Non-sustained ventricular tachycardia in patients with congenital heart disease: An important sign?

Ventricular Arrhythmias in Adults With Congenital Heart Disease, Part II: JACC State-of-the-Art Review

There are marked variations in the incidence of sudden cardiac death (SCD) and in the substrates for ventricular arrhythmias (VAs) across the gamut of congenital heart defects. In this 2-part review, patients with higher-risk forms of congenital heart disease (CHD) were conceptually categorized into those with discrete anatomic isthmuses for macro-reentrant ventricular tachycardia (VT) (Group A) and those with more diffuse or less well-defined substrates (Group B) that include patchy or extensive myocardial fibrosis. The latter category encompasses CHD lesions such as Ebstein anomaly, transposition of the great arteries with a systemic right ventricle (RV), and congenital aortic stenosis. For Group B patients, polymorphic VT and ventricular fibrillation account for a higher proportion of VA. The prognostic value of programmed ventricular stimulation is less well established, and catheter ablation plays a less prominent role. As cardiomyopathies evolve over time, pathophysiological mechanisms for VA among Groups A and B become increasingly blurred.

Device-detected non-sustained ventricular tachycardia in adult congenital heart disease without tetralogy of fallot

OBJECTIVES

To evaluate any association between non-sustained ventricular tachycardia (NSVT) detected by intra-cardiac device and clinical outcomes in repaired adult congenital heart disease (ACHD) without tetralogy of Fallot (TOF).

BACKGROUND

NSVT portends a higher risk of serious ventricular tachyarrhythmia in TOF. However its clinical significance when incidentally detected by implantable cardiac device is not well elucidated in non-TOF ACHD cohort.

METHODS

We performed a single center, retrospective, longitudinal follow-up study in repaired ACHD (≥ 18 years) patients without TOF who hosted a pacemaker or automatic implantable cardiac defibrillator (AICD). The cohort was divided based on presence/absence of device detected NSVT. The primary end-point was a composite of sustained ventricular tachycardia (VT), ventricular fibrillation (VF), or sudden cardiac death (SCD).

RESULTS

158 patients [male 56.3%, median (IQR) age of 35 (28-43) years at last follow-up] with longitudinal post-implant follow-up duration of 8 (5-12) years were included. NSVT was detected in 52 (33%) patients. The primary composite end-point was more frequent in NSVT group [11.5% vs. 2.8%; p = 0.04]. Patients with NSVT were i) older at the time of initial implant (age 25 vs. 18 years, p = 0.011) and more frequently demonstrated ii) systemic ventricular dysfunction (44% vs. 26%; p = 0.015), as well as iii) history of ventriculotomy (38% vs. 21%;p = 0.017).

CONCLUSIONS

In our repaired ACHD cohort, we noted a significant association between device-detected-NSVT and the primary composite end-point of sustained VT/VF or SCD. Systemic ventricular dysfunction and history of ventriculotomy were more frequent in the NSVT group and likely constituted the clinical milieu. This article is protected by copyright. All rights reserved.

Tachykarde Rhythmusstörungen bei EMAH – Aspekte der katheterinterventionellen Therapie

Tachykarde Rhythmusstörungen bei Erwachsenen mit angeborenem Herzfehler (EMAH) haben großen Einfluss auf Morbidität und Letalität dieser Patientengruppe. Sie basieren in der Mehrzahl auf erworbenen Substraten, die eine typische Langzeitfolge des angeborenen Herzfehlers (AHF) insbesondere nach herzchirurgischen Eingriffen darstellen. Antiarrhythmika können akut effektiv eingesetzt werden, sind aber als langfristige Behandlungsstrategie meist wenig verlässlich zur Unterdrückung von Tachykardierezidiven. Zusätzlich können Kontraindikationen bestehen bei eingeschränkter Ventrikelfunktion, hämodynamischen Rest-Fehlbelastungen, bradykardem Grundrhythmus sowie Arzneimittelnebenwirkungen. Vor diesem Hintergrund hat sich die katheterinterventionelle Ablationsbehandlung in den beiden letzten Jahrzehnten als Therapie der Wahl für die Mehrheit der Tachykardieformen bei EMAH mit zunehmend hohen Erfolgs- und niedrigen Komplikationsquoten etabliert.

Adults with Congenital Heart Disease and Arrhythmia Management

Arrhythmia management in adult congenital heart disease (ACHD) encompasses a wide range of problems from bradyarrhythmia to tachyarrhythmia, sudden death, and heart failure-related electrical dyssynchrony. Major advances in the understanding of the pathophysiology and treatments of these problems over the past decade have resulted in improved therapeutic strategies and outcomes. This article attempts to define these problems and review contemporary management for the patient with ACHD presenting with cardiac arrhythmia.

Hemodialysis Procedure-Associated Autonomic Imbalance and Cardiac Arrhythmias: Insights From Continuous 14-Day ECG Monitoring

Background

In patients with end‐stage kidney disease, sudden cardiac death is more frequent after a long interdialytic interval, within 6 hours after the end of a hemodialysis session. We hypothesized that the occurrence of paroxysmal arrhythmias is associated with changes in heart rate and heart rate variability in different phases of hemodialysis.

