Atrial antitachycardia pacing and atrial remodeling: A substudy of the international, randomized MINERVA trial

Pacemaker-induced atrial fibrillation reconsidered-associations with different pacing sites and prevention approaches

The incidence of atrial fibrillation (AF) is significantly higher in patients with pacemakers than in the general population, which could be due to patient characteristics and the diagnostic tool of the pacemaker in detecting atrial high-rate episodes and subclinical AF, but also to the pacemaker itself providing AF-promoting conditions. It is well known that high ventricular pacemaker burden increases the likelihood of AF occurrence. However, the sites of atrial and ventricular pacing may also influence the risk for AF. The conventional sites for atrial and ventricular pacing are in the right atrial appendage and in the right ventricular apex. However, growing evidence suggests that alternative pacing sites may be superior for the prevention of AF. Bachmann bundle pacing, for example, promotes interatrial excitation conduction, resulting in atrial synchronicity and a shorter total atrial activation time, which may be preventive for the occurrence of AF. Moreover, in recent years, new ventricular pacing sites have come into focus with His bundle and left bundle branch pacing. In addition to the hemodynamic and electrophysiological cardiac benefits, these new options may also offer benefits in the prevention of AF. This review provides an overview of pacing-induced AF mechanisms and the association with different pacing sites, as well as approaches for prevention of pacing-induced AF, highlighting different sites and modes of atrial pacing and the newer sites of ventricular pacing.

Actual conditions of atrial septal lead implantation and the factors related to successful implantation

BACKGROUND

Pacemaker leads were originally implanted into the right atrial appendage (RAA) and right ventricular apex, but septal pacing, which is more physiological, is becoming increasingly popular. The usefulness of atrial lead implantation in the RAA or atrial septum is inconclusive, and whether or not atrial septum implantation is accurate has not yet been verified.

METHODS

Patients who underwent pacemaker implantation between January 2016 and December 2020 were included. The success rate of atrial septal implantation was validated using thoracic computed tomography performed for any reason postoperatively. We examined factors related to the successful implantation of the atrial lead in the atrial septum.

RESULTS

Forty-eight people were included in this study. Lead placement was performed with a delivery catheter system (SelectSecure MRI SureScan; Medtronic Japan Co., Ltd., Tokyo, Japan) in 29 cases and a conventional stylet in 19 cases. The mean age was 74 ± 12 years old, and 28 (58%) were male. Successful atrial septal implantation was performed in 26 patients (54%), with only 4 (21%) successful implantations in the stylet group. There were no significant differences in the age, gender, body mass index (BMI), pacing P wave axis, duration, or amplitude between the atrial septal implantation group and non-septal groups. The only significant difference was for delivery catheter use [22 (85%) vs. 7 (32%), p < 0.001]. In multivariate logistic analysis, the use of a delivery catheter was independently associated with successful septal implantation [odds ratio (OR): 16.9, 95% confidence interval 3.0-90.9] after adjusting for the age, gender, and BMI.

CONCLUSION

The success rate of atrial septal implantation was very low at 54%, and only the use of a delivery catheter was associated with successful septal implantation. However, even with a delivery catheter, the success rate was 76%, so further investigations are warranted.

Platelet-to-Lymphocyte Ratio as an Independent Factor Associated With Atrial Tachyarrhythmia

Objective To investigate the relationship between the presence of atrial tachyarrhythmia (AT) and the platelet-to-lymphocyte ratio (PLR), which is a recently described inflammatory marker. Methods A total of 149 patients with AT and 187 healthy volunteers were included in this study. Complete blood count, serum lipids, and serum creatinine were tested, and dynamic electrocardiograms were performed routinely in all subjects. Student's t-test, Mann-Whitney U test, logistic regression analysis, and receiver operating characteristic curve analysis were used for statistical analysis. Results In the AT group, the proportions of patients with diabetes, hypertension, and coronary heart disease were higher than those in the control group. Higher blood platelet, low-density lipoprotein, neutrophil-to-lymphocyte ratio, and PLR were detected in the AT group. In addition, haemoglobin, lymphocytes, and the fastest ventricular rate were significantly lower in the AT group. Higher PLR was identified as independently associated with the presence of AT. When a cut-off value of 119.47 was used, the sensitivity and specificity of PLR for predicting AT were 79.2% and 81.3%, respectively. Conclusion Elevated PLR was associated with AT, suggesting that it might be useful in the future as an adjunct biomarker for the detection of the disease.

