Search

Sinus arrest and inappropriate sinus bradycardia are sinus node dysfunction (SND), which cause loss of consciousness. Cardiac pacing is recommended in patients with symptoms, such as syncope or dizziness. Several conditions can induce these arrhythmias; however, whether or not intracranial infectious diseases, such as herpes simplex encephalitis (HSE), can cause secondary SND is unclear. We encountered a patient with sinus arrest and transient sinus bradycardia associated with HSE. Since cardiac pause was never monitored and the bradycardia improved after HSE treatment, HSE was suspected to be the cause of SND. Although the underlying mechanisms have not yet been completely elucidated, HSE may cause secondary SND.

Because of its powerful genetics, the adult zebrafish has been increasingly used for studying cardiovascular diseases. Considering its heart rate of ~100 beats per minute at ambient temperature, which is very close to human, we assessed the use of this vertebrate animal for modeling heart rhythm disorders such as sinus arrest (SA) and sick sinus syndrome (SSS). We firstly optimized a protocol to measure electrocardiogram in adult zebrafish. We determined the location of the probes, implemented an open-chest microsurgery procedure, measured the effects of temperature, and determined appropriate anesthesia dose and time. We then proposed an PP interval of more than 1.5 seconds as an arbitrary criterion to define an SA episode in an adult fish at ambient temperature, based on comparison between the current definition of an SA episode in humans and our studies of candidate SA episodes in aged wild-type fish and Tg(SCN5A-D1275N) fish (a fish model for inherited SSS). With this criterion, a subpopulation of about 5% wild-type fish can be considered to have SA episodes, and this percentage significantly increases to about 25% in 3-year-old fish. In response to atropine, this subpopulation has both common SSS phenotypic traits that are shared with the Tg(SCN5A-D1275N) model, such as bradycardia; and unique SSS phenotypic traits, such as increased QRS/P ratio and chronotropic incompetence. In summary, this study defined baseline SA and SSS in adult zebrafish and underscored use of the zebrafish as an alternative model to study aging-associated SSS., Competing Interests: The authors have declared that no competing interests exist.

BACKGROUND Anti-LGI1 encephalitis is a type of autoimmune limbic encephalitis. This case report elucidates features of anti-LGI1 limbic encephalitis, focusing on clinical findings and outcome as well as on rarely reported sinus arrest and its pathophysiology. CASE REPORT A 49-year-old female patient presented at the Emergency Department (ED) because of twitching and an acute confusional state. Initial neurological examination revealed cognitive disturbance with disorientation, inattention, and amnestic deficits. While in the ED, twitching of the right arm was observed and shortly thereafter she experienced a sinus arrest. A temporary cardiac pacemaker was implanted. Laboratory investigations demonstrated mild hyponatremia and positive LGI1-IgG antibodies in serum. An initial head MRI was unremarkable and electroencephalography showed epileptic seizure activity starting focally in the left hemisphere synchronous with the intermittent twitching of the right arm. A seizure-suppressant therapy with levetiracetam, valproate, and gabapentin was initiated, as well as an immunosuppressive pulse therapy with methylprednisolone followed by a tapering oral regimen of prednisolone. Within a few days, the seizures ceased. One month later, neurocognitive test results were back to normal. At 2 years, mild depressive symptoms and anxiety disorder were the main clinical problems, as well as episodic migraine-like headaches. CONCLUSIONS Repetitive focal dystonic seizures, confusion, amnestic deficits, sinus arrest, and mild-to-moderate hyponatremia are pathognomonic features of anti-LGI1 limbic encephalitis. Sinus arrest may occur because of a direct pathophysiological dysfunction of the structures involved in autonomic cardiac rhythm control or as an ictal or postictal phenomenon. Early diagnosis and initiation of immunosuppressive therapy are both of utmost importance for favorable clinical outcome.

Obstructive sleep apnea (OSA) is associated with the occurrence of various kinds of bradyarrhythmia and tachyarrhythmia. The activation of the autonomic nerve system is an important causative factor of the pathogenesis of the arrhythmia in OSA patients. Previous studies have shown that the R-R interval is an effective parameter for evaluating autonomic nerve activities. However, whether or not OSA can induce variations in the R-R interval and whether or not continuous positive airway pressure (CPAP) therapy can improve these variations in OSA patients are unclear. The present study explored whether or not CPAP therapy could improve the regularity of the R-R interval.

