Cough-induced severe bradycardia and syncope in a dog.

A 10-year-old spayed female shih tzu dog was brought to the hospital because of recurring syncope that occurred simultaneously with a cough. Physical examination did not reveal an abnormal heart rhythm or abnormal heart sounds. Electrocardiography revealed sinus arrest of 4.7 s with intermittent escape beats during coughing. Additional examinations, including thoracic radiography, clinical pathology, and echocardiography, revealed no abnormalities of concern. Forty-eight-hour Holter monitoring captured 1 syncopal episode following severe coughing, during which the longest sinus arrest lasted 16 s with intermittent escape beats. This observation confirmed our strong suspicion that coughing was the cause of varying degrees of sinus arrest in this dog. Theophylline, codeine, and short-term prednisolone were prescribed to treat the dog's cough. The daily episodes of syncope ceased and coughing decreased. Subsequent 48-hour Holter monitoring revealed no abnormal pauses, and the owner did not report syncope. Theophylline and codeine were continued for 5 mo, during which time no syncope occurred. To our knowledge, this case provides the first clear evidence of a correlation between cough-induced sinus arrest and syncope in a veterinary patient, as confirmed by Holter monitoring and electrocardiography. Key clinical message: Cough-induced severe bradycardia and syncope were identified in a shih tzu dog. After the antitussive medication was adjusted, the signs resolved.

Bradycardie sévère et syncope provoquées par la toux chez un chienUne chienne shih tzu stérilisée âgée de 10 ans a été amenée à l'hôpital en raison d'une syncope récurrente survenue simultanément avec une toux. L'examen physique n'a révélé aucun rythme cardiaque anormal ni bruits cardiaques anormaux. L'électrocardiographie a révélé un arrêt sinusal de 4,7 s avec des battements d'échappements intermittents lors de la toux. Des examens complémentaires, notamment une radiographie thoracique, des analyses en pathologie clinique et une échocardiographie, n'ont révélé aucune anomalie préoccupante. Une surveillance Holter de 48 heures a capturé 1 épisode syncopal à la suite d'une toux sévère, au cours duquel l'arrêt sinusal le plus long a duré 16 s avec des battements d'échappements intermittents. Cette observation a confirmé nos fortes suspicions selon lesquelles la toux était la cause de divers degrés d'arrêt sinusal chez ce chien. De la théophylline, de la codéine et de la prednisolone de courte durée ont été prescrites pour traiter la toux du chien. Les épisodes quotidiens de syncope ont cessé et la toux a diminué. Une surveillance Holter ultérieure de 48 heures n'a révélé aucune pause anormale et le propriétaire n'a pas signalé de syncope. La théophylline et la codéine ont été poursuivies pendant 5 mois, période pendant laquelle aucune syncope ne s'est produite. À notre connaissance, ce cas constitue la première preuve claire d'une corrélation entre l'arrêt sinusal induit par la toux et la syncope chez un patient vétérinaire, comme le confirme la surveillance Holter et l'électrocardiographie.Message clinique clé :Une bradycardie et une syncope sévères induites par la toux ont été identifiées chez un chien shih tzu. Après ajustement du traitement antitussif, les signes ont disparu.(Traduit par Dr Serge Messier).

Bradycardia-dependent conduction block of the atrial tissue in a patient after double-chamber implantable cardioverter defibrillator implantation.

Seldom are reports of phase 4 block or bradycardia-dependent conduction block in atrial tissue found in the literature. Here, we describe the case of a patient with sick sinus syndrome with Torsade de Pointes who, following the implantation of a double-chamber implantable cardioverter defibrillator, developed intra-atrial bradycardia-dependent conduction block. The patient's optimal pacing parameters were achieved by raising the rate.

Ablation of myocardial autonomic ganglion plexus in the treatment of bradyarrhythmia A one-arm interventional study.

