Current knowledge for the risk factors of early permanent pacemaker implantation following transcatheter aortic valve replacement and what is next for the primary prevention?

In this editorial, we comprehensively summarized the preoperative risk factors of early permanent pacemaker implantation after transcatheter aortic valve replacement (TAVR) among patients with severe aortic stenosis from several renowned clinical studies and focused on the primary prevention of managing the modifiable factors, e.g., paroxysmal atrial fibrillation before the TAVR.

Coronary sinus ablations in pediatric patients with supraventricular arrhythmias

BACKGROUND

Intracoronary sinus ablations have been performed for various arrhythmical substrates. The aim of this study is to report our experience on pediatric patients of the safety and efficacy of ablations in the coronary sinus.

METHODS

This is a retrospective study of all patients who underwent ablations in the coronary sinus from October 2013 to October 2021 at a single center. Clinical presentation, type of arrhythmia causing tachycardia, ablation procedure, and outcome were recorded.

RESULTS

A total of 27 patients were included in the study. Nineteen (69%) of those followed up received a diagnosis of Wolff-Parkinson-White syndrome (WPW), 4 (15%) were cases of supraventricular tachycardia with concealed accessory pathway (AP), 2 (8%) were cases of focal atrial tachycardia, and 2 (8%) were cases of permanent junctional reciprocating tachycardia. Negative delta wave was noteworthy especially in lead II in 11/19 (58%) cases and coronary sinus diverticulum was detected in the WPW cases. Of those with manifest AP (19 cases), 15 (79%) had a high-risk AP and the AP in all WPW cases was adenosine unresponsive. Radiofrequency (RF) catheter ablation was performed in 25/27 (93%) cases during the procedure, and 16/25 (64%) of these were irrigated RF catheters. No complications were observed in the follow-up, including coronary artery injury.

CONCLUSIONS

Catheter ablation of supraventricular tachyarrhythmias can be accomplished effectively and potentially safely within the coronary sinus. Coronary sinus diverticula should be suspected in patients with manifest posteroseptal APs who have a previous failed ablation and typical electrocardiographic signs.

Usefulness of three-dimensional pulmonary vein-left atrium image reconstructed from non-enhanced computed tomography for atrial fibrillation ablation

Enhanced computed tomography (CT) is unsuitable for patients with reduced renal function and/or allergy for contrast medium (CM). CT image registration into an electroanatomic system (EAMS) is essential to perform pulmonary vein isolation (PVI) safely and smoothly in patients with atrial fibrillation (AF). To create three-dimensional pulmonary vein-left atrium (3D PV-LA) images from non-enhanced CT images to register them into EAMS for AF ablation. Using a non-enhanced ECG-gated image, 3D PV-LA images were generated by our developed techniques with an EnSite image analyzing tool for patients unfit for CM use (n = 100). Segmentation between tissues was performed as follows: tissues distal from or close to PV-LA were segmented in transverse slices to clearly show the whole LA. Tissues bordering PV-LA, including the pulmonary artery, left ventricle, and right atrium, were segmented manually with great care. Practical ablation parameters were compared with those obtained from enhanced CT (n = 100). 3D PV-LA image reconstruction from non-enhanced CT imaging required a longer time than that from enhanced CT (42 ± 6 vs 14 ± 3 min). All 100 PV-LA non-enhanced CT images were successfully reconstructed and registered into the EAM system without the need for re-segmentation. Practical ablation parameters, including procedural time and AF recurrence rate, did not differ between imaging methods. This study provides clinically useful information on a detailed methodology for 3D PV-LA image reconstruction using non-enhanced CT. Non-enhanced CT 3D PV-LA images were successfully registered into the EAM system and useful for patients unsuitable for CM use.

Propafenone versus amiodarone for supraventricular arrhythmias in septic shock: a randomised controlled trial

PURPOSE

Acute onset supraventricular arrhythmias can contribute to haemodynamic compromise in septic shock. Both amiodarone and propafenone are available interventions, but their clinical effects have not yet been directly compared.

