Evaluation of left ventricular dyssynchrony by ultra-high-frequency ECG in patients with non-LBBB conduction disorder treated with cardiac resynchronization therapy

Funding Acknowledgements

Type of funding sources: None.

Introduction

LBBB is a reliable left ventricular (LV) electrical dyssynchrony indicator. Patients with RBBB/IVCD are a heterogeneous group, where even with "larger" QRS complex expansion, LV dyssynchrony may not be present. Ultra-high-frequency (UHF) 14-lead ECG is a non-invasive method based on signal averaging that allows better assessment of local electrical activation of the ventricles than standard ECG. Our study aims to test the hypothesis of the usefulness of UHF ECG to select non-LBBB patients for cardiac resynchronization therapy (CRT) based on evidence of electrical dyssynchrony.

Methods

Using UHF ECG we analysed patients who underwent CRT implantation. The groups of patients with RBBB, IVCD, and LBBB were compared and the presence of electrical dyssynchrony (e-DYS) as a parameter of global ventricular activation, and delayed activation of the left ventricular lateral wall (LVLWd) as a marker of LV intravenricular dyssynchrony was assessed.

Results

UHF ECG was recorded in 49 patients treated with CRT. IVCD patients had lower e-DYS compared to LBBB patients (26±17 ms vs. 86±20 ms; p<0.0001) and lower LVLWd (26±16 ms vs. 83±22 ms; p<0.0001). In RBBB patients, e-DYS was -52±22 ms, corresponding to right ventricular delay. Delayed left ventricular free wall activation ("RBBB masking LBBB" activation pattern) was not found in any RBBB patient.

Conclusion

UHF ECG appears to be a promising tool to detect LV electrical dyssynchrony in non-LBBB candidates for cardiac resynchronization therapy. Delayed left ventricular free wall activation was not found in any RBBB patient. Our findings are consistent with the lack of effect of CRT in this group of patients.

Long-Term Impact of Body Mass Index on Survival of Patients Undergoing Cardiac Resynchronization Therapy: A Multi-Centre Study

Obesity is a risk factor for heart failure (HF), but its presence among HF patients may be associated with favorable outcomes. We investigated the long-term outcomes across different body mass index (BMI) groups, after cardiac resynchronization therapy (CRT), and whether defibrillator back-up (CRT-D) confers survival benefit. One thousand two-hundred seventy-seven (1,277) consecutive patients (mean age: 67.0 ± 12.7 years, 44.1% women, and mean BMI: 28.3 ± 5.6 Kg/m²) who underwent CRT implantation in 5 centers between 2000-2014 were followed-up for a median period of 4.9 years (IQR 2.4 to 7.5). More than 10% of patients had follow-up for ≥10 years. Patients were classified according to BMI as normal: <25.0 Kg/m², overweight: 25.0 to 29.9 Kg/m² and obese: ≥30.0 Kg/m². 364 patients had normal weight, 494 were overweight and 419 were obese. CRT-Ds were implanted in >75% of patients, but were used less frequently in obese individuals. The composite endpoint of all-cause mortality or cardiac transplant/left ventricular assist device (LVAD) occurred in 50.9% of patients. At 10-year follow-up, less than a quarter of patients in the lowest and highest BMI categories were still alive and free from heart transplant/LVAD. After adjustment BMI of 25 to 29.9 Kg/m² (HR = 0.73 [95%CI 0.56 to 0.96], p = 0.023) and use of CRT-D (HR = 0.74 [95% CI 0.55 to 0.98], p = 0.039) were independent predictors of survival free from LVAD/heart transplant. BMI of 25 to 29.9 Kg/m² at the time of implant was independently associated with favourable long-term 10-year survival. Use of CRT-D was associated with improved survival irrespective of BMI class.

Cardiac Resynchronization and Defibrillator Therapy (CRT-D) or CRT Alone (CRT-P) in patients with dilated cardiomyopathy and heart failure without late gadolinium enhancement (LGE) cardiac magnetic resonance imaging (CMRI) high-risk markers - CRT-REALITY study - Study design and rationale

BACKGROUND

Primary preventive implantation of implantable defibrillator (ICD) is according to current guidelines indicated in patients with heart failure NYHA (New York Heart Association) class II/III and LVEF <35%. Thanks to advances in heart failure pharmacotherapy, a decrease in mortality could render a benefit of ICD insufficient to justify its implantation in some patients.

