Junctional Escape Research Articles

C8. An Extremely Rare Case: Cardiac Contusion Presenting with an Atrioventricular Block, An Unfortunate Fall

Abstract Background Blunt cardiac injury (BCI), also referred to cardiac contusion, is a known cause of myocardial injury. It is often challenging to diagnose in the absence of clear diagnostic criteria. The clinical manifestation ranges from none to fatal arrhythmias to cardiac wall rupture seen on post-mortem examination. Cardiac biomarkers and electrocardiograms are usually helpful in identifying cardiac trauma but are not necessarily abnormal in all cases. Case Illustration A 55-year-old male with no history of cardiac disease was brought to the emergency department after a motor vehicle collision resulted in chest wall injury. The patient was found to have left clavicle fracture, left costae II-VII fractures, and hematothorax followed by chest tube insertion. The patient had multiple episodes of complete heart block with junctional escape rhythm alternate with high degree 2:1 AV conduction, and sometimes became a normal sinus rhythm. A temporary pacemaker was inserted. After the patient underwent the ORIF procedure, cardiac rhythm revealed normal sinus rhythm and temporary pacemaker is removed. Discussion High-degree AV block has been reported in human studies following BCI, secondary to necrosis, inflammation, or fibrotic changes in the subendocardial tissue. 50% of patients reviewed in the literature had a recurrence or permanent complete heart block requiring pacemaker implantation and complete heart block secondary to BCI which was associated with a 20% mortality in the post-traumatic period. Our patient developed a fatal heart block in the early period which could have easily been missed.

C95. The electrocardiographic changes in a hypertensive COVID-19 patient who received beta-blocker and favipiravir: a case report

BackgroundVarious electrocardiographic manifestations have been reported in COVID-19 which either result from myocarditis or insult-induced re-emerging of pre-existing condition. Some antiviruses used off-labelly for COVID-19, including favipiravir, are considered to be proarrhythmic. Meanwhile, anti-hypertensive drugs such as beta-blocker may induce bradyarrhythmia.Case SummaryA 69-year-old male with confirmed COVID-19 and a history of uncontrolled hypertension presented with blood pressure of 216/111mmHg at admission. No sign and symptom of acute target organ damage had been reported. His electrocardiography showed normal sinus rhythm (heart rate [HR] 60bpm). The echocardiographic finding revealed normal heart function. He received favipiravir for 5 days, intravenous nicardipine (0.5mcg/kgBW/hour), and peroral amlodipine (1x10mg), candesartan (1x16mg), and bisoprolol (1x2.5mg). During hospitalization, the HR fluctuated between 52-109. On the sixth day, a total atrioventricular (AV) block with junctional escape rhythm (HR 66bpm) was present. Both favipiravir and bisoprolol were ceased simultaneously. The AV block persisted for 4 days then transformed into a junctional rhythm for the next 3 days and sinus bradycardia (HR 48bpm) thereafter. No pacing was performed.DiscussionThe possible differential diagnoses in this case include sick sinus syndrome (SSS), COVID-19-induced myocarditis, and drug-induced. The SSS might explain the wide variability of the HR. There were some reports presenting the sinus node dysfunction as a manifestation of SARS-CoV-2 infection. Further evaluation using Holter and/or electrophysiological study is warranted. Drug-induced cause may be excluded because the bradyarrhythmia remained after the cessation of both beta-blocker and favipiravir.

C8. An Extremely Rare Case: Cardiac Contusion Presenting with an Atrioventricular Block, An Unfortunate Fall

