Remission of left ventricular systolic dysfunction and of heart failure symptoms after cardiac resynchronization therapy: temporal pattern and clinical predictors

MAgnetic resonance imaging based DUal lead cardiac Resynchronization therapy: A prospectIve Left Bundle Branch Pacing Study (MADURAI LBBP study)

BACKGROUND

Cardiac resynchronization therapy(CRT) is a class-I indication for LVEF≤35%, and heart failure(HF). LBBB associated nonischemic-cardiomyopathy (LB-NICM) with minimal or no scar by cardiac-magnetic-resonance(CMR) imaging may be associated with excellent prognosis following CRT. Left-bundle-branch-pacing(LBBP) can achieve excellent resynchronization in LBBB patients.

OBJECTIVES

Aim of our study was to prospectively assess feasibility and efficacy of LBBP with or without a defibrillator in patients with LB-NICM and LVEF ≤35%, risk stratified by CMR.

METHODS

Pts with LB-NICM, LVEF≤35% and HF were prospectively enrolled from 2019 to 2022. If the scar burden<10% by CMR, LBBP only (Group-I) and if ≥10%, LBBP+ICD(Group-II) was performed. Primary endpoints-1.Echocardiographic-response(ER)- ΔLVEF ≥15% at 6 months; 2.Composite of time to death, HFH or sustained VT/VF. Secondary endpoints-1.Echocardiographic-hyper-response(EHR-LVEF≥50%orΔLVEF ≥20%) at 6 and 12 months; 2.Indication for ICD-upgradation(persistent LVEF<35% at 12 months or sustained VT/VF) RESULTS: 120 patients were enrolled. CMR showed <10% scar-burden in 109 patients(90.8%). 4 patients opted for LBBP+ICD and withdrew. LBBP optimized-dual-chamber-pacemaker(LOT-DDD-P) was done in 101 patients and LOT-CRT-P in 4 patients(Group-I,n=105). Scar-burden ≥10% in 11 pts who underwent LBBP+ICD(Group-II). During mean-follow-up 21±12 months, primary endpoint of ER observed in 80%(68/85 pts) in Group-I vs 27%(3/11 pts) in Group-II(p-0.0001). Primary composite-endpoint of death,HFH or VT/VF occurred in 3.8% in group-I vs 33.3% in Group-II(p<0.0001). Secondary endpoint of EHR(LVEF≥50%) observed in 39.5%vs0%, 61.2%vs9.1% and 80%vs33.3% at 3, 6 and 12 months in group-I and group-II respectively.

CONCLUSION

CMR guided CRT using LOT-DDD-P appears to be a safe and feasible approach in LB-NICM and has the potential to reduce healthcare cost.

Heart failure with recovered ejection fraction: Current understanding and future prospects

Heart failure with reduced ejection fraction (HFrEF) is a prevalent kind of heart failure in which a significant amount of the ejection fraction can be repaired, and left ventricular remodeling and dysfunction can be reversed or even restored completely. However, a considerable number of patients still present clinical signs and biochemical features of incomplete recovery from the pathophysiology of heart failure and are at risk for adverse outcomes such as re-deterioration of systolic function and recurrence of HFrEF. Furthermore, it is revealed from a microscopic perspective that even if partial or complete reverse remodeling occurs, the morphological changes of cardiomyocytes, extracellular matrix deposition, and abnormal transcription and expression of pathological genes still exist. Patients with "recovered ejection fraction" have milder clinical symptoms and better outcomes than those with continued reduction of ejection fraction. Based on the unique characteristics of this subgroup and the existence of many unknowns, the academic community defines it as a new category-heart failure with recovered ejection fraction (HFrecEF). Because there is a shortage of natural history data for this population as well as high-quality clinical and basic research data, it is difficult to accurately evaluate clinical risk and manage this population. This review will present the current understanding of HFrecEF from the limited literature.

Incremental value of left ventricular shape parameters measured by gated SPECT MPI in predicting the super-response to CRT

BACKGROUND

The purpose of this study was to evaluate the predictive value of left ventricular (LV) shape parameters measured by gated SPECT myocardial perfusion imaging (MPI) in super-responders enrolled in the VISION-CRT trial.