OBJECTIVES: To study the complications and effectiveness of the treatment of chronic arrhythmias with cardiac Ganglion Plexus (GP) ablation, and to explore the value of the treatment of chronic arrhythmias with GP ablation. METHODS: This study was a one-arm interventional study of patients from the first hospital of Xinjiang Medical University and the People's Hospital of Xuancheng City admitted (09/2018-08/2021) because of bradyarrhythmia. The left atrium was modeled using the Carto3 mapping system. The ablation endpoint was the absence of a vagal response under anatomically localized and high-frequency stimulation guidance. Postoperative routine follow-up was conducted. Holter data at 3-, 6-, and 12-months were recorded. RESULTS: Fifty patients (25 male, mean age 33.16 ± 7.89 years) were induced vagal response by either LSGP, LIGP, RAGP, or RIGP. The heart rate was stable at 76 bpm, SNRT 1.092s. DC, DR, HR, SDNN, RMSSD values were lower than that before ablation. AC, SSR, TH values were higher than those before ablation, mean heart rate and the slowest heart rate were significantly increased. There were significant differences in follow-up data between the preoperative and postoperative periods (all p < 0.05). All the patients were successfully ablated, and their blood pressure decreased significantly. No complications such as vascular damage, vascular embolism and pericardial effusion occurred. CONCLUSIONS: Left Atrial GP ablation has good long-term clinical results and can be used as a treatment option for patients with bradyarrhythmia.

A Case of Symptomatic Bradycardia After Valve Replacement.

Editor's note: This is the next installment in a series on electrocardiogram (ECG) interpretation. Nurses in all settings should know the basics, as medications and physiological changes can cause cardiac arrhythmias. Each article will start with a brief case scenario and an ECG strip and then take you step by step through analyzing the heart rhythm.

Fetal bradycardia in open versus fetoscopic prenatal repair of spina bifida.

OBJECTIVE: To compare the occurrence of fetal bradycardia in open versus fetoscopic fetal spina bifida surgery. METHODS: This is a single-institution retrospective cohort study of patients undergoing open (n = 25) or fetoscopic (n = 26) spina bifida repair between 2017 and 2022. From October 2017 to June 2020, spina bifida repairs were performed via an open classical hysterotomy, and from November 2020 to June 2022 fetoscopic repairs were performed following transition to this technique. Fetal heart rate (FHR) in beats per minute (bpm) was recorded via echocardiography every 15 min during the procedure. Cohort characteristics, fetal bradycardia and maternal physiologic parameters were compared between the groups. RESULTS: Fetuses undergoing an open repair more frequently developed bradycardia defined as <110 bpm (32% vs. 3.8%, p = 0.008), and a trend was observed for FHR decreases more than 25 bpm from baseline (20% vs. 3.8%, p = 0.073). Profound bradycardia less than 80 bpm was rare, occurring in only three operations (two in open, one in fetoscopic repair) with two fetuses (one in each group) requiring emergency cesarean delivery. CONCLUSION: When compared to open fetal surgery, fetal bradycardia occurred less frequently in fetoscopic surgery despite a significantly greater anesthetic exposure and the use of the intraamniotic carbon dioxide insufflation.

Hypothermia, bradycardia, and hypotension during glucocorticoid or cyclosporine A therapy in a boy with Kikuchi-Fujimoto disease.

Kikuchi-Fujimoto disease (KFD) is an inflammatory disease of unknown aetiology characterised by fever and cervical lymphadenopathy. Although KFD is a self-limiting disease, patients with severe or long-lasting course require glucocorticoid therapy. We presently report a 17-year-old boy with KFD who had seven relapses since the onset at 4 years old. He suffered from hypothermia, bradycardia, and hypotension during the treatment with prednisolone or methylprednisolone. All of his vital signs recovered after cessation of the drug in addition to fluid replacement and warming. Thus, glucocorticoid was effective but could not be continued because of the adverse event. Although hypothermia developed during the treatment with 5 mg/kg/day of cyclosporine A (CsA) at his second relapse, he was successfully treated with lower-dose CsA (3 mg/kg/day). Thereafter, he had five relapses of KFD until the age of 12 years and was treated by 1.3-2.5 mg/kg/day of CsA. Hypothermia accompanied by bradycardia and hypotension developed soon after concomitant administration of ibuprofen at his fifth and sixth relapses even during low-dose CsA therapy. Conclusively, glucocorticoid, standard dose of CsA, or concomitant use of non-steroidal anti-inflammatory drugs may cause hypothermia, bradycardia, and hypotension and needs special attention. Low-dose CsA could be a choice for such cases with KFD.