Abstract Background Blunt cardiac injury (BCI), also referred to cardiac contusion, is a known cause of myocardial injury. It is often challenging to diagnose in the absence of clear diagnostic criteria. The clinical manifestation ranges from none to fatal arrhythmias to cardiac wall rupture seen on post-mortem examination. Cardiac biomarkers and electrocardiograms are usually helpful in identifying cardiac trauma but are not necessarily abnormal in all cases. Case Illustration A 55-year-old male with no history of cardiac disease was brought to the emergency department after a motor vehicle collision resulted in chest wall injury. The patient was found to have left clavicle fracture, left costae II-VII fractures, and hematothorax followed by chest tube insertion. The patient had multiple episodes of complete heart block with junctional escape rhythm alternate with high degree 2:1 AV conduction, and sometimes became a normal sinus rhythm. A temporary pacemaker was inserted. After the patient underwent the ORIF procedure, cardiac rhythm revealed normal sinus rhythm and temporary pacemaker is removed. Discussion High-degree AV block has been reported in human studies following BCI, secondary to necrosis, inflammation, or fibrotic changes in the subendocardial tissue. 50% of patients reviewed in the literature had a recurrence or permanent complete heart block requiring pacemaker implantation and complete heart block secondary to BCI which was associated with a 20% mortality in the post-traumatic period. Our patient developed a fatal heart block in the early period which could have easily been missed.

C95. The electrocardiographic changes in a hypertensive COVID-19 patient who received beta-blocker and favipiravir: a case report

BackgroundVarious electrocardiographic manifestations have been reported in COVID-19 which either result from myocarditis or insult-induced re-emerging of pre-existing condition. Some antiviruses used off-labelly for COVID-19, including favipiravir, are considered to be proarrhythmic. Meanwhile, anti-hypertensive drugs such as beta-blocker may induce bradyarrhythmia.Case SummaryA 69-year-old male with confirmed COVID-19 and a history of uncontrolled hypertension presented with blood pressure of 216/111mmHg at admission. No sign and symptom of acute target organ damage had been reported. His electrocardiography showed normal sinus rhythm (heart rate [HR] 60bpm). The echocardiographic finding revealed normal heart function. He received favipiravir for 5 days, intravenous nicardipine (0.5mcg/kgBW/hour), and peroral amlodipine (1x10mg), candesartan (1x16mg), and bisoprolol (1x2.5mg). During hospitalization, the HR fluctuated between 52-109. On the sixth day, a total atrioventricular (AV) block with junctional escape rhythm (HR 66bpm) was present. Both favipiravir and bisoprolol were ceased simultaneously. The AV block persisted for 4 days then transformed into a junctional rhythm for the next 3 days and sinus bradycardia (HR 48bpm) thereafter. No pacing was performed.DiscussionThe possible differential diagnoses in this case include sick sinus syndrome (SSS), COVID-19-induced myocarditis, and drug-induced. The SSS might explain the wide variability of the HR. There were some reports presenting the sinus node dysfunction as a manifestation of SARS-CoV-2 infection. Further evaluation using Holter and/or electrophysiological study is warranted. Drug-induced cause may be excluded because the bradyarrhythmia remained after the cessation of both beta-blocker and favipiravir.

Abstract 8870: Hemodynamic Impact of Atrial Pacing in Patients with Fontan Physiology and Junctional Rhythm: A Cardiac Catheterization Study

Introduction: Sinus node dysfunction is a common problem and can adversely impact patients who have undergone the Fontan operation (FO). In FO patients with an adequate junctional escape rhythm (JR), the benefit of atrial pacing to restore atrioventricular synchrony remains unclear. We studied the impact of atrial pacing on hemodynamics in patients with FO and JR undergoing cardiac catheterization. Methods: Data was collected retrospectively on all FO patients with JR who underwent atrial pacing during cardiac catheterization. Hemodynamics (pulmonary artery pressure, left atrial pressure, and cardiac index) were obtained at baseline and after atrial pacing for 5-10 minutes. Results: Six patients, with a mean age of 11 years (range 3-21) met inclusion criteria. The type of FO was extracardiac in 5 and a lateral tunnel in one. A pacing catheter was placed through the Fontan fenestration in 4, via the IVC recess behind the right atrium in 1, and via the left pulmonary artery in 1. Patients were paced 10 bpm faster than their JR rate (100 bpm in 3, 88 bpm in 1 and 70 bpm in 2. With pacing, there was a significant decrease in left atrial pressure from (mean ±SEM) 9.4 ± 1.1 mmHg to 5.8 ± 1.4 mmHg (p=0.02), a significant increase in cardiac index from 2.7 ± 0.4 L/min/m 2 to 3.5 ± 0.5 L/min/m 2 (p=0.03) and no significant change in pulmonary artery pressure, from 13mmHg ± 1.4 to 12.2mmHg ± 2.2 (p=0.1) Conclusion: In FO patients with JR, atrial pacing acutely decreased the left atrial pressure, increased the cardiac output and did not result in a significant change in the pulmonary artery pressure. Our study supports further investigation into the utility of prophylactic atrial pacemaker implantation in Fontan patients with significant durations of JR on ambulatory monitoring.