Background: Many patients with atrial fibrillation (AF) or atrial flutter (Aflutter) have concomitant sinus node dysfunction (SND). Ablation may result in injury to the sinus node complex or its blood supply resulting in sinus arrest and need for temporary pacing. We sought to characterize patients who develop acute SND (ASND) during/immediately after AF/Aflutter ablation., Methods: We performed a retrospective analysis of AF/Aflutter ablation patients between January 1, 2010 and February 28, 2015 to characterize those who required temporary pacemaker (TPM) implantation due to ASND (sinus arrest, sinus bradycardia <40 beats/min, or junctional rhythm with hemodynamic compromise) following atrial ablation., Results: Of 2,151 patients, eight patients (<0.5%) with ASND manifesting as sinus arrest (n = 2), severe sinus bradycardia (n = 2), and junctional rhythm with hemodynamic compromise (n = 4) were identified (all male, age 66 ± 9.9 years, 4/8 [50%] persistent AF). AF ablation was performed in four, atypical Aflutter in one, and AF/Aflutter in three patients. The ablation set consisted of: pulmonary vein (PV) isolation (n = 6), roof line ablation (n = 6), mitral annulus-left inferior PV line ablation (n = 5), left atrial appendage-mitral annulus ablation (n = 1), cavotricuspid isthmus ablation (n = 5), and isolation or ablation near the superior vena cava (SVC, n = 4). Patients with peri-SVC ablation were more likely to develop ASND (P = 0.03). All patients received TPM; six received permanent pacemaker before discharge, performed 3.5 days postablation (range 2-6 days). At 3-month device interrogation, all patients were atrially paced >50%., Conclusion: ASND is a rare complication of atrial ablation. It may be more common when peri-SVC ablation is performed and may necessitate permanent pacemaker implantation., (© 2016 Wiley Periodicals, Inc.)

Dynamic left ventricular outflow tract obstruction and left ventricular mid-cavity obliteration are phenomena that can complicate the postoperative course in patients who undergo surgical aortic valve replacement for aortic stenosis, and may be markers of increased morbidity and mortality. Recently, reports describing dynamic intraventricular obstruction following transcatheter aortic valve replacement (TAVR) have emerged. We report a case of dynamic left ventricular mid-cavity obstruction due to disordered atrioventricular synchrony immediately following TAVR, and its reversal with restoration of atrioventricular synchrony. This case highlights the essential role of atrial contraction in the management of this phenomenon.

A 67-year-old man who had a history of syncope was admitted because of effort angina. The sinus node (SN) was the single blood supply from the right coronary artery (RCA). After we implanted 2 everolimus-eluting stents for RCA, slow-flow occurred and the SN artery was occluded, and junctional escape rhythm was sustained. After the wiring to the occluded SN artery, junctional escape rhythm immediately recovered to sinus rhythm, and the patient achieved continuous sinus rhythm and stable hemodynamics. Given that acute SN ischemia is a possible cause of sinus dysfunction, careful choice of a percutaneous coronary intervention strategy should be taken into consideration if the SN artery is the single blood supply from the RCA and if syncopal history is present.

We describe asymptomatic sinus arrest and post-hiccup cough syncope in a patient with medullary infarction. A 78-year-old woman developed arrhythmia, hiccup, and cough syncope attacks. Neurological examination was not remarkable. Cough syncope occurs after hiccup attacks. Bradycardia and decreased blood pressure were also present after the beginning cough. Holter 24-hour electrocardiography monitor exhibited 65 episodes of asymptomatic sinus arrest more than 3 seconds. Magnetic resonance imaging disclosed acute infarction in the bilateral medial regions and the right tegmentum of the upper and middle medulla oblongata. Cerebral angiography showed severe atherosclerotic changes in the vertebral arteries. These clinicoradiological findings suggested that a distinct topography of medullary lesions could cause a series of cardiovascular and respiratory dysfunction. Thus, physicians should pay more attention to the medullary lesion in patients with arrhythmia and syncope., (Copyright © 2014 National Stroke Association. Published by Elsevier Inc. All rights reserved.)