METHODS

In this two-centre, prospective controlled parallel group double blind trial we recruited 209 septic shock patients with new-onset arrhythmia and a left ventricular ejection fraction above 35%. The patients were randomised in a 1:1 ratio to receive either intravenous propafenone (70 mg bolus followed by 400-840 mg/24 h) or amiodarone (300 mg bolus followed by 600-1800 mg/24 h). The primary outcomes were the proportion of patients who had sinus rhythm 24 h after the start of the infusion, time to restoration of the first sinus rhythm and the proportion of patients with arrhythmia recurrence.

RESULTS

Out of 209 randomized patients, 200 (96%) received the study drug. After 24 h, 77 (72.8%) and 71 (67.3%) were in sinus rhythm (p = 0.4), restored after a median of 3.7 h (95% CI 2.3-6.8) and 7.3 h (95% CI 5-11), p = 0.02, with propafenone and amiodarone, respectively. The arrhythmia recurred in 54 (52%) patients treated with propafenone and in 80 (76%) with amiodarone, p  < 0.001. Patients with a dilated left atrium had better rhythm control with amiodarone (6.4 h (95% CI 3.5; 14.1) until cardioversion vs 18 h (95% CI 2.8; 24.7) in propafenone, p = 0.05).

CONCLUSION

Propafenone does not provide better rhythm control at 24 h yet offers faster cardioversion with fewer arrhythmia recurrences than with amiodarone, especially in patients with a non-dilated left atrium. No differences between propafenone and amiodarone on the prespecified short- and long-term outcomes were observed.

Cardiac arrhythmias in viral infections

BACKGROUND

The current COVID-19 pandemic has led to many studies examining its arrhythmogenic effects. However, there are many other viruses that are capable of inducing arrhythmias that have not received as much attention. The objective of this study was to review common viruses and identify studies highlighting their arrhythmogenic effects.

METHODS AND RESULTS

In this review, we examined 15 viruses and the literature regarding their arrhythmogenic effects. The common mechanisms of action appear to be direct invasion of myocytes leading to immune mediated damage, infection of vascular endothelium, and alteration of cardiac ion channels.

CONCLUSIONS

This review highlights the growing evidence that supports the involvement of other viral infections in the development of arrhythmia. Physicians should be aware of these potentially life-threatening effects when caring for patients with these viruses, some of which are very common. Additional studies are required to better understand the complex mechanism and risk factors of cardiac arrhythmias in patients suffered from viral infections to determine whether the processes can be reversed or even prevented.

Mapping and Ablation of Atypical Atrial Flutters

Atypical atrial flutters are complex, hard-to-manage atrial arrhythmias. Catheter ablation has progressively emerged as a successful treatment option with a remarkable role played by irrigated-tip catheters and 3D electroanatomic mapping systems. However, despite the improvement of these technologies, the ablation results may be still suboptimal due to the progressive atrial substrate modification occurring in diseased hearts. Hence, a patient-tailored approach is required to improve the long-term success rate in this scenario, aiming at achieving specific procedure end points and detecting any potential arrhythmogenic substrate in each patient.

An overview of heart rhythm disorders and management in myotonic dystrophy type 1

Myotonic dystrophy type 1 (DM1) is the most common adult form of muscular dystrophy, presenting with a constellation of systemic findings secondary to a CTG triplet expansion of the noncoding region of the DMPK gene. Cardiac involvement is frequent, with conduction disease and supraventricular and ventricular arrhythmias being the most prevalent cardiac manifestations, often developing from a young age. The development of cardiac arrhythmias has been linked to increased morbidity and mortality, with sudden cardiac death well described. Strategies to mitigate risk of arrhythmic death have been developed. In this review, we outline the current knowledge on the pathophysiology of rhythm abnormalities in patients with myotonic dystrophy and summarize available knowledge on arrhythmic risk stratification. We also review management strategies from an electrophysiological perspective, attempting to underline the substantial unmet need to address residual arrhythmic risks for this population.