Pacemaker Implantation Following Heart Transplantation - Incidence and Risk Factors. Single-Center Experience.

BACKGROUND: Bradyarrhythmias, requiring pacemaker (PM) implantation, are common complications following orthotopic heart transplantation (HTx). Currently used heart transplantation methods are primarily the bicaval technique and the total heart transplantation technique. The aim of the study was to assess the incidence and risk factors, including donor parameters, of conduction disorders requiring pacing after HTx. METHODS: A population of 111 (52 ± 13 years, 91 (82%) men) heart recipients was divided into a group requiring PM implantation post-HTx and a group not requiring PM. We compared groups in terms of donor parameters, time of graft ischemia, transport and transplantation, and surgical techniques as the potential risk factors for significant bradyarrhythmias. RESULTS: Ten of 111 patients with HTx (9%) required PM implantation. The indication in 7 cases was sinus node dysfunction (SND), in 3 patients it was complete atrioventricular block (AV-block). In the PM group, the age of 48 ± 6 vs 40 ± 11 years (P = .0227) and the body mass index (BMI) 28 ± 3 vs 26 ± 4 kg/m2 (P = .0297) of the donor were significantly higher. There was no influence of organ transport time, ischemia time, and transplantation time. All patients requiring PM implantation were transplanted using the bicaval anastomosis: 10 (100%) vs 71 (70%) in the group not requiring PM (P = .044). CONCLUSIONS: The need for PM implantation post-HTx despite using new techniques is still common, especially in the group operated with the bicaval method. In addition, higher donor's age and BMI are risk factors of PM implantation, what is of importance as qualification criteria of donor hearts have been gradually extended.

[Bradyarrythmias in acute coronary syndromes]. / Bradyarythmies dans le syndrome coronarien aigu.

In up to 30-40% of the cases acute coronary syndrome (ACS) is complicated by cardiac arrhythmias. The latter can be benign or malignant and mainly occur during the first 24 hours after myocardial infarction. Ischemia time being the key factor, arrythmias decreased dramatically since the implementation of accelerated reperfusion strategies. Bradyarrhythmias are often benign and self-limiting and are less frequent than tachyarrhythmias but can sometimes require specific treatment. The objective of this article is to provide an update on bradycardia and conduction system disorders occurring during ACS and their management.

Le syndrome coronarien aigu (SCA) est compliqué d'arythmies cardiaques jusque dans 30 à 40 % des cas. Celles-ci peuvent être bénignes ou malignes et surviennent principalement durant les premières 24 heures après l'infarctus du myocarde (IDM). Le temps d'ischémie étant le facteur clé, elles sont en baisse depuis la mise en place de stratégies de reperfusion accélérées. Les bradyarythmies, souvent bénignes et spontanément résolutives, sont moins fréquentes que les tachyarythmies mais peuvent parfois nécessiter une prise en charge spécifique. L'objectif de cet article est une mise à jour sur les bradycardies et troubles de la conduction survenant lors d'un SCA ainsi que leurs prises en charge.

Impact of Cardiac Pacemaker Implantation in Patients With Acute Traumatic Cervical Spinal Cord Injury.

