Short PR Interval Research Articles

Electrocardiographic Clues for Early Diagnosis of Ventricular Pre-Excitation and Non-Invasive Risk Stratification in Athletes: A Practical Guide for Sports Cardiologists.

Ventricular pre-excitation (VP) is a cardiac disorder characterized by the presence of an accessory pathway (AP) that bypasses the atrioventricular node (AVN), which, although often asymptomatic, exposes individuals to an increased risk of re-entrant supraventricular tachycardias and sudden cardiac death (SCD) due to rapid atrial fibrillation (AF) conduction. This condition is particularly significant in sports cardiology, where preparticipation ECG screening is routinely performed on athletes. Professional athletes, given their elevated risk of developing malignant arrhythmias, require careful assessment. Early identification of VP and proper risk stratification are crucial for determining the most appropriate management strategy and ensuring the safety of these individuals during competitive sports. Non-invasive tools, such as resting electrocardiograms (ECGs), ambulatory ECG monitoring, and exercise stress tests, are commonly employed, although their interpretation can sometimes be challenging. This review aims to provide practical tips and electrocardiographic clues for detecting VP beyond the classical triad (short PR interval, delta wave, and prolonged QRS interval) and offers guidance on non-invasive risk stratification. Although the diagnostic gold standard remains invasive electrophysiological study, appropriate interpretation of the ECG can help limit unnecessary referrals for young, often asymptomatic, athletes.

Clinical, electrocardiographic, and diagnostic imaging features and outcomes in cats with electrocardiographic diagnosis of ventricular pre-excitation: a retrospective study of 23 cases (2010–2022)

Introduction/ObjectivesVentricular pre-excitation (VPE) occurs when atrial electrical impulses prematurely excite the ventricles through an aberrant muscle bundle known as an accessory pathway (AP). Orthodromic atrioventricular reciprocating tachycardia is a re-entrant, narrow complex supraventricular tachycardia (SVT), maintained through retrograde conduction over an AP. The study aimed to describe patient signalments, clinical signs, electrocardiographic (ECG) and diagnostic imaging features, treatments, prognostic variables, and outcomes in cats with ECG diagnosis of VPE. AnimalsTwenty-three cats diagnosed with VPE between January 2010 and August 2022 were included in this study. Materials and MethodsThis was a multicenter, retrospective study with twenty-three cats diagnosed with VPE between January 2010 and August 2022. Ventricular pre-excitation diagnosis was based on ECG evidence of shortened PR interval, delta wave, and prolonged QRS duration. The median survival time (MST) was estimated by the Kaplan-Meier curve. Log-rank tests were performed to assess for an association between clinical signs or presence of structural heart disease on the MST. ResultsFourteen (60.8%) cats with VPE also had SVT documented on ECG, with 7 of 14 with ECG confirmation of orthodromic atrioventricular reciprocating tachycardia. Four (17.4%) cats had suspected AP-mediated tachyarrhythmia based on associated clinical signs. Common presenting signs included collapse (15/23; 65.2%) and respiratory distress (14/23; 60.8%). Five (21.7%) cats were asymptomatic. Heart rate during SVT ranged from 310 to 420 bpm (median: 375 bpm). Initial treatment included atenolol (10/18), sotalol (5/18), diltiazem (2/18), and amiodarone (1/18). From the date of diagnosis, MST was 1872 days (5.1 years). ConclusionsThe majority of cats with VPE also had symptomatic SVT. The prognosis for cats with VPE is considered good with an MST of greater than five years.

Genome-Wide Association Study of Accessory Atrioventricular Pathways.

