Left Ventricular Stimulation With Electrical Latency Predicts Mortality in Patients Undergoing Cardiac Resynchronization Therapy

Clinical Usefulness of the Active Fixation Quadripolar Left Ventricular Lead Compared With the Passive Fixation Quadripolar Lead in Cardiac Resynchronization Therapy

BACKGROUND

This study compared the stability of the Medtronic Attain Stability Quad (ASQ), a novel quadripolar active fixation left ventricular (LV) lead with a side helix, to that of conventional quadripolar leads with passive fixation (non-ASQ) and evaluated their LV lead performance.

METHODS AND RESULTS

In all, 183 consecutive patients (69 ASQ, 114 non-ASQ) who underwent cardiac resynchronization therapy (CRT) between January 2018 and June 2021 were enrolled. Complications, including elevated pacing capture threshold (PCT) levels, phrenic nerve stimulation (PNS), and LV lead dislodgement, were analyzed during the postimplantation period until the first outpatient visit after discharge. The frequency of LV lead-related complications was significantly lower in the ASQ than non-ASQ group (14% vs. 30%, respectively; P=0.019). Specifically, LV lead dislodgement occurred only in the non-ASQ group, and elevated PCT levels were significantly lower in the ASQ group (7% vs. 23%; P=0.007). Kaplan-Meier analysis confirmed a significantly lower incidence of LV lead-related complications in the ASQ group (log-rank P=0.005). Cox multivariable regression analysis showed a significant reduction in lead-related complications associated with ASQ (hazard ratio 0.44; 95% confidence interval 0.23-0.83; P=0.011).

CONCLUSIONS

The ASQ group exhibited fewer LV lead-related complications requiring reintervention and setting changes than the non-ASQ group. Thus, the ASQ may be a favorable choice for CRT device implantation.

Impact of Q wave in synthesized V7-9 lead on long-term outcomes after cardiac resynchronization therapy

BACKGROUND

To investigate the relationship between the Q wave in synthesized V7-9 leads of a baseline electrocardiogram and clinical outcomes in patients with heart failure after cardiac resynchronization therapy (CRT) device implantation.

METHODS

Consecutive patients with heart failure and a left ventricular (LV) ejection fraction <35 % were retrospectively analyzed. Patients with Q waves in the synthesized V7-9 lead were defined as the qV7-9 group and those without Q waves in the synthesized V7-9 lead were defined as the non-qV7-9 group. Multivariate analysis was performed to compare all-cause mortality and incidence of hospitalization for heart failure between the two groups.

RESULTS

We included 108 eligible patients. Twenty-nine patients were classified into the qV7-9 group and 79 patients were classified into the non-qV7-9 group. There were 22 patients (20 %) with ischemic etiology, 67 (62 %) with New York Heart Association functional class II or III heart failure, and 91 (84 %) with a defibrillator. The presence of Q waves in the synthesized V7-9 lead was significantly associated with worse outcomes, even with optimal medical treatment (adjusted hazard ratio, 2.1; 95 % confidence interval, 1.16-3.72; p = 0.03).

CONCLUSION

In patients with heart failure and an LV ejection fraction of <35 %, the presence of Q waves in the synthetic V7-9 lead was associated with increased all-cause mortality and incidence of hospitalization after CRT device implantation.

Fixed complex electrograms during sinus rhythm and local pacing: potential ablation targets for persistent atrial fibrillation

In atrial fibrillation (AF) patients, complex electrograms during sinus rhythm (C-EGMs) could be pathological or not. We aimed to demonstrate whether local pacing was helpful to discern pathological C-EGMs. 126 persistent AF patients and 27 patients with left-side accessory pathway (LAP) underwent left atrial mapping during sinus rhythm. If C-EGMs were detected, local pacing was performed. If the electrograms turned normal, we defined them as non-fixed C-EGMs, otherwise as fixed C-EGMs. No difference was detected in the incidence and proportion of non-fixed C-EGMs between AF patients and LAP patients (101/126 vs. 19/27, P = 0.26; 9.1 ± 6.0% vs. 7.7 ± 5.7%, P = 0.28). However, the incidence and proportion of fixed C-EGMs were higher in persistent AF patients (87/126 vs. 1/27, P < 0.01; 4.3 ± 3.4% vs. 0.1 ± 0.5%, P < 0.01). Compared with non-fixed C-EGMs, fixed C-EGMs had lower amplitudes, longer electrogram durations and longer Stimuli-P wave internals. All AF patients received circumferential pulmonary vein isolation. Among AF patients with fixed C-EGMs, 45 patients received fixed C-EGMs ablation and 42 patients underwent linear ablation. Compared with linear ablation, fixed C-EGMs ablation reduced recurrence (HR: 0.43; 95% CI 0.21‐0.81; P = 0.011). Among patients without fixed C-EGMs ablation, the proportion of fixed C-EGMs was an independent predictor of ablation outcomes (HR for per percent: 1.13, 95% CI 1.01–1.28, P = 0.038). C-EGMs could be classified into fixed and non-fixed C-EGMs through local pacing. Fixed rather than non-fixed C-EGMs might indicate abnormal atrial substrates and fixed C-EGMs ablation improve outcomes of persistent AF ablation.

Optimizing lead placement for pacing in dyssynchronous heart failure: The patient in the lead

Cardiac resynchronization therapy (CRT) greatly reduces morbidity and mortality in patients with dyssynchronous heart failure. However, despite tremendous efforts, response has been variable and can be further improved. Although optimizing left ventricular lead placement (LVLP) is arguably the cornerstone of CRT, the procedure of LVLP using the transvenous approach has remained largely unchanged for more than 2 decades. Improvements have been developed using scar location and electrical and/or mechanical mapping, and interest in conduction system pacing as an alternative to biventricular pacing has emerged recently. Conduction system pacing is promising but may not be suitable for all patients with dyssynchronous heart failure. This review underscores the importance of a patient-tailored approach and discusses the potential applications of both conduction system pacing and targeted biventricular CRT.