Cardiac involvement and its clinical significance in patients with anorexia nervosa

Cardiac complications are a major concern in patients with anorexia nervosa (AN) which contribute to morbidity and mortality. However, limited information exists regarding risk factors for the development of these complications. Our objective was to investigate the prevalence and associated risk factors of cardiac involvement among children and adolescents with AN admitted to a tertiary pediatric hospital. We collected demographic, clinical, and laboratory data from individuals with AN hospitalized between 2011 and 2020 in Schneider Children's Medical Center in Israel. Diagnosis was based on established criteria (DSM-5). Patients with other co-morbidities were excluded. Cardiac investigations included electrocardiograms (ECG) and echocardiograms. We conducted correlation tests between cardiac findings and clinical and laboratory indicators. A total of 403 AN patients (81.4% were females) with a median age of 15 ± 2 years were included in the study. Sinus bradycardia was the most common abnormality, observed in 155 (38%) participants. Echocardiogram was performed in 170 (42.2%) patients, of whom 37 (22%) demonstrated mild cardiac aberrations. Among those aberrations, 94.6% could be attributed to the current metabolic state, including pericardial effusion (15.3%) and valve dysfunction (8.8%). Systolic or diastolic cardiac dysfunction, tachyarrhythmias, or conduction disorders were not observed. Patients with new echocardiographic aberration had significantly lower body mass index (BMI) at admission, and the prevalence of amenorrhea and hypotension was higher in this group.

CONCLUSIONS

The prevalence of cardiac involvement, except for sinus bradycardia, was notably low in our cohort. The presence of cardiac aberrations is correlated with several clinical variables: lower body mass index (BMI) and the presence of amenorrhea and hypotension at admission. Patients presenting with these variables may be at high risk for cardiac findings per echocardiography. Dividing the patients into high and low risk groups may enable targeted evaluation, while avoiding unnecessary cardiac investigations in low-risk patients.

WHAT IS KNOWN

• Cardiac involvement in anorexia nervosa (AN) patients is a major concern, which contributes to morbidity and mortality. • It is unknown which patients are prone to develop this complication.

WHAT IS NEW

• Cardiac complications in our cohort are less frequent compared to previous studies, and it is correlated with lower body mass index (BMI) at admission, and the prevalence of amenorrhea and hypotension.

Frequency of arrhythmias detected in 9440 feline electrocardiograms by breed, age, and sex

OBJECTIVES

The purpose of this study was to describe the frequency of arrhythmias detected in unsedated feline patients from general practice settings.

ANIMALS

A total 10,638 feline electrocardiograms (ECGs) were retrospectively collected of which 9440 met the inclusion criteria.

METHODS

Recordings were evaluated by a board-certified cardiologist. If an arrhythmia was present in the ECG tracing, the cardiologist categorized the arrhythmia using pre-established keywords.

RESULTS

At least one arrhythmia was observed in 249 cases (2.64%, 95% confidence interval (CI): 2.34-2.98, 249/9440), with the most common arrhythmia encountered being ventricular premature complexes (1.63%, 95% CI: 1.39%-1.91%, 154/9440). Ragdoll cats had the highest odds of arrhythmia (odds ratio (OR): 3.17, 95% CI: 1.43-6.17, P=0.036). Both geriatric (Age: 13+ years, OR: 1.70, 95% CI: 1.24-2.34, P=0.013) and senior (Age: 10-13 years, OR: 1.68, 95% CI: 1.19-2.37, P=0.003) cats had higher odds of having an arrhythmia than adult cats. The odds of male cats having an arrhythmia were slightly higher than female (OR: 1.36, 95% CI: 1.06-1.76, P=0.018).

CONCLUSIONS AND RELEVANCE

Of the 9440 ECGs included in this study, at least one arrhythmia was detected in 249 distinct cases. Arrhythmias were more common in older cats, male cats and the Ragdoll cat breed. While it is important to note that the presence of an arrhythmia alone does not always indicate the presence of heart disease, further research on the association between breed cardiac health is needed.

