Sex-Related Procedural Aspects and Complications in CRT Survey II: A Multicenter European Experience in 11,088 Patients

Electrical therapies in heart failure: Evolving technologies and indications

Device therapy for heart failure has rapidly evolved over 2 decades. The knowledge of indications, assessment lead and device technology has expanded to include CRT, leadless pacing and conduction system pacing such as His bundle and left bundle branch area pacing. But there is still a lack of evidence for these new technologies as well as for common indications such as atrial fibrillation and upgrading from a previous device. The role of personalized medicine will become increasingly important when selecting candidates for CRT, primary preventive ICD ablation procedures and emerging new devices such as cardiac contractility modulation (CCM). Rapidity of therapy is associated with outcome which will be a challenge. If properly implemented devices and drugs will have a large positive affect of HF outcomes.

Evolving Concepts in Cardiac Physiologic Pacing in the Era of Conduction System Pacing

Cardiac physiologic pacing (CPP) has become a well-established therapy for patients with cardiomyopathy (left ventricular ejection fraction <35%) in the presence of a left bundle branch block. In addition, CPP can be highly beneficial in patients with pacing-induced cardiomyopathy and patients with existing cardiomyopathy expected to have a right ventricular pacing burden of >40%. The benefits of CPP with traditional biventricular pacing are only realized if adequate resynchronization can be achieved. However, left ventricular lead implantation can be limited by individual anatomic variation within the coronary venous system and can be adversely affected by underlying abnormal myocardial substrate (i.e., scar tissue), especially if located within the basal lateral wall. In the last 7 years the investigation of conduction system pacing (CSP) and its potential salutary benefits are being realized and have led to a rapid evolution in the field of cardiac resynchronization pacing. However, supportive evidence for CSP for patients eligible for cardiac resynchronization remains limited compared with data available for biventricular cardiac resynchronization, mostly derived from leading CSP investigative centers. In this review, we perform an up-to-date comprehensive review of the available literature on CPP.

Quality improvement and the Rumsfeld Matrix

In this issue of the Journal, Chui and colleagues³ report on the results of a large retrospective observational study evaluating CRT-D utilization rates across hospitals, and the impact of this variation on mortality and readmission rates. The population included 30,134 guideline-eligible adult patients treated at 1,377 hospitals. Patients were identified using the National Cardiovascular Data Registry (NCDR) ICD registry with outcomes evaluated by linkage with Medicare claims data. The key findings include: (i) a wide variation in hospital rates of CRT-D utilization (range 0-100%), (ii) after adjustment of patient- and hospital-level characteristics, most of the variation in CRT-D utilization rates was attributable to the hospital in which the patient was receiving care (interclass correlation, 0.74), and (iii) a significant proportion of mortality and readmission were attributable to hospital variation in CRT utilization. Based on their findings, the authors suggest hospital rates of appropriate CRT-D implantation should be a be considered as a performance measure suitable for quality improvement, value-based care, and potentially public reporting.

Arrhythmias in Female Patients: Incidence, Presentation and Management

There is a growing appreciation for differences in epidemiology, treatment, and outcomes of cardiovascular conditions by sex. Historically, cardiovascular clinical trials have under-represented females, but findings have nonetheless been applied to clinical care in a sex-agnostic manner. Thus, much of the collective knowledge about sex-specific cardiovascular outcomes result from post hoc and secondary analyses. In some cases, these investigations have revealed important sex-based differences with implications for optimizing care for female patients with arrhythmias. This review explores the available evidence related to cardiac arrhythmia care among females, with emphasis on areas in which important sex differences are known or suggested. Considerations related to improving female enrollment in clinical trials as a way to establish more robust clinical evidence for the treatment of females are discussed. Areas of remaining evidence gaps are provided, and recommendations for areas of future research and specific action items are suggested. The overarching goal is to improve appreciation for sex-based differences in cardiac arrhythmia care as 1 component of a comprehensive plan to optimize arrhythmia care for all patients.

Left ventricular lead placement using inner guiding catheter alone in cardiac resynchronization therapy device implantation

BACKGROUND

Subselection inner catheters (Inner-Cath) are used adjunctively with outer guiding catheters (Outer-Cath) during cardiac resynchronization therapy (CRT) device implantation. This study aims to investigate the feasibility and efficacy of left ventricular lead placement (LV-LP) guided by Inner-Cath alone.

