Comparison Between Diltiazem and Cedilanid-D on Ventricular Rate Control of Atrial Fibrillation and Their Effect on Atrioventricular Conduction System.

Objectives This randomized study was designed to compare the safety and efficacy of intravenous diltiazem versus intravenous cedilanid-D （deslanoside） for ventricular rate control in patients with atrial fibrillation （AF）. Analysis of the effect on conduction system of these drugs was also performed. Methods Forty three patients with AF were randomly assigned to receive intravenous therapy with 0.25mg/kg diltiazem （n = 21） or 0.4rag cedilanid-D （n = 22）. If not effective at 120 minutes （〈 20% decrease in pretreatment ventricular rate or can not convert to sinus rhythm= another dose of diltiazem or 0.2mg cedilanid-D was administered. Blood pressure and electrocardiographic recordings were performed before and after 5, 10, 20, 30, 60 minutes of drug administration. Further recordings were performed at 120 minutes in noneffective patients, and at 180 minutes in patients who received second time drug administration. To evaluate the effect on conduction system of these two drugs by measuring PA, AH and HV intervals using His bundle electrogram test another nineteen sinus rhythm patients were randomized to dihiazem （n=9） and cedilanid （n= 10） group. His bundle electrogram recordings were performed before and after 5, 10, 20 and 30 minutes of drug administration. Statistical significance was assessed with the use of t test, Fisher＇s exact test, ANOVA and LSD methodology. Results At baseline and after 5, 10, 20, 30, 60 minutes of drug administration the heart rates （mean±SD） were（133±15）, （92±20）, （87±22）, （85 ±20）, （85±21）, （85 ±23）beats/minute in diltiazem group respectively and（ 140±21 ）, （ 122±24）, （118±25）, （110±26）, （112±25）, （110±28） beats/ minute in cedilanid-D group respectively. Heart rate reduction was higher in diltiazem group than cedilanid group during 5 （41±20 vs 17±14,P 〈 0.01）; 10 （46±21 vs 22±20, P〈0.01）; 20 （48±21 vs 29±22, P〈0.01 ） ; 30（48±22 vs 27±22,P〈0.01 ）and 60 minutes （48±23 vs 29±24, P〈 0.05）. Both drugs had no effect on both systolic and diastolic blood pressure （P 〉0.05） and no major side effects were noticed. Diltiazem maintained effective ventrieular rate in 20 patients, whereas eedilanid-D maintained in 15 patients within 180 minutes （95.2%vs 68.2%,P〈 0.05）. There were no statistical significance in baseline heart rate, age and weight between the two groups. Both diltiazem and cedilanid-D can increase AH interval, but have no effect on HV and PA intervals in sinus rhythm patients. Conclusions Both dihiazem and eedilanid-D decrease ventrieular heart rate, but heart rate reduction is significantly higher in diltiazem group, thus should be considered as a drug of choice for emergency control of ventrieular rate. Under clinical monitoring this dose of diltiazem seems to be safe and applicable in AF patients with congestive heart failure. Both drugs have no effect on PA and HV intervals but increase the AH interval thereby can reduce ventricular rate.

Using Three-Dimensional Lorenz Scatter Plots to Detect Patients with Atrioventricular Node Double Path Caused by Interpolated Ventricular Premature Systoles: A Case Study

A series of related electrophysiology phenomena can be caused by the occurrence of interpolated ventricular premature contraction.In our recent three-dimensional Lorenz R-R scatter plot research,we found that atrioventricular node double path caused by interpolated ventricular premature contraction imprints a specifi c pattern on three-dimensional Lorenz plots generated from 24-hour Holter recordings.We found two independent subclusters separated from the interpolated premature beat precluster,the interpolated premature beat cluster,and the interpolated premature beat postcluster,respectively.Combined with use of the trajectory tracking function and the leap phenomenon,our results reveal the presence of the atrioventricular node double conduction path.

Initial experiences of maintaining atrioventricular intrinsic conduction during cardiac resynchronization therapy in non-responders

Background Cardiac resynchronization therapy （CRT） is a major breakthrough in therapy for advanced heart failure patients; however, a number of key clinical research questions remain, perhaps most importantly the issue of why apparently suitable patients do not respond to CRT. Methods Seven patients, six males and one female, aged （56.43±6.13） years, all diagnosed with dilated cardiomyopathy, were included in this study. They were all non-responders to CRT who underwent routine optimization postoperatively, and received optimal drug therapy. On the basis of biventricular pacing, titrating various atrioventricular （AV） intervals were performed to get the true fusional QRS complexes composed of biventricular pacing and AV intrinsic conduction. Then, the effects of AV intrinsic conduction during CRT were evaluated. Results On the setting of AV intrinsic conduction during CRT, the true fusional QRS complexes were the narrowest, and all patients showed alleviation of symptoms, improvement of exercise tolerance, life quality and hemodynamic parameters during more than 6 months of follow-up. Conclusions Titrating AV intervals to get the true fusional QRS complexes composed of biventricular pacing and AV intrinsic conduction will be beneficial for non-responders to CRT. Maintaining AV intrinsic conduction during CRT may decrease the rates of non-resoonders to CRT.

Atrioventricular intrinsic conduction and cardiac resynchronization therapy

Cardiac resynchronization therapy （CRT） is a major breakthrough in therapy for patients with advanced congestive heart failure, however, a number of key clinical research questions remain, perhaps most importantly the issue of why apparently suitable patients do not respond to CRT. These issues are also relevant to patients who do respond to CRT as potentially their response might be further increased. Though patients do not respond to CRT because of many known postulated reasons, we review the importance of maintaining atrioventricular intrinsic conduction during CRT in this paper, which maybe is one of methods to reduce the rates of non-response to CRT.

Arrhythmic syncope: From diagnosis to management

Syncope is a concerning symptom that affects a large proportion of patients.It can be related to a heterogeneous group of pathologies ranging from trivial causes to diseases with a high risk of sudden death.However,benign causes are the most frequent,and identifying high-risk patients with potentially severe etiologies is crucial to establish an accurate diagnosis,initiate effective therapy,and alter the prognosis.The term cardiac syncope refers to those episodes where the cause of the cerebral hypoperfusion is directly related to a cardiac disorder,while arrhythmic syncope is cardiac syncope specifically due to rhythm disorders.Indeed,arrhythmias are the most common cause of cardiac syncope.Both bradyarrhythmia and tachyarrhythmia can cause a sudden decrease in cardiac output and produce syncope.In this review,we summarized the main guidelines in the management of patients with syncope of presumed arrhythmic origin.Therefore,we presented a thorough approach to syncope work-up through different tests depending on the clinical characteristics of the patients,risk stratification,and the management of syncope in different scenarios such as structural heart disease and channelopathies.