Incidence Of Conduction Disturbances Research Articles

Incidence of conduction disturbances in patients with diabetes mellitus: a comparison with age- and sex matched controls from a nationwide observational study

Abstract Background There are uncertainties about diabetes mellitus and the incidences of conduction disturbances regarding their different locations (sinus node disease [SND], atrio-ventricular block located above the His bundle or of infra-Hisian location) and their possible relation to the type of diabetes. We investigated whether diabetes confers higher relative rates of conduction disturbances, and whether this may depend on the type 1 (T1DM) or type 2 (T2DM) of diabetes mellitus. Methods All patients aged ≥18 seen in French hospitals in 2013 with at least 5 years of follow-up were identified and categorized by their diabetes status. A total of 77,499 patients with T1DM (age 60.9±18.3, 52% male) and 506,937 patients with T2DM (age 67.1±14.6, 54% male) were identified. They were matched 1:1 on age and sex with patients with no diabetes and followed over a mean period of 4.3±2.1 years (median 5.3, interquartile 2.8-5.8 years). We calculated incidence rates, incidence rate ratios and adjusted hazard ratios in patients with T1DM and T2DM (compared to age- and sex-matched controls with no diabetes) for the different types of conduction disturbances and for the need of treatment with cardiac implantable electronic device (CIED) such as pacemakers or implantable cardioverter defibrillators (ICD). Hazard ratios were adjusted for comorbidities known or suggested to be directly or indirectly associated with conduction disturbances and for those associated with a high mortality rate and less likely to reach high age with development of conduction disturbances or the need of CIED during follow-up. Results During 3,271,832 million person-years of follow-up, 126,217 patients with new-onset conduction disturbances or CIED implantation were identified. The incidence rates of conduction disturbances were higher in T1DM and T2DM patients than in control patients with no diabetes. This was seen for all-types of conduction disturbances: SND, atrioventricular block, left bundle branch block and right bundle branch block. Treatment with CIEDs were also more frequent in T1DM or T2DM patients than in control patients with no diabetes (see table). The independent associations of T1DM and T2DM with atrioventricular block, right or left bundle branch block and CIED implantation persisted in the multivariable analyses (adjusted HRs ranging from to 1.11 to 1.44, all p<0.0001). Conclusion In this large nationwide study, T1DM and T2DM were both associated with a higher rate of conduction disturbances and CIED implantations compared with age- and sex-matched controls. T1DM and T2DM remained independently associated with AV block after adjustment on comorbidities known to be positively or inversely associated with SND, atrioventricular block or CIED implantation. This also included a higher incidence or left and right bundle branch block, suggesting that the mechanism may not only be related to the influences of the autonomic nervous system or to the use of bradycardic agents.

Transcatheter Aortic Valve Replacement with the Self-Expandable Core Valve Evolut Prosthesis Using the Cusp-Overlap vs. Tricusp-View.

Despite the rapid increase in experience and technological improvement, the incidence of conduction disturbances in patients undergoing transcatheter aortic valve replacement (TAVR) with the self-expandable CoreValve Evolut valve remains high. Recently, a cusp-overlap view (COP) implantation technique has been proposed for TAVR with self-expandable valves offering an improved visualization during valve expansion compared to the three-cusp view (TCV). This study aims to systematically analyze procedural outcomes of TAVR patients treated with the CoreValve Evolut valve using a COP compared to TCV in a high-volume center. The primary endpoint was technical success according the 2021 VARC-3 criteria. A total of 122 consecutive patients (61 pts. TCV: April 2019 to November 2020; 61 pts. COP: December 2020 to October 2021) that underwent TAVR with the CoreValve Evolut prosthesis were included in this analysis. Although there was no difference in the primary endpoint technical success between TCV and COP patients (93.4% vs. 90.2%, OR 0.65, 95% CI 0.16, 2.4, p = 0.51), we observed a significantly lower risk for permanent pacemaker implantation (PPI) among COP patients (TCV: 27.9% vs. COP: 13.1%, OR 0.39, 95% CI 0.15, 0.97, p = 0.047). Implantation of the CoreValve Evolut prosthesis using the COP might help to reduce the rate of PPI following TAVR.

Conduction disturbances in low-surgical-risk patients undergoing transcatheter aortic valve replacement with self-expandable or balloon-expandable valves.