Common ECG interpretation software mistakes Part III: Computer errors that should never be missed

Electrocardiogram interpretation software mistakes can lead to incorrect diagnoses and inappropriate treatments. Occasionally, the consequences of not recognizing such mistakes are disastrous. This final chapter on software mistakes describes three relatively common computer errors that should never be missed because not recognizing them can result in stroke, cardiac arrest, and even death. In each of the scenarios covered, we describe the clinical background, and provide simple recommendations on how such mistakes can be easily identified and corrected.

Left atrial myxoma: an unusual cause of pre-syncope and symptomatic bradycardia

BACKGROUND

Atrial myxomas account for approximately 50% of all primary cardiac tumors. The size, location, risk of embolic event, and involvement of other cardiac structures, are all factors that contribute to the wide range of presentation for cardiac myxomas. Patients with myxomas may remain asymptomatic, while others may report symptoms such as fatigue and fever, dyspnea, and syncope. It is important to recognize arrhythmias as an uncommon symptom of myxomas.

CASE PRESENTATION

We report a rare case of a 67-year-old man who presented with pre-syncopal episodes, symptomatic bradycardia, and night sweats found to have a 5.5 × 5.1 × 3 cm myxoma in the left atrium. During diastole the mass caused dynamic flow obstruction across the mitral valve. The patient underwent surgical resection of the mass given his symptomatology and risk of embolic events. Removal of the myxoma resulted in resolution of both pre-syncopal episodes and the patient's sinus bradycardia.

CONCLUSION

Atrial myxomas are a rare cause of pre-syncope and symptomatic bradycardia. It is important to have a clinical suspicion for atrial myxomas given early diagnosis and surgical intervention are key in improving the prognosis of these patients. This case also highlights the importance of taking into account the source of the myxoma's blood supply in relationship to other cardiac structures, and further correlating these findings with clinical symptoms.

Changes in gap junction proteins Connexin30.2 and Connexin40 expression in the sinoatrial node of rats with dexmedetomidine-induced sinus bradycardia

BACKGROUND

Dexmedetomidine (Dex) is widely used, and its most common side effect is bradycardia. The complete mechanism through which Dex induces bradycardia has not been elucidated. This research investigates the expression of gap junction proteins Connexin30.2 (Cx30.2) and Connexin40 (Cx40) within the sinoatrial node of rats with Dex-induced sinus bradycardia.

METHODS

Eighty rats were randomly assigned to five groups. Saline was administered to rats in Group C. In the other four groups, the rats were administered Dex to induce bradycardia. In groups D₁ and D₂, the rats were administered Dex at a loading dose of 30 μg.kg^-1 and 100 μg.kg^-1 for 10 min, then at 15 μg.kg^-1.h^-1 and 50 μg.kg^-1.h^-1 for 120 min separately. The rats in group D₁A and D₂A were administered Dex in the same way as in group D₁ and D₂; however, immediately after the administration of the loading dose, 0.5 mg atropine was administered intravenously, and then at 0.5 mg.kg^-1.h^-1 for 120 min. The sinoatrial node was acquired after intravenous infusion was completed. Quantitative real-time polymerase chain reaction and western blot analyses were performed to measure mRNA and protein expression of Cx30.2 and Cx40, respectively.

RESULTS

The expression of Cx30.2 increased, whereas the expression of Cx40 decreased within the sinoatrial node of rats with Dex-induced sinus bradycardia. Atropine reversed the effects of Dex on the expression of gap junction proteins.

CONCLUSION

Dex possibly altered the expression of gap junction proteins to slow down cardiac conduction velocity in the sinoatrial node.

Prevalence, types and treatment of bradycardia in obstructive sleep apnea - A systematic review and meta-analysis

BACKGROUND

The association of obstructive sleep apnea (OSA) with bradycardia is not well-characterized, which may confer significant morbidity and mortality if left untreated. We sought to clarify the prevalence of comorbid OSA and bradycardia, and the effect of continuous positive airway pressure (CPAP) therapy on bradycardia outcomes.

