Diastolic asynchrony is more frequent than systolic asynchrony in dilated cardiomyopathy and is less improved by cardiac resynchronization therapy

Response rate in cardiac resynchronization therapy patients implanted with a left ventricular quadripolar lead and the MultiPoint™ pacing feature early activated. QUARTO III

BACKGROUND

Although cardiac resynchronization therapy (CRT) is beneficial in most heart failure patients, up to 40% do not respond to CRT. It has been suggested that multipoint left ventricle pacing (MPP) would increase the response rate.

AIM

To assess the CRT response rate at 6 months in patients implanted with a CRT device with the MPP feature activated early after the implant.

METHODS

This was a multicentre, prospective, open-label and non-randomized study. The primary endpoint was response to biventricular pacing defined as >15% relative reduction in left ventricular end-systolic volume (LVESV) comparing echocardiography measurements performed at baseline and 6 months by a core laboratory. Among secondary endpoints the combined endpoint of mortality or all-cause hospitalizations was evaluated. Primary study endpoint and clinical outcomes were compared to a Quarto II control cohort.

RESULTS

Totally, 105 patients were included. The response rate was 64.6% (97.5% lower confidence bound 53%). Mean relative reduction in LVESV was 25.3%, and mean absolute increase in LVEF was 9.4%. The subjects with device programmed using anatomical approach showed a trend towards higher responder rate than those using the electrical approach (72% vs. 61.1%, p = 0.32). Finally, the combined incidence of mortality and or all-cause hospitalizations at 6 month was 12.4%.

CONCLUSIONS

Early activation of MPP was not associated to an advantage increasing echocardiography responders to CRT at 6 months of follow-up. Nevertheless, patients programmed using widest pacing cathodes had a numerically higher responder rate. Finally, early activation of MPP was associated to a low incidence of clinical endpoints at 6 months of follow-up.

Relationship between intraventricular mechanical dyssynchrony and left ventricular systolic and diastolic performance: An in vivo experimental study

Left ventricular mechanical dyssynchrony (LVMD) refers to the nonuniformity in mechanical contraction and relaxation timing in different ventricular segments. We aimed to determine the relationship between LVMD and LV performance, as assessed by ventriculo-arterial coupling (VAC), LV mechanical efficiency (LVeff ), left ventricular ejection fraction (LVEF), and diastolic function during sequential experimental changes in loading and contractile conditions. Thirteen Yorkshire pigs submitted to three consecutive stages with two opposite interventions each: changes in afterload (phenylephrine/nitroprusside), preload (bleeding/reinfusion and fluid bolus), and contractility (esmolol/dobutamine). LV pressure-volume data were obtained with a conductance catheter. Segmental mechanical dyssynchrony was assessed by global, systolic, and diastolic dyssynchrony (DYS) and internal flow fraction (IFF). Late systolic LVMD was related to an impaired VAC, LVeff , and LVEF, whereas diastolic LVMD was associated with delayed LV relaxation (logistic tau), decreased LV peak filling rate, and increased atrial contribution to LV filling. The hemodynamic factors related to LVMD were contractility, afterload, and heart rate. However, the relationship between these factors differed throughout the cardiac cycle. LVMD plays a significant role in LV systolic and diastolic performance and is associated with hemodynamic factors and intraventricular conduction.

Mechanical dyssynchrony: How do we measure it, what it means, and what we can do about it

Left ventricular mechanical dyssynchrony (LVMD) is defined by a difference in the timing of mechanical contraction or relaxation between different segments of the left ventricle (LV). Mechanical dyssynchrony is distinct from electrical dyssynchrony as measured by QRS duration and has been of increasing interest due to its association with worse prognosis and potential role in patient selection for cardiac resynchronization therapy (CRT). Although echocardiography is the most used modality to assess LVMD, some limitations apply to this modality. Compared to echo-based modalities, nuclear imaging by gated single-photon emission computed tomography (GSPECT) myocardial perfusion imaging (MPI) has clear advantages in evaluating systolic and diastolic LVMD. GSPECT MPI can determine systolic and diastolic mechanical dyssynchrony by the variability in the timing in which different LV segments contract or relax, which has prognostic impact in patients with coronary artery disease and heart failure. As such, by targeting mechanical dyssynchrony instead of electrical dyssynchrony, GSPECT MPI can potentially improve patient selection for CRT. So far, few studies have investigated the role of diastolic dyssynchrony, but recent evidence seems to suggest high prevalence and more prognostic impact than previously recognized. In the present review, we provide an oversight of mechanical dyssynchrony.

Efficacy of His Bundle Pacing on LV Relaxation and Clinical Improvement in Heart Failure and LBBB

OBJECTIVES

This study aimed to compare acute hemodynamic improvements and responses to His bundle pacing (HBP) and conventional biventricular pacing (BVP).

BACKGROUND

HBP can correct left bundle branch block (LBBB) and may be an alternative cardiac resynchronization therapy (CRT) to BVP.

METHODS

Fourteen consecutive patients with heart failure (HF) and typical LBBB who required CRT were enrolled. The acute hemodynamic responses during HBP and BVP were compared using a micromanometer-tipped catheter inserted into the left ventricle (LV) before CRT. Each configuration was compared with AAI mode. A permanent HBP device was implanted when LBBB correction threshold was ≤1.5 V at 1.0 ms, and remaining patients were treated with BVP. Clinical and echocardiographic improvements were assessed during a 12-month follow-up period.

RESULTS

The LV contractile index (positive maximal rate of LV pressure rise [dP/dt_max]) increased similarly during HBP and BVP (18.8 ± 6.4% vs 18.0 ± 10.2%; P = 0.810). LV relaxation indices (negative dP/dt_max and tau) were significantly improved during HBP compared with BVP (negative dP/dt_max: 14.3% ± 5.5% vs 3.1% ± 8.1%; P < 0.001; tau: 7.2% ± 4.3% vs -0.8% ± 8.1%; P = 0.001). Nine (64%) patients received permanent HBP devices, while 5 patients were treated with BVP. The New York Heart Association functional class, LV ejection fraction, LV end-systolic volume, and B-type natriuretic peptide level improved in patients treated with HBP and BVP (all P < 0.05 vs baseline). Patients treated with HBP exhibited earlier and greater improvements of the LV ejection fraction and LV end-systolic volume than did those with BVP.

CONCLUSIONS

HBP improves systolic function and LV relaxation in patients with HF and LBBB. CRT via HBP produced earlier and greater clinical responses than BVP.

Diastolic dyssynchrony assessment by gated myocardial perfusion-SPECT in subjects who underwent cardiac resynchronization therapy

BACKGROUND

Left ventricular diastolic dyssynchrony (LVDD) can be assessed by gated myocardial perfusion single-photon emission computed tomography (GMP-SPECT). LVDD is an area of interest in subjects who underwent cardiac resynchronization therapy (CRT). The aim of this post hoc analysis was to assess the role of LVDD in subjects with CRT who were followed up at 6-month period.

MATERIAL & METHODS

Left ventricular diastolic dyssynchrony was assessed by GMP-SPECT at baseline and after CRT procedure in 160 subjects from 10 different cardiological centers. CRT procedure was performed as per current guidelines. Outcomes were defined as improvement in ≥1 New York Heart Association (NYHA) class, left ventricular ejection fraction (LVEF) by 5%, and reduction in end-systolic volume (ESV) by 15% and 5% points in Minnesota Living with Heart Failure Questionnaire. LVDD was defined as diastolic phase standard deviation ≥40 ± 14°.