METHODS

Study design: multicenter, prospective, randomized, controlled trial evaluating the benefit of implantation of Cardiac Resynchronization and Defibrillator Therapy (CRT-D) or CRT Alone (CRT-P) in non-ischemic patients with reduced left ventricle ejection fraction (LVEF) and optimal pharmacotherapy without significant mid-wall myocardial fibrosis detected by cardiac magnetic resonance (CMR). The primary end-point: Re-hospitalization for heart failure, ventricular tachycardia, major adverse cardiac events (MACE). The secondary end-points: Sudden cardiac death, cardiovascular death, resuscitated cardiac arrest or sustained ventricular tachycardia, device-related complications, and change in quality of life. Course of the study: After a pharmacotherapy is optimized and significant mid-wall myocardial fibrosis excluded, patients will be randomized 1:1 to CRT-P or CRT-D implantation.

DISCUSSION

If our hypothesis is confirmed, this could provide evidence for the management of these patients with a significant impact on common daily praxis and health care expenditures.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04139460.

Gender-specific risk of complications in catheter ablation for atrial fibrillation

Background

Catheter ablation is an established treatment modality for atrial fibrillation (AF). The risk of procedural complications is not negligible. Some studies suggested that female patients have a higher risk of complications.

Purpose

To identify gender-specific predictors of major complications (MCs) in patients undergoing catheter ablation for AF in a tertiary ablation centre.

Methods

A total of 4733 catheter ablations for AF (65% paroxysmal, 26% repeated procedures) were performed at our centre between January 2006 and August 2018. Patients (71% males) aged 60±10 years and had body mass index of 29±4 kg/m2 at the time of the procedure. Radiofrequency point-by-point ablation was employed in 96.3% procedures with the use of 3D navigation systems and facilitated by intracardiac echocardiography. Pulmonary vein isolation was mandatory; cavotricuspid isthmus and left atrial substrate ablation were performed in 22% and 38% procedures, respectively. MCs were defined as those that resulted in permanent injury, required intervention or prolonged hospitalization. Variables were assessed by uni- and multivariate analysis, two-sided α&lt;0.05 was considered significant.

Results

A total of 160 (3.4%) MCs were detected - 60 (4.4%) in females and 100 (2.9%) in males (P=0.012). Both lower body height and the presence of bundle branch block (BBB) were associated with MCs only in females; for left bundle branch block (LBBB), the effect size was higher. On the contrary, higher left ventricular end-diastolic diameter (LVEDd) and persistent AF were associated with MCs in males (Table).

Conclusion

Females have a higher risk of MCs during catheter ablation for AF. Body height, AF type, BBB, and LVEDd may belong among gender-specific risk factors for MCs in AF ablation procedures. Whether BBB and LVEDd represent true risk factors warrants a validation in further studies.

Funding Acknowledgement

Type of funding source: None

P1462Incidence of ventricular arrhythmias in cardiac resynchronization therapy and implantable cardioverter-defibrillator patients

Introduction

Implantation of a cardiac resynchronization therapy combined with cardioverter-defibrillator (CRT-D) is now common practice. Our study looked at the occurrence of the first adequate CRT-D therapy with respect to gender, treatment indication (primary or secondary prevention of sudden cardiac death) and the etiology of heart failure in long-term follow-up.

Methods

In the database of CRT-D patients implanted between 2005 and 2013 we analyzed the occurrence of treated episodes of ventricular arrhythmia (first shock or anti-tachycardic pacing).

Results

250 patients (22.8% females) with left bundle branch block or non-specific interventricular conduction delay were enrolled. 80% of patients were implanted in the primary and 20% in the secondary prevention of sudden cardiac death. During the follow-up of 5.5 ± 2.5 years, 46.4% of patients died for cardiac (25.6%) or non-cardiac (20.8%) reasons. CRT-D therapy occurred in 33.2% of patients (20.8% shock). In patients implanted in the primary prevention of sudden cardiac death the incidence of therapies was 25.5% vs. 64.0% in patients implanted in the secondary prevention of sudden cardiac death (P˂0.00001). The incidence of therapies between the group of patients with coronary artery disease and other causes of heart failure did not differ (33.3% vs. 32.9%, P = NS). Women were at a significantly lower risk of adequate shock (women 10.5% vs. men 23.8%, P = 0.01).

Conclusion

Adequate CRT-D therapy occurred in a quarter of patients implanted in the primary prevention of sudden cardiac death. In patients implanted in the secondary prevention of sudden cardiac death the incidence of therapies is significantly more frequent. The female gender predicts significantly lower incidence of adequate shock.