METHODS

One hundred and ninety-nine patients who met standard criteria for CRT from multiple centers were enrolled in this study. End-systolic eccentricity (ESE) and end-diastolic eccentricity (EDE) were measures of LV shape. Super-responders were the patients who had a relative increase in left ventricular ejection fraction (LVEF) ≥ 15%.

RESULTS

Complete data were obtained in 165 patients, and 43.6% of them were classified as super-responders. ESE was an independent predictor of CRT super-responders in univariate (OR 12.59, 95% CI 1.56-101.35, P = .017) and multivariate analysis (OR 35.71, 95% CI 1.66-766.03, P = .006). ESE had an incremental value over significant clinical and SPECT imaging variables, including angiotensin-converting enzyme inhibitors or angiotensin II receptor blocker, coronary artery disease, myocardial infarction, LVEF, end-diastolic volume index, and scar burden (AUC 0.82 vs. 0.80, sensitivity 0.68 vs. 0.65, specificity 0.82 vs. 0.78).

CONCLUSIONS

LV shape parameters derived from gated SPECT MPI have the promise to improve the prediction of the super-response to CRT. Moreover, ESE provides incremental value over existing clinical and nuclear imaging variables.

Reverse re-modelling chronic heart failure by reinstating heart rate variability

Heart rate variability (HRV) is a crucial indicator of cardiovascular health. Low HRV is correlated with disease severity and mortality in heart failure. Heart rate increases and decreases with each breath in normal physiology termed respiratory sinus arrhythmia (RSA). RSA is highly evolutionarily conserved, most prominent in the young and athletic and is lost in cardiovascular disease. Despite this, current pacemakers either pace the heart in a metronomic fashion or sense activity in the sinus node. If RSA has been lost in cardiovascular disease current pacemakers cannot restore it. We hypothesized that restoration of RSA in heart failure would improve cardiac function. Restoration of RSA in heart failure was assessed in an ovine model of heart failure with reduced ejection fraction. Conscious 24 h recordings were made from three groups, RSA paced (n = 6), monotonically paced (n = 6) and heart failure time control (n = 5). Real-time blood pressure, cardiac output, heart rate and diaphragmatic EMG were recorded in all animals. Respiratory modulated pacing was generated by a proprietary device (Ceryx Medical) to pace the heart with real-time respiratory modulation. RSA pacing substantially increased cardiac output by 1.4 L/min (20%) compared to contemporary (monotonic) pacing. This increase in cardiac output led to a significant decrease in apnoeas associated with heart failure, reversed cardiomyocyte hypertrophy, and restored the T-tubule structure that is essential for force generation. Re-instating RSA in heart failure improves cardiac function through mechanisms of reverse re-modelling; the improvement observed is far greater than that seen with current contemporary therapies. These findings support the concept of re-instating RSA as a regime for patients who require a pacemaker.

Prognostic effects of longitudinal changes in left ventricular ejection fraction with cardiac resynchronization therapy

Aims

Left ventricular ejection fraction (LVEF) is considered an indicator of cardiac resynchronization therapy (CRT). Longitudinal studies on the predictive value of LVEF are scarce. We aimed to comprehensively evaluate the prognostic role of LVEF in the outcomes of Chinese patients with CRT.

Methods and results

Three hundred ninety‐two patients were divided into three tertiles of LVEF: ≤25%, 25–30%, and 30–35%, and four groups by LVEF changes: <0% (negative response); ≥0% and ≤5% (non‐response); >5% and ≤15% (response); and >15% (super‐response). One hundred six patients were super‐responders. During a median follow‐up of 3.6 years, 141 reached the composite endpoint. Odds ratios (ORs) for super‐response depicted a reversed U‐shaped relationship for baseline LVEF with a peak at 25–30%. Independent predictors of super‐response were smaller left atrial diameter [odds ratio 0.897, 95% confidence interval (CI) 0.844–0.955, P = 0.001], smaller left ventricular end‐diastolic diameter (OR 0.937, 95% CI 0.889–0.989, P = 0.018), and higher estimated glomerular filtration rate (OR 1.018, 95% CI 1.001–1.035, P = 0.042) in Tertile 1; atrial fibrillation (OR 0.278, 95% CI 0.086–0.901, P = 0.033), left bundle branch block (OR 4.096, 95% CI 1.046–16.037, P = 0.043), and left ventricular end‐diastolic diameter (OR 0.929, 95% CI 0.876–0.986, P = 0.016) in Tertile 2; while female sex (OR 2.778, 95% CI 1.082–7.132, P = 0.034) and higher systolic blood pressure (OR 1.045, 95% CI 1.013–1.079, P = 0.006) in Tertile 3. An inverse association with the composite endpoint was found in Tertile 1 vs. Tertile 2 (hazard ratio 1.934, 95% CI 1.248–2.996, P = 0.003). The prognostic effects of CRT response in Tertile 3 and Tertile 1 varied significantly (P for trend = 0.017 and <0.001). Among three tertiles in super‐responders, event‐free survival was similar (P for trend = 0.143).