BACKGROUND: Cardiac pacemaker implantation may be indicated in patients with refractory bradycardia following a cervical spinal cord injury (CSCI). However, evidence about the impact of this procedure on outcomes is lacking. We planned a study to assess whether the implantation of a pacemaker would decrease mortality and hospital resource utilization in patients with CSCI. METHODS: Adult patients with CSCI in the Trauma Quality Improvement Program (TQIP) database between 2016 and 2019 were retrospectively analyzed. Patients were divided into "pacemaker" and "non-pacemaker" groups, and their baseline characteristics and clinical outcomes were analyzed. RESULTS: A total of 6774 cases were analyzed. The pacemaker group showed higher in-hospital rates of cardiac arrest, myocardial infarction, and longer duration of mechanical ventilation and ICU stay than the non-pacemaker group. Nevertheless, pacemaker placement was associated with a significant decrease in mortality (4.2% vs 26.0%, P < .01). CONCLUSIONS: Patients with CSCI requiring a pacemaker placement had better survival than those treated without a pacemaker. Pacemaker implantation should be highly considered in patients who develop refractory bradycardia after CSCI.

Severe bradycardia at acute medical take - Think about myxoedema coma.

We report two cases of myxoedema coma that presented to the acute medical take with severe bradycardia. These patients were initially misdiagnosed as bradyarrhythmia of primary cardiac origin. They were then diverted to the cardiology service at another district general hospital (DGH) for admissions. Both cases were subsequently diagnosed with myxoedema coma having screened thyroid function tests on arrival at the cardiology unit. Despite being treated for myxoedema coma, both patients unfortunately succumbed to the disease and later died in the hospital. These cases highlight that clinical suspicion and recognition of myxoedema coma remain significant challenges in a developed world despite readily available and highly sensitive thyroid hormone assays.

Apnea, Intermittent Hypoxemia, and Bradycardia Events Predict Late-Onset Sepsis in Infants Born Extremely Preterm.

OBJECTIVE: The objective of this study was to examine the association of cardiorespiratory events, including apnea, periodic breathing, intermittent hypoxemia (IH), and bradycardia, with late-onset sepsis for extremely preterm infants (<29 weeks of gestational age) on vs off invasive mechanical ventilation. STUDY DESIGN: This is a retrospective analysis of data from infants enrolled in Pre-Vent (ClinicalTrials.gov identifier NCT03174301), an observational study in 5 level IV neonatal intensive care units. Clinical data were analyzed for 737 infants (mean gestational age: 26.4 weeks, SD 1.71). Monitoring data were available and analyzed for 719 infants (47 512 patient-days); of whom, 109 had 123 sepsis events. Using continuous monitoring data, we quantified apnea, periodic breathing, bradycardia, and IH. We analyzed the relationships between these daily measures and late-onset sepsis (positive blood culture >72 hours after birth and ≥5-day antibiotics). RESULTS: For infants not on a ventilator, apnea, periodic breathing, and bradycardia increased before sepsis diagnosis. During times on a ventilator, increased sepsis risk was associated with longer events with oxygen saturation <80% (IH80) and more bradycardia events before sepsis. IH events were associated with higher sepsis risk but did not dynamically increase before sepsis, regardless of ventilator status. A multivariable model including postmenstrual age, cardiorespiratory variables (apnea, periodic breathing, IH80, and bradycardia), and ventilator status predicted sepsis with an area under the receiver operator characteristic curve of 0.783. CONCLUSION: We identified cardiorespiratory signatures of late-onset sepsis. Longer IH events were associated with increased sepsis risk but did not change temporally near diagnosis. Increases in bradycardia, apnea, and periodic breathing preceded the clinical diagnosis of sepsis.

Risk of Cardiac Arrhythmias Among Climbers on Mount Everest.