Abstract Figure. Adequate shock therapy

Combination of left ventricular reverse remodeling and brain natriuretic peptide level at one year after cardiac resynchronization therapy predicts long-term clinical outcome

Introduction

The aim of this study was to investigate the predictors of long-term clinical outcome of heart failure (HF) patients who survived first year after initiation of cardiac resynchronization therapy (CRT).

Methods

This was a single-center observational cohort study of CRT patients implanted because of symptomatic HF with reduced ejection fraction between 2005 and 2013. Left ventricle (LV) diameters and ejection fraction, New York Heart Association (NYHA) class, and level of N-terminal fragment of pro-brain natriuretic peptide (NT-proBNP) were assessed at baseline and 12 months after CRT implantation. Their predictive power for long-term HF hospitalization and mortality, and cardiac and all-cause mortality was investigated.

Results

A total of 315 patients with left bundle branch block or intraventricular conduction delay who survived >1 year after CRT implantation were analyzed in the current study. During a follow-up period of 4.8±2.1 years from CRT implantation, 35.2% patients died from cardiac (19.3%) or non-cardiac (15.9%) causes. Post-CRT LV ejection fraction and LV end-systolic diameter (either 12-month value or the change from baseline) were equally predictive for clinical events. For NT-proBNP, however, the 12-month level was a stronger predictor than the change from baseline. Both reverse LV remodeling and 12-month level of NT-proBNP were independent and comparable predictors of CRT-related clinical outcome, while NT-proBNP response had the strongest association with all-cause mortality. When post-CRT relative change of LV end-systolic diameter and 12-month level of NT-proBNP (dichotomized at -12.3% and 1230 ng/L, respectively) were combined, subgroups of very-high and very-low risk patients were identified.

Conclusion

The level of NT-proBNP and reverse LV remodeling at one year after CRT are independent and complementary predictors of future clinical events. Their combination may help to improve the risk stratification of CRT patients.

Very long-term survival and late sudden cardiac death in cardiac resynchronization therapy patients

AIMS

The very long-term outcome of patients who survive the first few years after receiving cardiac resynchronization therapy (CRT) has not been well described thus far. We aimed to provide long-term outcomes, especially with regard to the occurrence of sudden cardiac death (SCD), in CRT patients without (CRT-P) and with defibrillator (CRT-D).

METHODS AND RESULTS

A total of 1775 patients, with ischaemic or non-ischaemic dilated cardiomyopathy, who were alive 5 years after CRT implantation, were enrolled in this multicentre European observational cohort study. Overall long-term mortality rates and specific causes of death were assessed, with a focus on late SCD. Over a mean follow-up of 30 months (interquartile range 10-42 months) beyond the first 5 years, we observed 473 deaths. The annual age-standardized mortality rates of CRT-D and CRT-P patients were 40.4 [95% confidence interval (CI) 35.3-45.5] and 97.2 (95% CI 85.5-109.9) per 1000 patient-years, respectively. The adjusted hazard ratio (HR) for all-cause mortality was 0.99 (95% CI 0.79-1.22). Twenty-nine patients in total died of late SCD (14 with CRT-P, 15 with CRT-D), corresponding to 6.1% of all causes of death in both device groups. Specific annual SCD rates were 8.5 and 5.8 per 1000 patient-years in CRT-P and CRT-D patients, respectively, with no significant difference between groups (adjusted HR 1.0, 95% CI 0.45-2.44). Death due to progressive heart failure represented the principal cause of death (42.8% in CRT-P patients and 52.6% among CRT-D recipients), whereas approximately one-third of deaths in both device groups were due to non-cardiovascular death.

CONCLUSION

In this first description of very long-term outcomes among CRT recipients, progressive heart failure death still represented the most frequent cause of death in patients surviving the first 5 years after CRT implant. In contrast, SCD represents a very low proportion of late mortality irrespective of the presence of a defibrillator.

Very long-term survival and late sudden cardiac death in cardiac resynchronization therapy patients

Aims

The very long-term outcome of patients who survive the first few years after receiving cardiac resynchronization therapy (CRT) has not been well described thus far. We aimed to provide long-term outcomes, especially with regard to the occurrence of sudden cardiac death (SCD), in CRT patients without (CRT-P) and with defibrillator (CRT-D).