Hemodynamic Impact of Atrial Pacing in Patients with Fontan Physiology and Junctional Rhythm: A Cardiac Catheterization Study.

Sinus node dysfunction is a common problem and adversely impacts patients who have undergone the Fontan operation. In Fontan patients with an adequate junctional escape rhythm, the benefit of atrial pacing to restore atrioventricular synchrony remains unclear. Data were collected retrospectively on all Fontan patients with junctional rhythm who underwent atrial pacing during cardiac catheterization. Hemodynamics were obtained at baseline and after atrial pacing for 5-10min. Seven patients, mean age 10years (3-21) were studied. The type of Fontan was extracardiac in 6 and lateral tunnel in one. Patients were paced at 10bpm faster than their junctional rate. With pacing, there was a significant decrease in left atrial pressure from (mean ± SEM) 8.8 ± 2.6 to 5.5 ± 2.9mmHg (p = 0.02), a significant increase in cardiac index from 2.7 ± 0.8 to 3.5 ± 1 L/min/m2 (p = 0.01) and pulmonary blood flow from 2.1 ± 0.6 to 2.7 ± 0.7 L/min/m2 (p = 0.001), and no significant change in pulmonary artery pressure, from 13.4 ± 2.8 to 12.4mmHg ± 3.6 (p = 0.06) or pulmonary vascular resistance from 2.1 ± 0.86 to 3.25 ± 1.9 WU × M2 (p = 0.1). In Fontan patients with junctional rhythm, atrial pacing decreased the left atrial pressure, increased cardiac output and did not significantly change the pulmonary artery pressure. Our study supports further investigation into the utility of prophylactic atrial pacemaker implantation in Fontan patients with significant durations of JR on ambulatory monitoring.

Junctional Bradikardia pada Pasien Hiperkalemia

Hyperkalemia is a life-threatening electrolyte abnormality resulting in cardiac arrhythmia. Hyperkalemia may also cause bradycardia with junctional rhythm. However, the prevalence of hyperkalemia accompanying symptomatic bradycardia has only been explored in a few case reports. Thus we present a case of hyperkalemia with uncommon ECG findings. It has been reported that a 76 years old woman with type 2 diabetes mellitus, hyperkalemia and suspected coronary artery disease complaining about palpitation. Electrocardiography (ECG) showed junctional bradycardia with tall T wave and laboratory examination showed mild hyperkalemia (5.8 mmol/L). After one day of observation, severe hypotension was detected. Unexpectedly the cardiac rhythm was returned into the sinus after correction of hyperkalemia using calcium gluconate, insulin, dextrose, and salbutamol. As serum potassium level rises, sinoatrial and atrioventricular conduction was blocked, causing escape rhythm (junctional escape rhythm). In hyperkalemia, cardiotoxicity can be caused by an increase in resting membrane potential, decreased depolarization and duration of depolarization. When detected on ECG, hyperkalemia should be treated urgently and important to identify underlying causes or precipitating factors of hyperkalemia. Sinus node dysfunction is not excluded in this case. Hyperkalemia can present a bradycardia junctional rhythm. Although the increasing serum potassium levels were low, hyperkalemia may have affected the conduction system leading to the ECG changes.Keywords: hyperkalemia, junctional bradycardia, symptomatic bradycardia

Junctional Pacemaker May Replace the Sinoatrial Node

Junctional rhythm is usually seen in the clinic with different causes. We report a case of bicuspid aortic valve accompanied by sinoatrial node dysfunction. The junctional escape beat could accelerate with physiological needs and provided for the normal needs of daily life when dysfunction of the sinoatrial node occurred, which provides a new way for the treatment of sinoatrial node dysfunction. Our findings could be potentially significant for identifying causes and choosing appropriate treatment strategies by using ECG monitoring in the clinic in the future.