Understanding of the genetics of accessory atrioventricular pathways (APs) and affiliated arrhythmias is limited. To investigate the genetics of APs and affiliated arrhythmias. This was a genome-wide association study (GWAS) of APs, defined by International Classification of Diseases (ICD) codes and/or confirmed by electrophysiology (EP) study. Genome-wide significant AP variants were tested for association with AP-affiliated arrhythmias: paroxysmal supraventricular tachycardia (PSVT), atrial fibrillation (AF), ventricular tachycardia, and cardiac arrest. AP variants were also tested in data on other heart diseases and measures of cardiac physiology. Individuals with APs and control individuals from Iceland (deCODE Genetics), Denmark (Copenhagen Hospital Biobank, Danish Blood Donor Study, and SupraGen/the Danish General Suburban Population Study [GESUS]), the US (Intermountain Healthcare), and the United Kingdom (UK Biobank) were included. Time of phenotype data collection ranged from January 1983 to December 2022. Data were analyzed from August 2022 to January 2024. Sequence variants. Genome-wide significant association of sequence variants with APs. The GWAS included 2310 individuals with APs (median [IQR] age, 43 [28-57] years; 1252 [54.2%] male and 1058 [45.8%] female) and 1 206 977 control individuals (median [IQR] year of birth, 1955 [1945-1970]; 632 888 [52.4%] female and 574 089 [47.6%] male). Of the individuals with APs, 909 had been confirmed in EP study. Three common missense variants were associated with APs, in the genes CCDC141 (p.Arg935Trp: adjusted odds ratio [aOR], 1.37; 95% CI, 1.24-1.52, and p.Ala141Val: aOR, 1.55; 95% CI 1.34-1.80) and SCN10A (p.Ala1073Val: OR, 1.22; 95% CI, 1.15-1.30). The 3 variants associated with PSVT and the SCN10A variant associated with AF, supporting an effect on AP-affiliated arrhythmias. All 3 AP risk alleles were associated with higher heart rate and shorter PR interval, and have reported associations with chronotropic response. Associations were found between sequence variants and APs that were also associated with risk of PSVT, and thus likely atrioventricular reentrant tachycardia, but had allele-specific associations with AF and conduction disorders. Genetic variation in the modulation of heart rate, chronotropic response, and atrial or atrioventricular node conduction velocity may play a role in the risk of AP-affiliated arrhythmias. Further research into CCDC141 could provide insights for antiarrhythmic therapeutic targeting in the presence of an AP.

What an anesthesiologist should know about pediatric arrhythmias.

Identifying and treating pediatric arrhythmias is essential for pediatric anesthesiologists. Pediatric patients can present with narrow or wide complex tachycardias, though the former is more common. Patients with inherited channelopathies or cardiomyopathies are at increased risk. Since most pediatric patients present for anesthesia without a baseline electrocardiogram, the first identification of an arrhythmia may occur under general anesthesia. Supraventricular tachycardia, the most common pediatric tachyarrhythmia, represents a broad category of predominately narrow complex tachycardias. Stimulating events including intubation, vascular guidewire manipulation, and surgical stimulation can trigger episodes. Valsalva maneuvers are unreliable as treatment, making adenosine or other intravenous antiarrhythmics the preferred acute therapy. Reentrant tachycardias are the most common supraventricular tachycardia in pediatric patients, including atrioventricular reciprocating tachycardia (due to a distinct accessory pathway) and atrioventricular nodal reentrant tachycardia (due to an accessory pathway within the atrioventricular node). Patients with ventricular preexcitation, often referred to as Wolff-Parkinson-White syndrome, have a wide QRS with short PR interval, indicating antegrade conduction through the accessory pathway. These patients are at risk for sudden death if atrial fibrillation degenerates into ventricular fibrillation over a high-risk accessory pathway. Automatic tachycardias, such as atrial tachycardia and junctional ectopic tachycardia, are causes of supraventricular tachycardia in pediatric patients, the latter most typically noted after cardiac surgery. Patients with inherited arrhythmia syndromes, such as congenital long QT syndrome, are at risk of developing ventricular arrhythmias such as polymorphic ventricular tachycardia (Torsades de Pointes) which can be exacerbated by QT prolonging medications. Patients with catecholaminergic polymorphic ventricular tachycardia are at particular risk for developing bidirectional ventricular tachycardia or ventricular fibrillation during exogenous or endogenous catecholamine surges. Non-selective beta blockers are first line for most forms of long QT syndrome as well as catecholaminergic polymorphic ventricular tachycardia. Anesthesiologists should review the impact of medications on the QT interval and transmural dispersion of repolarization, to limit increasing the risk of Torsades de Pointes in patients with long QT syndrome. This review explores the key anesthetic considerations for these arrhythmias.