Objectives: Concomitant surgical atrial fibrillation (AF) ablation is a safe and feasible procedure, recommended in guidelines. Pacemaker dependency is a known complication of AF ablation. We sought to determine independent predictors for pacemaker implantation after surgical AF ablation., Methods: Between January 2003 and November 2012, 594 patients underwent concomitant surgical AF ablation. Various energy sources, including cryoablation (n = 139), unipolar radiofrequency (n = 278), and bipolar radiofrequency (n = 177), were used. Left atrial (n = 463, 77.9%) and biatrial (n = 131, 22.1%) ablation was performed. Univariate and multivariate logistic regression analysis was used to identify independent predictors for pacemaker implantation within 30 days after surgical AF ablation., Results: The mean patient's age was 68.6 ± 9.4 years, and 66.8% were male. No major ablation-related complications occurred. A total of 41 (6.9%) of patients received pacemaker implantation during the 30-day follow-up period. Indications for pacemaker implantation were atrioventricular block in 25 (60.9%) of patients, sinus bradycardia or sinus arrest in 9 (22.0%) of patients, and bradyarrhythmia in 7 (17.1%) of patients. Demographic data, type of surgical procedure, and type of energy source did not have a significant impact on pacemaker implantation rate. However, biatrial ablation led to a significant pacemaker implantation rate compared with isolated left-sided ablation (6.3% vs 13.6%; P = .028)., Conclusions: Concomitant surgical AF ablation showed a pacemaker implantation rate of 6.9% after 30-day follow-up. Univariate and multivariate analysis showed biatrial lesion set as the only statistically significant predictor for pacemaker implantation after surgical AF ablation., (Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Superior vena cava (SVC) syndrome is a complication resulting from long-term residence of leads or in-dwelling catheters at the SVC to right atrial (RA) junction. SVC syndrome management is complicated by variable responses to anticoagulation therapies and technically challenging interventional procedures, such as balloon dilatation or stent placement at the SVC-RA junction to relieve blood-flow obstruction. Potential complications resulting from angioplasty/stenting for SVC syndrome are serious and include stent migration, major bleeding, and embolism. Bradyarrhythmias have not been reported. We describe a case of balloon angioplasty and stenting for SVC syndrome in a dialysis patient that resulted in sinus arrest. The complication developed within hours of angioplasty/stenting of her chronic, non-thrombotic SVC obstruction. We highlight the management approach to this patient and discuss potential mechanisms underlying the complication.

Some forms of focal epilepsy, including temporal lobe epilepsy, are rarely associated with ictal bradycardia and sinus node arrest. We report a case of a previously healthy man presenting with syncope in whom telemetry revealed sinus arrest. Initial treatment was with permanent pacemaker implantation and it was only following a subsequent grand mal seizure that other symptoms suggestive of temporal lobe epilepsy were documented. Anti-epileptic medication was subsequently commenced with resolution of all symptoms. There are few previously reported cases of syncope and documented sinus node arrest as the presenting feature of temporal lobe epilepsy.

Background: Lithium is widely used to treat bipolar disorders. Lithium toxicity is generally caused by inappropriately high doses of lithium or impaired lithium excretion. Most lithium is eliminated via the kidneys and, since thyroid hormone increases tubular reabsorption of lithium, thyrotoxicosis could contribute to the development of lithium toxicity. We report a case of severe lithium toxicity that was apparently precipitated by the onset of thyrotoxicosis resulting from silent thyroiditis and dehydration., Patient Findings: The patient was a 64-year-old woman who was admitted for muscle weakness in the lower extremities, diarrhea, and palpitations. She had bipolar disorder and was being treated with lithium carbonate, which she discontinued one week before admission. Her circulating lithium levels had been monitored yearly. Early in her admission she was dehydrated and had febrile episodes, paroxysmal atrial fibrillation, and muscle weakness. Initially, fluid therapy was started, but she lost consciousness and had a cardiac arrest for 2 minutes due to prolonged sinus arrest. Chest compression and manual artificial ventilation were performed, and body surface pacing was started. Serum lithium was markedly elevated to 3.81 mEq/L (therapeutic range, 0.4-1.0 mEq/L), and thyroid hormone levels were increased (free triiodothyronine, 8.12 pg/mL; free thyroxine, 4.45 ng/dL), while thyrotropin (TSH) was suppressed (<0.01 μIU/mL). Hemodialysis was performed, and a temporary pacemaker was inserted for severe sinus bradycardia. The serum thyroglobulin was 4680 ng/mL (reference range, <32.7 ng/mL). A TSH receptor antibody test was negative. Glucocorticoid therapy and inorganic iodine (100 mg) were administered and continued until day 11. However, her neurological symptoms deteriorated with floppy quadriplegia and deep coma. She gradually recovered. On day 36, she was discharged without any neurological symptoms or thyrotoxicosis., Summary: A 64-year-old woman taking lithium for bipolar disorder developed lithium toxicity in the setting of what seemed likely to be a recent onset of thyrotoxicosis due to silent thyroiditis., Conclusions: Thyrotoxicosis may be a contributing cause of lithium toxicity, particularly if it is abrupt in onset and even with cessation of lithium therapy if renal function is compromised. Thyroid function should be assessed immediately in patients with suspected lithium toxicity.