METHODS

We systematically searched four electronic databases (PubMed, Embase, Cochrane Library, Scopus) for randomized or observational studies reporting the co-prevalence of sleep apnea and bradycardia or evaluated the use of CPAP on the incidence of bradycardias. We used random-effects models in all meta-analyses and evaluated heterogeneity using I².

RESULTS

We included 34 articles from 7204 records, comprising 4852 patients. Among patients with OSA, the pooled prevalence of daytime and nocturnal bradycardia were 25% (95% CI: 18.6 to 32.7) and 69.8% (95% CI: 41.7 to 88.2) respectively. Among patients with bradycardia, the pooled prevalence of OSA was 56.8% (95% CI: 21.5 to 86.3). CPAP treatment, compared to those without, did not significantly reduce the risk of daytime (two randomized trials; RR: 0.50; 95% CI: 0.11 to 2.21) or nocturnal bradycardia (one randomized-controlled trial and one cohort study; RR: 0.76; 95% CI: 0.48 to 1.20).

CONCLUSIONS

This meta-analysis demonstrates a high comorbid disease burden between OSA and bradycardia. Future research should explore the treatment effect of CPAP on bradycardia incidence, as compared to placebo.

The occurrence and risk factors of bradycardia after the Maze procedure in patients with atrial fibrillation and tricuspid regurgitation

Objective

To evaluate the occurrence and risk factors of bradycardia after the Maze procedure in patients with atrial fibrillation and tricuspid regurgitation.

Methods

All patients underwent mitral valve (MV) replacement and concomitant bi-atrial cut-and-sew Maze procedure along with other cardiac surgical procedures were recruited from the Department of Cardiovascular Surgery at the First Affiliated Hospital of Medical College of Xi'an Jiaotong University. According to the severity of tricuspid regurgitation, all patients were divided into mild tricuspid regurgitation group and moderate-to-severe tricuspid regurgitation group. The general clinical data, biochemical indexes, intraoperative and postoperative data were collected. The relationship between tricuspid regurgitation and sinus bradycardia after the Maze procedure was analyzed by multivariate logistic regression model.

Results

We enrolled 82 patients, including 24 males and 58 females. The patients had an average age of 56 ± 10 years old. There were 50 cases in mild tricuspid regurgitation group and 32 cases in moderate-to-severe tricuspid regurgitation group. Compared with the mild tricuspid regurgitation group, postoperative bradyarrhythmia (41% vs. 14%), pre-discharge bradyarrhythmia (63% vs. 14%), postoperative sinus bradycardia (34% vs. 10%) and pre-discharge sinus bradycardia (63% vs. 10%) in moderate-to-severe tricuspid regurgitation group were significantly increased (P < 0.01). In moderate-to-severe tricuspid regurgitation, the risk of sinus bradycardia increased after the Maze procedure (OR = 1.453, 95% CI 1.127–1.874), area under ROC curve was 0.81, the Jordan index was 0.665.

Conclusion

The severity of tricuspid regurgitation may be an important factor affecting sinus bradycardia after the Maze procedure. It can be considered as a factor to predict sinus bradycardia after the Maze procedure.

[CME-EKG 69/Answers: Sinus Pauses in Long-Term Monitoring]

CME-EKG 69/Answers: Sinus Pauses in Long-Term Monitoring Abstract. While the indication for a pacemaker therapy in patients with high-degree AV block or symptomatic bradycardias is straightforward in most cases, intermittent oligo- and asymptomatic sinus bradycardias and pauses turn out to be more challenging. In this case report potential causes, diagnostic steps and possible therapies will be discussed.

[CME-EKG 69: Sinus Pauses in Long-Term Monitoring]

CME-EKG 69: Sinus Pauses in Long-Term Monitoring Abstract. While the indication for a pacemaker therapy in patients with high-degree AV block or symptomatic bradycardias is straightforward in most cases, intermittent oligo- and asymptomatic sinus bradycardias and pauses turn out to be more challenging. In this case report potential causes, diagnostic steps and possible therapies will be discussed.