Oral administration of MnCl2 attenuated hyperlipidemia-related cardiac remodeling in ApoE-/- mice

Manganese chloride (MnCl2) has been shown to inhibit the Yes-associated protein (YAP) in high-fat diet-fed ApoE-/- mice. Although YAP has been implicated in atherogenesis, there are limited data on the effects of MnCl2 on cardiac remodeling. In this study, we discovered, by electrocardiography, that hyperlipidemia led to spontaneous supraventricular arrhythmia (SVA) in ApoE-/- (KO) mice, with 3 of 9 KO + MnCl2 mice (33%) exhibiting lower incidence of spontaneous SVA than KO mice (6 of 10 mice, 60%). Echocardiography revealed that reduced systolic function in KO mice was reversed by MnCl2 treatment. Oil Red O staining of the aortas and biochemical analysis of lipid levels showed that MnCl2 inhibited plaque formation in a lipid metabolism-independent manner. MnCl2 inhibited inflammatory cell infiltration and reduced fibrosis, as evidenced by hematoxylin and eosin, immunohistochemical and Masson's trichrome staining, respectively. Our findings demonstrate that spontaneous SVA and reduced systolic function were blocked by MnCl2. Our findings show that MnCl2 was useful in delaying cardiac remodeling and reducing susceptibility to spontaneous SVA in a mouse model of hyperlipidemia.

The role of atrial fibrillation as a prognostic factor in doberman pinschers with dilated cardiomyopathy and congestive heart failure

Atrial fibrillation (AF) in congestive heart failure (CHF) is associated with a high risk of mortality and shorter survival times in human and veterinary medicine. A retrospective review of medical records was performed to evaluate the impact of AF on survival times in Doberman Pinschers with dilated cardiomyopathy (DCM). Time of first onset of CHF and its role as a prognostic factor were also determined, as were predictors of AF development. Forty-eight client-owned purebred Doberman Pinschers with DCM and CHF were included; 23 dogs presented with AF and 25 dogs did not develop AF until immediately before cardiac-related death. Dogs with AF survived for significantly shorter times than those without AF (P = 0.043). For dogs with AF, mean and median survival times were 88.2 days and 22 days, respectively (range, 42.1-134.4 days); mean and median survival times for dogs without AF were 150.7 days and 98 days, respectively (range, 98.5-203 days). AF increased the risk of cardiac-related death (hazard ratio [HR], 2.371; 95% confidence intervals [CI], 1.14-4.95; P = 0.021). Biventricular and right atrial dilation was only present in dogs with AF and right atrial enlargement was the only significant predictor of AF after multivariate analysis (P < 0.001). Dogs with AF had significantly higher mean heart rates than dogs without AF (201 beats per min [bpm] vs. 132 bpm; P < 0.001). In conclusion, AF in Doberman Pinschers with DCM and CHF increased the risk of cardiac-related death and reduced survival time.

Vasopressin in Patients with Septic Shock and Dynamic Left Ventricular Outflow Tract Obstruction

PURPOSE

Left ventricular outflow tract obstruction (LVOTO) is a relatively uncommon but severe condition that may lead to hemodynamic impairment. It can be elicited by morphological (left ventricular hypertrophy, sigmoid septum, prominent papillary muscle, prolonged anterior mitral valve leaflet) and functional (hypovolemia, low afterload, hypercontractility, catecholamines) factors. We sought to determine the incidence of the most severe form of LVOTO in septic shock patients and describe the therapeutic effects of vasopressin.

METHODS

Over a period of 29 months, 527 patients in septic shock were screened for LVOTO. All were mechanically ventilated and treated according to sepsis bundles, including pre-load optimization and norepinephrine infusion. Vasopressin was added in addition to norepinephrine to reduce the adrenergic burden and decrease LVOTO.

RESULTS

Ten patients were diagnosed with the most severe form of LVOTO, including systolic anterior mitral valve motion (SAM) and severe mitral regurgitation (MR) with pulmonary oedema. The median norepinephrine dosage to obtain a mean arterial pressure of ≥70 mmHg was 0.58 mcg/Kg/min (IQR 0.40-0.78). All patients had a hyper-contractile left ventricle, septal hypertrophy, significant LVOTO (peak gradient 78 [56-123] mmHg) associated with SAM and severe MR with pulmonary oedema. Vasopressin (median 4 IU/h) allowed a significant reduction of norepinephrine (0.18 [0.14-0.30] mcg/kg/min; p = 0.01), LVOT gradient (35 [24-60] mmHg; p = 0.01) and MR with a significant paO₂/FiO₂ increase (174 [125-213] mmHg; p = 0.01).

