssynchrony in patients with chest pain and normal epicardial coronary arteries.

BACKGROUND: To detect ischemia in patients with angina and normal coronaries frequently represents a complex diagnosis. METHODS: To investigate whether left ventricular mechanical dyssynchrony by phase analysis contributes in the evaluation of patients with chest pain and normal coronaries, gated-SPECT myocardial perfusion imaging (MPI) at rest and 30 minutes post-stress was performed in 218 patients with normal epicardial coronaries, who were divided into two groups: those with summed difference score (SDS) ≥ 4 (54 patients, Group 1), and those with SDS < 4 (164 patients, Group 2). Intraventricular synchronism-phase standard deviation (PSD) and histogram bandwidth (HBW)-was evaluated by phase analysis. RESULTS: Women were significantly more frequent in Group 2 (those without ischemia in SPECT MPI): 113 (69%) vs 25 (46%), P = .00001. In males, left ventricular ejection fraction (LVEF) and ventricular volumes were not significantly different between patients with or without ischemia. However, ischemic females showed significantly higher ventricular volumes, minor post-stress LVEF and more negative delta LVEF (- 3.9 vs 0.34, P = .0008) than the non-ischemic ones. There was a significant post-stress increase of PSD and HBW among males, although not among females. According to SSS (≥ 4, with ischemia/necrosis; < 4, without ischemia/necrosis), post-stress PSD and HBW significantly increase both in male and female, and PSD and HBW were significantly higher in females with SSS ≥ 4 compared to those with SSS < 4 (PSD rest: 19.04° vs 11.72°, P < .0001; HBW rest: 58.85° vs 38.21°, P < .0001). PSD and HBW were also higher among males with SSS ≥ 4 compared to those with SSS < 4, although not significantly. CONCLUSION: Higher ventricular volumes in females and dyssynchrony are associated with inducible ischemia in MPI in patients with chest pain and normal coronaries. Stress-induced ischemia increases degree of dyssynchrony.

Fragmented QRS is associated with intraventricular dyssynchrony and independently predicts nonresponse to cardiac resynchronization therapy-Systematic review and meta-analysis.

BACKGROUND: Fragmented QRS (fQRS) is postulated to be associated with ventricular dyssynchrony and might be able to predict a nonresponse to cardiac resynchronization therapy (CRT) implantation. In this systematic review and meta-analysis, we aim to assess whether fQRS can be a marker of intraventricular dyssynchronies in patients with ischemic and nonischemic cardiomyopathy and whether it is an independent predictor of nonresponse in patients receiving CRT. METHODS: We performed a comprehensive search on topics that assesses fQRS and its association with intraventricular dyssynchrony and nonresponse to CRT up until September 2019. RESULTS: Fragmented QRS is associated with intraventricular dyssynchrony (OR 10.34 [3.39, 31.54], p < .001; I2 : 80% with sensitivity 76.8%, specificity 77%, LR+ 3.3, and LR- 0.3). Subgroup analysis showed that fQRS is associated with intraventricular dyssynchrony in patients with narrow QRS complex (OR 20.92 [12.24, 35.73], p < .001; I2 : 0%) and nonischemic cardiomyopathy (OR of 19.97 [12.12, 32.92], p < .001; I2 : 0%). Fragmented QRS was also associated with a higher time-to-peak myocardial sustained systolic (Ts-SD) (OR 15.19 [12.58, 17.80], p < .001; I2 : 0% and positive Yu index (OR 15.61 [9.07, 26.86], p < .001; I2 : 0%). Fragmented QRS has a pooled adjusted OR of OR of 1.70 [1.35, 2.14], p < .001; I2 : 62% for association with a nonresponse to CRT. QRS duration is found to be higher in nonresponders group mean difference -8.54 [-13.38, -3.70], p < .001; I2 : 70%. CONCLUSION: Fragmented QRS is associated with intraventricular dyssynchrony and is independently associated with nonresponse to cardiac resynchronization therapy.

Sensitivity Analysis of a Left Ventricle Model in the Context of Intraventricular Dyssynchrony.