Methods and results

A total of 1775 patients, with ischaemic or non-ischaemic dilated cardiomyopathy, who were alive 5 years after CRT implantation, were enrolled in this multicentre European observational cohort study. Overall long-term mortality rates and specific causes of death were assessed, with a focus on late SCD. Over a mean follow-up of 30 months (interquartile range 10–42 months) beyond the first 5 years, we observed 473 deaths. The annual age-standardized mortality rates of CRT-D and CRT-P patients were 40.4 [95% confidence interval (CI) 35.3–45.5] and 97.2 (95% CI 85.5–109.9) per 1000 patient-years, respectively. The adjusted hazard ratio (HR) for all-cause mortality was 0.99 (95% CI 0.79–1.22). Twenty-nine patients in total died of late SCD (14 with CRT-P, 15 with CRT-D), corresponding to 6.1% of all causes of death in both device groups. Specific annual SCD rates were 8.5 and 5.8 per 1000 patient-years in CRT-P and CRT-D patients, respectively, with no significant difference between groups (adjusted HR 1.0, 95% CI 0.45–2.44). Death due to progressive heart failure represented the principal cause of death (42.8% in CRT-P patients and 52.6% among CRT-D recipients), whereas approximately one-third of deaths in both device groups were due to non-cardiovascular death.

Conclusion

In this first description of very long-term outcomes among CRT recipients, progressive heart failure death still represented the most frequent cause of death in patients surviving the first 5 years after CRT implant. In contrast, SCD represents a very low proportion of late mortality irrespective of the presence of a defibrillator.

High-density epicardial activation mapping to optimize the site for video-thoracoscopic left ventricular lead implant

Background

The left ventricular (LV) lead local electrogram (EGM) delay from the beginning of the QRS complex (QLV) is considered a strong predictor of response to cardiac resynchronization therapy. We have developed a method for fast epicardial QLV mapping during video-thoracoscopic surgery to guide LV lead placement.

Methods

A three-port, video-thoracoscopic approach was used for LV free wall epicardial mapping and lead implantation. A decapolar electrophysiological catheter was introduced through one port and systematically attached to multiple accessible LV sites. The pacing lead was targeted to the site with maximum QLV. The LV free wall activation pattern was analyzed in 16 pre-specified anatomical segments.

Results

We implanted LV leads in 13 patients with LBBB or IVCD. The procedural and mapping times were 142 ± 39 minutes and 20 ± 9 minutes, respectively. A total of 15.0 ± 2.2 LV segments were mappable with variable spatial distribution of QLV-optimum. The QLV ratio (QLV/QRSd) at the optimum segment was significantly higher (by 0.17 ± 0.08, p < 0.00001) as compared to an empirical midventricular lateral segment. The LV lead was implanted at the optimum segment in 11 patients (at an adjacent segment in 2 patients) achieving a QLV ratio of 0.82 ± 0.09 (range 0.63–0.93) and 99.5 ± 0.6% match with intraprocedural mapping.

Conclusion

Video-thoracoscopic LV lead implantation can be effectively and safely guided by epicardial QLV mapping. This strategy was highly successful in targeting the selected LV segment and resulted in significantly higher QLV ratios compared to an empirical midventricular lateral segment.

Serum preadipocyte factor-1 concentrations in females with obesity and type 2 diabetes mellitus: the influence of very low calorie diet, acute hyperinsulinemia, and fenofibrate treatment

Appropriate differentiation capacity of adipose tissue significantly affects its ability to store lipids and to protect nonadipose tissues against lipid spillover and development of insulin resistance. Preadipocyte factor-1 (Pref-1) is an important negative regulator of preadipocyte differentiation. The aim of our study was to explore the changes in circulating Pref-1 concentrations in female subjects with obesity (OB) (n=19), females with obesity and type 2 diabetes mellitus (T2DM) (n=22), and sex- and age-matched healthy control subjects (C) (n=22), and to study its modulation by very low calorie diet (VLCD), acute hyperinsulinemia during isoglycemic-hyperinsulinemic clamp, and 3 months' treatment with PPAR-α agonist fenofibrate. At baseline, serum Pref-1 concentrations were significantly higher in patients with T2DM compared to control group, while only nonsignificant trend towards higher levels was observed in OB group. 3 weeks of VLCD decreased Pref-1 levels in both OB and T2DM group, whereas 3 months of fenofibrate treatment had no significant effect. Hyperinsulinemia during the clamp significantly suppressed Pref-1 levels in both C and T2DM subjects and this suppression was unaffected by fenofibrate treatment. In a combined population of all groups, circulating Pref-1 levels correlated positively with insulin, leptin and glucose levels and HOMA (homeostasis model assessment) index. We conclude that elevated Pref-1 concentrations in T2DM subjects may contribute to impaired adipose tissue differentiation capacity associated with insulin resistance in obese patients with T2DM. The decrease of Pref-1 levels after VLCD may be involved in the improvement of metabolic status and the amelioration of insulin resistance in T2DM patients.