RESULTS

Improvement in NYHA functional class occurred in 105 (65.6%), LVEF in 74 (46.3%), decrease in ESV in 86 (53.8%), and Minnesota score in 85 (53.1%) cases. Baseline LV diastolic standard deviation was 53.53° ± 20.85 and at follow-up 40.44° ± 26.1283; (P < 0.001). LVDD was not associated with improvement in clinical outcomes at follow-up.

CONCLUSION

CRT improves both systolic and diastolic dyssynchrony values at 6-month follow-up. LVDD at baseline is correlated with cardiac functionality at follow-up, but not with overall favorable clinical outcomes.

Left ventricular systolic and diastolic dyssynchrony to improve cardiac resynchronization therapy response in heart failure patients with dilated cardiomyopathy

BACKGROUND

The systolic and diastolic dyssynchrony is physiologically related, but measure different left ventricular mechanisms. Left ventricular systolic mechanical dyssynchrony (systolic LVMD) has shown significant clinical values in improving cardiac resynchronization therapy (CRT) response in the heart failure patients with dilated cardiomyopathy (DCM). Our recent study demonstrated that LV diastolic dyssynchrony (diastolic LVMD) parameters have important prognostic values for DCM patients. However, there are a limited number of studies about the clinical value of diastolic LVMD for CRT. This study aims to explore the predictive values of both systolic LVMD and diastolic LVMD for CRT in DCM patients.

METHODS

Eighty-four consecutive CRT patients with both DCM and complete left bundle branch block (CLBBB) who received gated resting SPECT MPI at baseline were included in the present study. The phase analysis technique was applied on resting gated short-axis SPECT MPI images to measure systolic LVMD and diastolic LVMD, characterized by phase standard deviation (PSD) and phase histogram bandwidth (PBW). CRT response was defined as ≥ 5% improvement of LVEF at 6-month follow-up. Variables with P < 0.10 in the univariate analysis were included in the multivariate cox analysis.

RESULTS

During the follow-up period, 59.5% (50 of 84) patients were CRT responders. The univariate cox regression analysis showed that at baseline QRS duration, non-sustained ventricular tachycardia (NS-VT), systolic PSD, systolic PBW, diastolic PSD, diastolic PBW, scar burden and LV lead in the scarred myocardium were statistically significantly associated with CRT response. The multivariate cox regression analysis showed that QRS duration, NS-VT, systolic PSD, systolic PBW, diastolic PSD, and diastolic PBW were independent predictive factors for CRT response. Furthermore, the rate of CRT response was 94.4% (17 of 18) in patients whose LV lead was in the segments with both the first three late contraction and the first three late relaxation; by contrast, the rate of CRT response was only 6.7% (1 of 15, P < 0.000) in patients whose LV lead was in the segments with neither the first three late contraction nor the first three late relaxation.

CONCLUSION

Both systolic LVMD and diastolic LVMD from gated SPECT MPI have important predictive values for CRT response in DCM patients. Pacing at LV segments with both late contraction and late relaxation has potential to increase the CRT response.

Prognostic value of left-ventricular systolic and diastolic dyssynchrony measured from gated SPECT MPI in patients with dilated cardiomyopathy

BACKGROUND

Left-ventricular systolic dyssynchrony (LVSD) has been an important prognostic factor in the patients with dilated cardiomyopathy (DCM). However, the association between the LV diastolic dyssynchrony (LVDD) and clinical outcome is not well established. This study aims to evaluate the prognostic values of both systolic and diastolic dyssynchrony in patients with DCM.

METHODS

Fifty-two patients with DCM were enrolled and divided into two groups according to cardiac deaths from the follow-up data. The phase-analysis technique was applied on resting gated short-axis SPECT MPI images to measure LV systolic and diastolic dyssynchrony, including phase standard deviation (PSD), phase histogram bandwidth (PBW), and phase entropy (PE). Variables with P < 0.10 in the univariate analysis were included in the multivariate cox analysis.

RESULTS

During the follow-up period (2.9 ± 1.7 years), 18 (34.6%) cardiac deaths were observed. Compared with survivors, patients with cardiac death had lower LVEF (P = 0.011), and more severe LV systolic and diastolic dyssynchrony. The univariate cox regression analysis showed that hypertension, NT-proBNP, LVEF, systolic PSD, systolic PE, and diastolic PBW were statistically significantly associated with cardiac death. The multivariate cox regression analysis showed that systolic PE and diastolic PE were independent predictive factors for cardiac death. Furthermore, the receiver operating characteristic (ROC) analysis, when applied into the combination of systolic PE and diastolic PE for predicting cardiac death, had an area under curve (AUC) of 0.766, a sensitivity of 0.765, and a specificity of 0.722.

CONCLUSIONS

Both the LVSD and LVDD parameters from SPECT MPI have important prognostic values for DCM patients. Both systolic PE and diastolic PE are independent prognostic factors for cardiac death.

Diastolic dyssynchrony and its exercise-induced changes affect exercise capacity in patients with heart failure with reduced ejection fraction

BACKGROUND

Left ventricular diastolic dyssynchrony is common in patients with heart failure with reduced ejection fraction (HFREF). Little is known however, about its pathophysiology and clinical effects. Herein is hypothesized that presence of diastolic dyssynchrony at rest or at exercise may importantly contribute to HF symptoms. The aim was to investigate the influence of diastolic dyssynchrony and its exercise-induced changes on exercise capacity in HFREF patients.

METHODS

Patients with stable, chronic HF, left ventricular ejection fraction < 35%, sinus rhythm and QRS ≥ 120 ms were eligible for the study. Rest and cyclo-ergometer exercise echocardiography were performed. Diastolic dyssynchrony was defined as opposing-wall-diastolic-delay ≥ 55 ms measured in tissue-Doppler imaging. Exercise capacity was assessed by peak oxygen consumption (VO2peak). Association between diastolic dyssynchrony and VO2peak was assessed in univariate regression analysis and further adjusted for possible confounders.

RESULTS

Fourty eight patients were included (aged 63.7 ± 12.2). Twenty-seven (56.25%) had diastolic dyssynchrony at rest and 13 (27%) at exercise. Twenty-two (46%) experienced a change in diastolic dyssynchrony status during exercise. In univariate models diastolic dyssynchrony at rest or at exercise were associated with lower VO2peak (beta coefficient = -3.8, p = 0.004; beta coefficient = -3.6, p = 0.02, respectively). However, the ability to restore diastolic synchronicity during exercise was associated with higher VO2peak (beta coefficient = 3.4, p = 0.04) and remained an important predictor of exercise capacity after adjustment for age and HF etiology.

CONCLUSIONS

The ability to restore diastolic synchronicity at exercise predicts exercise capacity in patients with HFREF.

Clinical Influence and Predictors of Pacing-Induced Mechanical Asynchrony in Patients with Normal Cardiac Function with Ventricular Lead Placed in Non-Apical Position

Right ventricular apical (RVA) pacing often causes left ventricular (LV) mechanical asynchrony, which is enhanced by impaired cardiac contraction and intrinsic conduction abnormality. However, data on patients with normal cardiac function and under RV non-apical (non-RVA) pacing are limited.We retrospectively investigated 97 consecutive patients with normal ejection fraction who received pacemaker implantation for atrioventricular block with the ventricular lead placed in a non-RVA position. We defined mechanical asynchrony as discoordinate contraction between opposing regions of the LV wall evaluated by echocardiography. Asynchrony was detected in 9 (9%) patients at baseline and in 38 (39%) under non-RVA pacing (P < 0.001). Asynchrony at baseline was significantly associated with complete left bundle branch block (CLBBB) [odds ratio (OR) = 20.8, P < 0.001]. Asynchrony under non-RVA pacing was significantly associated with left anterior fascicular block (LAFB) (OR = 7.14, P < 0.001) and CLBBB (OR = 13.3, P = 0.002) at baseline. New occurrence of asynchrony was significantly associated with LAFB at baseline (OR = 5.88, P = 0.001). During a median follow-up period of 4.8 years, the incidence of device-detected atrial fibrillation (AF) was more frequent in patients who developed asynchrony than in those who did not (53.3% versus 27.5%, hazard ratio = 2.17, 95% confidence interval = 1.02-4.61, P = 0.03).In patients with normal cardiac function, LAFB at baseline was significantly associated with new occurrence of mechanical asynchrony under non-RVA pacing. Abnormal contraction had a significant influence on the incidence of device-detected AF.