The objective of the current study was to propose a sensitivity analysis of a 3D left ventricle model in order to assess the influence of parameters on myocardial mechanical dispersion. A finite element model of LV electro-mechanical activity was proposed and a screening method was used to evaluate the sensitivity of model parameters on the standard deviation of time to peak strain. Results highlight the importance of propagation parameters associated with septal and lateral segments activation. Simulated curves were compared to myocardial strains, obtained from echocardiography of one healthy subject and one patient diagnosed with intraventricular dyssynchrony and coronary artery disease. Results show a close match between simulation and clinical strains and illustrate the model ability to reproduce myocardial strains in the context of intraventricular dyssynchrony.

ECG parameters to predict left ventricular electrical delay.

AIMS: Left ventricular (LV) dyssynchrony lengthens the left ventricular electrical delay (LVED), measured from QRS onset to the first peak of the LV electrogram. We constructed an ECG model to predict LVED noninvasively. METHODS: Intrapatient LVED was measured during a baseline vs nonselective His bundle pacing (nHBP) protocol. This setup provided paired synchronic/non-synchronic LVEDs, allowing intrapatient comparisons. Crosscorrelation of leads II and V6 was accomplished and extracted features together with age and gender fed a linear mixed effects model to predict LVED. RESULTS: Hemodynamic increments were consistent with LVED advances under nHBP in a subset of 17 patients (dP/dtmax, baseline: 938.82 ± 241.95 mm Hg/s vs nHBP: 1034.94 ± 253.63 mm Hg/s, p = 6.24e-4). The inclusion of the area under V6 (AV 6) and the time shift of R-peaks obtained from the crosscorrelation signal (CorS) grouped by patient significantly improved LVED estimation with respect to the model based only on QRS duration, age and gender (p = 1.7e-5). CONCLUSIONS: Interlead ECG changes explained LVED, providing clues about the electrical impulse conduction within the left ventricle noninvasively.

Intraventricular Dyssynchrony among patients with left bundle branch block.

OBJECTIVE: To determine the frequency of intraventricular dyssynchrony among patients with left bundle branch block. METHODS: The study was conducted at Hayatabad Medical Complex, Peshawar, from January, 2017 to July, 2017. All patients aged 18 years and above with Left Bundle Branch Block (LBBB) on ECG with or without heart failure were included in the study. Patients with valvular heart disease, predominant diastolic heart failure, acute coronary syndromes or coronary revascularization in last three months and atrial fibrillation were excluded. Tissue Doppler Imaging (TDI) parameters were measured from 2-D images in apical 4-chamber and 2-chamber views. Consecutive non-probability sampling technique was used for sample collection. RESULTS: Our study included 159 patients. Mean age was 52 years with SD ± 2.74. Ninety-nine (62%) patients were male and 60 (38%) patients were female. One hundred and three (65%) patients had heart failure while 56 (35%) patients didn't have heart failure. More over in our study 124 (78%) patients had Intraventricular dyssynchrony while 35(22%) patients didn't have Intraventricular dyssynchrony. CONCLUSION: The incidence of Intraventricular dyssynchrony is high among patients with heart failure and left bundle branch block.

A new use for maximum deflection index: Detection of intraventricular dyssynchrony.

AIM: CRT has been shown to be very beneficial for patients with reduced LVEF, symptomatic HF and increased QRS width. But many patients do not benefit from CRT. Maximum deflection index (MDI) is a quantitive measure of the rapidity of depolarization of the myocardium. In previous studies, high MDI was found to indicate epicardial origin of ventricular tachycardia. We aimed to detect the relationship between echocardiographic intraventricular dyssynchrony and MDI. METHODS: We included 144 patients with HF, QRS≥120ms, LBBB, NYHA II-IV, LVEF<35% and scheduled for CRT (90 male, 54 female; mean age 65.3±9.9years). Septal-lateral >60ms delay for the beginning of systolic velocity in TDI and septum-posterior >130ms delay in M-mode were accepted as intraventricular dyssynchrony. The MDI was calculated by dividing the time from onset of the QRS complex to the earliest point of maximum deflection in V5-V6 by the QRS duration. RESULTS: Septal-lateral delay was associated with MDI and QRS width in bivariate analysis. In logistic regression analysis, MDI (beta=0,264, p=0.001) and QRS width (beta=0,177, p=0.028) were found to be independent parameters for predicting significant septal-lateral delay. MDI was also associated with significant septum-posterior delay in bivariate correlations and ROC curve (p<0.05 for all). In bivariate analysis MDI was associated with intraventricular dyssynchrony in both non-strict LBBB (r=0.261, p=0.010) and strict LBBB (r=0.305, p=0.035) groups. CONCLUSION: MDI is closely associated with all echocardiographic intraventricular dyssynchrony parameters. We suggest that MDI may be used as a marker to detect patients with increased intraventricular dyssynchrony. It may be useful to integrate MDI to CRT patient selection procedure in order to minimize nonresponders.