Importance: Arterial hypoxemia, electrolyte imbalances, and periodic breathing increase the vulnerability to cardiac arrhythmia at altitude. Objective: To explore the incidence of tachyarrhythmias and bradyarrhythmias in healthy individuals at high altitudes. Design, Setting, and Participants: This prospective cohort study involved healthy individuals at altitude (8849 m) on Mount Everest, Nepal. Recruitment occurred from January 25 to May 9, 2023, and data analysis took place from June to July 2023. Exposure: All study participants underwent 12-lead electrocardiogram, transthoracic echocardiography, and exercise stress testing before and ambulatory rhythm recording both before and during the expedition. Main Outcome: The incidence of a composite of supraventricular (>30 seconds) and ventricular (>3 beats) tachyarrhythmia and bradyarrhythmia (sinoatrial arrest, second- or third-degree atrioventricular block). Results: Of the 41 individuals recruited, 100% were male, and the mean (SD) age was 33.6 (8.9) years. On baseline investigations, there were no signs of exertional ischemia, wall motion abnormality, or cardiac arrhythmia in any of the participants. Among 34 individuals reaching basecamp at 5300 m, 32 participants climbed to 7900 m or higher, and 14 reached the summit of Mount Everest. A total of 45 primary end point-relevant events were recorded in 13 individuals (38.2%). Forty-three bradyarrhythmic events were documented in 13 individuals (38.2%) and 2 ventricular tachycardias in 2 individuals (5.9%). Nine arrhythmias (20%) in 5 participants occurred when climbers were using supplemental bottled oxygen, whereas 36 events (80%) in 11 participants occurred at lower altitudes when no supplemental bottled oxygen was used. The proportion of individuals with arrhythmia remained stable across levels of increasing altitude, while event rates per 24 hours numerically increased between 5300 m (0.16 per 24 hours) and 7300 m (0.37 per 24 hours) before decreasing again at higher altitudes, where supplemental oxygen was used. None of the study participants reported dizziness or syncope. Conclusion and Relevance: In this study, more than 1 in 3 healthy individuals experienced cardiac arrhythmia during the climb of Mount Everest, thereby confirming the association between exposure to high altitude and incidence of cardiac arrhythmia. Future studies should explore the potential implications of these rhythm disturbances.

Effects of bradycardia, hypoxemia and early intubation on bronchopulmonary dysplasia in very preterm infants: An observational study.

BACKGROUND: Bronchopulmonary dysplasia (BPD) is the most common pulmonary complication in preterm infants. OBJECTIVES: The study aimed to explore the effects of bradycardia, hypoxemia, and early intubation on BPD in very preterm infants. METHODS: This is a prospective observational cohort study. Preterm infants with a mean gestational age of 28.67 weeks were recruited from two level III neonatal intensive care units (NICUs) in Taiwan. Continuous electrocardiography was used to monitor heart rates and oxygen saturation (SpO2). Infants were monitored for heart rates of <100 beats per minute and SpO2 levels of <90 % lasting for 30 s. Generalized estimating equations were used to analyze the effects of bradycardia, hypoxemia, and early intubation on BPD in very preterm infants. Model fit was visually assessed using receiver operating characteristic curve analysis. RESULTS: Bradycardia, hypoxemia, and early intubation significantly increased the odds of BPD among the preterm infants (N = 39) during NICU stay; the odds ratios for bradycardia, hypoxemia, and early intubation for BPD versus non-BPD were 1.058, 1.013, and 29.631, respectively (all p < 0.05). A model combining bradycardia, hypoxemia, and early intubation accurately predicted BPD development (area under the curve = 0.919). CONCLUSIONS: Bradycardia, hypoxemia, and early intubation significantly increased the odds of BPD among very preterm infants during NICU stay. The model combining bradycardia, hypoxemia, and early intubation accurately predicted BPD development.

Flecainide causing elevated capture thresholds on pacemaker implantation.

Flecainide is a Vaughan Williams class 1c antiarrhythmic used to treat supraventricular and ventricular arrhythmias. It has been described as a rare cause for increased pacemaker capture thresholds. We describe a report of a patient, in her early 80s, presenting with tachy-brady syndrome on a background of permanent atrial fibrillation. She was treated with metoprolol and flecainide by her private cardiologist. Permanent right ventricular chamber pacing was recommended for her slow heart rate. At insertion of her single chamber pacemaker, she was noted to have elevated capture thresholds despite appropriate lead positioning. A flecainide level was elevated at 1.1 µg/mL, and it was subsequently ceased. This was associated with a rapid improvement in her capture threshold. Flecainide should be considered as a cause for elevated pacing thresholds at the time of implant. Particular care should be taken for at-risk groups such as the elderly and patients with renal impairment.

