Pacing Follow Up Techniques and Trouble Shooting During Biventricular Pacing

Cardiac resynchronization has proven to be a useful adjunct therapy for heart failure patients with ventricular conduction disturbances. However, new issues have emerged including the follow-up and trouble-shooting of the biventricular devices. Peri-implant and immediate post-implant follow-up is necessary if procedure-related complications are to be revealed and proper system functioning ensured. Additionally, during the long-term follow-up the optimum device functioning should be evaluated, as should the patient's clinical and functional improvement. Finally, trouble-shooting resulting from the use of biventricular devices is another matter that needs to be addressed and physicians active in the field should continually upgrade their knowledge in the constantly evolving technologies of cardiac resynchronizers.     

Pacing induced cardiomyopathy

Pacing induced cardiomyopathy (PICM) is most commonly defined as a drop in left ventricle ejection fraction (LVEF) in the setting of chronic, high burden right ventricle (RV) pacing. Recent data suggest, however, that some individuals may experience the onset of heart failure symptoms more acutely after pacemaker implantation. Definitions of PICM which emphasize drop in LVEF may underestimate the incidence of deleterious effects from RV pacing. Treatment of PICM has primarily focused on upgrade to cardiac resynchronization therapy (CRT) when LVEF has dropped. However, emerging data suggest that conduction system pacing (CSP) may offer an opportunity to prevent PICM in the first place.     

Pacing in cardiomyopathy

Permanent cardiac pacing is an established treatment for the prevention of syncope or sudden death in patients with heart block or sinus node disease. Recent observations underscore the use of pacing in patients with various forms of cardiomyopathy, i.e. hypertrophic, dilated and tachycardia-induced cardiomyopathy. The evidence favouring the use of pacing in patients with cardiomyopathy is mainly derived from retrospective and uncontrolled investigations and the data from the scarce randomized investigations are rather disappointing. Therefore, the indications for pacing remain controversial.     

Trans-oesophageal Dual-Chamber Pacing

Non-invasive Dual-Chamber Pacing was performed with low threshold current using a newly developed trans-oesophageal lead-electrode in one healthy volunteer.     

Pacing in children

Fourteen children had a permanent pacemaker implanted between May 1967 and July 1983. Postoperative complete heart block was the indication in nine cases, congenital complete heart block in three, and sick sinus syndrome in two. Two patients died, one suddenly and one after aortic valve replacement. A total of 48 pulse generators were implanted; five patients were given an isotopic pacemaker. Twelve patients had epicardial leads implanted initially, and two received a transvenous endocardial system. The lead system implanted initially remained without malfunction in only seven patients. In the other seven patients 20 lead malfunctions occurred. Psychological maturity and physical development seemed to be normal in all 14 children. Improvement in equipment and technique will improve the outlook for paced children in the future.     

Left Ventricular Endocardial Pacing and Multisite Pacing to Improve CRT Response

Cardiac resynchronization therapy (CRT) is an established treatment for patients with moderate-to-severe heart failure and a wide QRS complex. However, the amount of reverse remodeling and clinical improvement is highly variable and poorly predictable. The left ventricular pacing site is of critical importance for the CRT response but is often imposed by the coronary sinus anatomical constraints and may result in suboptimal resynchronization. Alternative pacing sites, such as endocardial LV pacing or multisite pacing, have been proposed to improve CRT response rates and may be considered in nonresponders to standard resynchronization. However, adequately powered randomized studies are required to determine whether these pacing strategies result in improved outcome.     

Clinical Outcomes of His Bundle Pacing Compared to Right Ventricular Pacing

Background

Right ventricular pacing (RVP) is associated with heart failure and increased mortality. His bundle pacing (HBP) is a physiological alternative to RVP.

Left Bundle Branch Pacing for Cardiac Resynchronization Therapy: Nonrandomized On-Treatment Comparison With His Bundle Pacing and Biventricular Pacing

BackgroundLeft bundle branch pacing (LBBP) is a novel method for delivering cardiac resynchronization therapy (CRT). We compared on-treatment outcomes with His bundle pacing (HBP) and biventricular pacing (BVP) in this nonrandomized observational study.MethodsConsecutive patients with left-ventricular ejection fraction (LVEF) ≤ 40% and typical left bundle branch block (LBBB) referred for CRT received BVP, HBP, or LBBP. QRS duration, pacing threshold, LVEF, and New York Heart Association (NYHA) class were assessed.ResultsOne hundred thirty-seven patients were recruited: 49 HBP, 32 LBBP, and 54 BVP; 2 did not receive CRT. The majority of patients had nonischemic cardiomyopathy. Mean paced QRS duration was 100.7 ± 15.3 ms, 110.8 ± 11.1 ms, and 135.4 ± 20.2 ms during HBP, LBBP, and BVP, respectively. HBP and LBBP demonstrated a similar absolute increase (Δ) in LVEF (+23.9% vs +24%, P = 0.977) and rate of normalized final LVEF (74.4% vs 70.0%, P = 0.881) at 1-year follow-up. This was significantly higher than in the BVP group (Δ LVEF +16.7% and 44.9% rate of normalized final LVEF, P < 0.005). HBP and LBBP also demonstrated greater improvements in NYHA class compared with BVP. LBBP was associated with higher R-wave amplitude (11.2 ± 5.1 mV vs 3.8 ± 1.9 mV, P < 0.001) and lower pacing threshold (0.49 ± 0.13 V/0.5 ms vs 1.35 ± 0.73 V/0.5 ms, P < 0.001) compared with HBP.ConclusionLBBP appears to be a promising method for delivering CRT. We observed similar improvements in symptoms and LV function with LBBP and HBP. These improvements were significantly greater than those seen in patients treated with BVP in this nonrandomized study. These promising findings justify further investigation with randomized trials.     

右室永久起搏电极嵌入位置的研究

本文观测204例右室起搏导管电极的嵌入位置,比较各种位置具有相同起搏阈值的例数、心腔内心电图图形及电极脱位的机会。认为除右室心尖部外,与其同一水平的右室流入道以及靠近室间隔的部位,亦有良好的起搏效果。由于有多个部位可供选择,故可缩短X线照射时间及手术时间,对高度依赖起搏的危重患者的抢救,更有裨益。     

Single-Chamber Rate Adaptive Pacing

Ventricular rate adaptiie pacemaker are the pacing systems of choice in patients with atrioventricular block and permanent or persistent atrial arrhythmias. A number of different pacemaker models are available, relying on different sensors of activity or metabolic demand. None of the sensors are perfect, each having its own advantages and disadvantages. Rate adaptive pacing is possible in the atrium as well as the ventricle, and at rial systems have a role in the management of patients with a poor sinus node response to exercise (chronotropic incompetence). The major groups of rate adaptive pacemakers are discussed in the following article, together with indications for use and possible future developments.