Local electrogram delay recorded from left ventricular lead at implant predicts response to cardiac resynchronization therapy: retrospective study with 1 year follow up

Background

Considerable proportion of patients does not respond to the cardiac resynchronization therapy (CRT). This study investigated clinical relevance of left ventricular electrode local electrogram delay from the beginning of QRS (QLV). We hypothesized that longer QLV indicating more optimal lead placement in the late activated regions is associated with the higher probability of positive CRT response.

Methods

We conducted a retrospective, single–centre analysis of 161 consecutive patients with heart failure and LBBB or nonspecific intraventricular conduction delay (IVCD) treated with CRT. We routinely intend to implant the LV lead in a region with long QLV. Clinical response to CRT, left ventricular (LV) reverse remodelling (i.e. decrease in LV end-systolic diameter - LVESD ≥10%) and reduction in plasma level of NT-proBNP >30% at 12-month post-implant were the study endpoints. We analyzed association between pre-implant variables and the study endpoints.

Results

Clinical CRT response rate reached 58%, 84% and 92% in the lowest (≤105 ms), middle (106-130 ms) and the highest (>130 ms) QLV tertile (p < 0.0001), respectively. Longer QRS duration (p = 0.002), smaller LVESD and a non-ischemic cardiomyopathy (both p = 0.02) were also univariately associated with positive clinical CRT response. In a multivariate analysis, QLV remained the strongest predictor of clinical CRT response (p < 0.00001), followed by LVESD (p = 0.01) and etiology of LV dysfunction (p = 0.04). Comparable predictive power of QLV for LV reverse remodelling and NT-proBNP response rates was observed.

Conclusion

LV lead position assessed by duration of the QLV interval was found the strongest independent predictor of beneficial clinical response to CRT.

Blood glucose control by a model predictive control algorithm with variable sampling rate versus a routine glucose management protocol in cardiac surgery patients: a randomized controlled trial

CONTEXT

Elevated blood glucose levels occur frequently in the critically ill. Tight glucose control by intensive insulin treatment markedly improves clinical outcome.

OBJECTIVE AND DESIGN

This is a randomized controlled trial comparing blood glucose control by a laptop-based model predictive control algorithm with a variable sampling rate [enhanced model predictive control (eMPC); version 1.04.03] against a routine glucose management protocol (RMP) during the peri- and postoperative periods.

SETTING

The study was performed at the Department of Cardiac Surgery, University Hospital.

PATIENTS

A total of 60 elective cardiac surgery patients were included in the study.

INTERVENTIONS

Elective cardiac surgery and treatment with continuous insulin infusion (eMPC) or continuous insulin infusion combined with iv insulin boluses (RMP) to maintain euglycemia (target range 4.4-6.1 mmol/liter) were performed. There were 30 patients randomized for eMPC and 30 for RMP treatment. Blood glucose was measured in 1- to 4-h intervals as requested by each algorithm during surgery and postoperatively over 24 h.

MAIN OUTCOME MEASURES

Mean blood glucose, percentage of time in target range, and hypoglycemia events were used.

RESULTS

Mean blood glucose was 6.2 +/- 1.1 mmol/liter in the eMPC vs. 7.2 +/- 1.1 mmol/liter in the RMP group (P < 0.05); percentage of time in the target range was 60.4 +/- 22.8% for the eMPC vs. 27.5 +/- 16.2% for the RMP group (P < 0.05). No severe hypoglycemia (blood glucose < 2.9 mmol/liter) occurred during the study. Mean insulin infusion rate was 4.7 +/- 3.3 IU/h in the eMPC vs. 2.6 +/- 1.7 IU/h in the RMP group (P < 0.05). Mean sampling interval was 1.5 +/- 0.3 h in the eMPC vs. 2.1 +/- 0.2 h in the RMP group (P < 0.05).

CONCLUSIONS

Compared with RMP, the eMPC algorithm was more effective and comparably safe in maintaining euglycemia in cardiac surgery patients.