Devices in heart failure; diagnosis, detection and disease modification

INTRODUCTION/BACKGROUND

Implantable cardiac devices are widely used in chronic heart failure (CHF) therapy. This review covers current CHF treatment with electronic cardiac devices, areas of discussion and emerging technologies.

SOURCES OF DATA

A comprehensive search of available literature resources including Pubmed, MEDLINE and EMBASE was performed. National and international guidelines were accessed.

AREAS OF AGREEMENT

Excessive right ventricular pacing is detrimental to cardiac function. Cardiac resynchronization therapy is beneficial in specific individuals with CHF.

AREAS OF CONTROVERSY

Implantable cardioverter defibrillators might not benefit all. Optimizing CRT delivery. Remote monitoring seems not to be of benefit in CHF.

GROWING POINTS

Device-based optimization.

AREAS TIMELY FOR DEVELOPING RESEARCH

Personalization of device therapy. Focussing implantable cardioverter defibrillator therapy. What to do at implantable cardioverter defibrillator box change?

Evaluation of left and right ventricular systolic and diastolic electromechanical synchrony in older people: a population-based observational study

It is unknown whether physiological ageing also goes along with electromechanical asynchrony of contraction. Aim of the study was to evaluate synchrony of contraction in older people with ("non-healthy") or without ("healthy") evidence for structural cardiac disease. In 547 persons (age 76.7+/-5.5 years, 306 male, 241 female) recruited from a population-based cohort of the ActiFE-Ulm study including a random sample of people >/=65 years old living in the region of Ulm, Germany, various PW- and TDI-Doppler based markers for asynchrony were obtained by echocardiography. Within a subgroup of 84 healthy subjects, at most minimal systolic and diastolic asynchrony was found. Concerning systolic asynchrony, similar observations were made within the non-healthy subgroup. However, extent of diastolic left ventricular intraventricular asynchrony and also - by tendency - diastolic interventricular asynchrony was increased in comparison to the healthy subgroup. To conclude, no evidence that physiological ageing might go along with relevant left or right ventricular systolic or diastolic electromechanical asynchrony was found in our study. Furthermore, our population-based data support the results from other clinical studies with rather selected cohorts that structural heart diseases might go along with increased diastolic asynchrony.

Cellular and Molecular Aspects of Dyssynchrony and Resynchronization

Dyssynchronous contraction of the ventricle significantly worsens morbidity and mortality in patients with heart failure (HF). Approximately one-third of patients with HF have cardiac dyssynchrony and are candidates for cardiac resynchronization therapy (CRT). The initial understanding of dyssynchrony and CRT was in terms of global mechanics and hemodynamics, but lack of clinical benefit in a sizable subgroup of recipients who appear otherwise appropriate has challenged this paradigm. This article reviews current understanding of these cellular and subcellular mechanisms, arguing that these aspects are key to improving CRT use, as well as translating its benefits to a wider HF population.

Diastolic Dyssynchrony in Acute ST Segment Elevation Myocardial Infarction and Relationship with Functional Recovery of Left Ventricle

Background

Incidence of diastolic dyssynchrony (DD) and its impact on functional recovery of left ventricle (LV) after ST segment elevation myocardial infarction (STEMI) is not known.

Methods

Consecutive patients with STEMI who underwent successful revascularization were prospectively enrolled. Echocardiography with tissue Doppler imaging was performed within 48 hours of admission and at 6 months. LV end-diastolic volume index (EDVI), end-systolic volume index (ESVI), ejection fraction (EF), and left atrial volume index (LAVI) were calculated. Diastolic delay was calculated from onset of QRS complex to peak of E wave in tissue Doppler image and presented as maximal temporal difference between peak early diastolic velocity of 6 basal segments of LV (TeDiff). Study patients were compared with demographically matched control group.

Results

Forty eight consecutive patients (55 ± 10 years, 88% male) and 24 controls (56 ± 6 years, 88% male) were included. TeDiff was higher in STEMI than in controls (35.9 ± 19.9 ms vs. 26.3 ± 6.8 ms, p = 0.025). Presence of DD was higher in STEMI than controls (58% vs. 33%, p = 0.046) according to calculated cut-off value (≥ 29 ms). There was no correlation between TeDiff and change in EDVI, ESVI, and LAVI at 6 months, however TeDiff and change in EF at 6 months was positively correlated (r = 0.328, p = 0.023). Patients with baseline DD experienced remodeling less frequently compared to patients without baseline DD (11% vs. 38%, p = 0.040) during follow-up.

Conclusion

STEMI disrupts diastolic synchronicity of LV. However, DD during acute phase of STEMI is associated with better recovery of LV thereafter. This suggests that DD is associated with peri-infarct stunned myocardium that is salvaged with primary intervention as well as infarct size.

Cellular and Molecular Aspects of Dyssynchrony and Resynchronization

Dyssynchronous contraction of the ventricle significantly worsens morbidity and mortality in patients with heart failure (HF). Approximately one-third of patients with HF have cardiac dyssynchrony and are candidates for cardiac resynchronization therapy (CRT). The initial understanding of dyssynchrony and CRT was in terms of global mechanics and hemodynamics, but lack of clinical benefit in a sizable subgroup of recipients who appear otherwise appropriate has challenged this paradigm. This article reviews current understanding of these cellular and subcellular mechanisms, arguing that these aspects are key to improving CRT use, as well as translating its benefits to a wider HF population.

The use of multisite left ventricular pacing via quadripolar lead improves acute haemodynamics and mechanical dyssynchrony assessed by radial strain speckle tracking: initial results

AIMS

The objective of the present study was to evaluate the effect of multipoint pacing (MPP) on acute haemodynamics, cardiac contractility, and left ventricle (LV) dyssynchrony, in comparison with conventional cardiac resynchronization therapy (CRT).

METHODS AND RESULTS

An open-label, non-randomized, single-centre, prospective study was designed. Twenty-seven consecutive patients were included. Evaluation of pacing configurations was performed in a random order. Transthoracic echocardiography was used to obtain haemodynamic and dyssynchrony parameters. Left ventricular ejection fraction (LVEF) was significantly superior in MPP compared with baseline (38.4 ± 1.8% vs. 26.1 ± 2.2%; P < 0.001), and in conventional pacing configuration compared with baseline (33.2 ± 1.8% vs. 26.1 ± 2.2%; P = 0.007). Cardiac index (CI) was increased by 21.8 ± 5.4% and 34.7 ± 5.1% in conventional and MPP configurations, respectively (P = 0.19). Percentage of acute responders (CI increase ≥10%) was 62.9 and 85.2% in conventional and MPP, respectively (P < 0.001). LV dyssynchrony was defined by radial strain rate parameters. Baseline anteroseptal-to-posterior wall time delay was 168 ± 21 ms. It was reduced until 70.4 ± 29 ms in conventional and -6.6 ± 11 ms in MPP (conventional vs. baseline P = 0.04; MPP vs. conventional P = 0.05). Standard deviation of the time-to-peak radial strain of the 6 LV basal segments was 101 ± 9.7, 80.3 ± 9.2, and 66 ± 8.03 ms in baseline, conventional, and MPP configurations, respectively (MPP vs. basal P = 0.012). Finally, we observed a positive correlation (r = 0.69) between reduction in dyssynchrony and CI increase (P < 0.0001).