Myocardial function reclassification: Echocardiographic strain patterns in patients with chronic Chagas cardiomyopathy and intraventricular dyssynchrony.

BACKGROUND: We aimed to identify, among Chronic Chagas Cardiomyopathy (CCC) patients with left ventricular dysfunction (LVD) and non-left bundle branch block (non-LBBB), subgroups with different functional and mechanical patterns of global longitudinal strain (GLS) and intraventricular dyssynchrony (IVD) at rest and after exercise stress test, and reclassify them using a new echocardiographic approach. METHODOLOGY: In this single-center cross-sectional study, 40 patients with CCC, left ventricular ejection fraction (LVEF) ≤ 35% and non-LBBB underwent rest echocardiography and then treadmill exercise stress echocardiography with GLS and IVD analysis. The sample was divided into four groups, based on GLS and IVD significant variation between rest and exercise: GLS + IVD+ (9 patients); GLS + IVD- (9 patients); GLS-IVD+ (10 patients); GLS-IVD- (10 patients). RESULTS: At rest, median LVEF was 28% (21.3%-33%) and GLS (-7% (-5%/-9.3%), were not different among groups. The average response of GLS was an increase of 0.74% over rest values, and the average response of IVD was a decrease of 6.9 ms. Group GLS-IVD+ presented more dyssynchrony at rest (p = 0.01). Left atrial (LA) volume (higher in GLS-IVD-) (p = 0.022) and TAPSE (higher in GLS + IVD+) (p = 0.015) were also different among groups at baseline. Of the 40 patients evaluated, 27 (67.5%) had very severe LVD (GLS < -8%). In addition, among these patients, 11 patients had contractile reserve after undergoing stress echocardiography. CONCLUSIONS: In patients with CCC, severe LVD and non-LBBB, the evaluation of GLS and IVD between rest and exercise was able to reclassify myocardial function and to identify subgroups with contractile reserve and significant dyssynchronopathy.

Impact of early post-stress 99mTc sestamibi ECG-gated SPECT myocardial perfusion imaging on the detection of ischemic LV dyssynchrony: an early step in the stunning cascade.

Transient alterations in ventricular conduction and synchronized cardiac performance have been reported in experimental models of myocardial ischemia. In post-stress 99mTc-sestamibi-gated-SPECT myocardial perfusion imaging (MPI), the time elapsed between tracer injection and image acquisition could influence the detection of ischemic left ventricular mechanical dyssynchrony (LVMD). We aimed at evaluating whether early vs. delayed post-stress MPI improve ischemic LVMD detection using the phase analysis parameters standard deviation (SD) and histogram bandwidth (HB) and to assess the correlation between stress-induced changes in SD and HB and other functional parameters. We prospectively studied 32 control subjects (Group-1) and 60 ischemic patients (Group-2). Stress-induced changes were calculated as stress minus rest (Δ). LVMD was defined as post-stress increases of either SD or HB. Group-2 showed higher ΔSD and ΔHB in early than in delayed images: early ΔSD: 1.63 (- 0.37 to 4.83) vs. delayed ΔSD: - 0.39 (- 3.82 to 1.74); early ΔHB: 2.50 (- 4 to 12) vs. ΔHB delayed: - 4 (- 15.75 to 4), all p < 0.01. ΔSD and ΔHB correlated linearly with ΔLV-ejection-fraction (EF) and ΔLV-end systolic-volume (ESV) in early images, all p < 0.01. Early images detected LVMD in more patients than delayed scans (78% vs. 38%; p < 0.01) All patients with LVEF drop in early post-stress evaluation had LVMD. Early post-stress images improve ischemic LVMD detection. Ischemic LVEF and LVESV changes correlate with ΔSD and ΔHB.

Intraventricular synchronism assessment by gated-SPECT myocardial perfusion imaging in cardiac resynchronization therapy. Does cardiomyopathy type influence results?