Conclusions

Left ventricular ejection fraction of 25–30% is associated with a better prognosis of super‐response. Predictors of super‐response are different for LVEF tertiles. CRT responses would have better prognostic performance than LVEF tertiles at baseline, which should be considered when clinicians screening eligible patients for CRT.

Heart Failure Duration Combined with Left Atrial Dimension Predicts Super-Response and Long-Term Prognosis in Patients with Cardiac Resynchronization Therapy Implantation

Background

Response to cardiac resynchronization therapy (CRT) varies significantly among patients. This study aimed to identify baseline characteristics that could predict super-response to CRT and to evaluate the long-term prognosis in super-responders.

Methods

We retrospectively reviewed the data of 73 consecutive patients who received CRT. Patients were considered as super-responders after 6-month follow-up when NYHA class reduction to I or II combined with left ventricular ejection fraction (LVEF) ≥ 50% was observed. Patients were divided into super-responders group and non-super-responders group. All-cause mortality or hospitalization for heart failure (HF) was referred to the combined end point.

Results

17 (23.3%) patients were super-responders. HF duration, left atrial dimension (LAD), and left bundle branch block (LBBB) were independent predictors of super-response to CRT. The combination of HF duration and LAD could provide more robust prediction of super-response than standalone HF duration (0.899 versus 0.789, Z = 2.207, P = 0.027) or standalone LAD (0.899 versus 0.775, Z = 2.487, P = 0.013). super-responders had excellent LV reverse remodeling. The cumulative incidences of combined end point were significantly lower in the super-responders group, LAD ≤ 42mm group, and combination of HF duration ≤ 48 months and LAD ≤ 42mm group. LBBB remained associated with a lowered risk of the combined end point (HR: 0.19, 95% CI: 0.07-0.57, P = 0.003), whereas LAD was associated with a raised risk of the combined end point (HR: 1.09, 95% CI: 1.02-1.17, P = 0.014).

Conclusions

HF duration, LAD, and LBBB independently predicted super-response. The combination of HF duration and LAD makes more robust prediction of CRT super-response. Super-responders had excellent LV reverse remodeling and decreased the incidences of the combined end point. LBBB and LAD were independently associated with the combined end point.

Is renal denervation still a treatment option in cardiovascular disease?

The role of renal sympathetic denervation (RDN) has been the topic of ongoing debate ever since the impressive initial results. The rationale of RDN is strong and supported by non-clinical studies, which lies in uncoupling the autonomic nervous crosstalk between the kidneys and the central nervous system. Since we know that cardiovascular diseases, such as hypertension, atrial, ventricular arrhythmias and heart failure (HF) are related to sympathetic (over)activity, modulation of the renal nerve activity appears to be a reasonable and attractive therapeutic target in these patients. This review will focus on the existing evidence and potential future perspectives for RDN as treatment option in cardiovascular disease.

Gender-Based Differences in Cardiac Resynchronization Therapy Response

Cardiac resynchronization therapy (CRT) has been shown to have a multitude of beneficial effects in select patients with systolic heart failure, by enhancing reverse remodeling, improving quality of life and functional status, reducing risk of heart failure admission, and most importantly, improving survival. Although women were underrepresented in the clinical trials, they were demonstrated to derive greater therapeutic benefit from CRT compared with men. Importantly, women were noted to derive benefit at a lesser degree of QRS prolongation than men, well below the now generally accepted cutoff of QRS ≥150 milliseconds.