Despite a considerable improvement in TAVR devices and procedures, together with a reduction in procedural complications, the rate of conduction disturbances (CD) remained stable over the years. Indeed, the CD rate is still significantly higher than in surgical aortic valve replacement, and represents one of the main limitations to the expansion of TAVR to younger low-risk patients. The aim of the present study was to assess the incidence and predictors of CD in low-risk patients undergoing TAVR. Among 637 patients without preexisting CD who underwent TAVR, 116 (18.2%) were considered at low surgical risk. Up to 25% of low-risk patients presented with persistent CD at discharge. The pacemaker implantation rate was similar in the low-risk group compared to the intermediate-/high-risk group (8.7% vs 10.6%, p = 0.55). Moreover, the rate of new persistent left bundle branch block (LBBB) following TAVR was also similar between both groups (18.1% vs 22.1%, p = 0.34). At 1-year follow-up, LBBB was persistent in 62.5% of patients and 3 of them required a pacemaker implantation. Depth of valve implantation, baseline QRS duration and mean aortic transvalvular gradient were identified as independent predictors of CD in low-risk patients. Patients at low surgical risk showed an equivalent CD rate than intermediate-/high-risk patients. The depth of valve implantation was the main predictor of CD in low-risk patients undergoing TAVR. Baseline QRS duration and mean aortic transvalvular gradient were also associated with increased CD.

Implantation percutanée de valve aortique et troubles conductifs

Transcatheter aortic valve implantation (TAVI) is currently becoming the treatment of choice for patients with calcific aortic stenosis. Despite several technical improvements, the incidence of conduction disturbances has not diminished and remains TAVI's major complication. These disturbances include the occurrence of left bundle branch block and/or high-grade atrioventricular block often requiring pacemaker implantation. The proximity of the aortic valve to the conduction system (conduction pathways) accounts for the occurrence of these complications. Several factors have been identified as carrying a high risk of conduction disturbances like the presence of pre-existing right bundle branch block, the type of valve implanted, the volume of aortic and mitral calcifications, the size of the annulus and the depth of valve implantation. Left bundle branch block is the most frequent post TAVI conduction disturbance. Whereas the therapeutic strategy for persistent complete atrioventricular block is simple, it becomes complex in the presence of fluctuating changes in PR interval and left bundle branch block duration. The QRS width threshold value (150-160 ms) indicative of the need for pacemaker implantation is still being debated. Although there are currently no recommendations regarding the management of these conduction disturbances, the extension of TAVI indications to patient at low surgical risk calls for a standardization of our practice. However, a decision algorithm was recently proposed by a group of experts composed of interventional cardiologists, electrophysiologists and cardiac surgeons. There are still uncertainties about the appropriate timing of pacemaker implantation and the management of new onset left bundle branch block.

PREDICTORS OF CARDIAC CONDUCTION DISTURBANCES AFTER TRANSCATHETER AORTIC VALVE IMPLANTATION USING SELFEXPANDABLE VALVES

Background: The advent of transcatheter aortic valve implantation (TAVI) represented a paradigm shift for treating patients with severe symptomatic aortic stenosis (AS) who are at high or prohibitive surgical risk. With the growing experience in this field, the rate of periprocedural complications has decreased over time and TAVI has been increasingly performed with a minimalist approach, evolving into a safe procedure with predictable outcomes. However, unlike other procedural complications, the incidence of conduction disturbances which could be in the form of bundle branch blocks, oratrioventricular blocks, has failed to decrease in recent times, with reports suggesting an increased risk associated with the use of some newer-generation transcatheter valves. Aim of the work: To determine the predictors of cardiacconduction disturbances after transcatheter aortic valve implantation. Patients and Methods: From January 2017 to April 2019, we included 38 consecutive patients with severe symptomatic AS underwent TAVI using self-expandable valves (CoreValve or Evolut R) or the balloon expandable Sapien XT valve at the Ain Shams University Hospitals. All patients were subjected to electrocardiographic evaluation pre- and post-TAVI and at 30 days. Several parameters were studied including preprocedural parameters: clinical, electrocardiographic, echocardiographic, and CT derived parameters, and procedural parameters: type and size of the valve, the use of balloon pre- and post- implantation dilatation, and depth ofimplantation. All quantitative parameters were indexed to body surface area (BSA). Results: Conduction disturbances were seen in 16 patients (42.1%), in which 10 patients (26.3%) experienced left bundle branch block (LBBB), 6 patients (15.8%) experienced complete heart block (CHB), with only one of them (2.6%) experienced permanent CHB requiring permanent pacemaker implantation (PPI). Multivariate logistic regression analysis for pre-procedural predictors showed that the presence of basal septal calcification is the most powerful independent predictor (OR: 98.73, 95% CI: 7.63 to 1278.23, p 75.00% is the most powerful independent procedural predictor (OR:16.00, 95% CI: 2.12 to 120.65, p 0.007). Conclusion: Conduction disturbances remain a common complication of TAVI. Presence of basal septal calcification is a risk factor that increase patient propensity for developing such complication after TAVI. The relationship between depth of implantation and membranous septum is a strong independent procedural predictor and prospective validation of its cut-offs is needed.