Objectives: Important adjustments in the autonomic nervous system occur during sleep. Bradycardia, due to increased vagal tone, and hypotension, caused by reduction of sympathetic activity, may occur during non rapid eye movement (REM) sleep (NREM). Increased sympathetic activity, causing increased heart rate, is conversely a feature of phasic REM sleep. During REM sleep, sinus arrests and atrioventricular (AV) blocks unrelated to apnea or hypopnea have been described. These arrhythmias are very rare and only a few cases have been reported in the literature., Patients/methods: Following an ECG performed for other reasons, two patients with no history of sleep complaints nor symptoms of heart failure or heart attack were referred to our center for nocturnal brady-arrhythmias., Results: 24h ECG Holter recorded several episodes of brady-arrhythmia with sinus arrest in the first patients and brady-arrhythmias with complete AV block in the second patient. In both patients, episodes of brady-arrhythmia were prevalent in the second part of the night. Nocturnal polysomnography (PSG) demonstrated that episodes occurred only during REM sleep, particularly during phasic events. Treatment with pacemaker was considered only for the patient with complete AV blocks., Conclusions: These types of brady-arrhythmias are usually detected accidentally due to their lack of symptoms. It has been suggested that in some patients they may lead to sudden unexpected death. Thus, the identification of predisposing factors is mandatory in order to prevent potentially dangerous arrhythmic events., (Copyright © 2012 Elsevier B.V. All rights reserved.)

A 32-year-old Spanish man presented to hospital after a second episode of syncope immediately following exercise. On admission, his vitals signs were stable and he had a regular heart rate of 60 bpm. ECG and transthoracic echocardiogram were normal. He completed 15 min of a BRUCE protocol exercise test. One minute and ten seconds into recovery, he lost consciousness. His ECG demonstrated sinus arrest with pauses of up to 5 s and subsequently junctional ectopy. After 38 s, his heart returned to sinus rhythm at a rate of 140 bpm and he regained consciousness. Vasovagal syncope following exercise in the absence of structural heart disease is uncommonly reported. When cases of exercise-related syncope in patients with structurally normal hearts have been reported, the typical patient is a young male who engages in physical training. Treatment strategies in patients suffering with vasovagal asystole are necessarily empirical, and careful judgement based on the specific features of the individual cases needs to be employed.

A 5-month-old female infant presented with new-onset acute lymphoblastic leukemia and hyperleukocytosis with white blood cell count of 352 × 10(9) cells/L. She developed sinus pauses and hypoxemic respiratory failure. A manual single volume exchange blood transfusion was done with complete resolution of sinus pauses and hypoxemia.

This case report describes a 63-year-old man referred with right-sided glossopharyngeal neuralgia. Magnetic resonance imaging (MRI) demonstrated asymmetry of the PICA vessels. A microvascular decompression was performed and complete remission of symptoms followed. After 14 months the neuralgia recurred, this time accompanied by sinus bradycardia/sinus arrest during attacks causing discomfort and syncopes. An MRI now demonstrated an arterial loop at the site of the vagoglossopharyngeal complex leaving the brainstem. After another microvascular decompression, complete remission of symptoms was observed.

The aim of the work was to evaluate the prevalence of cardiac rhythm and conductance disturbances in patients with early manifestations of metabolic syndrome (MS). 24-hour ECG monitoring was undertaken in 105 patients meeting AHA/NHLBI (2005) MS criteria and in 79 healthy subjects. Exclusion criteria were the presence of diabetes mellitus, CHD, and obesity (body mass index > 40 kg/m2). MS was associated with an increased number of supraventicular extrasystoles (628.9 +/- 49.5 vs 415.9 +/- 57.9, p < 0.05) and ventricular extrasystoles (34.4 +/- 9.9 vs 11.8 +/- 6.5 for paired ones and 9.5 +/- 3.7 vs 2.2 +/- 4.0 for group ones, p < 0.05), higher frequency of tachyarrhythmia (supraventicular tachycardia: 18.1 vs 7.6%, p < 0.05; atrial fibrillation: 9.5 vs 2.5, p < 0.05; sinus node arrest: 6.7 vs 0%, p < 0.05). Regression analysis revealed significant correlation between arrhythmias and the number of components of the disease. It is concluded that cause-and-effect relationship between MS and cardiac rhythm disturbances is apparent at the early stage of the disease.