PURPOSE: To analyze the evolution post-cardiac resynchronization therapy (CRT) in left ventricular non-compaction (LVNC) cardiomyopathy (CM) patients compared to other types of CM, according to clinical and functional variables, by using gated-SPECT myocardial perfusion imaging (MPI). METHODS: Ninety-three patients (60 ± 11 years, 28% women) referred for pre-CRT assessment were studied and divided into three groups: 1 (non-ischemic CM with LVNC, 11 patients), 2 (ischemic CM, 28 patients), and 3 (non-ischemic CM, 53 patients). All were studied by a 99mTc-MIBI gated-SPECT MPI at rest pre-CRT implantation and 6 ± 1 months after, including intraventricular dyssynchrony assessment by phase analysis. Quality of life was measured by the Minnesota Living with Heart Failure Questionnaire (MLHFQ). RESULTS: No differences in sex, atherosclerotic risk factors other than smoking habit, and MLHFQ results were found among groups. LVNC CM patients were younger, with greater QRS width and lower left ventricular ejection fraction (LVEF) at baseline, but the differences were not significant. No significant differences were found at baseline regarding ventricular function, although end-systolic volume was slightly higher in LVNC CM patients. Mean SRS was significantly higher (p < 0.0001) in ischemic patients (14.9) versus non-ischemic ones (8.7 in group 1 and 9 in group 2). At baseline, LVNC CM patients were significantly more dyssynchronous: Their phase standard deviation (PSD) was higher (89.5° ± 14.2°) versus groups 2 (65.2° ± 23.3°) and 3 (69.7° ± 21.7°), p = 0.007. Although the quality of life significantly improved in all groups, non-ischemic patients (with or without LVNC) showed a higher LVEF increase and volumes reduction at 6 months post-CRT. Dyssynchrony reduced post-CRT in all groups. Nevertheless, those more dyssynchronous at baseline (LVNC CM) exhibited the most significant intraventricular synchronism improvement: PSD was reduced from 89.5° ± 14.2° at baseline to 63.7° ± 20.5° post-CRT (p = 0.028). Six months post-CRT, 89% of patients were responders: 11 (100%) of those with LVNC CM, 25 (86%) of those with ischemic CM, and 47 (89%) of patients with non-ischemic CM. No patient with LVNC CM had adverse events during the follow-up. CONCLUSION: CRT contributes to a marked improvement in non-ischemic CM patients with non-compaction myocardium. Phase analysis in gated-SPECT MPI is a valuable tool to assess the response to CRT.

Left intraventricular dyssynchrony caused by a false tendon.

Left ventricular (LV) false tendons are usually benign, intraventricular myocardial structures, which may cause functional malfunction or deformation of the LV cavity due to mechanical stretching and dilatation of the LV wall. We present a case of non-ischemic cardiomyopathy complicated with intraventricular dyssynchrony that was caused by complete left bundle branch block and the mechanical pressure exerted by the stiff false tendon on the weakened mid-septum during systole.

The Association of Left Ventricular Hypertrophy with Intraventricular Dyssynchrony at Rest and during Exercise in Hypertensive Patients.

BACKGROUND: Impaired exercise tolerance with dyspnea is common in hypertensive patients and this may be due to the exaggeration of nonuniform ventricular activation during exercise. So we want to evaluate the effect of left ventricular hypertrophy (LVH) on systolic intraventricular dyssynchrony during exercise. METHODS: A total of 85 patients with hypertension who having exertional dyspnea and 30 control individuals were enrolled. Exercise stress echocardiography was performed using a symptom limited, multistage supine bicycle test. To evaluate the dyssynchrony of left ventricular (LV), we calculated the standard deviation (SD) of the averaged time-to-peak systolic velocity (TPs-SD, ms) of 12 middle and basal LV segments obtained from the three standard apical views at rest and peak exercise. RESULTS: There was no significant difference in systolic blood pressure (BP) and heart rate between the two groups. TPs-SD was significantly higher in patients with LVH at rest (31.5 ± 12.1 vs. 22.0 ± 12.6 ms, p = 0.002) with exaggeration of the degree at peak exercise (39.0 ± 11.9 vs. 24.6 ± 13.3 ms, p < 0.001). Multiple regression analysis showed LV mass index was independently associated with LV dyssynchrony at peak exercise (ß = 0.515, p = 0.001) when controlled for age, sex, and systolic BP at peak exercise. CONCLUSION: Intraventricular systolic dyssynchrony during exercise is significantly associated with the degree of LVH in hypertensive patients.