CONCLUSION

Vasopressin allowed a reduction of norepinephrine with subsequent LVOTO reduction and hemodynamic improvement of the most severe form of LVOTO, which represented 1.9% of all septic shock patients.

Clinical and procedural implications of congenital vena cava anomalies in adults: A systematic review

BACKGROUND

Although congenital vena cava (CVC) anomalies in adults have implications for surgical and radiological interventions, the literature is scare and disparate. The aim of this systematic review was to assess cardiovascular clinical and procedural implications of CVC anomalies in adults without congenital heart disease.

METHODS AND RESULTS

We searched PubMed and EMBASE from database conception through October 2018 for English-language studies describing the epidemiology of CVC anomalies or their clinical or procedural implications in humans. Two independent reviewers screened 7093 records and identified 16 relevant studies. We found two major implications of CVC anomalies: 1) congenital inferior vena cava (CIVC) anomalies are associated with a 50-100-fold higher risk of deep venous thrombosis, particularly among younger patients, and 2) persistent left superior vena cava (PLSVC) is associated with a 2-3-fold higher risk of supraventricular arrhythmias. PLSVC also poses technical challenges to cardiovascular electronic device implantation, requiring alterations in surgical approach and lengthening procedure and X-ray exposure times. Due to the large disparity in reported prevalence rates of CIVC anomalies, we performed a meta-analysis of CIVC anomaly prevalence including 8 studies, which showed a weighted prevalence of 6.8% (95% CI, 4.5-9.2%).

CONCLUSION

These findings challenge the notion that CVC anomalies are rare and asymptomatic in adults. Rather, the literature indicates that CVC anomalies are not uncommon and have important clinical and procedural implications. To further understand the prevalence and implications of CVC anomalies, a robust US population-based study and nationwide registry is warranted in the current era of venous interventions.

Synthetic Cannabinoids and Cardiac Arrhythmia Risk: Review of the Literature

Synthetic cannabinoids (SCBs) are widely used recreational substances especially among adults. Although they have been considered as safe during the marketing process, our knowledge about their adverse effects has evolved since years. SCBs are associated with various cardiac events including acute myocardial infarction and sudden cardiac death. There is also growing evidence that SCBs are associated with cardiac arrhythmia development both in acute and chronic exposure. SCBs have been shown to be associated with both supraventricular and ventricular arrhythmias. However, the exact mechanism of the SCB related arrhythmia remains unknown. Understanding the exact association and possible mechanisms may help us to identify high risk patients at an early stage and to develop treatment modalities to prevent or reverse the arrhythmic effects of SCBs.

Predictors and outcomes of atrial tachyarrhythmia among patients with implantable defibrillators

BACKGROUND

Atrial tachyarrhythmias (ATAs) are common among heart failure (HF) patients.

OBJECTIVE

The purpose of this study was to assess predictors for the development of new ATA and its components (atrial fibrillation/flutter [AF], supraventricular tachycardia [SVT]), and their association with subsequent clinical outcomes.

METHODS

We assessed predictors for first and recurrent ATA, AF, and SVT among 1500 patients in MADIT-RIT (Multicenter Automatic Defibrillator Implantation Trial-Reduce Inappropriate Therapy). We also investigated the association of new ATA, AF, or SVT with subsequent ventricular arrhythmia (VA), adverse events (HF hospitalization, syncope, or death), or death by time-dependent analysis.

RESULTS

During 17 months of follow-up, 286 patients (19%) developed new ATA, of whom 92 (6%) had AF and 194 (12%) had SVT. Younger age (≤65 years), diastolic blood pressure ≥72 mm Hg, heart rate ≥63 bpm, absence of diabetes, and prior atrial arrhythmia were independent predictors of ATA. Prior atrial arrhythmia was the only predictor of AF (hazard ratio 3.14; P <.001). New ATA was associated with significantly increased risk for subsequent VA (HR 2.12; P <.001), increased adverse events (HR 1.42; P <.001), and death (HR 1.85; P = .038). New AF and new SVT were both independently associated with >2-fold increased risk for the development of subsequent VA (HR 2.21; P = .012l and HR 2.15; P <.001, respectively) and adverse events.