Deficiency of CXXC finger protein 1 leads to small changes in heart rate but moderate epigenetic alterations and significant protein downregulation of hyperpolarization-activated cyclic nucleotide-gated 4 (HCN4) ion channels in mice

BACKGROUND

The normal cardiac rhythm is generated in the sinoatrial node (SAN). Changes in ionic currents of the SAN may cause sinus arrhythmia. CXXC finger protein 1 (Cfp1) is an epigenetic regulator that is involved in transcriptional regulation of multiple genes.

OBJECTIVE

The purpose of this study was to explore whether Cfp1 controls SAN function through regulation of ion channel-related genes.

METHODS

Electrophysiological study, patch clamp recording, reverse transcriptase polymerase chain reaction, optical mapping, chromatin immunoprecipitation, and immunofluorescence staining were performed to evaluate the function of SAN and underlying mechanism on Cfp1 heterozygous knockout (Cfp1^+/-) mice.

RESULTS

Heart rate was slower slightly and SAN recovery time was longer in Cfp1^+/- mice than controls. Whole-cell patch-clamp recording showed that the firing rate of action potentials was reduced in Cfp1^+/- mice. The density of I_f current was reduced by 66% in SAN cells of Cfp1^+/- mice but the densities of I_Ca, I_Ca-L, and I_Ca-T were not changed. The hyperpolarization-activated cyclic nucleotide-gated 4 (HCN4) mRNA level in SAN tissue of Cfp1^+/- mice was reduced. The HCN4 protein was significantly decreased in SAN cells and tissues after heterozygous deletion of Cfp1. Chromatin immunoprecipitation assay on cultured HL-1 cells demonstrated that Cfp1 was enriched in the promoter regions of HCN4. Knockdown of Cfp1 reduced H3K4 trimethylation, H3K9 acetylation, and H3K27 acetylation of HCN4 promoter region.

CONCLUSION

Deficiency of Cfp1 leads to small changes in heart rate by moderate epigenetic modification alterations and significant protein downregulation of HCN4 ion channels in mice.

A rare HCN4 variant with combined sinus bradycardia, left atrial dilatation, and hypertrabeculation/left ventricular noncompaction phenotype

INTRODUCTION AND OBJECTIVES

HCN4 variants have been reported to cause combined sick sinus syndrome (SSS) and left ventricular noncompaction (LVNC) cardiomyopathy. This relationship has been proven in few cases and no previous patients have associated left atrial dilatation (LAD). Our objective was to study a familial disorder characterized by SSS, LAD, and hypertrabeculation/LVNC and to identify the underlying genetic and electrophysiological characteristics.

METHODS

A family with SSS and LVNC underwent a clinical, genetic, and electrophysiological assessment. They were studied via electrocardiography, Holter recording, echocardiography, and exercise stress tests; cardiac magnetic resonance imaging was additionally performed in affected individuals. Genetic testing was undertaken with targeted next-generation sequencing, as well as a functional study of the candidate variant in Chinese hamster ovary cells.

RESULTS

Twelve members of the family had sinus bradycardia, associated with complete criteria of LVNC in 4 members and hypertrabeculation in 6 others, as well as LAD in 9 members. A HCN4 c.1123C>T;(p.R375C) variant was present in heterozygosis in all affected patients and absent in unaffected individuals. Electrophysiological analyses showed that the amplitude and densities of the HCN4 currents (I_HCN4) generated by mutant p.R375C HCN4 channels were significantly lower than those generated by wild-type channels.

CONCLUSIONS

The combined phenotype of SSS, LAD, and LVNC is associated with the heritable HCN4 c.1123C>T;(p.R375C) variant. HCN4 variants should be included in the genetic diagnosis of LVNC cardiomyopathy and of patients with familial forms of SSS, as well as of individuals with sinus bradycardia and LAD.