Impact of Smokeless Tobacco on Cardiovascular Disease Risk in a Nigerian Metropolitan City.

The use of smokeless tobacco products (STP) as a substitute for tobacco smoking is driving increasing consumption of these products especially in developing countries. The study sought to make comparison of cardiovascular risk profile between chronic STP users and suitably matched tobacco-naïve controls. This is a preliminary report from the cross sectional part of a two-arm prospective study of Smokeless Tobacco Products Composition and Exposure Outcome in Enugu metropolis, Nigeria. Consecutively recruited current Smokeless tobacco users, who had no history of cigarette smoking, aged 18years and above, residing in selected communities in Enugu metropolis, Nigeria were recruited for the study from October 2022 to July 2023. Age and sex matched non-tobacco users from same localities as the study subjects served as controls. Written informed consent to participate in the study was obtained from all study participants. All participants were screened by the investigators, using the study case report forms, to obtain data on medical history, demographic, clinical, laboratory, and electrocardiographic evaluation. Data from 54 STP-users and 54 non-STP-users (mean age 56.58 ± 8.15years) were analyzed. Anthropometric parameters were similar in both groups. Smokeless tobacco users had higher erect and supine blood pressure indices as well asgreater postural drop in systolic blood pressure. The occurrence of diabetes mellitus (20.37% versus 5.56%) and hypertension (25.93%; 11.11%) was significantly higher in the STP-users than in the non-user population, (p = 0.02192 and 0.04751 respectively). Electrocardiographic evaluation showed significantly increased QTc and dispersions of P-wave, QRS and QT intervals as well as reduced PR interval in STP users. Electrocardiographic abnormalities observed in STP users include left ventricular hypertrophy, left atrial enlargement, ST-segment elevation, short PR interval and long QTc. Use of smokeless tobacco products is associated with increased risk burden of diabetes mellitus and hypertensive heart disease. Electrocardiographic findings linked to STP-use in this study are features consistent with arrhythmia, ventricular repolarization abnormality, myocardial hypertrophy and ischaemia, suggesting that smokeless tobacco products are not safe substitutes for tobacco smoking.

Recurrent Orthodromic SVT AVRT with Multiple Accessory Pathway in WPW Syndrome: Ablate All or Not?

Background: Patients diagnosed with Wolff-Parkinson-White syndrome (WPW) have a relatively low, nevertheless persistent risk of unexpected mortality. However, this risk can be effectively mitigated by applying radiofrequency catheter ablation targeting the accessory pathway. It is difficult to accurately study predictors because only a minority of patients develop potentially malignant arrhythmias (MA) or passed away, despite essential risk variables being relatively well-known.1 This study aimed to describe ablation in WPW syndrome. Case presentation: A 16-year-old male presents with symptoms characterized by palpitations during intense physical exertion, followed by chest pain episodes. The physical examination, CXR, laboratorium, and echocardiography were all within the normal range; his ECG showed shortened PR interval and a delta wave with a positive delta wave at V1 and mostly positive at the inferior lead. He also has recorded ECG when the patient has a tachycardia event with SVT AVRT orthodromic pattern. He underwent EP Study and had several accessory pathways at the posteroseptal mitral annulus and anteroseptal tricuspid. The decision was made to perform ablation on the posteroseptal accessory pathway located at the mitral annulus. An electrophysiology (EP) investigation was conducted at the anteroseptal tricuspid annulus, which did not induce tachyarrhythmia. Conclusion: Wolff-Parkinson-White syndrome is a congenital cardiac pathway formation, with not all accessory pathways causing tachyarrhythmias. Ablation therapy is necessary for patients with multiple pathways, with pathways with an ERP less than 250 being the only option. Keyword: Ablation, Multiple Accessories Pathway, SVT AVRT Orthodromic, WPW Syndrome.

Assessment of Heart Rate Variability in Children with Mitral Valve Prolapse.