CONCLUSION

Among MADIT-RIT patients, younger age, absence of diabetes, higher blood pressure, higher heart rate, and prior atrial arrhythmia predicted device-detected ATA. Both AF and SVT were associated with increased risk for subsequent VA and adverse events. Aggressive management should be considered in HF patients who develop new-onset, device-detected ATA to improve clinical outcomes.

Linking the heart and the brain: Neurodevelopmental disorders in patients with catecholaminergic polymorphic ventricular tachycardia

BACKGROUND

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an uncommon inherited arrhythmia disorder characterized by adrenergically evoked ventricular arrhythmias. Mutations in the cardiac calcium release channel/ryanodine receptor gene (RYR2) are identified in the majority of patients with CPVT. RyR2 is also the major RyR isoform expressed in the brain.

OBJECTIVE

The purpose of this study was to estimate the prevalence of intellectual disability (ID) and other neurodevelopmental disorders (NDDs) in RYR2-associated CPVT (CPVT1) and to study the characteristics of these patients.

METHODS

We reviewed the medical records of all CPVT1 patients from 12 international centers and analyzed the characteristics of all CPVT1 patients with concomitant NDDs. We functionally characterized the mutations to assess their response to caffeine activation. We did not correct for potential confounders.

RESULTS

Among 421 CPVT1 patients, we identified 34 patients with ID (8%; 95% confidence interval 6%-11%). Median age at diagnosis was 9.3 years (interquartile range 7.0-14.5). Parents for 24 of 34 patients were available for genetic testing, and 13 of 24 (54%) had a de novo mutation. Severity of ID ranged from mild to severe and was accompanied by other NDDs in 9 patients (26%). Functionally, the ID-associated mutations showed a markedly enhanced response of RyR2 to activation by caffeine. Seventeen patients (50%) also had supraventricular arrhythmias. During median follow-up of 8.4 years (interquartile range 1.8-12.4), 15 patients (45%) experienced an arrhythmic event despite adequate therapy.

CONCLUSION

Our study indicates that ID is more prevalent among CPVT1 patients (8%) than in the general population (1%-3%). This subgroup of CPVT1 patients reveals a malignant cardiac phenotype with marked supraventricular and ventricular arrhythmias.

Early experience with intravenous sotalol in children with and without congenital heart disease

BACKGROUND

Arrhythmias are common in the pediatric population. In patients unable to take oral medications or in need of acute therapy, options of intravenous (IV) antiarrhythmic medications are limited. Recently IV sotalol has become readily available, but experience in children is limited.

OBJECTIVE

The purpose of this study was to describe our initial experience with the use of IV sotalol in the pediatric population.

METHODS

A retrospective study of all pediatric patients receiving IV sotalol was performed. Patient demographic characteristics, presence of congenital heart disease, arrhythmia type, efficacy of IV sotalol use, and adverse effects were evaluated.

RESULTS

A total of 47 patients (26 (55%) male and 24 (51%) with congenital heart disease) received IV sotalol at a median age of 2.05 years (interquartile range 0.07-10.03 years) and a median weight of 12.8 kg (interquartile range 3.8-34.2 kg), and 13 (28%) received IV sotalol in the acute postoperative setting. Supraventricular arrhythmias occurred in 40 patients (85%) and ventricular tachycardia in 7 (15%). Among 24 patients receiving IV sotalol for an active arrhythmia, acute termination was achieved in 21 (88%). Twenty-three patients received IV sotalol as maintenance therapy for recurrent arrhythmias owing to inability to take oral antiarrhythmic medications; 19 (83%) were controlled with sotalol monotherapy. No patient required discontinuation of IV sotalol secondary to adverse effects, proarrhythmia, or QT prolongation.

CONCLUSION

IV sotalol is an effective antiarrhythmic option for pediatric patients and may be an excellent agent for acute termination of active arrhythmias. It was well tolerated, with no patient requiring discontinuation secondary to adverse effects.