Arrhythmia in COVID-19

The current outbreak of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) also known as coronavirus disease 2019 (COVID-19) has quickly progressed to a global pandemic. There are well-documented cardiac complications of COVID-19 in patients with and without prior cardiovascular disease. The cardiac complications include myocarditis, heart failure, and acute coronary syndrome resulting from coronary artery thrombosis or SARS-CoV-2-related plaque ruptures. There is growing evidence showing that arrhythmias are also one of the major complications. Myocardial inflammation caused by viral infection leads to electrophysiological and structural remodeling as a possible mechanism for arrhythmia. This could also be the mechanism through which SARS-CoV-2 leads to different arrhythmias. In this review article, we discuss arrhythmia manifestations in COVID-19.

Life-threatening cardiac arrhythmias in congenital central hypoventilation syndrome

Congenital central hypoventilation syndrome (CCHS) patients are at risk for life-threatening cardiac arrhythmias, and presentation is dependent on their PHOX2B gene mutation. We describe the presentation of life-threatening arrhythmias in our cohort of CCHS patients. We reviewed the records of 72 CCHS patients seen at CHLA from 2004 to 2018. Data collected included demographics, PHOX2B genotype, ventilatory support, clinical symptoms, ambulatory cardiac monitoring results, and presence of cardiac pacemaker. Sixteen of 72 patients had evidence of potential life-threatening cardiac arrhythmias. PHOX2B genotypes were 20/25 polyalanine repeat expansion mutation (PARM), 20/26 PARM, 20/27 PARM, 20/32 PARM, and c.245C > T non-polyalanine repeat mutation. 11/16 patients were ventilated during sleep only. Symptoms included syncope, dizziness, chest pain, tingling in the left arm, and palpitations. 15/16 patients had recorded ambulatory cardiac monitoring. 5/16 patients were symptomatic without significant sinus pauses. 12/16 patients had implantation of cardiac pacemakers. 9/12 had significant sinus pauses on ambulatory monitoring, and 7/12 patients were symptomatic.Conclusion: CCHS patients have potential life-threatening arrhythmias requiring cardiac pacemaker implantation. Many of these patients are symptomatic with significant sinus pauses on ambulatory monitoring. However, some symptomatic patients with no significant pauses on ambulatory monitoring may still require cardiac pacemaker implantation.What is Known:• CCHS patients are at risk for life-threatening sinus pauses and require cardiac pacemaker implantation.What is New:• CCHS patients regardless of PHOX2B genotype are at risk for significant sinus pauses. Many CCHS patients with significant sinus pause on ambulatory cardiac monitoring are symptomatic and most present with syncope. Some symptomatic patients do not have significant sinus pauses but may still require cardiac pacemaker implantation.

Cardiac rhythm and pacemaking abnormalities in patients affected by endemic pemphigus in Colombia may be the result of deposition of autoantibodies, complement, fibrinogen, and other molecules

BACKGROUND

We previously showed that one-third of patients affected by endemic pemphigus foliaceus in El Bagre, Colombia (El Bagre-EPF), display autoreactivity to the heart.

OBJECTIVE

The purpose of this study was to investigate rhythm disturbances with the presence of autoantibodies and correlate them with ECG changes in these patients.

METHODS

We performed a study comparing 30 patients and 30 controls from the endemic area, matched by demographics, including age, sex, weight, work activities, and comorbidities. ECG as well as direct and indirect immunofluorescence, immunohistochemistry, and confocal microscopic studies focusing on cardiac node abnormalities were performed. Autopsies of 7 patients also were reviewed.

RESULTS

The main ECG abnormalities seen in the El Bagre-EPF patients were sinus bradycardia (in one-half), followed by left bundle branch block, left posterior fascicular block, and left anterior fascicular block compared with the controls. One-third of the patients displayed polyclonal autoantibodies against the sinoatrial and/or AV nodes and the His bundle correlating with rhythm anomalies and delays in the cardiac conduction system (P <.01). The patient antibodies colocalized with commercial antibodies to desmoplakins I and II, p0071, armadillo repeat gene deleted in velo-cardio-facial syndrome (ARVCF), and myocardium-enriched zonula occludens-1-associated protein (MYZAP; Progen Biotechnik) (P <.01).