Symptomatic bradyarrhythmias in the athlete-Underlying mechanisms and treatments.

Bradyarrhythmias including sinus bradycardia and atrioventricular (AV) block are frequently encountered in endurance athletes especially at night. While these are well tolerated by the young athlete, there is evidence that generally from the fifth decade of life onward, such arrhythmias can degenerate into pathological symptomatic bradycardia requiring pacemaker therapy. For many years, athletic bradycardia and AV block have been attributed to high vagal tone, but work from our group has questioned this widely held assumption and demonstrated a role for intrinsic electrophysiological remodeling of the sinus node and the AV node. In this article, we argue that bradyarrhythmias in the veteran athlete arise from the cumulative effects of exercise training, the circadian rhythm and aging on the electrical activity of the nodes. We consider contemporary strategies for the treatment of symptomatic bradyarrhythmias in athletes and highlight potential therapies resulting from our evolving mechanistic understanding of this phenomenon.

Transvenous Pacemaker Placement: A Review for Emergency Clinicians.

BACKGROUND: Transvenous pacemaker placement is an integral component of therapy for severe dysrhythmias and a core skill in emergency medicine. OBJECTIVE: This narrative review provides a focused evaluation of transvenous pacemaker placement in the emergency department setting. DISCUSSION: Temporary cardiac pacing can be a life-saving procedure. Indications for pacemaker placement include hemodynamic instability with symptomatic bradycardia secondary to atrioventricular block and sinus node dysfunction; overdrive pacing in unstable tachydysrhythmias, such as torsades de pointes; and failure of transcutaneous pacing. Optimal placement sites include the right internal jugular vein and left subclavian vein. Insertion first includes placement of a central venous catheter. The pacing wire with balloon is then advanced until electromechanical capture is obtained with the pacer in the right ventricle. Ultrasound can be used to guide and confirm lead placement using the subxiphoid or modified subxiphoid approach. The QRS segment will demonstrate ST segment elevation once the pacing wire tip contacts the endocardial wall. If mechanical capture is not achieved with initial placement of the transvenous pacer, the clinician must consider several potential issues and use an approach to evaluating the equipment and correcting any malfunction. Although life-saving in the appropriate patient, complications may occur from central venous access, right heart catheterization, and the pacing wire. CONCLUSIONS: An understanding of transvenous pacemaker placement is essential for emergency clinicians.

Trigeminocardiac Reflex During Temporomandibular Joint Surgery: A Systematic Review and Update for the Surgeons.

PURPOSE: Temporomandibular joint (TMJ) surgery is being increasingly performed globally with considerable success leading to improved quality of life for patients affected with disabling temporomandibular disorders. One of the most unusual phenomena noted during maxillofacial surgery due to stimulation of the trigeminal nerves is the Trigeminocardiac reflex (TCR), which causes sudden bradycardia and hypotension causing alarm and distress to the surgical and anesthetic team. The purpose of this systematic review is to identify the frequency and discuss the pathophysiology of the TCR especially during TMJ surgery. METHODS: The authors performed a systematic review by searching PubMed, Embase, Ovid, and Cochrane databases between 1946 and 2023 to identify studies that reported on the development of TCR during TMJ surgery. Non-English publications and those with inadequate details were excluded. RESULTS: Thirty-six papers reporting on the development of the TCR during oral and maxillofacial procedures were noted. Six papers reported specifically on TCR during TMJ surgery. A total of 25 subjects developed TCR during TMJ surgery. The mean age of the subjects was 31 (standard deviation 17.16) years. Twenty-three subjects (92%) developed bradycardia while 2 subjects (8%) developed asystole. All subjects recovered. The most common stimulant noted in these papers leading to TCR was manipulation and distraction of the TMJ. CONCLUSION: Although TCR is uncommon, it can occur during TMJ surgery, and it behooves the surgeon and anesthesia team to be aware of the potential for TCR to ensure adequate and timely treatment.