Conduction disturbances after transcatheter aortic valve implantation

Since its introduction in 2002, the number of transcatheter aortic valve implantation (TAVI) procedures has grown exponentially. Although technical advances have been made in valve technology and its implantation system, conduction disturbances (CD) remain the most common complication of the procedure. CD have a negative impact on the prognosis of patients for reasons such as the worsening of left ventricular ejection fraction, the need for a pacemaker or the increased risk of sudden cardiac death. Several factors have been associated with higher risk of CD, including prior right bundle-branch block, valve type and deep valve placement inside the left ventricular outflow tract.Whilst CD are the most common complications of TAVI, there is still no general agreement on the optimal strategy to minimize its incidence. In this review we will approach the current evidence for the pathophysiology, incidence, clinical implications and management of CD in TAVI.

Conduction Disturbances After Transcatheter Aortic Valve Replacement: Current Status and Future Perspectives.

Transcatheter aortic valve replacement (TAVR) has become a well-accepted option for treating patients with aortic stenosis at intermediate to high or prohibitive surgical risk. TAVR-related conduction disturbances, mainly new-onset left bundle-branch block and advanced atrioventricular block requiring permanent pacemaker implantation, remain the most common complication of this procedure. Furthermore, improvements in TAVR technology, akin to the increasing experience of operators/centers, have translated to a major reduction in periprocedural complications, yet the incidence of conduction disturbances has remained relatively high, with perhaps an increasing trend over time. Several factors have been associated with a heightened risk of conduction disturbances and permanent pacemaker implantation after TAVR, with prior right bundle-branch block and transcatheter valve type and implantation depth being the most commonly reported. New-onset left bundle-branch block and the need for permanent pacemaker implantation may have a significant detrimental association with patients' prognosis. Consequently, strategies intended to reduce the risk and to improve the management of such complications are of paramount importance, particularly in an era when TAVR expansion toward treating lower-risk patients is considered inevitable. In this article, we review the available evidence on the incidence, predictive factors, and clinical association of conduction disturbances after TAVR and propose a strategy for the management of these complications.

Sensitivity and Specificity of Cardiac Tissue Discrimination Using Fiber-Optics Confocal Microscopy.

Disturbances of the cardiac conduction system constitute a major risk after surgical repair of complex cases of congenital heart disease. Intraoperative identification of the conduction system may reduce the incidence of these disturbances. We previously developed an approach to identify cardiac tissue types using fiber-optics confocal microscopy and extracellular fluorophores. Here, we applied this approach to investigate sensitivity and specificity of human and automated classification in discriminating images of atrial working myocardium and specialized tissue of the conduction system. Two-dimensional image sequences from atrial working myocardium and nodal tissue of isolated perfused rodent hearts were acquired using a fiber-optics confocal microscope (Leica FCM1000). We compared two methods for local application of extracellular fluorophores: topical via pipette and with a dye carrier. Eight blinded examiners evaluated 162 randomly selected images of atrial working myocardium (n = 81) and nodal tissue (n = 81). In addition, we evaluated the images using automated classification. Blinded examiners achieved a sensitivity and specificity of 99.2±0.3% and 98.0±0.7%, respectively, with the dye carrier method of dye application. Sensitivity and specificity was similar for dye application via a pipette (99.2±0.3% and 94.0±2.4%, respectively). Sensitivity and specificity for automated methods of tissue discrimination were similarly high. Human and automated classification achieved high sensitivity and specificity in discriminating atrial working myocardium and nodal tissue. We suggest that our findings facilitate clinical translation of fiber-optics confocal microscopy as an intraoperative imaging modality to reduce the incidence of conduction disturbances during surgical correction of congenital heart disease.

Electrocardiographic and Holter Study for immediate and mid-term incidence of conduction disturbances after transcatheter perimembranous ventricular septal defect device closure with Amplatz duct occluders

Electrocardiographic and Holter Study for immediate and mid-term incidence of conduction disturbances after transcatheter perimembranous ventricular septal defect device closure with Amplatz duct occluders

Variables associated with pacemaker implantation in postoperative patients of cardiac surgery in a university hospital

In postoperative cardiac patients, the incidence of conduction disturbances is between 1 to 4% depending on the complexity of the surgical procedure, the intraoperatory complications and the need for reintervention. These disorders lead to the need for electrical support, transient or permanent by a pacemaker. So far, there are few data in the literature regarding the potential factors related to the need for a pacemaker in postoperative cardiac surgery.