The incidence and outcomes of delayed response to cardiac resynchronization therapy

BACKGROUND

The incidence and clinical outcomes of delayed response to cardiac resynchronization therapy (CRT) have not been well clarified. We aimed to observe the incidence and prognosis of delayed response and to identify its possible mechanisms.

METHODS

A total of 115 CRT patients were retrospectively analyzed in our study. Patients who met the enrollment criteria were divided into two groups: group A, conventional responders who showed response at 1-year follow-up, and group B, delayed responders who showed response after 1-year follow-up. CRT response was defined as an absolute increase of ≥10% in left ventricular ejection fraction.

RESULTS

Fifty-two patients (61 ± 12 years, 37 male) experienced conventional response to CRT and 17 patients (63 ± 11 years, 10 male) experienced delayed response. The mean follow-up time was 5.2 ± 2.4 years. The incidence of delayed response was 14.8% (17/115). All-cause mortality and hospitalization rates for heart failure were similar for delayed and conventional responders. Multivariate logistic regression analysis revealed that scar burden > 35% was an independent predictor of CRT delayed response (odds ratio 8.794, P  =  0.038).

CONCLUSIONS

A significant proportion of patients demonstrated delayed response to CRT. The delayed responders had a good prognosis that was similar to that of conventional responders. More scar burden might be related to the incidence of delayed response.

Effect of Gender on Outcomes After Cardiac Resynchronization Therapy in Patients With a Narrow QRS Complex

Background—

In EchoCRT, a randomized controlled trial evaluating the effect of cardiac resynchronization therapy (CRT) in patients with a QRS duration of <130 ms and echocardiographic evidence of left ventricular dyssynchrony, the primary outcome (death from any cause or first hospitalization for worsening heart failure) occurred more frequently in the CRT-ON when compared with the control group. In this prespecified subgroup analysis, we evaluated the effect of sex on clinical outcome in EchoCRT.

Methods and Results—

In EchoCRT, 585 (72%) of included patients were men. At baseline, male patients had a higher incidence of ischemic cardiomyopathy and longer QRS duration. On uni- and multivariable analysis, no significant interaction was observed regarding sex for the primary or any of the secondary end points. Numerically, a higher all-cause mortality was observed in male patients randomized to CRT-ON versus CRT-OFF on univariable analysis (hazard ratio, 1.83; 95% confidence interval, 1.08–3.12); however, no statistically significant interaction compared with females randomized to CRT-ON versus CRT-OFF was noted (hazard ratio, 0.99; P interaction, 0.56). There was no difference in the primary safety end point of system-related complications, including CRT system- and implantation-related events.

Conclusions—

The largest hazard for all-cause mortality in EchoCRT was observed in men randomized to CRT-ON; the comparison with women did not reach statistical significance, which may be because of the premature termination of the trial and the limited data. These results suggest that male sex may be a risk factor for harm by CRT in patients with narrow QRS width, an observation which deserves further investigation.

Clinical Trial Registration—

URL: https://clinicaltrials.gov . Unique identifier: NCT00683696.

Management of Patients With Recovered Systolic Function

Advancements in the treatment of heart failure (HF) with systolic dysfunction have given rise to a new population of patients with improved ejection fraction (EF). The management of this distinct population is not well described due to a lack of consensus on the definition of myocardial recovery, a scarcity of data on the natural history of these patients, and the absence of focused clinical trials. Moreover, an improvement in EF may have different prognostic and management implications depending on the underlying etiology of cardiomyopathy. This can be challenging for the clinician who is approached by a patient inquiring about a reduction of medical therapy after apparent EF recovery. This review explores management strategies for HF patients with recovered EF in a disease-specific format.

Association of apical rocking with super-response to cardiac resynchronisation therapy

Background

Super-responders to cardiac resynchronisation therapy (CRT) show an exceptional improvement in left ventricular ejection fraction (LVEF). Previous studies showed that apical rocking was independently associated with echocardiographic response to CRT. However, little is known about the association between apical rocking and super-response to CRT.