CONCLUSION

MPP showed a further reduction in LV dyssynchrony compared with conventional biventricular pacing. Moreover, MPP resulted in an additional improvement in LVEF and in CI, and this was translated into a higher number of acute responders to CRT.

What is the lowest value of left ventricular baseline ejection fraction that predicts response to cardiac resynchronization therapy?

Background

Cardiac resynchronization therapy (CRT) is an effective treatment option for patients with refractory heart failure. However, many patients do not respond to therapy. Although it has been thought that there was no relation between response to CRT and baseline ejection fraction (EF), the response rate of patients with different baseline LVEF to CRT has not been evaluated in severe left ventricular systolic dysfunction. We aimed to investigate any difference in response to CRT between the severe heart failure patients with different baseline LVEF.

Material/Methods

In this study, 141 consecutive patients (mean age 59±13 years; 89 men) with severe heart failure and complete LBBB were included. Patients were divided into 3 groups according to their baseline LVEF: 5–15%, Group 1; 15–25%, Group 2, and 25–35%, Group 3. NYHA functional class, LVEF, LV volumes, and diameters were assessed at baseline and after 6 months of CRT. A response to CRT was defined as a decrease in LVSVi (left ventricular end-systolic volume index) ≥10% on echocardiography at 6 months.

Results

After 6 months, a significant increase of EF and a significant decrease of LVESVi and LVEDVi after 6 months of CRT were observed in all groups. Although the magnitude of improvement in EF was biggest in the first group, the percentage of decrease in LVESVi and LVEDVi was similar between the groups. The improvement in NYHA functional class was similar in all EF subgroups. At 6-month follow-up, 100 (71%) patients showed a reduction of >10% in LVESVi (mean reduction: −15.5±26.1 ml/m²) and were therefore classified as responders to CRT. Response rate to CRT was similar in all groups. It was 67%, 75%, and 70% in Group 1, 2, and 3, respectively, at 6-month follow-up (p>0.05). There was no statistically significant relation between the response rate to CRT and baseline LVEF, showing that the CRT has beneficial effects even in patients with very low LVEF.

Conclusions

It seems there is no lower limit for baseline LVEF to predict non-response to CRT in eligible patients according to current guidelines.

Role of nuclear cardiology for guiding device therapy in patients with heart failure

Heart failure is a dynamic condition with high morbidity and mortality and its prognosis should be reassessed frequently, particularly in patients for whom critical treatment decisions may depend on the results of prognostication. In patients with heart failure, nuclear cardiology techniques are useful to establish the etiology and the severity of the disease, while fewer studies have explored the potential capability of nuclear cardiology to guide cardiac resynchronization therapy (CRT) and to select patients for implantable cardioverter defibrillators (ICD). Left ventricular synchrony may be assessed by radionuclide angiography or gated single-photon emission computed tomography myocardial perfusion scintigraphy. These modalities have shown promise as predictors of CRT outcome using phase analysis. Combined assessment of myocardial viability and left ventricular dyssynchrony is feasible using positron emission tomography and could improve conventional response prediction criteria for CRT. Preliminary data also exists on integrated positron emission tomography/computed tomography approach for assessing myocardial viability, identifying the location of biventricular pacemaker leads, and obtaining left ventricular functional data, including contractile phase analysis. Finally, cardiac imaging with autonomic radiotracers may be useful in predicting CRT response and for identifying patients at risk for sudden cardiac death, therefore potentially offering a way to select patients for both CRT and ICD therapy. Prospective trials where imaging is combined with image-test driven therapy are needed to better define the role of nuclear cardiology for guiding device therapy in patients with heart failure.

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.

Hisian area and right ventricular apical pacing differently affect left atrial function: an intra-patients evaluation

AIMS

Right ventricular apex (RVA) pacing has adverse effects on left atrial (LA) function and may contribute to atrial arrhythmias. The effects of Hisian area (HA) pacing on LA function are still lacking. The objective of this study is to assess the left ventricular (LV) electromechanical activation/relaxation, systolic (S), diastolic (D) phases, and their effects on LA function during pacing from HA and RVA.

METHODS AND RESULTS

Thirty-seven patients with normal cardiac function underwent permanent HA pacing. In all patients, a RVA backup lead was added. The patients first underwent 3 months of HA pacing, followed by 3 months of RVA pacing. After each 3-month period, we compared by echocardiography: S-D LV electromechanical delay (S-D EMD), S-D intra-LV dyssynchrony, LV S-D phases, and their function evaluated by myocardial performance index (MPI) and mitral annular tissue Doppler early diastolic velocity (E'), pulmonary arterial systolic pressure (PASP), and LA function (LA phasic volumes and their emptying fraction). Right ventricular apex compared with HA pacing increased S-D EMD (P < 0.001) and intra-LV dyssynchrony (P < 0.001). As a consequence, a significant longer LV isovolumetric contraction time (P < 0.001) and LV isovolumetric relaxation time (P = 0.05) were measured during RVA compared with HA pacing, whereas LV ejection time was shorter (P = 0.033). Moreover, HA pacing resulted in significantly better MPI (P = 0.039), higher value of E' (P = 0.049), and lower PASP (P < 0.001). Finally, RVA compared with HA pacing was associated to higher LA volumes pre-atrial contraction (P = 0.001) and minimal volume (P = 0.003) with reduction in passive emptying fraction (P < 0.001) and total emptying fraction (P = 0.005).

CONCLUSION

Hisian area compared with RVA pacing resulted in a more physiological LV electromechanical activation/relaxation and consequently better LA function.

Catheterization diastolic pressures correlate with diastolic dyssynchrony in patients with single right ventricles

INTRODUCTION

Diastolic dyssynchrony has correlated with pulmonary capillary wedge pressures in patients with normal cardiac anatomy. No data exist in single right ventricle (sRV) patients. Goal of this study was to determine if diastolic dyssynchrony in sRV patients correlates with ventricular end-diastolic pressures (VEDP).

METHODS

Tissue Doppler imaging (TDI) and strain rate (SR) analysis of sRV patients undergoing catheterization were performed. Time interval from onset of QRS to peak TDI e'-wave was obtained. Differences in intervals were calculated: QRS (RV) - QRS (IVS) and QRS (RV) - QRS (LV). Time interval from onset of QRS to peak strain rate early diastolic wave (SRe) was obtained for the 6 segment model sRV. Standard deviation of the 6 SRe time intervals was calculated. Correlation of VEDP with timing intervals was analyzed.

RESULTS

Forty sRV patients were evaluated. Age was 2.8 ± 3.5 years. Catheterization VEDP of the sRV was 9.3 ± 3.9 mmHg (median 8 mmHg range 4-24 mmHg). QRS (RV) - QRS (IVS) was 22.3 ± 18.1 msec and QRS (RV) - QRS (LV) was 23.7 ± 19.0 msec. SRe standard deviation of the sRV was 61.6 ± 23.9 msec. There was no significant correlation with VEDP and QRS (RV) - QRS (IVS) (r = 0.1, P = NS) or with QRS (RV) - QRS (LV) (r = 0.2, P = NS). There was a significant correlation of VEDP with the SRe standard deviation value (r = 0.4, P < 0.05).