Frequency of Conduction Disturbances After Edwards SAPIEN Percutaneous Valve Implantation

Disturbances in atrioventricular conduction and the additional need for a permanent pacemaker are recognized complications after transcatheter aortic valve replacement (TAVR). We analyzed the incidence of postprocedural conduction disorders and the need for permanent pacemaker implantation in patients undergoing TAVR with the Edwards SAPIEN valve. In 125 consecutive patients with symptomatic, severe aortic stenosis undergoing TAVR, a standard 12-lead electrocardiogram was obtained before and serially after the procedure. The cohort was divided into 2 groups with regard to the post-TAVR appearance of conduction disturbances, defined as left bundle branch block, right bundle branch block, fascicular hemiblock, atrioventricular block, and the need for a permanent pacemaker. The patients with and without conduction disturbances were compared. After TAVR, 19 patients (15.2%) met the study definition of a "new conduction defect" and 5 patients (4%) required a permanent pacemaker because of an advanced atrioventricular block. New left bundle branch block appeared in 5 patients (4%) and left anterior hemiblock in 9 (7.2%). No new right bundle branch block or left posterior hemiblock was observed. Although most baseline, echocardiographic, and procedural characteristics were equally distributed, the patients with new conduction disturbances more often had diabetes mellitus and peripheral vascular disease. Also, they more often were taking an angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker, and the procedure was performed more often with apical access (12 [63.2%] vs 7 with femoral access [36.8%], p = 0.002). In conclusion, although the incidence of conduction disturbances was high after TAVR using the Edwards SAPIEN valve, with a significant increase in the rate of left bundle branch block and left anterior hemiblock, the need for permanent pacemaker implantation after TAVR with this valve remained low.

Conduction disturbances in coronary artery bypass surgery

Background: Conduction disturbances are very common after coronary artery bypass grafting (18–45%). Long cross-clamp time, method of cardioplegia, depth of hypothermia, and patient age are some of the risk factors. We planned this study to ascertain the effect of crystalloid or tepid blood cardioplegia (CP) on conduction disturbances. Methods: One hundred patients were randomly divided into two groups. The first group received tepid blood CP and the second received cold crystalloid CP. St. Thomas II CP was used as CCP and the same CP was mixed with blood with a ratio of 4:1 in the tepid CP group. In both groups as an initial bolus, a 10 to 15 ml/kg CP was infused with a pressure of 75 mmHg. Additionally, 400 ml of CP were given every 20 min during the cross clamping period in addition to infusion of 50–100 ml of CP after each distal anastomosis. Blood samples for CK, CK-MB, LDH and Troponin T measurements were obtained at induction, before bypass, after cross clamping, before de-clamping, after de-clamping and after bypass. Postoperative ECGs were analyzed by a cardiologist. Results: There were no deaths in both groups but the mean hospitalization was 8.4±1.7 days in group I, and 14.4±3.1 days in group II ( P=0.004). Although there were significant rises in CK, CK-MB, LDH and Troponin T levels in both groups after CPB or de-clamping, the difference in increment between the two groups was not significant. Twelve patients in group II (24%) developed new fascicular blocks, four of these caused hemodynamic instability and needed inotropic treatment but only one was discharged with LAHB. Four patients in group I (8%) also developed new conduction disturbances within the first hour, but all completely resolved. Incidence of conduction disturbances was significantly increased in the crystalloid CP group ( P=0.019). Conclusion: There were no significant differences in cardiac enzyme measurements between cold crystalloid and tepid blood CP, but crystalloid CP caused more fascicular blocks. We conclude that myocardial protection was equal in both cardioplegia methods whereas conduction disturbances have been assumed to be caused by cold injury to the conduction tissues.

Electrical ablation of atrial muscle. II. Early and late electrophysiologic observations in canine atria