Objectives

To determine the independent association of LV apical rocking with super-response to CRT in a large cohort.

Methods

A cohort of 297 consecutive heart failure patients treated with primary indication for CRT-D were included in an observational registry. Apical rocking was defined as motion of the left ventricular (LV) apical myocardium perpendicular to the LV long axis. ‘Super-response’ was defined by the top quartile of LVEF response based on change from baseline to follow-up echocardiogram. Best-subset regression analysis identified predictors of LVEF super-response to CRT.

Results

Apical rocking was present in 45 % of patients. Super-responders had an absolute mean LVEF increase of 27 % (LVEF 22.0 % ± 5.7 at baseline and 49.0 % ± 7.5 at follow-up). Apical rocking was significantly more common in super-responders compared with non-super-responders (76 and 34 %, P < 0.001). In univariate analysis, female gender (OR 2.39, 95 % CI 1.38–4.11), lower LVEF at baseline (OR 0.91 95 % CI 0.87–0.95), non-ischaemic aetiology (OR 4.15, 95 % CI 2.33–7.39) and apical rocking (OR 6.19, 95 % CI 3.40–11.25) were associated with super-response. In multivariate analysis, apical rocking was still strongly associated with super-response (OR 5.82, 95 % CI 2.68–12.61). Super-responders showed an excellent clinical prognosis with a very low incidence of heart failure admission, cardiac mortality and appropriate ICD therapy.

Conclusion

Apical rocking is independently associated with super-response to CRT.

Electronic supplementary material

The online version of this article (doi:10.1007/s12471-015-0768-4) contains supplementary material, which is available to authorized users.

Long-Term Echocardiographic Response to Cardiac Resynchronization Therapy in Initial Nonresponders

OBJECTIVES

The aim of this study was to investigate the frequency and clinical implications of a delayed echocardiographic response to cardiac resynchronization therapy (CRT).

BACKGROUND

Long-term prognosis for CRT patients is routinely based on the assessment of echocardiograms after 6 to 12 months of therapy. Some patients, however, may require a longer period of therapy before echocardiographic improvements are detectable.

METHODS

This observational study included all patients with heart failure (HF) receiving a CRT device at a single center from 2003 to 2011. Eligible patients met current indications and had technically adequate echocardiograms from before implantation, approximately 1 year after implantation (mid-term), and ≥3 years after implantation (long-term). A positive echocardiographic response to CRT was defined as a reduction in left ventricular end-systolic volume ≥15%. All-cause mortality was compared for patients in 3 response groups: mid-term responders, long-term responders, and nonresponders.

RESULTS

During this study, 294 patients met the study criteria. Of the 120 patients who were nonresponders after 1 year, 52 (43%) experienced a delayed positive response. Delayed, long-term responders had mortality and hospitalization rates similar to mid-term responders and significantly lower than nonresponders.

CONCLUSIONS

Among patients surviving at least 3 years after implantation of a CRT device and with echocardiographic follow-up, a significant portion of nonresponders after 1 year of CRT experience a delayed echocardiographic response after a longer period of time. Survival and hospitalization rates were similar for all echocardiographic responders, regardless of the time at which the response occurred.

Predictors and outcomes of "super-response" to cardiac resynchronization therapy

BACKGROUND

Cardiac resynchronization therapy (CRT) has been shown to improve heart failure (HF) symptoms and survival. We hypothesized that a greater improvement in left-ventricular ejection fraction (LVEF) after CRT is associated with greater survival benefit.

METHODS AND RESULTS

In 693 patients across 2 international centers, the improvement in LVEF after CRT was determined. Patients were grouped as non-/modest-, moderate-, or super-responders to CRT, defined as an absolute change in LVEF of ≤5%, 6-15%, and >15%, respectively. Changes in New York Heart Association (NYHA) functional class and left ventricular end-diastolic dimension (LVEDD) were assessed for each group. There were 395 non-/modest-, 186 moderate-, and 112 super-responders. Super-responders were more likely to be female and to have nonischemic cardiomyopathy, lower creatinine, and lower pulmonary artery systolic pressure than non-/modest- and moderate-responders. Super-responders were also more likely to have lower LVEF than non-/modest-responders. There was no difference in NYHA functional class, mitral regurgitation grade, or tricuspid regurgitation grade between groups. Improvement in NYHA functional class (-0.9 ± 0.9 vs -0.4 ± 0.8 [P < .001] and -0.6 ± 0.8 [P = .02]) and LVEDD (-8.7 ± 9.9 mm vs -0.5 ± 5.0 and -2.4 ± 5.8 mm [P < .001 for both]) was greatest in super-responders. Kaplan-Meier survival analysis revealed that super-responders achieved better survival compared with non-/modest- (P < .001) and moderate-responders (P = .049).