Reactive atrial-based antitachycardia pacing therapy reduces atrial tachyarrhythmias

BACKGROUND

Reactive atrial-based antitachycardia pacing (rATP) aims to terminate atrial tachyarrhythmia/atrial fibrillation (AT/AF) episodes when they spontaneously organize to atrial flutter or atrial tachycardia; however, its effectiveness in the real-world has not been studied. We used a large device database (Medtronic CareLink, Medtronic, Minneapolis, MN, USA) to evaluate the effects of rATP at reducing AT/AF.

METHODS

Pacemaker, defibrillator, and resynchronization device transmission data were analyzed. Eligible patients had device detected AT/AF during a baseline period but were not in persistent AT/AF immediately preceding first transmission. Note that 1:1 individual matching between groups was conducted using age, sex, device type, pacing mode, AT/AF, and percent ventricular pacing at baseline. Risks of AT/AF events were compared between patients with rATP-enabled versus control patients with rATP-disabled or not available in the device. For matched patients, AT/AF event rates at 2 years were estimated by Kaplan-Meier method, and hazard ratios (HRs) were calculated by Cox proportional hazard models.

RESULTS

Of 43,440 qualifying patients, 4,203 had rATP on. Matching resulted in 4,016 pairs, totaling 8,032 patients for analysis. The rATP group experienced significantly lower risks of AT/AF events lasting ≥1 day (HR 0.81), ≥7 days (HR 0.64), and ≥30 days (HR 0.56) compared to control (P < 0.0001 for all). In subgroup analysis, rATP was associated with reduced risks of AT/AF events across age, sex, device type, baseline AT/AF, and preventive atrial pacing.

CONCLUSIONS

Among real-world patients from a large device database, rATP therapy was significantly associated with a reduced risk of AT/AF. This association was independent of whether the patient had a pacemaker, defibrillator, or resynchronization device.

EHRA White Paper: knowledge gaps in arrhythmia management—status 2019

Clinicians accept that there are many unknowns when we make diagnostic and therapeutic decisions. Acceptance of uncertainty is essential for the pursuit of the profession: bedside decisions must often be made on the basis of incomplete evidence. Over the years, physicians sometimes even do not realize anymore which the fundamental gaps in our knowledge are. As clinical scientists, however, we have to halt and consider what we do not know yet, and how we can move forward addressing those unknowns. The European Heart Rhythm Association (EHRA) believes that scanning the field of arrhythmia / cardiac electrophysiology to identify knowledge gaps which are not yet the subject of organized research, should be undertaken on a regular basis. Such a review (White Paper) should concentrate on research which is feasible, realistic, and clinically relevant, and should not deal with futuristic aspirations. It fits with the EHRA mission that these White Papers should be shared on a global basis in order to foster collaborative and needed research which will ultimately lead to better care for our patients. The present EHRA White Paper summarizes knowledge gaps in the management of atrial fibrillation, ventricular tachycardia/sudden death and heart failure.

Technology Advances to Improve Response to Cardiac Resynchronization Therapy: What Clinicians Should Know

Cardiac resynchronization therapy (CRT) is a well-established treatment for symptomatic heart failure patients with reduced left ventricular ejection fraction, prolonged QRS duration, and abnormal QRS morphology. The ultimate goals of modern CRT are to improve the proportion of patients responding to CRT and to maximize the response to CRT in patients who do respond. While the rate of CRT nonresponders has moderately but progressively decreased over the last 20 years, mostly in patients with left bundle branch block, in patients without left bundle branch block the response rate is almost unchanged. A number of technological advances have already contributed to achieve some of the objectives of modern CRT. They include novel lead design (the left ventricular quadripolar lead, and multipoint pacing), or the possibility to go beyond conventional delivery of CRT (left ventricular endocardial pacing, His bundle pacing). Furthermore, to improve CRT response, a triad of actions is paramount: reducing the burden of atrial fibrillation, reducing the number of appropriate and inappropriate interventions, and adequately predicting heart failure episodes. As in other fields of cardiology, technology and innovations for CRT delivery have been at the forefront in transforming-improving-patient care; therefore, these innovations are discussed in this review.