B-PO04-135 PERCUTANEOUS AND THORACOTOMY BASED SINUS NODE ABLATION USING NANOSECOND PULSED ELECTRIC FIELDS

Sinus node (SN) modification/ ablation is a treatment option for inappropriate sinus tachycardia. It is often achieved using radiofrequency ablation which is slow given the point to point nature of treatments. Nanosecond pulse electric fields (nsPEF) are an emerging, rapid energy delivery modality which offers tissue selectivity. We explored whether acute SN ablation can be achieved with nsPEF. In two canine models, general anesthesia was administered along with paralytics. Pericardial access was obtained percutaneously in one animal and via thoracotomy in the other (Fig 1A, 1D). The area of earliest right atrial activation was identified. Electrograms were recorded before and after nsPEF energy delivery near the SN using a CellFX™ generator (Pulse Biosciences, Hayward, CA). SN ablation was achieved in both animals after delivery of 10-20 Joules of energy via nsPEF. Total duration of nsPEF sequences in each animal was <1 min. There was absence of atrial electrograms with a junctional escape rhythm in the first animal (Fig 1B, 1C) after monopolar nsPEF. Atrial activity from a left sided focus was seen in the second animal (Fig 1E, 1F) after bipolar nsPEF. Phrenic capture persisted after both sinus node ablations post paralytic withdrawal. All changes persisted beyond 30 minutes of energy delivery after which the animals were euthanized. In acute canine experiments, energy delivery via nsPEF was able to quickly ablate the SN percutaneously and via thoracotomy. nsPEF effect on cardiac tissue was demonstrated functionally without requiring histology.

A case of total atrioventricular (AV) block with acute coronary syndrome at a Negara tertiary care hospital: a diagnostic and therapeutic challenge in a resource-limited setting

Background: Total atrioventricular (AV) block describes a conduction disturbance from the atria to the ventricles via conduction through the atrioventricular node (AV node), acute coronary syndromes of mechanism, and being to cause mortality.Case Illustration: A 57-year-old man came with complaints of weakness two months ago, worsening for the last one week accompanied by left side chest pain. The patient is an active smoker without a history of chronic disease. ECG shows a total AV block with a junctional escape rhythm. Patients were treated with 1x75mg clopidogrel therapy, 1 x 80 mg aspirin, 3 x 5 mg ISDN, 5 mg / kg BW / minute, dopamine drip and 1 x 25 mg spironolactone. After being treated for three days with an increase in the maximum dopamine dose, the patient still felt weakness and chest pain on the left side, so the patient was referred to a tertiary hospital for echocardiography and percutaneous coronary intervention (PCI). Conclusion: a total atrioventricular (AV) block after an acute MI is a rare case. Clinical suspicion and proper evaluation of patients is essential for an early diagnosis, referral, and timely definitive treatment, to decrease the morbidity and mortality associated with this disease. Successful reperfusion at AV node is beneficial to the conduction system.

A Case of Prenatal Diagnosis of Congenital Total AV Block on VSD and PDA with Ultrasound