Mitral valve prolapse (MVP) is a heart valve anomaly with specific electrocardiographic findings and arrhythmia. A predominant sympathetic tone and diminished vagal activity have been reported especially in symptomatic MVP patients. In the current study, we aim to review heart rate variability (HRV) parameters of MVP children in order to determine if there is an impaired autonomic regulation. The data of children with MVP were retrospectively analyzed. Demographic characteristics, body mass index, symptomatology, MVP type and mitral regurgitation, MVP-related electrocardiographic changes, arrhythmia, and HRV parameters in 24-h Holter monitoring were recorded. HRV parameters of the control group were obtained from children applying for sport participation. Statistical significance limit was accepted as p < 0.05. 154 of the patients (74.8%) were girls, the median age was 13.58 ± 2.99years. While MVP patients had shorter PR intervals, those who had syncope had longer PR intervals. Short PR distance may be a feature of MVP, long PR distance may be a condition associated with syncope with the underlying paroxysmal atrioventricular block. Moreover, the minimum heart rate was significantly lower in the MVP group compared to the control and there were no significant differences in terms of remaining parameters. The number of low LF values was higher in MVP patients than the control. Comparing HRV values of groups by gender, we found that overall HRV parameters were lower in girls with MVP while minimum, maximum, and average heart rate were lower in boys with MVP. Impaired HRV associated with MVP could be age, gender, and symptom related. In addition, low LF may indicate impaired baroreflex sensitivity in MVP patients.

Cardiac Findings in Patients 6-60 Months of Age Filipinos with Acute Malnutrition: A Preliminary Study

There is a consensus that cardiac size is reduced in proportion to body mass in malnourished children, but with conflicting findings in cardiac functions. This descriptive-cross sectional study was conducted at a tertiary hospital to evaluate the cardiac findings among patients 6-60 months old with acute malnutrition using chest x-ray, electrocardiogram (ECG), and 2-D echocardiogram (2D-echo). Included in the study were 22 patients. Fourteen (14) of whom had moderate acute malnutrition (MAM) while 8 had severe acute malnutrition (SAM). Both the MAM and SAM groups have cardiothoracic (CT) ratios within normal range but lower than the mean for MAM patients 6-36 months old. ECG studies generally showed low R wave amplitude in both groups and shortened PR interval in the SAM group. Sinus tachycardia appeared to be more common in the SAM group at 50% (4/8) compared to the MAM group at 21% (3/14). 2D-echo measurements of chamber and wall dimensions on both groups were within normal limits; comparison of both groups showed the SAM group had lower left atrial dimensions and left ventricular end-systolic dimensions (LVESD) compared to the MAM group (p values of 0.006 and 0.037 respectively). Pulmonary artery pressure was higher in SAM compared to MAM with a p value of 0.026. In both groups, systolic and diastolic functions were within normal range. MAM patients 6-36 months of age have CT ratios lower than the mean. Low R wave amplitudes are seen in both groups. Those with SAM have more tachycardia and shorter PR interval. There is a trend for the SAM group to have a smaller left atrial and left ventricular end-systolic dimensions and higher pulmonary artery pressure. Systolic and diastolic functions are preserved in both groups. These cardiac findings are suggestive of the effects of malnutrition on the heart.

ECG at the Bedside: Atrial Bigeminy with Alternating long and Short PR Interval

The admission electrocardiogram of an 88-year-old woman, showed sinus rhythm, biphasic P waves in leads II, III, with the terminal vector directed upward, P duration 130 msec, PR interval 200 msec, consistent with advanced inter-atrial block. Next, atrial bigeminy occurred originating in the left atrium and delaying the sinus P waves. With the ectopic P’ measuring 60 msec, the likely path of left atrial stimuli to delaying the sinus node was through Bachmann’s bundle, by retrograde conduction. This means that inter-atrial conduction via Bachmann bundle.

Serial Electrocardiograms Show Acute Onset of Inverted P Waves in a 62-Year-Old-Male with Chest Pain

Iatrogenic events are common causes of EMS encounters. This report present the case of a 62-year-old male who presented with new-onset chest pain after his primary care provider increased his diltiazem dose to better control atrial fibrillation. The patient presented with nausea, vomiting, diaphoresis, and 8/10 sub-sternal chest pain. Sequential ECGs captured the initiation of a junctional rhythm indicated by negative (inverted) P waves and a shortened PR interval. The patient had also been prescribed dofetilide (Tikosyn), which can raise diltiazem levels. The case emphasizes the importance of recognizing arrhythmias associated with retrograde A/V conduction and raises awareness of potential iatrogenic events as causes for pre-hospital encounters.