CONCLUSION

One-third of the patients affected by El Bagre-EPF have rhythm abnormalities that slow the conduction of impulses in cardiac nodes and the cardiac conduction system. These abnormalities likely occur as a result of deposition of autoantibodies, complement, and other inflammatory molecules. We show for the first time that MYZAP is present in cardiac nodes.

Cannabinoids and Symptomatic Bradycardia

Cannabinoids, the bioactive components of marijuana, have adverse cardiovascular consequences, including symptomatic sinus bradycardia, sinus arrest and ventricular asystole. Physicians should be aware of these deleterious consequences which can appear in otherwise healthy persons who are chronic marijuana users.

Knockdown of cardiac Kir3.1 gene with siRNA can improve bradycardia in an experimental sinus bradycardia rat model

The objective of this study was to explore whether the inhibition of potassium inwardly rectifying channel (Kir3.1) with short interfering RNA (siRNA) can improve bradycardia in an experimental sinus bradycardia rat model. 54 Sprague Dawley (SD) rats were randomly divided into three groups: experimental group, control group, and sham group. Sinus bradycardia model was established in SD rats through chemical ablation of sinoatrial (SA) node with 20% formaldehyde. Variations of Kir3.1 expression at mRNA and protein level were examined with qPCR and Western blotting. Electrocardiograms (ECG) of rats at 3 days and 1, 2, 3, and 4 weeks after chemical ablation and lentivirus injection were recorded and differences were compared among the three groups. The differences among multiple groups were analyzed by one-way analysis of variance (ANOVA). It was found through RT-PCR and Western blot that the mRNA and protein levels of Kir3.1 at sinoatrial node areas were decreased by 42 ± 7% and 31 ± 7% in comparison with control group, respectively (P < 0.05 in both comparisons) after 4 weeks of chemical ablation/injection. Whole-cell patch clamp data showed that the lentiviral construct could significantly inhibit the potassium current of a muscarinic acetylcholine-sensitive K⁺ channel, I_KACh. ECG data showed that the heart rate of experimental group increased after 3 days of chemical ablation/injection and lasted for at least 4 weeks after the chemical ablation/injection (heart rate increased 15.4 ± 3.8% in comparison with control group, P < 0.05). Inhibition of Kir3.1 could rescue sinus bradycardia induced by chemical ablation of SA node with 20% formaldehyde at least partly through inhibiting I_KACh channel.

Sinus bradycardia after intravenous pulse methylprednisolone therapy in patients with systemic lupus erythematosus

Sinus bradycardia is reported as an adverse effect of high-dose glucocorticoid therapy. We report three cases of systemic lupus erythematosus, wherein intravenous pulse methylprednisolone was administered. The patients' average baseline heart rate was 72 beats/min, which decreased 30% from baseline at 61 h after beginning the therapy. The average minimum heart rate was 38 beats/min, and this rate continued for 169 h on average. No other causes for bradycardia were found, suggesting that the administration of glucocorticoid pulse therapy resulted in decreased heart rate.

Normal Sinus Rhythm-Sinus Bradycardia is Common in Young Children Post-extracardiac Fontan

We hypothesized that normal sinus rhythm-sinus bradycardia is common in young children following extracardiac Fontan. After excluding patients with sinus pauses, junctional rhythm, tachy-brady syndrome, frequent ectopics, or ectopic atrial rhythm, we found an ambulatory 24-h Holter monitor average heart rate of 78 ± 12 beats per minute (bpm) in 33 post-extracardiac Fontan children with a median age of 6 years (5-10). A 24-h average heart rate of 78 ± 12 bpm is statistically significantly lower than a 24-h average heart rate value of 90 ± 10 bpm derived from a similarly aged control population (p < 0.01). We conclude that after excluding those with significant arrhythmias, normal sinus rhythm-sinus bradycardia is common in children post-extracardiac Fontan.