CONCLUSION

Diastolic dyssynchrony correlated with VEDP in patients with sRV physiology. Future studies are needed to determine the significance of these findings.

Electromechanical dyssynchrony and resynchronization of the failing heart

Patients with heart failure and decreased function frequently develop discoordinate contraction because of electric activation delay. Often termed dyssynchrony, this further decreases systolic function and chamber efficiency and worsens morbidity and mortality. In the mid- 1990s, a pacemaker-based treatment termed cardiac resynchronization therapy (CRT) was developed to restore mechanical synchrony by electrically activating both right and left sides of the heart. It is a major therapeutic advance for the new millennium. Acute chamber effects of CRT include increased cardiac output and mechanical efficiency and reduced mitral regurgitation, whereas reduction in chamber volumes ensues more chronically. Patient candidates for CRT have a prolonged QRS duration and discoordinate wall motion, although other factors may also be important because ≈30% of such selected subjects do not respond to the treatment. In contrast to existing pharmacological inotropes, CRT both acutely and chronically increases cardiac systolic function and work, yet it also reduces long-term mortality. Recent studies reveal unique molecular and cellular changes from CRT that may also contribute to this success. Heart failure with dyssynchrony displays decreased myocyte and myofilament function, calcium handling, β-adrenergic responsiveness, mitochondrial ATP synthase activity, cell survival signaling, and other changes. CRT reverses many of these abnormalities often by triggering entirely new pathways. In this review, we discuss chamber, circulatory, and basic myocardial effects of dyssynchrony and CRT in the failing heart, and we highlight new research aiming to better target and implement CRT, as well as leverage its molecular effects.

Left ventricular systolic and diastolic dyssynchrony assessed by phase analysis of gated SPECT myocardial perfusion imaging: a comparison with speckle tracking echocardiography

OBJECTIVE

The objective of this study was to compare left ventricular (LV) systolic and diastolic dyssynchrony parameters measured by phase analysis on gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) with those measured by speckle tracking echocardiography (STE).

MATERIALS AND METHODS

Two patient groups were enrolled from the Chang Bing Show Chwan Memorial Hospital. The systolic group consisted of patients with reduced LV ejection fraction (LVEF) of <50 % as assessed by routine echocardiography. The diastolic group consisted of patients with normal LVEF (>50 %) and diastolic dysfunction according to routine echocardiography (E/A <1, E/E' >8). LV systolic and diastolic dyssynchrony parameters were calculated using STE as the maximal peak-time delay between peak radial strains of two opposing LV walls and as the standard deviation of the time to peak radial strains in 6 mid-LV segments. All of the patients had gated SPECT MPI within 6 ± 11 days post STE. Phase analysis was performed on the resting gated SPECT MPI images to calculate systolic and diastolic phase standard deviation and phase histogram bandwidth as markers of LV systolic and diastolic dyssynchrony, respectively.

RESULTS

Fifty-two consecutive patients (40 men, mean age = 66 ± 13 years, LVEF = 34.4 ± 10.2 %) were enrolled in the systolic group, whereas 30 consecutive patients (15 men, mean age = 69 ± 11 years, LVEF = 72.3 ± 4.7 %, E/A all <1, E/E' = 11.7 ± 2.2) were enrolled in the diastolic group. LV systolic and diastolic dyssynchrony parameters measured by phase analysis of gated SPECT MPI and STE were correlated well in both systolic and diastolic groups, respectively.

CONCLUSION

Phase analysis on gated SPECT MPI showed good correlations with STE and is suitable for the assessment of LV systolic and diastolic dyssynchrony. As assessed with the phase analysis and STE techniques, the patients with severe LV systolic dysfunction had severe LV systolic dyssynchrony, but the patients with LV diastolic dysfunction were not necessarily with LV diastolic dyssynchrony, indicating that the LV diastolic dyssynchrony parameters characterized independent mechanisms of LV regional diastolic function.

Update on diastolic heart failure or heart failure with preserved ejection fraction in the older adults

Nearly half of all heart failure (HF) patients have diastolic HF (DHF) or clinical HF with normal or near-normal left ventricular ejection fraction (LVEF). Although the terminology has not been clearly defined, it is increasingly being referred to as HF with preserved ejection fraction (HFPEF). The prevalence of HFPEF increases with age, especially among older women. Identifying HFPEF is important because the etiology, pathogenesis, prognosis, and optimal management may differ from that for systolic HF (SHF) or HF with reduced ejection fraction. The clinical presentation of HF is similar for both SHF and HFPEF. As in SHF, HFPEF is a clinical diagnosis. Once a clinical diagnosis of HF has been made, the presence of HFPEF can be established by confirming a normal or near-normal LVEF, often by an echocardiogram. HFPEF is often associated with a history of hypertension, concentric left ventricular hypertrophy, vascular stiffness, and left ventricular diastolic dysfunction. As in SHF, HFPEF is also associated with poor outcomes. While therapies with angiotensin-converting enzyme inhibitors and beta-blockers improve outcomes in SHF, there is currently no such evidence of their benefits in older HFPEF patients. In this review recent advances in the diagnosis and management of HFPEF in older adults are discussed.

Prevalence of cardiac dyssynchrony and correlation with atrio-ventricular block and QRS width in dilated cardiomyopathy: an echocardiographic study

INTRODUCTION

Cardiac dyssynchrony causes disorganised cardiac contraction, delayed wall contraction and reduced pumping efficiency. We aimed to assess the prevalence of different types of dyssynchrony in patients with dilated cardiomyopathy (DCM), and to establish the correlation between atrio-ventricular block and atrio-ventricular dyssynchrony (AVD), and between impaired intra-ventricular conduction and the existence of inter-ventricular dyssynchrony (inter-VD) and intra-left ventricular dyssynchrony (intra-LVD).

METHODS

We included 40 patients in New York Heart Association stage III or IV, admitted consecutively with DCM with severe left ventricular dysfunction (left ventricular end-diastolic diameter ≥ 60 mm and/or ≥ 30 mm/m(2)) and left ventricular ejection fraction < 35%. Electrocardiographic and echocardiographic data were evaluated in all patients. Patients were divided into two groups: group 1: eight patients, with a QRS duration ≥ 120 ms, and all presented with left bundle branch block; group 2: 32 patients with a narrow QRS < 120 ms.

RESULTS

Overall, the mean age was 54.7 ± 16.8 years and patients in group 1 were older (67.2 ± 13.6 vs 51.5 ± 15.8 years, p = 0.01). The prevalence of atrio-ventricular dyssynchrony (AVD), inter-VD and intra-LVD was respectively 40, 47.5 and 70%. Two patients (5%) did not exhibit dyssynchrony. AVD was present with a similar frequency in the two groups (37.5% in group 1 vs 40.6% in group 2, p = 0.8). There was no correlation of the magnitude of AVD with the duration of the PR interval (from the beginning of the P wave to the beginning of the QRS complex) (r(2) = 0.02, p = 0.37) or the QRS width (r(2) = 0.01, p = 0.38). A greater proportion of patients with inter-VD was observed in group 1 (87.5 vs 60%, p = 0.03). There was a trend towards a more important inter-ventricular mechanical delay according to QRS width (r(2) = 0.009, p = 0.06). The proportion of intra-LVD was similar in all groups, with a high prevalence (87.5% in group 1 and 65.6% in group 2, p = 0.39).

CONCLUSION

The assessment of cardiac dyssynchrony is possible in our country. Intra-ventricular mechanical dyssynchrony had a high prevalence in patients with DCM, irrespective of the QRS width. These data emphasise the usefulness of echocardiography in the screening of patients.

