Very delayed sinus arrest during complete remission of diffuse large B-cell lymphoma invading right atrium.

Diffuse large B-cell lymphoma (DLBCL)-associated arrhythmias may be due to cardiac involvement or may be chemotherapy-induced. There have been no reports of significant arrhythmias with normal cardiac function occurring during the complete remission of DLBCL. A 57-year-old female, who had had no history of abnormal electrocardiograms (ECGs) in annual medical checkups, was admitted to our hospital because of low-grade fever, night sweats, and weight loss. On admission, ECG revealed a variable rhythm consisting of sinus beats and occasional escape beats. Computed tomography and 18F-fluorodeoxyglucose positron emission tomography and computed tomography (FDG-PET/CT) revealed two masses in the right atrium (RA) and the uterus. Total hysterectomy was performed, and pathological findings were consistent with diffuse large B-cell lymphoma (DLBCL). Chemotherapy (R-CHOP) was initiated. After two chemotherapy cycles, RA tumors disappeared, and bradyarrhythmia simultaneously converted to sinus rhythm without antiarrhythmic drug therapy. Six months after completion of chemotherapy, FDG-PET/CT revealed negative uptake in the RA and the uterus. The patient attained complete remission of DLBCL, but ECG showed bradycardia because of sinus arrest. Our case suggests that DLBCL-induced arrhythmia can occur even after its remission and should be monitored.

Aging-associated sinus arrest and sick sinus syndrome in adult zebrafish.

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.

Syncope and Twitching at the Emergency Department.

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.

Continuous Positive Airway Pressure Therapy Improves Heterogeneity of R-R intervals in a Patient with Obstructive Sleep Apnea Syndrome.

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.

Acute Sinus Node Dysfunction after Atrial Ablation: Incidence, Risk Factors, and Management.

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.

Suicide left ventricle due to conduction disturbance following transcatheter aortic valve replacement and reversal with restoration of sinus rhythm: is there life after death?

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.

Pause for thought? Syncope and sinus arrest as the presenting feature of temporal lobe epilepsy.

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.

Sinus arrest following angioplasty and stenting for superior vena cava syndrome.

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.

Predictors for permanent pacemaker implantation after concomitant surgical ablation for atrial fibrillation.

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.

A case of sinus arrest and post-hiccup cough syncope in medullary infarction.

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.

Sinus dysfunction after stent implantation in the right coronary artery immediately recovered after reflow in the sinus node artery.

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.

Lithium toxicity precipitated by thyrotoxicosis due to silent thyroiditis: cardiac arrest, quadriplegia, and coma.

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.