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

OBJECTIVETo quantitatively assess the effects of cardiac resynchronization therapy (CRT) in patients with advanced congestive heart failure by real-time 3-dimensional(3D) echocardiography (RT-3DE).

METHODSEighteen patients with advanced congestive heart failure underwent CRT with New York Heart association(NYHA) class III and IV and wide QRS complex (>120 ms) were included (17 dilated cardiomyopathy and 1 ischemic cardiomyopathy). Before CRT and 8 months after CRT, the clinical and RT-3DE parameters and outcome were analyzed.

RESULTSThe biventricular pacemaker was successfully implanted in 17 patients (94.4%). Compared with before CRT, NYHA class of patients decreased by 1.5 class (P < 0.01), left ventricular ejection fraction increased by 25% (P < 0.01), left ventricular end systolic volume decreased by 38% (P < 0.01), left ventricular systolic dyssynchrony index (SDI) improved significantly (14.2% before CRT vs. 9.8% after CRT, P < 0.01 ) post CRT. Change in SDI and change in LVEF was positively correlated (r = 0.62, P < 0.01) . The procedure complications and outcome during and after CRT included coronary sinus dissection (n = 1), left ventricular lead dislodgement (n = 1), phrenic nerve stimulation (n = 1), sudden cardiac death (n = 1). Three non-response patients were complicated with atrial fibrillation, nonspecific intraventricular block and dilated cardiomyopathy with postero-lateral scar tissue.

CONCLUSIONSCRT could improve the cardiac function, correct the mechanical desynchronization and reverse left ventricular remodeling in patients with congestive heart failure, and SDI quantification by RT-3DE could predict increase of LVEF after CRT, however, there were complications related to the implantation procedure and possibilities of non-response.

Adult ; Aged ; Cardiac Pacing, Artificial ; methods ; Cardiac Resynchronization Therapy ; Echocardiography, Three-Dimensional ; Female ; Heart Failure ; therapy ; Humans ; Male ; Middle Aged ; Treatment Outcome

OBJECTIVETo observe the incidence and explore the potential factors of nonresponse to cardiac resynchronization therapy(CRT)in patients with severe chronic congestive heart failure.

METHODCRT was performed in 119 patients with NYHA function class III-IV and left ventricular ejection fraction ≤ 35% [96 men and 23 women, age (60.5 ± 11.3) years].

RESULTSSeven patients died for different reasons between 1 - 6 months post CRT and clinical and echocardiographic (Echo) data at 6 months post CRT were analyzed from the remaining 112 patients. The incidence of nonresponse to CRT was 28.57%. Compared to the response group, complete right bundle branch block, longer course of congestive heart failure, higher pulmonary systolic pressure and serum creatinine level and non-optimal target vessels positioning of the left ventricle lead (the great cardiac vein and the middle cardiac vein) were the independent predictors for nonresponse after CRT (all P < 0.05). Compared with nonresponse group, the dosages of digoxin and diuretics used for heart failure were significantly reduced in response group (P < 0.01).

CONCLUSIONSThe incidence of nonresponse after CRT was 28.57% in this patient cohort. Higher pulmonary systolic pressure and serum creatinine level and non-optimal target vessels positioning of the left ventricle lead (the great cardiac vein and the middle cardiac vein) were the independent predictors for nonresponse after CRT.

Adult ; Aged ; Aged, 80 and over ; Cardiac Pacing, Artificial ; Cardiac Resynchronization Therapy ; Defibrillators, Implantable ; Female ; Heart Failure ; therapy ; Humans ; Incidence ; Male ; Middle Aged ; Treatment Outcome

OBJECTIVETo evaluate the value of 64-slice computed tomography (MDCT) in previsualization the cardiac veins anatomy before the implantation of cardiac resynchronization therapy (CRT).

METHODSThe 64-slice CT scans of 21 patients [10 men, age (61.6 ± 9.7) years] were obtained and analyzed before the implantation of CRT. Retrograde coronary venography was performed during intraoperational fluoroscopy. The coronary sinus (CS) and the main tributaries were measured.

RESULTSSimilar images to those obtained during the CRT implantation procedure were obtained by MDCT in 71% of the patients. The coronary sinus was clearly visible in all cases, the measured ostium was (12.1 ± 4.2) mm, and the angle between the CS and the vertical plane was (99 ± 12) degrees. In 90% of patients, at least one vein was clearly visible in the target area. Among the target veins, the posterolateral vein was visible in most cases (86%) and the lateral vein was visible in 48% of the patients.

CONCLUSIONMDCT is an effective and noninvasive method for previsualization of the cardiac venous system, which may facilitate optimal left ventricular lead positioning for CRT implantation.

Aged ; Cardiac Pacing, Artificial ; Cardiac Resynchronization Therapy ; Coronary Angiography ; Female ; Heart Failure ; diagnostic imaging ; therapy ; Humans ; Male ; Middle Aged ; Tomography, Spiral Computed

OBJECTIVEVentricular resynchronization might be achieved via minimally invasive left ventricular epicardial lead placement.

METHODSix patients with congestive heart failure underwent minimally invasive left ventricular epicardial lead placement after failed coronary sinus cannulation were followed up for 1 year, cardiac function and LV lead threshold were evaluated.

RESULTSThere were no in-hospital deaths, intraoperative complications and diaphragm stimulation. Correct lead positioning was achieved in all 6 patients. LV lead thresholds remained unchanged [(1.2 ± 0.5) V vs (1.1 ± 0.4) V, P = 0.68] at 12 months follow-up. Improvements on 6 min walking test [(327 ± 77) m vs (267 ± 68) m, P = 0.001], LVEF [(26.1 ± 6.0)% vs (38.2 ± 4.7)%, P = 0.004], and NYHA functional class were evidenced at 12 months follow-up.

CONCLUSIONMinimally invasive left ventricular epicardial lead placement is a safe and reliable technique and should be considered as an alternative option in case of difficult coronary venous anatomy and inability to position the lead for resynchronization therapy.

Adult ; Cardiac Pacing, Artificial ; methods ; Cardiac Resynchronization Therapy ; Female ; Heart Failure ; surgery ; Heart Ventricles ; surgery ; Humans ; Male ; Middle Aged ; Pericardium ; surgery