CONCLUSIONS

Improvement in HF symptoms and survival after CRT is proportionate to the degree of improvement in LV systolic function. Super-response is more likely in women, those with nonischemic substrate, and those with lower pulmonary artery systolic pressure.

The influence of left ventricular ejection fraction on the effectiveness of cardiac resynchronization therapy: MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy)

OBJECTIVES

The aim of this study was to evaluate the relationship between left ventricular (LV) ejection fraction and clinical outcome to cardiac resynchronization therapy (CRT) in mild heart failure patients enrolled in MADIT-CRT [corrected].

BACKGROUND

Left ventricular ejection fraction (LVEF) is a surrogate marker of heart failure (HF) status and associated risk. Data on the effectiveness of cardiac resynchronization therapy with defibrillator (CRT-D) in patients with mild HF and better LVEF are limited.

METHODS

In the MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy) study, the echocardiography core laboratory assessed baseline LVEF independent of the enrolling centers and identified a range of LVEFs, including those >30% (i.e., beyond the eligibility criteria). Echocardiographic response with CRT, defined as percent change in left ventricular end-diastolic volume (LVEDV), was analyzed in 3 prespecified LVEF groups: >30%, 26% to 30%, and ≤25%. The primary endpoint was HF or death. Secondary endpoint included all-cause mortality.

RESULTS

LVEF was evaluated in 1,809 study patients. There were 696 (38%) patients with LVEF >30% (in the range of 30.1% to 45.3%); 914 patients (50.5%) with LVEF 26% to 30%; and 199 patients with LVEF ≤25% (11%). The mean reduction in LVEDV with CRT-D therapy at the 1-year follow-up was directly related to increasing LVEF (LVEF >30%: 22.3%; LVEF 26% to 30%: 20.1%; and LVEF ≤25%: 18.7% reduction, respectively [p = 0.001]). CRT-D treatment similarly reduced the risk of HF/death in patients with LVEF >30% (hazard ratio [HR]: = 0.56 [95% confidence interval (CI): 0.39 to 0.82], p = 0.003), LVEF 26% to 30% (HR: 0.67: [95% CI: 0.50 to 0.90], p = 0.007), and LVEF ≤25% (HR: 0.57 [95% CI: 0.35 to 0.95], p = 0.03; all p values for LVEF-by-treatment interactions >0.1).

CONCLUSIONS

In MADIT-CRT, the clinical benefit of CRT was evident regardless of baseline LVEF, including those with LVEF >30%, whereas the echocardiographic response was increased with increasing LVEF, indicating that CRT might benefit patients with better LVEF. (Multicenter Automatic Defibrillator Implantation With Cardiac Resynchronization Therapy [MADIT-CRT]; NCT00180271).

Low-dose dobutamine test associated with interventricular dyssynchrony: a useful tool to identify cardiac resynchronization therapy responders: data from the LOw dose DObutamine stress-echo test in Cardiac Resynchronization Therapy (LODO-CRT) phase 2 study

BACKGROUND

Cardiac resynchronization therapy (CRT) is effective in patients with heart failure, but 30% to 50% of subjects are classified as nonresponders. Identifying responders remains a challenging task.

AIMS

The LODO-CRT trial investigated the association between left ventricular contractile reserve (LVCR) and clinical and echocardiographic long-term CRT response.

METHODS

This is a multicenter, prospective, observational study. Left ventricular contractile reserve was detected using a dobutamine stress echocardiography test, defined as an ejection fraction increase of >5 points. Clinical CRT response was defined as the absence of major cardiovascular events (ie, cardiovascular death or heart failure hospitalization). Echocardiographic response was defined as a left ventricle end-systolic volume reduction of >10%.