Electrical ablation techniques (ECT) have had limited success in achieving control of arrhythmias originating in the right atrial free wall (RAFW). To ascertain determinants for successful ECT, we studied the clinical and cellular electrophysiologic effects of electrical abiation of the RAFW. After performing electrical ablation of the RAFW in 12 beagle pupples, the following studies were performed: Holter monitoring first 24 hours (eight pupples), and 11 weeks later (four puppies); clinical electrophysiologic study (four pupples); and microelectrode study (ME) eight puppies). Arrhythmias (AR) and conduction disturbances (CD) frequently occurred immediately following ECT: ventricular tachycardia (VT) (seven pupples), junctional tachycardia (one puppy), and asystole or complete AV block (AVB) (four puppies). Holter monitoring during the first 24 hours after ECT revealed VT (four puppies), frequent ventricular premature depolarizations (one puppy), and type 2 second-degree AVB (four pupples). AR were rarely seen late after ECT. During clinical EP study 11 weeks after abiation, atrial fibrillation was induced in three of four puppies; none had AR prior to ECT. Early ME study revealed a nonhomogeneous atrial infarct—a central zone of “dead” cells surrounded by peripherai islands of depressed cellular activity. Cells with normal action potential characteristics were noted in between. We conclude that (1) Electrical ablation of the RAFW is associated with a high incidence of early AR and CD. (2) Because of the nonhomogeneous nature of tissue injury produced during ECT, careful atrial mapping is critically important. (3) Local regions of conduction delay and block may provide a substrate for the late development of atrial arrhythmias.

Multicentre investigation of myocardial protection with cold cardioplegia.

In order to analyze factors of importance for the efficiency of myocardial protection during open-heart surgery, a study was made of 144 patients undergoing isolated aortic valve replacement with various cardioplegic techniques. The cardioplegia was of Bretschneider type in 54 cases, St Thomas in 31 and Ringer-potassium type in 11 cases. Single or multi-dose blood cardioplegia was used in 11 cases and continuous blood cardioplegia in 30 cases. Local cardiac hypothermia was additionally employed in all patients. The efficiency of myocardial protection was assessed mainly from the incidence of postoperative conduction disturbances, myocardial enzyme release and need for inotropic support. All patients survived the operation. In 20% surgery was followed by transient or persistent disturbance of conduction, in 9% by abnormally increased CK-MB release and in 5% by requirement for inotropic support. Preoperative risk factors such as high age or severe left ventricular (LV) hypertrophy or dysfunction had little influence on the results. Patients in whom aortic stenosis (AS) was dominant in the complex with aortic insufficiency (AS + AI) showed 20-hour postoperative CK-MB enzyme activity twice as high as those with pure aortic insufficiency. The most important factors in myocardial protection were the duration of aortic occlusion and the myocardial temperature during cardioplegia. When the aortic occlusion lasted more than 80 min there was a 32% incidence of conduction disturbances and 20-hour CK-MB activity thrice as high as after shorter occlusion. Patients with mean myocardial temperature below 18 degrees C during cardioplegia invariably had low enzyme activities, which indicated good myocardial protection. The best overall results were obtained in patients operated on during hypothermia at 25-27 degrees C, with single or multi-dose blood cardioplegia and with efficient local cooling of the heart.

Conduction disturbances after surgical correction of ventricular septal defect by the atrial approach.

Conduction disturbances have been documented after correction of ventricular septal defects by the ventricular route. Recently, repair of the ventricular septal defect has been through the right atrium to overcome damage to the conduction system and a right ventriculotomy. Thirty-nine children with ventricular septal defects under the age of 5 years were operated upon by the atrial route (group 1). The incidence of conduction disturbances in this group was compared with that occurring in 19 children of comparable age with a ventricular septal defect repaired via a right ventriculotomy (group 2). Complete right bundle-branch block developed in 13 of 39 children (33.3%) in group 1, compared with 15 of 19 children (78.9%) in group 2. This was a statistically significant reduction in complete right bundle-branch block in group 1. The incidence of left axis deviation occurring with complete right bundle-branch block was similarly statistically reduced. Transient complete heart block and arrhythmias were not statistically different in the two groups. The atrial approach to the repair of the ventricular septal defect significantly reduced the incidence of complete right bundle-branch block alone and occurring with left axis deviation.

Conduction disturbances in patients with calcified mitral annulus diagnosed by echocardiography

Clinical, radiologic and histo-pathological observations have suggested that conduction disturbances (CD) are frequent in patients with calcified mitral annulus (CMA). To determine the incidence of CD, 65 consecutive patients with CMA were studied. Sixty-five normal individuals, matched for age and sex served as a control group. CMA has been identified by M-mode echocardiography, cross-sectional echo and image amplifier fluoroscopy. CD were present in 23 patients with CMA as compared to seven patients in the control group (p less than 0.01). Three patients developed complete atrioventricular block (4.6%) during hospitalization requiring artificial pacemakers. We conclude that, 1) early detection of CMA in the elderly is useful in predicting a higher incidence of CD. 2) Complete heart block is more frequent in patients with CMA. 3) Frequent ECG follow-up in these patients has proven to be useful in avoiding serious clinical complications.