Radiofrequency ablation has been associated with changes in autonomic function. In this case, a 52-year-old woman was referred for electrophysiologic study of recurrent supraventricular tachycardia. Typical slow/fast atrioventricular node re-entry tachycardia was induced and confirmed during the study. Radiofrequency ablation of the slow pathway of the atrioventricular node led to sinus arrest, which resolved once ablation was stopped. Given the distance of the ablation site from the sinus node, we inferred that mechanisms other than direct injury to the sinus node were involved. To our knowledge, this is only the 2nd reported finding of sinus arrest during slow-pathway ablation of the atrioventricular node. This case highlights the complex interaction between the autonomic nervous system and the cardiac conduction system. Possible mechanisms include a Bezold-Jarisch reflex and modification of the intrinsic autonomic nervous system.

A 63-year-old man presented with recurrent syncopal attacks associated with swallowing and right-sided throat pain. Immediately after admission, he presented a 16-s asystolia. The patient's clinical history was unremarkable except for previous postimplant periodontitis. Several episodes of severe bradycardia and sinus pauses, always associated with painful deglutition, were recorded subsequently. X-ray orthopanthomography and magnetic resonance imaging of the neck confirmed several areas of periodontitis around the previous dental implants and right mastoid inflammation. A barium swallow and fibre-optic endoscopy also revealed a small sliding hiatus hernia and distal chronic oesophageal inflammation. Despite complete dental curettage, antibiotics and antigastro-oesophageal reflux therapy, only partial relief of the pain and incomplete resolution of the arrhythmic disorder were obtained after 3 weeks, and the patient underwent pacemaker implantation. At 1-month follow-up, however, he reported the complete relief of the throat pain; subsequent Holter monitoring showed normal sinus rhythm, without pacemaker-induced electrical activity.

We report a patient with herpes simplex virus (HSV) encephalitis presenting as recurrent syncope due to sinus node arrest. Although the patient's initial presentation suggested a primary cardiac cause, an eventual diagnosis of HSV encephalitis was supported by computed tomography scan and magnetic resonance imaging, and confirmed by HSV polymerase chain reaction. The mechanism of cardiac arrhythmias in HSV encephalitis remains unclear; however, cardiac monitoring should be considered in all patients in whom the diagnosis is suspected. With diagnosis and appropriate management, a permanent pacemaker is generally not indicated. This case report highlights the importance of considering potentially reversible causes of collapse secondary to sinus node dysfunction beyond primary cardiac causes.

We examined the frequency of side-branch occlusion of the sinus node (SN) artery and of the subsequent sinus arrest in 80 consecutive patients who underwent percutaneous coronary intervention (PCI) for proximal right coronary artery (RCA) lesions. Side-branch occlusion of the SN artery occurred during PCI in 14 (17.5%) patients. Sinus arrest with junctional escape rhythm developed in 4 (28.6%) of these 14 patients. Temporary ventricular pacing was performed for one patient. The junctional escape rhythm disappeared in all of the patients within 3 days of the SN artery occlusion. The frequency of a single blood supply to the SN by the SN artery originating from the RCA did not differ significantly between the patients with and without sinus arrest (4/4 [100%]) vs 9/10 [90%]). In conclusion, although side-branch occlusion of the SN artery often occurs during PCI for proximal RCA lesions, where the SN artery originated, it does not always produce sinus arrest even in cases of a single blood supply to the SN by the SN artery originating from the RCA. Even though sinus arrest is caused by the occlusion of the SN artery, this bradyarrhythmia seems to disappear in the short term.

A 64-year-old woman presented with bradycardia from sinus pauses during exacerbations of postherpetic trigeminal distribution neuralgia. She had underlying systemic lupus erythematosus. Sphenopalatine ganglion blockade was employed to treat her pain. The episodes of bradycardia resolved with successful alleviation of pain. This report emphasizes that a sphenopalatine ganglion blockade can be employed in the treatment and prevention of sinus arrest associated with postherpetic trigeminal distribution neuralgia.