METHODS

A total of 74 patients undergoing de novo CRT implantation were investigated. LV-LP was initially guided by Inner-Cath in 42 patients (Inner-Cath group) and Outer-Cath in 32 patients (Outer-Cath group). In the Inner-Cath group, a 7Fr Inner-Cath was advanced to the coronary sinus through a 7 Fr sheath inserted in a subclavian vein. In the Outer-Cath group, 9Fr or 10Fr Outer-Caths were used. Success rate of LV-LP, additional use of inner or outer catheters and procedure-related complications were compared between groups.

RESULTS

LV-LP was successful in all patients in the Inner-Cath group, while LV-LP had to be abandoned in two patients (6.3%) of the Outer-Cath group due to CS perforation caused by Outer-Cath manipulation. Procedure time was significantly shorter in the Inner-Cath group (148 vs. 168 min; p = .024). Deployment of both an inner and outer cath became necessary less frequently for the Inner-Cath group (4.8% vs. 56.3%; p < .001). Mechanical CS injuries due to guiding catheter manipulation were only observed in the Outer-Cath group (0% vs. 15.6%, p = .013).

CONCLUSION

LV-LP guided by Inner-Cath alone was feasible in over 95% of the patients without severe complications. This methodology for LV-LP may be preferable in CRT candidates with severe LV dysfunction in terms of shorter procedure time, smaller guiding sheath, and less procedure-related complications.

Cardiac resynchronization therapy with or without defibrillation: a long-standing debate

Cardiac resynchronization therapy (CRT) was shown to improve cardiac function, reduce heart failure hospitalizations, improve quality of life and prolong survival in patients with severe left ventricular dysfunction and intraventricular conduction disturbances, mainly left bundle branch block, on optimal medical therapy with ACE-inhibitors, β-blockers and mineralocorticoid receptor antagonists up-titrated to maximum tolerated evidence-based doses. CRT can be achieved by means of pacemaker systems (CRT-P) or devices with defibrillation capabilities (CRT-D). CRT-Ds offer an undoubted advantage in the prevention of arrhythmic death, but such an advantage may be of lesser degree in non-ischemic heart failure aetiologies. Moreover, the higher CRT-D hardware complexity compared to CRT-P may predispose to device/lead malfunctions and the higher current drainage may cause a shorter battery duration with consequent premature replacements and the well-known incremental complications. In a period of financial constraints, also device costs should be carefully evaluated, with recent reports suggesting that CRT-Ps may be favoured over CRT-Ds in patients with non-ischemic cardiomyopathy and no prior history of cardiac arrhythmias from a cost-effectiveness point of view. The choice between a CRT-P or a CRT-D device should be patient-tailored whenever straightforward defibrillator indications are not present. The Goldenberg score may facilitate this decision-making process in ambiguous settings. Age, comorbidities, kidney disease, atrial fibrillation, advanced functional class, inappropriate therapy risk, implantable device infections and malfunctions are factors potentially reducing the expected benefit from defibrillating capabilities. Future prospective, randomized controlled trials are warranted to directly compare the efficacy and safety of CRT-Ps and CRT-Ds.

Sex-Specific Patterns of Mortality Predictors Among Patients Undergoing Cardiac Resynchronization Therapy: A Machine Learning Approach

Background: The relative importance of variables explaining sex-related differences in outcomes is scarcely explored in patients undergoing cardiac resynchronization therapy (CRT). We sought to implement and evaluate machine learning (ML) algorithms for the prediction of 1- and 3-year all-cause mortality in CRT patients. We also aimed to assess the sex-specific differences in predictors of mortality utilizing ML. Methods: Using a retrospective registry of 2,191 CRT patients, ML models were implemented in 6 partially overlapping patient subsets (all patients, females, or males with 1- or 3-year follow-up). Each cohort was randomly split into training (80%) and test sets (20%). After hyperparameter tuning in the training sets, the best performing algorithm was evaluated in the test sets. Model discrimination was quantified using the area under the receiver-operating characteristic curves (AUC). The most important predictors were identified using the permutation feature importances method. Results: Conditional inference random forest exhibited the best performance with AUCs of 0.728 (0.645-0.802) and 0.732 (0.681-0.784) for the prediction of 1- and 3-year mortality, respectively. Etiology of heart failure, NYHA class, left ventricular ejection fraction, and QRS morphology had higher predictive power, whereas hemoglobin was less important in females compared to males. The importance of atrial fibrillation and age increased, while the importance of serum creatinine decreased from 1- to 3-year follow-up in both sexes. Conclusions: Using ML techniques in combination with easily obtainable clinical features, our models effectively predicted 1- and 3-year all-cause mortality in CRT patients. Sex-specific patterns of predictors were identified, showing a dynamic variation over time.