Clinical utilisation of implantable loop recorders in adults with Fabry disease-a multi-centre snapshot study.

Fabry disease (FD) is an X-linked deficiency of alpha-galactosidase-A, leading to lysosomal storage of sphingolipids in multiple organs. Myocardial accumulation contributes to arrhythmia and sudden death, the most common cause of FD mortality. Therefore, there is a need for risk stratification and prediction to target device therapy. Implantable loop recorders (ILRs) allow for continual rhythm monitoring for up to 3 years. Here, we performed a retrospective study to evaluate current ILR utilisation in FD and quantify the burden of arrhythmia that was detected, which resulted in a modification of therapy. This was a snapshot assessment of 915 patients with FD across three specialist centres in England during the period between 1 January 2000 and 1 September 2022. In total, 22 (2.4%) patients underwent clinically indicated ILR implantation. The mean implantation age was 50 years and 13 (59%) patients were female. Following implantation, nine (41%) patients underwent arrhythmia detection, requiring intervention (six on ILR and three post-ILR battery depletion). Three patients experienced sustained atrial high-rate episodes and were started on anticoagulation. Three had non-sustained tachyarrhythmia and were started on beta blockers. Post-ILR battery depletion, one suffered complete heart block and two had sustained ventricular tachycardia, all requiring device therapy. Those with arrhythmia had a shorter PR interval on electrocardiography. This study demonstrates that ILR implantation in FD uncovers a high burden of arrhythmia. ILRs are likely to be underutilised in this pro-arrhythmic cohort, perhaps restricted to those with advanced FD cardiomyopathy. Following battery depletion in three patients as mentioned above, greater vigilance and arrhythmia surveillance are advised for those experiencing major arrhythmic events post-ILR monitoring. Further work is required to establish who would benefit most from implantation.

Electrophysiological basis of cardiac arrhythmia in a mouse model of myotonic dystrophy type 1.

Introduction: Myotonic dystrophy type 1 (DM1) is a multisystemic genetic disorder caused by the increased number of CTG repeats in 3' UTR of Dystrophia Myotonia Protein Kinase (DMPK) gene. DM1 patients experience conduction abnormalities as well as atrial and ventricular arrhythmias with increased susceptibility to sudden cardiac death. The ionic basis of these electrical abnormalities is poorly understood. Methods: We evaluated the surface electrocardiogram (ECG) and key ion currents underlying the action potential (AP) in a mouse model of DM1, DMSXL, which express over 1000 CTG repeats. Sodium current (INa), L-type calcium current (ICaL), transient outward potassium current (Ito), and APs were recorded using the patch-clamp technique. Results: Arrhythmic events on the ECG including sinus bradycardia, conduction defects, and premature ventricular and atrial arrhythmias were observed in DMSXL homozygous mice but not in WT mice. PR interval shortening was observed in homozygous mice while ECG parameters such as QRS duration, and QTc did not change. Further, flecainide prolonged PR, QRS, and QTc visually in DMSXL homozygous mice. At the single ventricular myocyte level, we observed a reduced current density for Ito and ICaL with a positive shift in steady state activation of L-type calcium channels carrying ICaL in DMSXL homozygous mice compared with WT mice. INa densities and action potential duration did not change between DMSXL and WT mice. Conclusion: The reduced current densities of Ito, and ICaL and alterations in gating properties in L-type calcium channels may contribute to the ECG abnormalities in the DMSXL mouse model of DM1. These findings open new avenues for novel targeted therapeutics.