Methods and Results

We conducted a prospective ancillary study of the Predictors of Arrhythmic and Cardiovascular Risk in End Stage Renal Disease cohort. Continuous ECG monitoring was performed using an ECG patch, and short‐term heart rate variability was measured for 3 minutes every hour (by root mean square of the successive normal‐to‐normal intervals, spectral analysis, Poincaré plot, and entropy), up to 300 hours. Out of enrolled participants (n=28; age 54±13 years; 57% men; 96% black; 33% with a history of cardiovascular disease; left ventricular ejection fraction 70±9%), arrhythmias were detected in 13 (46%). Nonsustained ventricular tachycardia occurred more frequently during/posthemodialysis than pre‐/between hemodialysis (63% versus 37%, P=0.015). In adjusted for cardiovascular disease time‐series analysis, nonsustained ventricular tachycardia was preceded by a sudden heart rate increase (by 11.2 [95% CI 10.1–12.3] beats per minute; P<0.0001). During every‐other‐day dialysis, root mean square of the successive normal‐to‐normal intervals had a significant circadian pattern (Mesor 10.6 [ 95% CI 0.9–11.2] ms; amplitude 1.5 [95% CI 1.0–3.1] ms; peak at 02:01 [95% CI 20:22–03:16] am; P<0.0001), which was replaced by a steady worsening on the second day without dialysis (root mean square of the successive normal‐to‐normal intervals −1.41 [95% CI −1.67 to −1.15] ms/24 h; P<0.0001).

Conclusions

Sudden increase in heart rate during/posthemodialysis is associated with nonsustained ventricular tachycardia. Every‐other‐day hemodialysis preserves circadian rhythm, but a second day without dialysis is characterized by parasympathetic withdrawal.

Hidden burden of arrhythmias in patients with small atrial septal defects: a nationwide study

Background

In recent Danish nationwide register-based study, adults with small, unrepaired atrial septal defects (ASD) have increased risk of pneumonia, atrial fibrillation (AF) and stroke. Moreover, they revealed higher mortality than the background population.

Objective

In this nationwide study, we evaluate the hidden burden of atrial and ventricular arrhythmias in adult patients with a small, unrepaired ASD without a previous diagnosis of AF.

Methods

All Danish patients, aged 18–65, diagnosed between 1953 and 2011 with an unrepaired ASD and no documented AF were invited for 7 days Holter-recording, echocardiography and 6 min walk test. The first 48 hours Holter-recording was completely analysed, while only AF was screened for throughout all 7 days. Furthermore, the entire patient group were characterised using the unique Danish registries.

Results

A total of 151 patients (mean age 32 years) were included. Approximately 80% of the patients had spontaneous closure of their defect. Despite this, occult arrhythmias were frequent. The most common arrhythmia was supraventricular tachycardia (n=24, 16%) with non-sustained atrial arrhythmias in 21 patients and AF in two patients. A considerable number of patients had non-sustained ventricular tachycardia (n=12, 8%). Patients with ASD and tachyarrhythmias had increased right ventricular to left ventricular diastolic area in echocardiography and higher age when compared with ASD patients without arrhythmias.

Conclusion

Adult patients with small, unrepaired ASD have a hidden burden of both atrial and ventricular tachyarrhythmias. The mechanism likely relates to the residua of previous right-heart volume overload and incomplete reverse remodelling. Our results support guidelines recommending continued follow-up of patients with small, unrepaired ASD.

Genotype Positive Long QT Syndrome in Patients With Coexisting Congenital Heart Disease

Congenital long QT syndrome (LQTS) is characterized by QT prolongation with predisposition to life-threatening arrhythmia. There have been sporadic reports of LQTS coexisting with more common forms of congenital heart disease (CHD). However, the diagnosis of LQTS when CHD is present may be confounded by several common variables including postoperative electromechanical factors predisposing to ventricular arrhythmia, intrinsic, and postoperative QRS abnormalities. This report documents a single-center experience with patients who have both genetically confirmed LQTS and CHD to examine their modes of presentation and factors associated with making the diagnosis of LQTS in this patient population, as well as potential confounding variables that may mask or delay both LQTS diagnosis and initiation of therapy. A retrospective review was performed of subjects with confirmed LQTS and associated CHD from 1999 to January 2017. Genetic analysis was performed predominantly using commercially available panel testing. A chart review included detailed analysis of electrocardiograms, 24-hour 3-lead rhythm monitors and exercise stress test tracings as well as the genetic test reports. QT intervals were measured using Bazett's formula. Eleven patients were identified. Four patients had LQTS type 1, 6 had LQTS type 2, and 1 had a disease-associated mutation in KCNQ1 and a variant of unknown significance in KCNH2 gene. Two patients had positive cascade screening. Arrhythmia presentations of the LQTS were at both extremes of the cohort age range (in-utero and midchildhood age). There was a seeming overrepresentation of conotruncal anomalies and/or arch anomalies, with 7 of the 11 patients. In conclusion, the diagnosis of LQTS may be challenging in the setting of CHD (a prolonged ST segment may be helpful), and high index of suspicion is required. The overall incidence of LQTS in CHD appears extremely rare, but the diagnosis and true incidence may be masked by confounding electrocardiogrpahic findings and other variables common in CHD.

Development of Tachyarrhythmias Late After the Fontan Procedure: The Role of Ablative Therapy

Patients with a Fontan circulation are at a high risk of developing a variety of cardiac dysrhythmias after cardiac surgery. These dysrhythmias are most often supraventricular tachyarrhythmias (SVT), but ventricular tachyarrhythmias (VT) may also occur. Mechanisms underlying SVT are variable, including both ectopic activity and reentry. Over time, successive SVT may be caused by different mechanisms. The acute success rate of ablative therapy of atrial tachyarrhythmias is considerably high yet during long-term follow-up 'recurrences' frequently occur. It is most likely that these 'recurrences' are caused by a progressive atrial cardiomyopathy instead of arrhythmogeneity of prior ablative lesions.