31 Cardiac magnetic resonance findings in patients with Type 1 myotonic dystrophy

Aims Heart disease is a major determinant of prognosis in type 1 myotonic dystrophy (DM1), second only to respiratory complications. Cardiac imaging, possibly including cardiac magnetic resonance (CMR), is recommended in patients with DM1. However, limited information is available on CMR findings and their prognostic significance in DM1. Methods and results We identified all patients with DM1 evaluated from 2009 to 2020 in a CMR laboratory with an established collaboration with a Neuromuscular Disorder Unit. Thirty-four patients were retrieved (21 males, aged 45 ± 12). By the time of CMR examination, 90% had neuromuscular symptoms (mean duration 17 ± 13 years), 13 (38%) had previous reports of atrioventricular block (n = 12 1st degree, n = 1 2nd degree type 1), 30 (88%) of intraventricular conduction disturbances (n = 5 left bundle branch block, n = 5 right bundle branch block, n = 3 left anterior fascicular block, n = 17 other non-specific or incomplete intraventricular conduction delay), 4 (12%) of atrial fibrillation or flutter. No patient had a device. At CMR, 5 (15%) patients had left ventricular (LV) systolic dysfunction [LV ejection fraction (LVEF) <50%] and 4 (12%) a depressed right ventricular (RV) function (RVEF <50%). Compared to age- and sex-specific reference values for our laboratory (Figure 1 left), 12 (35%) patients showed a decreased LV end-diastolic volume index (LVEDVi), 7 (21%) a decreased LV mass index (LVMi), and 29 (85%) a decreased LVMi/LVEDVi ratio. Nine (26%) patients had mid-wall late gadolinium enhancement (LGE, mean extent 4.5 ± 2.0% of LVM; n = 8 septal, n = 4 inferolateral, n = 2 inferior, n = 1 anterolateral, see Figure 1 middle), and 14 (41%) some areas of fatty infiltration (n = 9 involving the LV, n = 13 the RV). Native T1 in the interventricular septum (1,041 ± 53 ms) approached the upper reference limit (1089 ms), and the extracellular volume was slightly increased (33 ± 2%, reference values <30%). Over a median follow-up of 2.5 years (interquartile interval: 1.5–4.0), 2 (6%) patients died for infectious and respiratory complications, 5 (15%) underwent device implantation (n = 4 PM; n = 1 ICD), and 4 (12%) had a documentation of high-risk (Lown class ≥4) ventricular ectopic beats (VEBs). Among all CMR variables collected, higher values of LVMi/LVEDVi ratio emerged as univariate predictor of all-cause death (P = 0.044). At logistic regression analysis, anteroseptal wall thickness was associated with the need for device implantation (P = 0.028), while LGE mass was associated with high-risk VEBs (P = 0.026) (Figure 1 right). Conclusions Patients with DM1 display several structural and functional cardiac abnormalities, with variable degrees of cardiac muscle hypotrophy, fibrosis, and fatty infiltration. The possibility to predict the need for device implantation, ventricular arrhythmias, and all-cause or cardiovascular mortality should be verified in larger cohorts.

Cardiac implantable electronic devices in Bulgaria: results from the electronic registry BG-Pace for the period 2019-2021