A rare cause of mixed hypertrophic and dilated phenotype cardiomyopathy – the MELAS syndrome

Abstract Introduction MELAS is a systemic hereditary condition that can present as hypertrophic or mixed hypertrophic and dilated phenotype cardiomyopathy in young individuals, although a late-onset form is also described in the literature. Genetic testing is essential for correct diagnosis and appropriate management. Case presentation We present the case of a 22-year-old male who was referred to our center after being diagnosed with NYHA class III heart failure with a mixed hypertrophic and dilated cardiomyopathy. His medical history included stroke episodes, seizures, progressive hypoacusis, neurocognitive impairment, and muscle atrophy. Lactic acidosis and elevated CK levels were also noted. The ECG revealed short PR interval and delta wave in lateral leads. TTE showed mildly dilated and hypertrophied LV and RV with severe biventricular systolic impairment. The CMR study was relevant for ring-like subepicardial fibrosis, predominantly in the medium and apical segments. Brain MRI showed multifocal supratentorial subcortical stroke-like lesions in both cerebral hemispheres, involving multiple vascular territories and following a migratory pattern. Genetic testing confirmed a pathogenic MT-TL1 mutation (m.324A&gt;G) and the patient was diagnosed with MELAS. Further management included specific lifestyle recommendations and cascade genetic screening, as well as starting GDMT for HFrEF. Three months after discharge, his clinical status improved. However, the LVEF remained reduced. After careful consideration, an ICD was implanted for primary prevention. Conclusion A red-flag approach in this young patient, which took into consideration the stroke-like episodes, lactic acidosis, seizures, hypoacusis, myopathy, as well as the short PR interval, led to the correct diagnosis, further confirmed by using the appropriate genetic test. Failure to diagnose affects the patient’s prognosis, as their prognosis and clinical status are influenced by enforcing specific recommendations.

Heart rate stability in a clinical setting and after a short exercise in healthy male volunteers.

Limited data exist on heart rate stabilization in the domiciled nature of phase I clinical studies, particularly when frequent measurements of QT intervals are involved. The present analysis aimed to evaluate heart rate stability in the domiciled nature of, and stabilization after a short exercise. Fifty-six healthy male subjects were included in this analysis. Data during a domiciled clinical setting and after a short exercise were analysed. Mean values of 30 s intervals of collected electrocardiographical data (PR, RR, QT and QTcF intervals) during a 10-min supine resting period in a domiciled nature or after walking up and down three stories (100 steps) were compared to baseline values using paired t-tests or compared to the intrasubject standard deviation. Stable heart rates and stable QTcF intervals observed immediately upon assuming a supine position in the domiciled clinical setting. After the short exercise, PR interval and RR interval were significantly (p < 0.05) shorter for up to 120 s (mean value -9.8 ± 7.2 ms) and 30 s (-160 ± 165 ms, p < 0.05), respectively. QT and QTcF intervals were significantly (p < 0.05) shorter for up to 90 and 120 s postexercise, respectively. Both QT and QTcF intervals stabilized after 2 min, but QT interval remained prolonged while QTcF interval returned to baseline levels. In a clinical setting, male volunteers do not require a waiting period for electrocardiographic parameter normalization. However, accurate measurement of these parameters following a short exercise necessitates a minimum 2-min resting interval.

