Cardiac Pacing, Artificial ; Cardiac Resynchronization Therapy ; Electrocardiography ; Heart Conduction System

OBJECTIVE: Physiologic cardiac pacing is a novel technique which has been largely popularized in recent decades. His bundle pacing (HBP) has been long considered the most physiologic pacing method; however, with the widespread implementation of this method, its disadvantages have become apparent. In this context, left bundle branch pacing (LBBP)-directly engaged in the His-Purkinje system-has been foreseen as the best pacing method to mimic physiologic activation patterns. This review aimed to summarize recent approaches to physiologic cardiac pacing. DATA SOURCES: This review included fully peer reviewed publications up to July 2018, found in the PubMed database using the keywords "His bundle branch pacing," "right ventricular pacing," and "physiologic pacing." STUDY SELECTION: All selected articles were in English, with no restriction on study design. RESULTS: The HBP has been studied worldwide, and is currently considered the most physiologic pacing method. However, it has disadvantages, such as high pacing threshold, unsatisfactory sensing and long procedure times, among others. Although LBBP is theoretically superior to HBP, the clinical relevance of this difference remains under debate, as few large randomized clinical trials with LBBP have been published. CONCLUSIONS Although HBP indeed appears to be the most physiologic pacing method, it has certain shortcomings, such as high pacing threshold, difficult implantation due to specific anatomic features, and others. Further studies are required to clarify the clinical significance of LBBP.
Cardiac Catheterization ; Cardiac Pacing, Artificial ; Cardiac Resynchronization Therapy ; Humans ; Randomized Controlled Trials as Topic

Bundle-Branch Block/therapy* ; Cardiac Pacing, Artificial ; Cardiac Resynchronization Therapy ; Electrocardiography ; Humans ; Treatment Outcome

Cardiac Pacing, Artificial ; Cardiac Resynchronization Therapy ; Heart Failure/therapy* ; Humans ; Treatment Outcome

Aged ; Cardiac Pacing, Artificial ; Cardiac Resynchronization Therapy ; Female ; Heart Ventricles ; Humans

Humans ; Cardiac Resynchronization Therapy ; Cardiac Pacing, Artificial ; Heart Ventricles ; Heart Failure/therapy* ; Treatment Outcome ; Electrocardiography ; Ventricular Function, Left

Cardiac resynchronization therapy (CRT) has been proven its value in adult patients with congestive heart failure of low ejection fraction and wide QRS duration. Contrast to adult patients, CRT has been rarely applied for young patients. We report on a 9-yr-old boy with progressive left ventricular (LV) dilatation and dysfunction following chronic VVI pacemaker therapy for congenital complete atrioventricular block associated with maternal anti-SSA/Ro and SSB/La antibody. His LV dysfunction was improved after epicardially established CRT.
Antibodies, Antinuclear/metabolism ; Atrioventricular Block/congenital/therapy ; Cardiac Pacing, Artificial/*adverse effects ; *Cardiac Resynchronization Therapy ; Child ; Chronic Disease ; Electrocardiography ; Heart Ventricles ; Humans ; Male ; Natriuretic Peptide, Brain/blood ; Sjogren's Syndrome/immunology ; Ventricular Dysfunction, Left/etiology/radiography/*therapy

OBJECTIVETo assess the feasibility and safety of using the modified active fixation pacing leads model to pace the right ventricular outflow tract septum.

METHODSA total of 136 patients undergoing artificial heart pacemaker implantation with active fixation pacing leads were randomized into two groups to receive conventional right ventricular outflow tract pacing (CRVOTP) or modified right ventricular outflow tract pacing (MRVOTP). The electrode lead wire core was modeled in a double-curved three-dimensional shape in CRVOTP group and in a J-shaped bend in MRVOTP group before fixation at the right ventricular outflow tract septum.

RESULTSRight ventricular outflow tract septum pacing was achieved successfully in all the patients. None of patients experienced serious complications. No significant differences were found between the two groups in the number of times of electrode fixation, pacing thresholds, impedance, R wave height or QRS wave width during the operation, but MRVOTP was associated with a reduced time of X -ray exposure and operation (P<0.05) due to the convenience in electrode modeling and in passing the leads through the tricuspid annulus and the direct access to the right ventricular outflow tract septum. Postoperative follow-up of the patients showed no incidence of active fixation pacing lead dislocation and comparable pacing thresholds of the ventricular electrodes, impedance, R wave height and QRS wave width between the two groups.

CONCLUTIONSUsing the modified active fixation pacing leads model to pace the right ventricular outflow tract septum can reduce the time of X -ray exposure and operation with a low probability of lead damage.

Cardiac resynchronization therapy (CRT) has became an alternative treatment in patients with severe medically refractory heart failure in recent years. Several large studies have demonstrated the effectiveness of CRT, which can improve the atrioventricular, interventricular, and intraventricular dyssynchronies. Echocardiography can be used to evaluate cardiac mechanical synchrony by means of M-mode, pulse Doppler, tissue Doppler, 3D, and other techniques, and can therefore be used to screen patients, select lead location, optimize pacemaker parameters, and follow up patients who have undergone CRT. This article reviews the strength and shortcomings of some commonly used echocardiographic techniques when they are applied in patients with heart failure.
Cardiac Pacing, Artificial ; Heart Failure ; diagnostic imaging ; therapy ; Humans ; Ultrasonography

BACKGROUNDRight ventricular apical pacing has been reported to reduce cardiac performance. But there are few reports on the effects of dual chamber (DDD) pacing on cardiac function compared to sinus rhythm. In this study, we evaluated the effects of right atrial and ventricular DDD pacing on cardiac function and ventricular contraction synchrony using equilibrium radionuclide angiography.

METHODSTen patients implanted with a right atrial and ventricular DDD pacemaker underwent equilibrium radionuclide angiography. The scintigraphic data were obtained during sinus rhythm and pacing rhythm. Cardiac function parameters were obtained semimanually. Phase analysis was used to study the ventricular activation sequence and ventricular synchrony.

RESULTSThe left ventricular 1/3 ejection fraction decreased significantly during pacing compared with that during sinus rhythm [(23.4 +/- 6.1)% vs (27.7 +/- 4.5)%, P = 0.01]. Regional ejection fraction also decreased during pacing, although the difference was not statistically significant. Phase analysis showed that the right ventricle was activated earlier than the left ventricle during pacing, and that the phase shift was significantly greater during pacing than that during sinus rhythm [64.13 degrees +/- 16.80 degrees vs 52.88 degrees +/- 9.26 degrees, P = 0.007]. The activation of both ventricles occurred simultaneously during sinus rhythm, with the activation sequence from proximal septum or base of left ventricle to apex. The earliest activation during pacing occurred at the right ventricular apex, and subsequently spread to the base and left ventricle.

CONCLUSIONRight atrial and ventricular DDD pacing impairs left ventricular systolic function and ventricular synchrony.