Landiolol for managing post-operative atrial fibrillation

Beta-blockers are a potential option to manage peri-operative atrial fibrillation. Landiolol is a new ultra-short beta-blocker with a half-life of only 4 minutes and very high beta-1 selectivity which has been used for treatment and prevention of atrial fibrillation in pulmonary surgery and gastro-intestinal surgery. Due to its limited negative inotropic effect and high beta-1 selectivity landiolol allows for control of heart rate with minimal impact on blood pressure. Landiolol is well tolerated by the respiratory system. Additional benefits are related to the regulation of the inflammatory response and blunting of the adrenergic pathway. There is a limited number of trials with total of 61 patients undergoing lung resection or oesophagectomy who developed post-operative atrial fibrillation and were treated with landiolol. The experience with landiolol for prevention is more documented than landiolol application for treatment of post-operative atrial fibrillation. There are 9 comparative studies with a total of 450 patients administered landiolol for prevention of post-operative atrial fibrillation. The use of low dosage (5-10mcg/kg/min) is usually sufficient to rapidly control heart rate which is associated with earlier and higher rate of conversion to sinus rhythm as compared to the controls. The excellent tolerance of landiolol at lower dosage (3-5mcg/kg/min) allows to initiate prophylactic use during surgery and postoperatively. Landiolol prophylaxis is associated with reduced incidence of post-operative atrial fibrillation without triggering adverse events related to a beta-blockade.

Landiolol for managing atrial fibrillation in intensive care

Landiolol is an injectable ultrashort acting beta-blocker with high beta1 selectivity indicated for heart rate control of atrial fibrillation in the emergency and critical care setting. Accordingly, landiolol is associated with a significantly reduced risk of arterial hypotension and negative inotropic effects. Based on this particular profile along with the clinical experience in Japan for more than a decade landiolol represents a promising agent for the management of elevated heart rate and atrial fibrillation in intensive care patients even with catecholamine requirements. This article provides a review and perspective of landiolol for heart rate control in intensive care patients based on the current literature.

Propafenone for supraventricular arrhythmias in septic shock-Comparison to amiodarone and metoprolol

PURPOSE

The occurence of supraventricular arrhythmias associate with an unfavourable prognosis in septic shock. Propafenone could be a feasible antiarrhythmic.

MATERIALS AND METHODS

Patients collected over a period of 24months were divided into the three groups based on antiarrhythmic: Group1(amiodarone), Group2(propafenone), Group3(metoprolol). Type of arrhythmia, cardioversion rates, demographic, haemodynamic, laboratory parameters were recorded in the first 24h. The outcome data were compared between the groups.

RESULTS

234 patients (99.1% ventilated) were included, the prevailing arrhythmia was acute onset atrial fibrillation (AF,69.7%). Except for the dosage of noradrenaline (0.35(0.14-0.78) in Group1(n=142)vs 0.25(0.10-0.50),p<0.01 in Group2(n=78)vs 0.14(0.07-0.25)μg/kg·min,p<0.05 in Group3(n=14)) the ejection fraction of left ventricle, rates of renal replacement therapy, arterial lactate and procalcitonin levels were not different between the groups. The cardioversion rate in Group1(74%) was lower than in Group2(89%) and Group3(92%). ICU and 28-day mortalities of Group1 were not significantly higher than in Group2 and Group3. Multivariate analysis demonstrated higher 12-month mortality in Group1 than in Group2 (HR1.58(1.04;2.38),p=0.03).

CONCLUSIONS

Propafenone demonstrated a higher cardioversion rate than amiodarone with a similar impact on the outcome. Patients remaining in acute onset arrhythmia did not demonstrate significantly higher ICU, 28-day and 12-month mortalities compared to those successfully cardioverted or to those having chronic AF.

Paroxysmal Supraventricular Tachycardia: Pathophysiology, Diagnosis, and Management

Paroxysmal supraventricular tachycardia (PSVT) is a well-known and thoroughly studied clinical syndrome, characterized by regular tachycardia rhythm with sudden onset and abrupt termination. Most patients present with palpitations and dizziness, and their electrocardiogram demonstrates a narrow QRS complex and regular tachycardia with hidden or inverted P waves. PSVT is caused by re-entry due to the presence of inhomogeneous, accessory, or concealed conducting pathways. Hemodynamically stable patients are treated by vagal maneuvers, intravenous adenosine, diltiazem, or verapamil, hemodynamically unstable patients are treated by cardioversion. Patients with symptomatic and recurrent PSVT can be treated with long-term drug treatment or catheter ablation.