Objective : To report the diagnosis and management of congenital total AV block on VSD and PDA in pregnancy.Method : A case reportCase : A 37-year-old multiparous woman G4P3A0H2 24- 25 weeks of preterm pregnancy with fetal bradycardia, VSD, PDA with ultrasonography and CTG results was FHR 70 bpm. At 37- 38 weeks of pregnancy, termination of pregnancy was performed by cesarean delivery with preparation for complication of fetal AV block. A male baby was born with weight 2600 gram and APGAR score of 8/9. Immediate echocardiography result was situs solitus, VSD PM LR shunt, PDA LR shunt, good left ventricular function, left aortic arch and EF 74%. ECG result was sinus bradycardia, total AV block with junctional escape rhythm. Sternotomy and PPM implantation was performed by cardiothoracic surgeon three hours after the baby was born. Post PPM implantation, ECG results was HR 165 bpm and chest X- rays interpretation was cardiomegaly with plethora. Mother and baby came home in good condition on the 6th day of treatment. On the next baby’s control at 4.5 months obtained a weight of 5.4 kg with the echocardiography results was solitus, VSD PM LàR shunt, VSD muscular multiple 3 pieces LàR shunt, PDA LàR shunt, good right and left ventricular function, and left arch. The child got captopril 2x1.5 mg and planned for a 6-month repeat echocardiography.Conclusion : Congenital of total AV block on VSD and PDA is confirmed by prenatal diagnosis and preparation for comprehensive multidisciplinary management.Keywords: congenital total AV block, fetal bradycardia, fetal echocardiography, PPM, ultrasound

Expert consensus document on automated diagnosis of the electrocardiogram: The task force on automated diagnosis of the electrocardiogram in Japan. Part 1: Nomenclature for diagnosis and abnormal findings.

As these terms should accurately represent the abnormal findings and conditions as much as possible, we propose to unify these terms into terminologies that are not confusing and easy to understand for everyone.

Severe secondary hyperkalemia and arrhythmia from drug interactions between calcium\u2010channel blocker and voriconazole: a case presentation

BackgroundPatients with kidney disease may have concurrent hypertension and infection. Dihydropyridine calcium-channel blockers (CCB) are the most popular class of antihypertensive drugs used in clinical settings and can be metabolized by cytochrome P450 isoenzyme 3A4 (CYP3A4). Voriconazole is a commonly used antifungal treatment and a CYP3A4-inhibitor. Insufficient attention to drug interactions from the concomitant use of CCB and voriconazole may result in serious adverse reactions.Case presentationHere, we report a patient with acute kidney injury on stable anti-neutrophil cytoplasm antibody associated vasculitis who developed hyperkalemia resulting in sinus arrest with junctional escape rhythm attributed to drug interactions of CCB with voriconazole. This is a very rarely reported case and may be an under-recognized complication. After continuous renal replacement therapy and changing the anti-hypertensive drugs, symptoms, and laboratory abnormalities of the patient fully recovered.ConclusionsThis case warns us of severe consequences of drug interactions. Co-prescription of CYP3A4-inhibitors with calcium-channel blockers increases the risk of hypotension and acute kidney injury, which may further induce hyperkalemia and arrhythmia.

Reversible acute Fontan circulation failure secondary to retrogradely conducted junctional rhythm: clinical echocardiographic correlation

BackgroundSequential atrioventricular activation plays a critical role in the physiology of Fontan circulation. Although bradycardia is usually well tolerated, retrogradely conducted junctional rhythm may acutely increase atrial pressure impairing cardiac output. Echocardiographic evaluation can reveal clues of this hemodynamic condition. The clinical impact of arrhythmic disturbance on the follow up of patients who had undergone total cavo-pulmonary connection is well recognized but the role of, transient periods of retrogradely conducted junctional rhythm on the immediate post-operative course is less defined.Case presentationWe describe two cases of acute Fontan circulatory failure due to postoperative retrogradely conducted junctional escape rhythm despite an adequate heart rate and circadian variation. The patients rapidly improved after atrial pacing, allowing discharge with a minimal dose of diuretic.ConclusionIn the absence of any hemodynamic target, hearth rhythm should be systematically checked after TCPC irrespective of adequacy of heart rate. Likewise, efficiency of temporary atrial pacing should be granted and surgeons should have a low threshold for epicardial lead implantation.

Cardiac Pacemaker in Pregnancy: How to Manage?