Impact of antihypertensive treatment on left ventricular systolic dyssynchrony in treatment-naïve hypertensive patients

Dyssynchrony is common in asymptomatic patients with hypertension. We sought to investigate the impact of antihypertensive treatment on dyssynchrony in patients with hypertension. A total of sixty patients who had uncomplicated hypertension that had never been treated (treatment-naïve hypertensive patients) underwent echocardiographic evaluations of left ventricular (LV) dyssynchrony at baseline and after a 6-month treatment with antihypertensive drugs. The measured parameters were as follows: (1) the s.d. of 12 LV-segment time-to-peak systolic velocities (Ts-SD12), and (2) the maximal difference between peak systolic velocities of any 2 of the 12 segments (Ts-Max). Patients with Ts-SD12 ≥ 33 ms or Ts-Max ≥ 100 ms were regarded as having LV systolic dyssynchrony. Patients with systolic dyssynchrony (group 1, n = 29) and without systolic dyssynchrony (group 2, n = 31) were compared. Among the patients in group 1, antihypertensive treatment significantly improved LV systolic dyssynchrony (ΔTs-SD12, -13.1 ms; P<0.001 and ΔTs-Max, -34.0 ms; P = 0.003), whereas it did not demonstrate additional benefit among group 2 patients. The change in LV systolic dyssynchrony was significantly associated with changes in the mean annulus E' velocity, mean annulus S' velocity and mean annulus E'/A' ratio, but not with changes in blood pressure and LV mass index. It is likely that chronic antihypertensive treatment could reverse the LV systolic dyssynchrony and simultaneously improve subclinical systolic and diastolic function in patients with hypertension and LV systolic dyssynchrony.

Left ventricular diastolic dyssynchrony assessed with phase analysis of gated myocardial perfusion SPECT: a comparison with tissue Doppler imaging

Purpose

The aim of the current study was to evaluate the feasibility of phase analysis on gated myocardial perfusion SPECT (GMPS) for the assessment of left ventricular (LV) diastolic dyssynchrony in a head-to-head comparison with tissue Doppler imaging (TDI).

Methods

The population consisted of patients with end-stage heart failure of New York Heart Association functional class III or IV with a reduced LV ejection fraction of ≤35%. LV diastolic dyssynchrony was calculated using TDI as the maximal time delay between early peak diastolic velocities of two opposing left ventricle walls (diastolic mechanical delay). Significant LV diastolic dyssynchrony was defined as a diastolic mechanical delay of >55 ms on TDI. Furthermore, phase analysis on GMPS was performed to evaluate LV diastolic dyssynchrony; diastolic phase standard deviation (SD) and histogram bandwidth (HBW) were used as markers of LV diastolic dyssynchrony.

Results

A total of 150 patients (114 men, mean age 66.0 ± 10.4 years) with end-stage heart failure were enrolled. Both diastolic phase SD (r = 0.81, p < 0.01) and diastolic HBW (r = 0.75, p < 0.01) showed good correlations with LV diastolic dyssynchrony on TDI. Additionally, patients with LV diastolic dyssynchrony on TDI (>55 ms) showed significantly larger diastolic phase SD (68.1 ± 13.4° vs. 40.7 ± 14.0°, p < 0.01) and diastolic HBW (230.6 ± 54.3° vs. 129.0 ± 55.6°, p < 0.01) as compared to patients without LV diastolic dyssynchrony on TDI (≤55 ms). Finally, phase analysis on GMPS showed a good intra- and interobserver reproducibility for the determination of diastolic phase SD (ICC 0.97 and 0.88) and diastolic HBW (ICC 0.98 and 0.93).

Conclusion

Phase analysis on GMPS showed good correlations with TDI for the assessment of LV diastolic dyssynchrony.

Echocardiographic assessment of interventricular and intraventricular mechanical synchrony in normal dogs

OBJECTIVES

The aims of this prospective study are to (1) generate normal ranges for interventricular and intraventricular mechanical synchrony in dogs, and (2) generate normal ranges for tissue Doppler imaging (TDI) velocity imaging and speckle tracking strain imaging assessment of segmental intraventricular mechanical synchrony in dogs.

ANIMALS

10 prospectively recruited healthy dogs.

METHODS

Dogs were excluded if they had abnormal historical, physical examination, echocardiographic, ECG or systolic blood pressure findings. Interventricular mechanical synchrony was assessed using time difference between left and right ventricular pre-ejection periods. Intraventricular mechanical synchrony was assessed using both M-mode and color M-mode septal to posterior wall mechanical delay (SPWMD). Intraventricular segmental mechanical synchrony was assessed using both color TDI and speckle tracking strain analysis of segmental myocardial motion during systole and diastole.

RESULTS

All synchrony measures were found to be independent of age or body weight. Normal range for mechanical interventricular synchrony was found to be -10.2 to 12.6 ms. Assessment of mechanical intraventricular synchrony using either M-mode or color M-mode SPWMD was found to be associated with an extremely wide normal range, limiting clinical applicability. Normal ranges for segmental intraventricular mechanical synchrony assessed using either color TDI or speckle tracking were found to be comparable to those published for human subjects.

CONCLUSIONS

Interventricular and intraventricular mechanical synchrony in dogs is independent of age and body weight. The normal ranges identified in this study form a basis for assessment of normal versus abnormal mechanical synchrony in canine cardiovascular disease patients.

Effect of biventricular pacing on diastolic dyssynchrony

OBJECTIVES

This study sought to examine the changes in diastolic dyssynchrony with cardiac resynchronization therapy (CRT).

BACKGROUND

Little is known about the effect of CRT on diastolic dyssynchrony.

METHODS

Consecutive heart failure patients (n = 266, age 65.7 ± 10.0 years) underwent color-coded tissue Doppler imaging at baseline, 48 h, and 6 months after CRT. Systolic and diastolic dyssynchrony were defined as maximal time delay in peak systolic and early diastolic velocities, respectively, in 4 basal LV segments. CRT responders were defined as those with ≥15% decrease in LV end-systolic volume at 6 months.

RESULTS

Baseline LVEF was 25.2 ± 8.1%; 63.5% patients were CRT responders. Baseline incidence of systolic and diastolic dyssynchrony, and a combination of both was 46.2%, 51.9%, and 28.6%, respectively. Compared to nonresponders, responders had longer baseline systolic (79.2 ± 43.4 ms vs. 45.4 ± 30.4 ms; p < 0.001) and diastolic (78.5 ± 52.0 ms vs. 50.1 ± 38.2 ms; p < 0.001) delays. In follow-up, systolic delays (45.4 ± 31.6 ms at 48 h; 38.9 ± 26.2 ms at 6 months; p < 0.001) and diastolic delays (49.4 ± 36.3 ms at 48 h; 37.7 ± 26.0 ms at 6 months; p < 0.001) improved only in responders.

CONCLUSIONS

At baseline: 1) diastolic dyssynchrony was more common than systolic dyssynchrony in HF patients; 2) nonresponders had less baseline diastolic dyssynchrony compared to responders. After CRT: 1) diastolic dyssynchrony improved only in responders. Further insight into the pathophysiology of diastolic dyssynchrony and its changes with CRT may provide incremental information on patient-specific treatments.

Left ventricular dyssynchrony in patients showing diastolic dysfunction without overt symptoms of heart failure

BACKGROUND/AIMS

Few studies have assessed left ventricular (LV) dyssynchrony in cases of diastolic dysfunction that do not include overt symptoms of heart failure. We hypothesized that systolic or diastolic dyssynchrony involves unique features with respect to the degree of diastolic impairment in isolated diastolic dysfunction.