RESULTS

A total of 221 CRT-indicated patients were studied (80% presented LVCR). During a mean follow-up of 15 ± 5 months, 17 patients died and 16 were hospitalized due to heart failure. The proportion of clinical responders was 155 (88%) of 177 and 33 (75%) of 44 (P = .036) in the groups with and without LVCR, respectively. Kaplan-Meier analysis showed a significant difference in cardiac survival/hospitalization between patients with and without LVCR. The proportion of echocardiographic responders was 144 (87%) of 166 and 16 (42%) of 38 in the groups with and without LVCR (P < .001), respectively; LVCR showed 90% sensitivity and 87% positive predictive value to prefigure echocardiographic CRT responders. Multivariable analysis identified LVCR and interventricular dyssynchrony as independent predictors of CRT response. The concomitant presence of both factors showed 99% specificity and 83% sensitivity in detecting responders.

CONCLUSION

The presence of LVCR helps in predicting a clinical and echocardiographic CRT response. Concomitant assessment of LVCR and interventricular dyssynchrony accurately stratifies responder and nonresponder patients.

Cardiac resynchronisation therapy response predicts occurrence of atrial fibrillation in non-ischaemic dilated cardiomyopathy

AIM

The aim of this study was to determine whether or not cardiac resynchronization therapy (CRT) has a favourable effect on the incidence of new-onset atrial fibrillation (AF) in a homogeneous population of patients with non-ischaemic idiopathic-dilated cardiomyopathy and severe heart failure.

METHODS

We designed a single-centre prospective study and enrolled 58 patients AF naïve when received CRT. After 1 year of follow-up our population was subdivided into responders (72.4%) and non-responders (27.6%), so as to compare the incidence of AF after 1, 2 and 3 years of follow-up in these two groups.

RESULTS

Already after 1 year, there was a significant (p < 0.05) difference in new-onset AF in non-responder patients with respect to responders (18.2% vs. 3.3%). These data were confirmed at 2 years (33.3% vs. 12.2%) and 3 years (50.0% vs. 15.0%) follow-up. In particular, 3 years after device implantation non-responders had an increased risk to develop new-onset AF (OR = 5.67).

CONCLUSIONS

This is the first study analysing long-term effects of CRT in a homogeneous population of patients with non-ischaemic dilated cardiomyopathy, indicating the favourable role of this non-pharmacological therapy on the prevention of AF.

Predictors for restoration of normal left ventricular function in response to cardiac resynchronization therapy measured at time of implantation

There are no parameters predicting the individual probability of "full response" to cardiac resynchronization therapy (CRT). The aim of this work was to find prognostic factors of full clinical and echocardiographic responses (i.e., ≥50% left ventricular ejection fraction [LVEF] and New York Heart Association class I) after 1 year of CRT. This was a prospective follow-up study that involved 2 hospitals. Patients (n = 75) with advanced heart failure (64 ± 9 years of age, 87% men, LVEF 24 ± 7%) who received CRT were followed for 17 ± 9 months. Univariate and multivariate regression analyses were used to identify predictors of full CRT response. A nomogram predicting the individual probability of full CRT response during follow-up was calculated. There were 13 patients with restoration of normal LVEF versus 62 without (mean LVEF 56% ± 5% vs 31% ± 8%, respectively, p <0.001). Predictors of full response included cause of heart disease, baseline QRS width, and degree of QRS shortening in response to CRT. Patients with nonischemic heart disease, baseline QRS width ≤150 ms, and QRS shortening ≥40 ms in response to CRT had a >75% probability of restoration of normal LVEF. In conclusion, our nomogram using a combination of cause, baseline QRS width, and degree of QRS shortening in response to CRT allows assessment of individual probability of full response. This observation awaits further confirmation from larger series.

BIVentricular versus right ventricular antitachycardia pacing to terminate ventricular tachyarrhythmias in patients receiving cardiac resynchronization therapy: the ADVANCE CRT-D Trial

BACKGROUND

This multicenter, prospective, randomized, controlled, parallel trial compares the efficacy of biventricular (BIV) versus right ventricular (RV) antitachycardia pacing (ATP) in terminating all kinds of ventricular tachycardia (VT).