The current study analyses the activity in cardiac pacing in Bulgaria in 2019, 2020 and 2021 based on data derived from a national registry of patients with cardiac electronic implantable devices (CIEDs). Materials and methods. Data from the national registry BG-Pace in the period 08.2019-06.2021 was retrospectively studied. Demographic data, procedure and device type, pacing mode, etiology, symptoms, preimplantation ECG, number of implantations and centre and operator volumes were analysed. Results. Six thousand nine hundred forty-nine devices were implanted by 47 operators in 28 centres for the study period. Median age was 75 (IQR 68-81, 21-103) years in males and 77 (IQR 71-82, 17-98) years in females, P< 0.05. The largest number of devices were implanted in the age group 70-79 years. The most commonly implanted CIEDs were antibradycardia devices with a total of 486.7/million implantations for the period 08.2019-08.2020 and 353.9/million for the period 08.2020-06.2021. Implanted cardioverter-defibrillators demonstrated a growth from 14.1/million to 20.1/million in the period 08.2020 – 06.2021. The number of all implantations dropped signifi cantly during the two epidemic waves of COVID-19. The mean number of implantations per centre and per operator for the whole period was 232.3±204 (2-705) and 148±139.1 (2-660), respectively. Dual chamber device implantations were more prevalent, representing 65.8% of implantations in AV block I and II degree, 63.5% in complete AV block, 59.8% in intraventricular conduction disturbances and 60.9% in sick sinus syndrome. Pacing modes with atrial sensing represented more than 55% of the implantations for all indications. Increasing age was associated with signifi cantly more common use of VVI pacing mode (P < 0.001). Conclusion. The national registry BG-Pace includes systematic clinical, demographical and procedural data for CIED implantations in Bulgaria. Results demonstrate lower number of implantations compared to the average European volume. There was a signifi cant drop in the implantation rate during the two waves of COVID-19.

Significance of Ectopic Beats in Post Aortic Valve Replacement Arrhythmia Patients

Objective: The incidence of new onset arrhythmia after conventional aortic valve replacement (AVR) is relatively high whereby atrial fibrillation (AF) in particular (30-40%). Arrhythmias increase postoperative morbidity, mortality and consequently health costs. The need for a reliable method for early detection and discrimination between low and high risk patients is therefore indispensable. For this reason this study examined the possible correlation between electrophysiological abnormalities on continuous ECG recordings and the initiation of arrhythmia directly after surgery. Methods and Results: Both ECG and clinical data was collected from the hospitals filing system for all patient (n=107) who underwent surgical Aortic Valve Replacement (AVR) for non-rheumatic aortic valve stenosis or insufficiency for the period from January 2010 to December 2018. Continuous ECG data was converted into ISHNE-format and analyzed by using Synescope™ software. Data showed that one minute prior to arrhythmia, AF in particular, an increase of both supraventricular premature beats (SVPB) and missed beats (MB) was detected (n=33; P<0,05). However there was no correlation between arrhythmia and the overall SVPB incidence (n=33). Twenty-one out of 33 AVR patients developed a de novo intraventricular conductance delay directly after cardioplegic arrest, which persisted in 7 cases. Conclusions: Although there is an increase of both SVPB and MB prior to arrhythmia startup, it is still questionable what is the true predictive value of these findings are. Additionally it appeared that a temporarily intraventricular conduction delay (IVCD) is a common finding after AVR.

The development of a new, simple electrocardiographic method for the estimation of the latest activated left ventricular site

Background Current cardiac resynchronization therapy (CRT) works by pacing the latest activated left ventricular (LV) site. The estimation of the location of the latest activated LV site (LALVS) may be important to determine the optimal position of the LV electrode during CRT or to predict the patient response to the current CRT technique devised to pace the LALVS usually present in patients with left bundle branch block (LBBB) pattern. Methods We used a modified 12-lead ECG algorithm originally devised and used by other authors* for a different purpose, to identify the segment of origin of ventricular tachycardia in the 16-segment American Heart Association LV model by analyzing the QRS axis in the limb and chest leads. We hypothesized that modifying this ECG algorithm by using the secondary ST vector axis instead of the QRS axis in the limb and chest leads, we can apply this ECG method to estimate the LALVS instead of the site of origin of the ventricular tachycardia. The resultant secondary ST vector is directed 180o away from the LALVS. Using this ECG method we determined the LALVS in 22 patients with LBBB and 20 patients with nonspecific intraventricular conduction disturbance (NICD) patterns and heart failure. To validate the ECG method, we also estimated the LALVS by echocardiography using 3D parametric imaging and 2D speckle tracking. Results The LALVS determined by the electrocardiographic method and echocardiogrpahy in the 16-segment model matched (was in the same or adjacent segment) in 38/42 (90.5%) patients and among these patients complete matching (the LALVSs were in the same segment) was found in 16/38 (42%) and partial matching (the LALVSs were in adjacent segments) in 22/38 (58%) patients. When the LBBB and NICD groups were separated to patients with ≥150 ms and &lt;150 ms QRS duration subgroups, the LALVSs of the ≥150 ms subgroup were almost exclusively in the anterolateral (or anterior) or inferolateral areas and those of the &lt;150 ms subgroup were in the above mentioned areas or sometimes at other sites located remote from these areas. Conclusions The novel, simple surface electrocardiographic method could as reliably estimate the approximate location of LALVS as echocardiography. The possible explanation for the effectivity of CRT in patients with sinus rhythm with intraventricular conduction disturbance and ≥150 ms QRS duration is that their LALVS is at the same most distant areas (anterolateral, anterior, inferolateral) from the initial septal activation site where the LV electrodes are positioned during application of the current CRT technique. FUNDunding Acknowledgement Type of funding sources: None.