Catheter ablation of atrial fibrillation in patients with concomitant sinus bradycardia-Insights from the German Ablation Registry

AIMS

This investigation addresses procedural characteristics of catheter ablation in patients with atrial fibrillation (AF) and sinus bradycardia.

METHODS

From the prospective, multi-center German Ablation Registry 1073 patients with sinus rhythm at the time of AF ablation were divided into two groups according to heart rate at start of procedure (A, <60 beats per minute (bpm), n=197; B, 60-99bpm, n=876).

RESULTS

Acute procedural success was high (≥98%) and similar between groups. Procedure duration and energy application time were increased in group A (180min vs. 155min and 2561s vs. 1879s, respectively). Major complications were more frequent in group A (2.2% vs. 0.5%), and a greater proportion of these patients was discharged under antiarrhythmic medication (64% vs. 52%).

CONCLUSION

Catheter ablation of AF with concomitant sinus bradycardia is associated with high procedural efficacy, longer procedure- and energy application durations, and a slightly elevated complication rate.

Torsades de pointes after adenosine administration

Adenosine can produce arrhythmias, which are generally short living. It may induce PACs and PVCs, sinus bradycardia, and atrial fibrillation. There have been reports of transient polymorphic VT (torsades de pointes) in patients with LQTS and others in people with normal QT interval. We report a case of a long episode of polymorphic VT induced by adenosine. A 27 year old woman received 6 mg adenosine for PSVT, which terminated and torsades de pointes developed, persisting for 17 seconds and terminated spontaneously. This is the longest described duration of the torsades after adenosine administration in patients with normal QT interval.

Sinus bradycardia during hypothermia in comatose survivors of out-of-hospital cardiac arrest - a new early marker of favorable outcome?

BACKGROUND

Bradycardia is a common finding in patients undergoing therapeutic hypothermia (TH) following out-of-hospital cardiac arrest (OHCA), presumably as a normal physiological response to low body temperature. We hypothesized that a normal physiological response with sinus bradycardia (SB) indicates less neurological damage and therefore would be associated with lower mortality.

METHODS

We studied 234 consecutive comatose survivors of OHCA with presumed cardiac etiology and shockable primary rhythm, who underwent a full 24-h TH-protocol (33°C) at a tertiary heart center (years: 2004-2010). Primary endpoint was 180-day mortality; secondary endpoint was favorable neurological outcome (180-day cerebral performance category: 1-2).

RESULTS

SB, defined as sinus rhythm <50 beats per minute during TH, was present in 115 (49%) patients. Baseline characteristics including sex, witnessed arrest, bystander cardiopulmonary resuscitation and time to return of spontaneous circulation were not different between SB- and no-SB patients. However, SB-patients were younger, 57±14 vs. 63±14 years, p<0.001 and less frequently had known heart failure (7% vs. 20%, p<0.01). Patients experiencing SB during the hypothermia phase of TH had a 17% 180-day mortality rate compared to 38% in no-SB patients (p<0.001), corresponding to a 180-day hazard ratio (HRadjusted=0.45 (0.23-0.88, p=0.02)) in the multivariable analysis. Similarly, SB during hypothermia was directly associated with lower odds of unfavorable neurological outcome (ORunadjusted=0.42 (0.23-0.75, p<0.01).

CONCLUSION

Sinus bradycardia during therapeutic hypothermia is independently associated with a lower 180-day mortality rate and may thus be a novel, early marker of favorable outcome in comatose survivors of OHCA.

Sinus node dysfunction in adult systemic lupus erythematosus flare: A case report

Cardiac involvement can affect up to 50% of the systemic lupus erythematosus (SLE) patients but conduction system disturbances in SLE are less commonly described. For an early detection of this complication in the acute phase of SLE a whole cardiovascular examination and periodic electrocardiographic monitoring are recommended. We describe a patient who was diagnosed with flare up of lupus activity manifesting as sinus node dysfunction presenting as profound sinus bradycardia. She was successfully treated with high-dose methylprednisolone therapy.