METHODS

Five hundred twenty-six patients implanted with a cardiac resynchronization therapy defibrillator (CRT-D) device were enrolled and randomized 1:1 to either BIV (266) or RV (260) ATP (single burst 8 pulse, 88% coupling interval) and were followed up for 12 months.

RESULTS

During 12 months' follow-up, 1,077 ventricular episodes in 180 patients were detected and classified: 634 true VTs divided into 69 ventricular fibrillation (VF) (11%), 202 fast ventricular tachycardia (FVT) (32%), and 363 VT (57%). A comparable first ATP efficacy (BIV 65% vs RV 68%, P = .59) was observed in FVT + VT, in VT zone (BIV 62% vs RV 71%, P = .25), and in FVT zone (BIV 71% vs RV 61%, P = .34). A trend toward lower accelerations during ATP applied to FVT was observed in the BIV group (3.5% BIV vs 10.2% RV, P = .163). No syncope/presyncope occurred during ATP for FVT in the BIV group versus 4 events (3.2%) in the RV group (P = .016). biventricular ATP was more effective in treating FVT in coronary artery disease (CAD) patients (P = .032), whereas both modalities presented similar efficacy in patients with non-CAD etiology (P = .549).

CONCLUSIONS

Antitachycardia pacing is effective in patients implanted with a CRT-D device. No significant differences in efficacy emerged between BIV- and RV-delivered ATP in the general population, whereas BIV ATP seems to present a safer profile in ischemic patients.

Identification and characterization of super-responders after cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) has been shown to induce a spectacular effect on left ventricular (LV) function in certain patients. Our aim was to analyze and characterize the super-responders (SRs) to CRT using echocardiography in 186 patients with a conventional indication according to the European Society Cardiology guidelines. The investigation took place before and 6 months after implantation. CRT-SRs were defined by an improvement of the New York Heart Association functional class and LV ejection fraction to > or = 50% in absolute values associated with a relative LV end-systolic volume reduction of > or = 15%. Of the 186 patients, 18 (9.7%) were identified as CRT-SRs and had a significantly lower prevalence of ischemic etiology (11%), lower LV dimensions, lower left atrial volume, and greater global longitudinal strain at baseline. Receiver operating characteristics curves identified global longitudinal strain as the strongest parameter for predicting CRT-SRs, with a cutoff value of -12% (area under the curve 0.87, sensitivity 71%, and specificity 85%, p <0.01). In conclusion, in the present retrospective study, only a left atrial volume <55 ml and global longitudinal strain < or = -12% were independent predictors of CRT-SRs.

Cardiac resynchronization therapy utilization for heart failure: findings from IMPROVE HF

BACKGROUND

Cardiac resynchronization therapy (CRT) has established efficacy for patients with systolic heart failure (HF). Treatment rates and factors associated with CRT utilization among eligible patients in outpatient cardiology practices have not been well studied.

METHODS

IMPROVE HF is a prospective cohort study designed to characterize current management of patients with chronic HF and left ventricular ejection fraction <or=35% in a registry of outpatient cardiology practices located throughout the United States. Baseline data were abstracted by trained chart review specialists from May 31, 2005, through June 22, 2007, for 15,381 patients attending 167 outpatient cardiology practices. Multivariable analyses of patient and practice characteristics identified predictors of CRT for eligible patients.

RESULTS

A total of 1,373 patients were eligible for CRT based on current guideline criteria, and 533 (38.8%) received a CRT device, with 84.1% of these treated with a CRT-defibrillator. Cardiac resynchronization therapy use varied widely among practices, with 11.1% at the 25th percentile and 53.4% at the 75th percentile. Patient age, insurance, longer QRS duration, and practice location were independently associated with higher CRT utilization rates among eligible patients, whereas sex, HF etiology, and other clinical and laboratory parameters were not.

CONCLUSIONS

Despite being evidence based and guideline recommended, CRT is underutilized in eligible patients with significant variations associated with age, insurance, QRS duration, and geographic location of practices. Practice-specific performance improvement initiatives may be needed to reduce variations in use of CRT for eligible patients.