The Case Files

The Case Files

#5209 ALGALSIDASE-BETA STABILIZES RENAL AND CARDIAC INVOLVEMENT: A FOLLOW-UP STUDY OF A BRAZILIAN FABRY DISEASE FAMILY

Abstract Background and Aims Fabry Disease (FD) is a multisystemic disorder that affects the function of major organs, such as the kidneys, the heart and the central nervous system, reducing the quality of life and leading ultimately to premature death. Early diagnosis and timely treatment are the cornerstones to change the natural history of this disorder. Method To evaluate clinical, laboratory and renal histological profiles of FD patients with a classic pathogenic variant (p.G35V), identified by targeted screening in hemodialysis patients followed by family screening, who were under enzyme replacement therapy (ERT), algalsidase-beta (0.1 mg/kg/e.o.w), for at least 48 months. Kidney biopsy was performed at baseline. Glomerular filtration rate, estimated according to the CKD-Epi equation, 24h-urinary protein and albumin were measured annually. Cardiac manifestations were evaluated by eletrocardiogram, transthoracic echocardiography (TTE) or magnetic resonance imaging (cMRI) at baseline and at the end of the study. cMRI was not performed in the index patient, due to CKD 5D, and in a pregnant female patient. Results Nine patients (age: 33.8±12.3 years) were followed-up for 80.67±5.43 months. Their main clinical manifestations were hypohidrosis (67%) gastrointestinal symptoms (56%), cornea verticilata and acroparesthesia (100%). Angiokeratomas were present only in males (100%). Five (56%) and 3 (33%) patients presented CKD G1 and G2, respectively. Only the index case presented CKD G5D. Short PR interval was observed in 44.4%. LVH was detected by TTE in 2 patients (index case and a 46-years old female); whereas based on cMRI no patient had LVH and one female had myocardial fibrosis. Patients received ERT for 70.22±12.92 months, together with adequate adjunctive therapy. eGFR and proteinuria / albuminuria remained stable during the follow-up in both sexes. Female patients presented a mean reduction of LV mass index of 9.73g/m2 (CI95%: -26.9 - 6.8). Patients who started ERT older than 30 years tended to have a higher interventricular septal thickness at the end of the follow-up (8.4 ± 2.2 vs 10.0 ± 2.7 mm; P = .08). Concerning the kidney biopsy findings, patients with higher proteinuria presented more global glomeruli sclerosis; and mild interstitial fibrosis (5%) could be detected even among young patients with normal albuminuria and eGFR. There was a significant correlation between baseline global glomeruli sclerosis and albuminuria at baseline (r=0.9; P = .01) and at the end of the follow-up (r=0.87; P = .01); and between baseline interstitial fibrosis and proteinuria at the end of the follow-up (r=0.80; P = .03). Conclusion Females with a pathogenic variant (p.G35V) for FD may develop cardiac and renal injury. FD-related renal histological changes and chronic tissue damage may be present before clinical and laboratory signs of renal dysfunction. Persistence of proteinuria during ERT might be related to the presence of interstitial fibrosis. Treatment with ERT may stabilize renal and cardiac involvement in FD. Regular monitoring and adequate pathogenetic and adjunctive treatment should be offered to FD patients of both sexes. Kidney biopsy is an important tool to evaluate pre-clinical renal involvement. Timely treatment may potentially change the natural history of the disease.

PO-05-147 RIGHT ON Q: WIDE-COMPLEX TACHYCARDIA IN SETTING OF DEXTROPOSITION

Dextroposition is a rare cardiac malformation defined as rightward cardiac displacement with leftward apex, vs. dextrocardia, which is rightward base-axis orientation. We report the second known case of dextroposition with accessory pathway, presenting as preexcited atrial tachycardia. Abnormal anatomy complicates ECG localization and pathway ablation. N/A N/A A 50-year-old woman was admitted with respiratory distress due to EBV infection. Chest X-ray showed right-sided heart. A month later, she presented in wide-complex tachycardia, rate 205 bpm. She was cardioverted after minimal response to procainamide/adenosine. Post-cardioversion ECG showed short PR interval and preexcitation, confirming presence of accessory pathway. However, the wide-complex tachycardia had morphology identical to baseline, supporting preexcited atrial tachycardia over AVRT. Despite X-ray findings and reverse R-wave progression in precordial leads, presence of left axis deviation and initial negative deflection in aVR argued against dextrocardia. Moreover, aVR had negative T- and P-waves, findings associated with levocardia. Thus, dextroposition was suspected. Millstein and Arruda criteria suggested posteroseptal accessory pathway, but no data on their applicability in right-sided heart exist. EP study was performed. Eccentric VA conduction was noted. Earliest activation was at proximal coronary sinus. During isoproterenol infusion, patient went into atrial tachycardia, cycle length 420ms. Multiple AT foci were identified, including at right atrial appendage and tricuspid annulus. During ablation, patient developed atrial fibrillation with preexcited RR <250ms, confirming high-risk accessory pathway. Given numerous AT foci and high risk, it was decided to focus on pathway over tachycardia sites. Pathway was successfully ablated at ostia of coronary sinus and middle cardiac vein. One prior case of accessory pathway ablation in dextroposition has been reported. This patient had left lateral pathway and multiple congenital abnormalities including lung hypoplasia. While our patient was found to have multifocal atrial tachycardia, she had no clinical or radiographic lung disease. ECG changes in dextroposition are less predictable than in dextrocardia; they vary with cardiac rotation, axis position, and lead position. Comorbid accessory pathway is rare; ECG-anatomy relationship is ill-defined. Structural abnormalities pose individual challenges during electrophysiologic procedures.