The Management of Supraventricular Tachyarrhythmias in Patients with Pulmonary Arterial Hypertension

BACKGROUND

Atrial remodelling in pulmonary arterial hypertension (PAH) may lead to higher incidence of supraventricular arrhythmias (SVA). The purpose of this study was to evaluate the efficiency and safety of various methods for treatment of SVA in this group.

METHODS

This was a single centre study. Forty-eight patients (33 women and 15 men) aged 19-77 years (median 49 years) were enrolled. There were 30 patients with idiopathic PAH, 10 had PAH associated with connective tissue disease, and eight with congenital heart disease. A retrospective analysis was performed to estimate the prevalence and type of supraventricular arrhythmias, as well as efficiency and safety of treatment methods. Mean follow-up period was 28.8±17.7 months.

RESULTS

Supraventricular arrhythmias occurred in 17 patients (35%) and appeared to be atrial fibrillation, flutter or tachycardia. Supraventricular arrhythmias coexisted with elevated mean right atrial pressure in 75%. Four patients had more than one type of SVA. A flutter-like macro-reentrant form of atrial tachycardia dependent on cavo-tricuspid isthmus was found in four cases. The treatment of SVA included typical methods: antiarrhythmic drugs, direct current cardioversion (DCC), and radiofrequency (RF) ablation. All of the therapeutic methods were effective in managing acute arrhythmia. Three patients required re-ablation. Overall mortality: 14 patients (29%) in the whole study group, including six in SVA group (35%) and eight without SVA (26%).

CONCLUSIONS

In patients with PAH DCC, pharmacological cardioversion and RF ablation can be applied safely and effectively. Flutter-like macro-reentrant atrial tachycardia dependent on cavo-tricuspid isthmus is observed in this group. It is more challenging, but possible, to successfully treat this arrhythmia with RF ablation.

Cardiorenal axis and arrhythmias: Will renal sympathetic denervation provide additive value to the therapeutic arsenal?

Disruption of sympathetic tone may result in the occurrence or maintenance of cardiac arrhythmias. Multiple arrhythmic therapies that intervene by influencing cardiac sympathetic tone are common in clinical practice. These vary from pharmaceutical (β-blockers, angiotensin-converting enzyme inhibitors, and calcium antagonists) to percutaneous/surgical (cardiac sympathetic denervation) interventions. In some patients, however, these therapies have insufficient prophylactic and therapeutic capabilities. A safe and effective additional therapy wherein sympathetic drive is further attenuated would be expedient. Recently, renal sympathetic denervation (RSD) has been subject of research for various sympathetic nervous system-related diseases. By its presumed afferent and efferent sympatholytic effects, RSD might indirectly attenuate sympathetic outflow via the brain to the heart but might also reduce systemic catecholamine excretion and might therefore reduce catecholamine-sensitive arrhythmias. RSD is subject of research for various sympathetically driven arrhythmias, both supraventricular and ventricular. In this review, we give an overview of the rationale behind RSD as potential therapy in mediating arrhythmias that are triggered by a disrupted sympathetic nervous system and discuss the presently available results from animal and human studies.

Extraction of respiratory myogram interference from the ECG and its application to characterize sleep-related breathing disorders in atrial fibrillation

BACKGROUND AND PURPOSE

Present methods to extract respiratory myogram interference (RMI) from the Holter-ECG and assess effect of supraventricular arrhythmias (SVAs) onto ECG-based detection of sleep-related breathing disorders (SRBDs) and AHI estimation.

METHODS

RMI was quantified as residual energy after ECG cancellation or high-pass filtering for different windowing constellations. In 140 cases without (SET_A) and 10 cases with persistent SVAs (SET_B), respiratory polysomnogram annotations served as reference for SRDB detection from Holter-ECGs. We applied our previously published method to identify SRDBs in 1-min epochs and estimate the AHI based on joint modulations in RMI and QRS-area.