Despite the increasing use of permanent cardiac pacemakers in a younger patient population, there are little data related to pregnancy. Normal physiologic alterations of pregnancy need to be taken into account in the management of the pregnant woman with a pacemaker in place. Similarly, gestational events including the potential for surgical intervention require a basic knowledge of pacemaker technology and monitoring. We present a case of a patient with junctional escape rhythm and was implanted pacemaker during pregnancy. A 24 years old women referred from obstetric outpatient clinic with asymptomatic bradycardia and cryptogenic stroke 2 years earlier. ECG shows sinus arrest with junctional escape rhythm. After multi-disciplinary discussion, team decided to implant double chamber pacemaker implantation. The pacemaker setting is adjusted to prepare caesarean section at 39 weeks gestation with delivery of an aterm infant. The postoperative course was uneventful. Pre-pregnancy pacemaker settings were re-established after the postpartum period. The current literature on managing pregnant patients with pacemakers is quite limited. Such patients require a multidisciplinary approach to care. Electromagnetic Interference (EMI) should be noticed.

Complete Heart Block In Pregnancy : A Case Report

Background: Complete heart block occurs due to various pathological conditions that cause an infiltration, fibrosis, or lose the connection from a part of the cardiac conduction system. Complete heart block in pregnancy is often caused by congenital anomalies. Around 30% cases, complete heart block remain asymptomatic and not detected until adulthood and may present in pregnancy state and puerperium. When the reversible cause of the AV Block cannot be found, the permanent pacemaker or temporary pacemaker may be indicated when the patients show the symptoms.&#x0D; Case Illusration: A-21 year old female, G2P0A1 preterm pregnancy (27-28 weeks) with bradycardia. From electrocardiograph examination revealed Total AV Block with junctional escape rhytym. Transthoracic echocardiogram shows massive tricuspid regurgitation, early phase of peripartum cardiomyopathy and ejection fraction 36-40%. Caesarean section was peformed due to PPROM. A male baby was born with birth weight of 1100 grams, 32 centimeters of body length and APGAR score of 7/9. The baby was died in NICU on day care 4th, with suspected respiratory problem.&#x0D; Conclusion: Complete heart block in pregnancy is a rare condition. This condition could remain asymptomatic and not detected until pregnancy. Multidisciplinary approach, close monitoring of the symptoms and cardiac functions are needed for patients with CHB.

A Validated Smartphone-based Electrocardiogram Reveals Severe Bradyarrhythmias during Immobilizing Restraint in Mice of Both Sexes and Four Strains.

Mouse handling and restraint affect behavior, physiology, and animal welfare, yet little information is available on how various mouse restraint methods affect cardiovascular parameters. We validated the use of a smartphone-based ECG sys- tem in mice by performing simultaneous smartphone and telemetry ECG recordings in conscious, restrained mice and in anesthetized mice. We observed that mice held in standard immobilizing restraint ("scruffing") experienced severe bradycardia. Mice of both sexes and 4 different strains (BALB/cJ, C57BL/6J, DBA/2J, and FVB/nJ) were restrained by 3 handlers using 3 different restraint methods: light restraint; 3-finger restraint, which creates a dorsal transverse fold of skin; and the standard immobilizing restraint, which creates a dorsal longitudinal fold of skin that results in a crease on the ventral neck. Regardless of the handler, immobilizing restraint, but not 3-finger restraint, produced severe bradycardia with irregular rhythm in all 4 strains and both sexes, with an average decrease in heart rate of 31%, or 211 bpm, and a maximal decrease of 79%, or 542 bpm. When evaluated using telemetry, immobilizing restraint produced severe arrhythmias such as junctional and ventricular escape rhythms, and second- and third-degree atrioventricular block. Sinus pauses were observed for an average of 4 min, but up to 6.8 min after release from immobilizing restraint. Atropine administration to C57BL/6J mice attenuated immobilizing restraint-induced bradycardia, supporting the hypothesis that pressure on cervical baroreceptors during stretching of the neck skin results in a vagally-mediated reflex bradycardia. Because of these profound cardiovascular effects, we recommend using the light or 3-finger restraint and avoiding or minimizing the use of immobilization restraint while handling mice.