Incidental WPW Pattern in a Patient of Acute Coronary Syndrome: Case Report and Review of Literature

Electrocardiographic features of a short PR interval, a delta wave, and a wide QRS complex constitutes a Wolff-Parkinson-White (WPW) pattern. Asymptomatic electrocardiographic findings are defined as a WPW pattern. Symptomatic patients with these electrocardiographic features have WPW syndrome. WPW syndrome may predispose to arrhythmias such as paroxysmal atrial tachycardia, atrial fibrillation and ventricular tachycardia. Patient’s with WPW syndrome at risk for sudden cardiac death. It is important to recognize the common electrocardiographic characteristics of WPW pattern. The advent of electrophysiological studies (EPS) and radiofrequency ablation has revolutionized the management of WPW syndrome. We are presenting an incidental case report of WPW pattern in a middle aged female with acute coronary syndrome. Keywords: Wolff-Parkinson-White Syndrome, Wolff-Parkinson-White Pattern, Pre-excitation, Accessory pathway, WPW pattern in ACS

Multiple accessory pathways coexisting with a persistent left superior vena cava: a case report

BackgroundWolff–Parkinson–White syndrome is characterized by a short PR interval (delta-wave), long QRS complex, and the appearance of paroxysmal supraventricular tachycardia. Patients with Wolff–Parkinson–White syndrome usually have one accessory pathway, whereas cases with multiple accessory pathways are rare. Persistent left superior vena cava is a vascular anomaly in which the vein drains into the right atrium through the coronary sinus at the junction of the left internal jugular and subclavian veins due to abnormal development of the left cardinal vein. The simultaneous presence of multiple accessory pathways and persistent left superior vena cava has not been reported before.Case presentationA 56-year-old Japanese man with a 5-year history of palpitations was referred for radiofrequency catheter ablation due to increased frequency of tachycardia episodes in the previous 2 months. Persistent left superior vena cava was confirmed by transthoracic echocardiography and computed tomography. An electrophysiological study revealed that the accessory pathways were located in the left lateral wall, anterolateral wall, and posteroseptal region. They were completely ablated with radiofrequency energy application.ConclusionsWe reported an extremely rare case of a patient with multiple accessory pathways and persistent left superior vena cava. Our case may suggest a potential embryological relationship between the multiple accessory pathways and persistent left superior vena cava.

Prolonged PR interval and incidence of atrial fibrillation, heart failure admissions, and mortality in patients with implanted cardiac devices: A real-world survey

Prolongation of the PR interval has long been considered a benign condition, particularly in the setting of nonstructural heart disease. The purpose of this study was to investigate the effect of PR interval on various well-adjudicated cardiovascular outcomes using a large real-world population data of patients with implanted dual-chamber permanent pacemakers or implantable cardioverter-defibrillators. PR intervals were measured during remote transmissions in patients with implanted permanent pacemakers or implantable cardioverter-defibrillators. Study endpoints (time to the first occurrence of AF, heart failure hospitalization [HFH], or death) were obtained between January 2007 and June 2019 from the deidentified Optum de-identified Electronic Health Record dataset. A total of 25,752 patients (age 69.3 ± 13.9 years; 58% male) were evaluated. The average intrinsic PR interval was 185 ± 55 ms. In the subset of 16,730 patients with available long-term device diagnostic data, a total of 2555 (15.3%) individuals developed AF during 2.59 ± 2.18 years of follow-up. The incidence of AF was significantly higher (up to 30%) in patients with a longer PR interval (ie, PR interval ≥270 ms; P < .05). Time-to-event survival analysis and multivariable analysis showed that PR interval ≥190 ms was significantly associated with higher incidence of AF, HFH, or HFH or death when compared with shorter PR intervals (P< .05 for all 3 parameters). In a large real-world population of patients with implanted devices, PR interval prolongation was significantly associated with increased incidence of AF, HFH, or death.