RESULTS

Sensitivity and specificity of 0.855/0.860 in SET_A dropped to 0.831/0.75 in SET_B. A significantly higher number of wake events in SET_B likely contribute to the asymmetric decrease and is consistent with a tendency to overestimate the AHI.

CONCLUSIONS

Despite reduced accuracy, RMI and QRS-area appear relatively robust against SVA and promise Holter-based detection at least of medium to severe SRBDs also in patients with SVAs.

CHADS2 and CHA2DS2-VASc scores can predict thromboembolic events after supraventricular arrhythmia in the critically ill patients

PURPOSE

Prediction of arterial thromboembolic events (ATEs) in relation to supraventricular arrhythmia (SVA) has been poorly investigated in the intensive care unit (ICU). We aimed at evaluating CHADS2 and CHA2DS2-VASc scores to predict SVA-related ATE in the ICU.

METHODS

We conducted a prospective observational study including all the patients except those in the postoperative course of cardiac surgery who presented SVA lasting 30 seconds or longer during their ICU stay. We looked for ATE during ICU stay, at the first and sixth month of follow-up after ICU discharge.

RESULTS

During the 15-month study period, 108 (12.8%) of 846 ICU patients experienced SVA with 12 SVA-related ATE occurring 6 days (3; 13) (median, 10%-90% percentiles) after SVA onset. In our SVA patients, CHADS2 score was 2 (0; 5), and CHA2DS2-VASc score 3 (0; 7). Both CHADS2 (odds ratio (OR), 1.6 [1.1; 2.4]; P = .01) and CHA2DS2-VASc scores (OR, 1.4 [1.04; 1.8]; P = .03) were significantly associated with ATE onset. However, the most accurate threshold for predicting ATE was CHADS2 score of 4 or higher. Using a multivariate analysis, only patient's history of stroke was associated with ATE onset (OR, 9.2 [2.4; 35]; P = .001).

CONCLUSION

CHADS2 and CHA2DS2-VASc scores are predictive of SVA-related thromboembolism in the critically ill patient.

Conversion of supraventricular arrhythmia to normal rhythm by propofol and remifentanil: three cases report

We experienced conversion of supraventricular arrhythmia to normal sinus rhythm in three patients during general anesthesia using propofol and remifentanil. This may be related to direct inhibition of the cardiac conduction system or activation of the parasympathetic system. The literature review suggests that propofol and remifentanil have antiarrhythmic potential, reverting supraventricular arrhythmia during anesthesia.

Magnetic navigation in adults with atrial isomerism (heterotaxy syndrome) and supraventricular arrhythmias

AIMS

We analysed the type and mechanism of supraventricular arrhythmias encountered in a series of symptomatic adults with atrial isomerism undergoing catheter ablation procedures.

METHODS AND RESULTS

The study population included consecutive adults with atrial isomerism who had previously undergone surgical repair or palliation of the associated anomalies. Patients underwent electrophysiological study for symptomatic arrhythmia in our institution between 2010 and 2012 using magnetic navigation in conjunction with CARTO RMT and three-dimensional (3D) image integration. Eight patients (five females) with a median age of 33 years [interquartile range (IQR) 24-39] were studied. Access to the cardiac chambers of interest was obtained retrogradely via the aorta using remotely navigated magnetic catheters in six patients. Radiofrequency ablation successfully targeted twin atrioventricular (AV) nodal reentrant tachycardia in two patients, atrial fibrillation (AF) in three, focal atrial tachycardia (AT) mainly originating in the left-sided atrium in four patients, and macro-reentrant AT dependent on a right-sided inferior isthmus in three patients. The median fluoroscopy time was 3.0 min (IQR 2-11). After a median follow-up of 10 months (IQR 6-21), five of the ablated patients are free from arrhythmia; two patients experienced episodes of self-terminated AF and AT, respectively, within one month post-ablation; the remaining patient had only non-sustained AT during the electrophysiological study and was managed medically.

CONCLUSION

Various supraventricular tachycardia mechanisms are possible in adults with heterotaxy syndrome, all potentially amenable to radiofrequency ablation. The use of remote magnetic navigation along with 3D mapping facilitated the procedures and resulted in a short radiation time.