METHODS

We examined 105 subjects with no history of overt symptoms of heart failure and a left ventricular ejection fraction > 50% for mechanical dyssynchrony using tissue Doppler imaging.

RESULTS

In terms of longitudinal dyssynchrony, four cases showed (6.3%) LV intraventricular systolic dyssynchrony (SDS(LV)), whereas none had LV intraventricular diastolic dyssynchrony (DDS(LV)) or co-existing systolic dyssynchrony. Radial dyssynchrony (RD) was found in six cases (9.4%). After adjusting for age, SDS(LV) and DDS(LV) were found to be significantly related to increases in the E/E' ratio (r = 0.405 and p < 0.001 vs. r = 0.216 and p = 0.045, respectively). RD at the base and apex was also significantly related to increases in E/E' (r = 0.298 and p = 0.002 vs. r = 0.196 and p = 0.045, respectively).

CONCLUSIONS

Systolic and diastolic dyssynchrony in subjects with isolated diastolic dysfunction but without overt symptoms of heart failure was not as common as in patients with diastolic heart failure; however, the systolic and diastolic intraventricular time delay increased with increases in the E/E' ratio, an indicator of diastolic dysfunction.

Assessment of right ventricular diastolic function by tissue Doppler imaging in patients with acute right ventricular myocardial infarction

BACKGROUND

It is known that right ventricular systolic parameters as assessed by color tissue Doppler imaging (TDI) are abnormal in patients with inferior wall ST elevation myocardial infarction (IWMI) with right ventricular myocardial infarction (RVMI). This study was undertaken to determine right ventricular diastolic function as assessed by TDI in patients with acute RVMI.

METHODS

Thirty-five patients with first IWMI were studied and compared with 20 age-matched healthy controls, and categorized into those with (14 patients) and without (21 patients) RVMI based on standard ECG criteria. Peak systolic, peak early and late diastolic velocities (Sm, Em, and Am), Em/Am ratio along with time to Sm (ECG Q-Sm) and time to Em (ECG Q-Em) were acquired from the apical 4-chamber view at the lateral side of tricuspid annulus using TDI.

RESULTS

Sm, Em, and Em/Am ratio was reduced significantly in patients with RVMI as compared with those without RVMI and healthy individuals (Sm [11.1 + or - 2.9] vs. [14 + or - 1.9] and [14.5 + or - 2.1] cm/sec, P < 0.01; Em [9.2 + or - 3.5] vs. [12.9 + or - 3] and [14.0 + or - 2.0] cm/sec, P < 0.01; Em/Am ratio 0.53 + or - 0.2 vs. 0.78 + or - 0.19 and 0.8 + or - 0.3 [P < 0.0001]). Among the intervals, there was significant prolongation of Q-Em (558 + or - 14.8 vs. 507 + or - 16.2 and 480 + or - 20 ms [P < 0.0001]) but Q-Sm and Am were not statistically different between the groups.

CONCLUSION

Right ventricular TDI diastolic parameters are abnormal in patients with RVMI. The method of recording the velocities and time intervals are simple and can be used to assess right ventricular diastolic function in patients with RVMI. (Echocardiography 2010;27:539-543).

Left ventricular diastolic mechanical dyssynchrony and associated clinical outcomes in children with dilated cardiomyopathy

BACKGROUND

We investigated diastolic mechanical dyssynchrony and its relation to clinical status in pediatric dilated cardiomyopathy (DCM).

METHODS AND RESULTS

We calculated a diastolic and systolic dyssynchrony index (standard deviation of time to peak tissue early diastolic/systolic velocity in 12 left ventricular segments) in 33 children with DCM and 46 control subjects. A threshold to diagnose diastolic dyssynchrony was determined, and cardiac function and clinical outcomes were compared between DCM patients with and without diastolic dyssynchrony. Left ventricular wall motion was more synchronized in diastole than in systole. The diastolic dyssynchrony index was significantly higher in children with DCM than in control subjects (28.1+/-18.1 versus 9.1+/-3.8 ms, P<0.0001). A 17-ms threshold indicated the presence of diastolic dyssynchrony. Patients who died or underwent transplantation had greater diastolic dyssynchrony (diastolic dyssynchrony index 37.9+/-20.5 versus 22.1+/-13.8 ms, P=0.01), and the rate of transplant-free survival appeared to be worse for DCM patients with diastolic dyssynchrony than for patients with synchronous DCM (hazard ratio 2.98, P=0.11; hazard ratio adjusted for disease duration 2.95, P=0.17).

CONCLUSIONS

Left ventricular diastolic mechanical dyssynchrony is common in pediatric DCM, especially in patients who subsequently experience transplantation or death, and may be associated with a decreased length of transplantation-free survival.

Right-to-left ventricular diastolic delay in chronic thromboembolic pulmonary hypertension is associated with activation delay and action potential prolongation in right ventricle

BACKGROUND

Delayed left ventricle (LV)-to-right ventricle (RV) peak shortening results in cardiac output reduction in patients with chronic thromboembolic hypertension (CTEPH) and other types of pulmonary arterial hypertension. Why the synchrony between LV and RV is lost is unknown. We hypothesized that RV electrophysiological remodeling, notably, conduction slowing and action potential prolongation, contribute to this loss in synchrony.

METHODS AND RESULTS

We conducted epicardial mapping during pulmonary endarterectomy in 26 patients with CTEPH and compared these findings with clinical, hemodynamic, and echocardiographic variables. We consecutively placed a multielectrode grid on the epicardium of the RV free wall and LV lateral wall. These regions corresponded to RV and LV areas where echocardiographic Doppler sample volumes were placed to measure RV-to-LV diastolic interventricular delay. RV and LV epicardial action potential duration was assessed by measuring activation-recovery interval. Onset of diastolic relaxation of RV free wall with respect to LV lateral wall (diastolic interventricular delay) was delayed by 38+/-31 ms in patients with CTEPH versus -12+/-13 ms in control subjects (P<0.001), because, in patients with CTEPH, RV completed electric activation later than LV (65+/-20 versus 44+/-7 ms, P<0.001) and epicardial action potential duration, as assessed by activation-recovery interval measurement, was longer in RV free wall than in LV lateral wall (253+/-29 versus 240+/-22 ms, P<0.001).

CONCLUSIONS

Additive effects of electrophysiological changes in RV, notably, conduction slowing and action potential prolongation, assessed by epicardial activation-recovery interval, contribute to diastolic interventricular delay in patients with CTEPH.

A randomized comparison of triple-site versus dual-site ventricular stimulation in patients with congestive heart failure

OBJECTIVES

We compared the effects of triple-site versus dual-site biventricular stimulation in candidates for cardiac resynchronization therapy.

BACKGROUND

Conventional biventricular stimulation with a single right ventricular (RV) and a single left ventricular (LV) lead is associated with persistence of cardiac dyssynchrony in up to 30% of patients.

METHODS

This multicenter, single-blind, crossover study enrolled 40 patients (mean age 70 +/- 9 years) with moderate-to-severe heart failure despite optimal drug treatment, a mean LV ejection fraction of 26 +/- 11%, and permanent atrial fibrillation requiring cardiac pacing for slow ventricular rate. A cardiac resynchronization therapy device connected to 1 RV and 2 LV leads, inserted in 2 separate coronary sinus tributaries, was successfully implanted in 34 patients. After 3 months of biventricular stimulation, the patients were randomly assigned to stimulation for 3 months with either 1 RV and 2 LV leads (3-V) or to conventional stimulation with 1 RV and 1 LV lead (2-V), then crossed over for 3 months to the alternate configuration. The primary study end point was quality of ventricular resynchronization (Z ratio). Secondary end points included reverse LV remodeling, quality of life, distance covered during 6-min hall walk, and procedure-related morbidity and mortality. Data from the 6- and 9-month visits were combined to compare end points associated with 2-V versus 3-V.