Comparing predictors of permanent pacemaker insertion after TAVR in new-generation versus early generation heart valves

Introduction Transcatheter Aortic Valve Replacement (TAVR) has emerged as the standard of care for patient with severe aortic stenosis. Conduction abnormalities leading to permanent pacemaker (PPM) implantation is one of the most common complication after TAVR. Newer generation valves (NGV) such as Sapien S3, XT and Evolut are widely being used in real time practice. The aim of this analysis is to compare the predictors associated with increased risk of PPM implantation after TAVR in newer generation valves (NGV) as compared to older generation valves (OGV). Methods A comprehensive literature search was performed in PubMed, Embase, and Cochrane to identify relevant trials. Summary effects were calculated using a DerSimonian and Laird random-effects model as odds ratio with 95% confidence intervals for all the clinical endpoints. Results 18 observational studies with 16,004 patients were identified. The incidence of PPM implantation after TAVR in our analysis was 8.9%. For the NGV, right bundle branch block (RBBB) and atrioventricular (AV) block were independent predictors of PPM insertion after TAVR. Baseline heart rate, presence of atrial fibrillation, and baseline intraventricular conduction delay were not significant predictors. However, for the OGV, risk of PPM implantation after TAVR was higher in presence of RBBB, depth of implant, valve size/annulus size, presence of atrial fibrillation and post-procedure AV block. Conclusions Our analysis identified 2 factors that were significantly associated with increased risk of PPM insertion after TAVR in NGV compared to 6 factors with OGV. With the increasing physician expertise with TAVI and use of NGV, the incidence of post TAVR PPM insertion has reduced but baseline RBBB and AV conduction block still continue to be significant predictors of increased PPM insertion after TAVR. FUNDunding Acknowledgement Type of funding sources: None.

Conduction system pacing in heart failure patients

Direct conduction system pacing delivers more physiological cardiac activation and can potentially correct intraventricular conduction disturbances and restore normal activation pathways. Permanent pacing that maintains cardiac electromechanical synchrony is essential in heart failure and reduced left ventricular ejection fraction. Conduction system pacing has recently emerged as an alternative to right ventricular pacing and biventricular resynchronization therapy. In this article, we review conduction system pacing in heart failure patients.

Why pacing of conduction system?

Cardiac pacing since the 50th of the last century is the standard of care for patients with bradycardia. The aims of this therapy have changed over the decades from a life-saving option to achieve the most physiologic “prosthesis” of the conduction system in patients with atrioventricular blocks and improve depolarization sequence in those with heart failure and intraventricular conduction abnormalities. In the last years, direct conduction system pacing methods are developing very quickly. His bundle pacing, direct left bundle branch pacing with its modifications were introduced into clinical practice. Lack of big, randomized trials and technical aspects of these new modes of pacing caused that these methods haven’t achieved a high class of recommendation in recently published guidelines of the European Society of Cardiology.