Safety of Exercise Testing in the Clinical Chinese Population.

This 18-year cross-sectional study was conducted to provide data on the safety of exercise testing in the clinical Chinese population. We retrospectively identified exercise tests completed at Xiangya Hospital of Central South University from January 1, 2002 to December 31, 2019. From 43,130 unique individuals (50.9% female), a total of consecutive 50,142 tests (standard exercise testing 29,466; cardiopulmonary exercise testing 20,696) were retrieved. Demographics, patients' medical history, exercise testing characteristics, and exercise testing-related adverse events were described. Safety data is expressed as the number of adverse events per 10,000 tests, with 95% confidence interval. The average patients' age was 51 ± 13 years. The majority of patients were diagnosed with at least one disease (N = 44,941, 89.6%). Tests were maximal or symptom-limited. Common clinical symptoms included dizziness (6,822, 13.6%), chest pain or distress (2,760, 5.5%), and musculoskeletal limitations (2,507, 5.0%). Out of 50,142 tests, three adverse events occurred, including one sustained ventricular tachycardia, one sinus arrest with junctional escape rhythm at a rate of 28 bpm, and one syncopal event with fecal and urinary incontinence. The rate of adverse events was 0.8 events per 10,000 tests (95% confidence interval, 0.2–3.0) in men, 0.4 per 10,000 tests (0.7–2.2) in women, and 0.6 per 10,000 tests (0.21.8) total. This study represents the largest dataset analysis of exercise testing in the clinical Chinese population. Our results demonstrate that clinical exercise testing is safe, and the low rate of adverse events related to exercise testing might be due to the overall changes in clinical practice over time.

Spontaneous Termination of Ventricular Fibrillation Captured on Implantable Loop Recorder

A 75-year-old gentleman self-presented following a syncopal event while using a cross trainer at the gym, without prodromal symptoms or chest pain prior to the event. An implantable loop recorder (ILR) had been inserted 12 months earlier following an episode on unexplained syncope on a background of persistent atrial fibrillation. Interrogation of his ILR (Figure) revealed that the patient was in AF transitioning into ventricular flutter (A), subsequent ventricular fibrillation (VF) (B) and then asystole (C) with spontaneous return of circulation in the form of a junctional escape rhythm (D).

Inter/Intra-Atrial Dissociation in Patients With Maze Procedure and Its Clinical Implications: Pseudo-Block and Pseudo-Ventricular Tachycardia.

BackgroundSevere conduction delay and inter/intra‐atrial dissociation may occur in patients who undergo an extensive catheter ablation or a maze procedure for atrial tachyarrhythmia. We report a series of patients with inter/intra‐atrial dissociation that mimicked complete atrioventricular block or ventricular tachycardia.Methods and ResultsWe retrospectively reviewed the medical records of 7 patients who were referred for the evaluation of atrioventricular block (patients 1–6) or ventricular tachycardia (patient 7) that occurred after biatrial maze procedure and valvular surgery. During the electrophysiologic study, slow atrial or junctional escape rhythm dissociated from isolated atrial activity mimicked complete atrioventricular blocks. Intra‐atrial dissociation of the right atrium or left atrium was observed. Atrioventricular nodal conduction from the nondissociated atrium to the ventricle was preserved in all patients, while the conduction from the dissociated atrium was blocked. In patient 7, the pacing of the ventricle by tracking of atrial tachycardia from the nondissociated left atrium/coronary sinus mimicked ventricular tachycardia during pacemaker interrogation. A total of 5 patients received new permanent pacemaker implantations during the index hospitalization for the surgery (n=2) or as a deferred procedure (n=3) according to the treatment for sick sinus syndrome.ConclusionsPseudo‐atrioventricular block or pseudo‐ventricular tachycardia may occur because of inter/intra‐atrial dissociation after a maze procedure. The selection of patients for permanent pacemaker implantation should be determined based on the patient’s symptoms and the status of the escape pacemaker and not on the apparent atrioventricular block. Proper diagnosis is important to avoid unnecessary implantation of a pacemaker or a defibrillator.