RESULTS

Data eligible for protocol-defined analyses were available in 26 patients. No significant difference in Z ratio, quality of life, and 6-min hall walk was observed between 2-V and 3-V. However, a significantly higher LV ejection fraction (27 +/- 11% vs. 35 +/- 11%; p = 0.001) and smaller LV end-systolic volume (157 +/- 69 cm(3) vs. 134 +/- 75 cm(3); p = 0.02) and diameter (57 +/- 12 mm vs. 54 +/- 10 mm; p = 0.02) were observed with 3-V than with 2-V. There was a single minor procedure-related complication.

CONCLUSIONS

Cardiac resynchronization therapy with 1 RV and 2 LV leads was safe and associated with significantly more LV reverse remodeling than conventional biventricular stimulation.

Acute pacing-induced dyssynchronous activation of the left ventricle creates systolic dyssynchrony with preserved diastolic synchrony

INTRODUCTION

Patients with heart block have conventionally received a pacemaker that stimulates the right ventricular apex (RVA) to restore heart rate control. While RVA pacing has been shown to create systolic dyssynchrony acutely, dyssynchrony can also occur in diastole. The effects of acute RVA pacing on diastolic synchrony have not been investigated. RVA pacing acutely impairs diastolic function by increasing the time constant of relaxation, decreasing the peak lengthening rate and decreasing peak negative dP/dt. We therefore hypothesized that acute RVA pacing would cause diastolic dyssynchrony in addition to creating systolic dyssynchrony.

METHODS AND RESULTS

Fourteen patients (13 +/- 4 years old) with non-preexcited supraventricular tachycardia underwent ablation therapy with subsequent testing to confirm elimination of the tachycardia substrate. Normal cardiac structure and function were then documented on two-dimensional echocardiography and 12-lead electrocardiography prior to enrollment. Tissue Doppler images were collected during normal sinus rhythm (NSR), right atrial appendage pacing (AAI), and VVI-RVA pacing during the postablation waiting interval. Systolic and diastolic dyssynchrony were quantified using cross-correlation analysis of tissue Doppler velocity curves. Systolic dyssynchrony increased 81% during RVA pacing relative to AAI and NSR (P < 0.01). Diastolic synchrony was not affected by the different pacing modes (P = 0.375).

CONCLUSION

Acute dyssynchronous activation of the LV created by RVA pacing resulted in systolic dyssynchrony with preserved diastolic synchrony in pediatric patients following catheter ablation for treatment of supraventricular tachycardia. Our results suggest that systolic and diastolic dyssynchrony are not tightly coupled and may develop through separate mechanisms.

Isolated diastolic dysfunction--diagnostic value of tissue Doppler imaging, colour M-mode and N-terminal pro B-type natriuretic peptide

INTRODUCTION

For diagnosis of diastolic dysfunction of the left ventricle (DDF), measurement of relaxation velocity (V(R)) by tissue Doppler imaging (V(R)), flow propagation velocity of transmitral inflow (v(p)) as well as the measurement of serum levels of N-terminal pro b-type natriuretic peptide (NT-proBNP) compete with the standard echocardiographic DDF-measures because of several disadvantages of the latter.

METHODS

We examined the diagnostic value of method 1, 2 and NT-proBNP in 120 patients with echocardiographic-proven DDF and in 20 patients without. Patients were classified according to the DDF-stage by standard echocardiographic parameters (transmitral E/A-ratio, deceleration time, isovolumetric relaxation time) into stage I, II and III and furthermore subdivided by the presence of dyspnoea.

RESULTS

V(R) and v(p) were significantly lower in patients with DDF than in patients without DDF, with no difference between the various DDF stages. Symptomatic patients showed a trend to a lower V(R). NT-proBNP was elevated in patients with DDF: Symptomatic patients with a DDF at stage I and patients with a DDF at stage II and III independent of the presence of symptoms had elevated NT-proBNP levels.

CONCLUSION

All three methods tested identified patients with DDF. NT-proBNP and v(p) were able to discriminate between symptomatic and asymptomatic patients.

Systolic and Diastolic Dyssynchrony in Patients With Diastolic Heart Failure and the Effect of Medical Therapy

OBJECTIVES

The purpose of this study was to determine the prevalence of systolic and diastolic dyssynchrony in diastolic heart failure (DHF) patients and identify the effects of medical therapy.

BACKGROUND

The prevalence of systolic and diastolic dyssynchrony in DHF patients is unknown with no data on the effects of medical therapy on dyssynchrony.

METHODS

Patients presenting with DHF (n = 60; 61 +/- 9 years old, 35 women) underwent echocardiographic imaging simultaneous with invasive measurements. An age-matched control group of 35 subjects and 60 patients with systolic heart failure (SHF) were included for comparison. Systolic and diastolic dyssynchrony were assessed by tissue Doppler and defined using mean and SD values in the control group.

RESULTS

Systolic dyssynchrony was present in 20 patients (33%) with DHF and 24 patients (40%) with SHF and was associated in both groups with significantly worse left ventricular (LV) systolic and diastolic properties (p < 0.05 vs. control group and patients without systolic dyssynchrony). Diastolic dyssynchrony was present in 35 patients (58%) with DHF and 36 patients (60%) with SHF and had significant inverse correlations with mean wedge pressure and time constant of LV relaxation. In DHF patients, medical therapy resulted in significant shortening of diastolic time delay (39 +/- 23 ms to 28 +/- 20 ms; p = 0.02) but no significant change in systolic interval (p = 0.15). Shortening of diastolic time delay correlated well with tau shortening after therapy (r = 0.85; p < 0.001).

CONCLUSIONS

Systolic dyssynchrony occurs in 33% of DHF patients, and diastolic dyssynchrony occurs in 58%. Medical therapy results in significant shortening of the diastolic intraventricular time delay which is closely related to improvement in LV relaxation.

Effects of Stimulation Site on Diastolic Function in Cardiac Resynchronization Therapy

BACKGROUND

Cardiac resynchronization therapy (CRT) improves left ventricular (LV) systolic function and clinical status, and prolongs survival of patients suffering from heart failure. An optimal LV site selection is key with respect to improvements in systolic function, though whether a site-specific effect on diastolic function exists is unclear. This study compared the effects of CRT on changes in systolic and diastolic function from 2 LV stimulation sites.

METHODS

We studied 21 patients in New York Heart Association functional classes >/= III, and a LV ejection fraction < 0.30 and QRS duration > 130 ms. CRT leads were placed in the right ventricle, right atrium, and coronary sinus tributaries. LV stimulation was applied from the postero-lateral and antero-lateral wall. A LV conductance catheter was used to measure LV systolic and diastolic function. Systolic responders had > 10% changes in dP/dt(max), and diastolic responders < 10% changes in tau during CRT versus baseline. Response was highly dependent on LV lead position for both diastolic and systolic function. Diastolic responders decreased from 29% to 10% of patients, and systolic responders from 76% to 48%, in the best versus the worst lead position, respectively. Improvements in diastolic function were less pronounced than in systolic function (relative change -14% vs +28%, P < 0.05). Overall, 45% were both systolic and diastolic responders, 17% were both systolic and diastolic nonresponders, and 38% had opposite responses.

CONCLUSIONS

Changes in systolic and diastolic function were both highly dependent on the LV stimulation site. Diastolic function was less influenced by CRT and a high proportion of patients had discordant results.