Mechanism-based therapy of non-cardiac syncope: a practical guide.

The term non-cardiac syncope includes all forms of syncope, in which primary intrinsic cardiac mechanism and non-syncopal transient loss of consciousness can be ruled out. Reflex syncope and orthostatic hypotension are the most frequent aetiologies of non-cardiac syncope. As no specific therapy is effective for all types of non-cardiac syncope, identifying the underlying haemodynamic mechanism is the essential prerequisite for an effective personalized therapy and prevention of syncope recurrences. Indeed, choice of appropriate therapy and its efficacy are largely determined by the syncope mechanism rather than its aetiology and clinical presentation. The two main haemodynamic phenomena leading to non-cardiac syncope include either profound hypotension or extrinsic asystole/pronounced bradycardia, corresponding to two different haemodynamic syncope phenotypes, the hypotensive and bradycardic phenotypes. The choice of therapy-aimed at counteracting hypotension or bradycardia-depends on the given phenotype. Discontinuation of blood pressure-lowering drugs, elastic garments, and blood pressure-elevating agents such as fludrocortisone and midodrine are the most effective therapies in patients with hypotensive phenotype. Cardiac pacing, cardioneuroablation, and drugs preventing bradycardia such as theophylline are the most effective therapies in patients with bradycardic phenotype of extrinsic cause.

Safety and efficacy of cardioneuroablation for vagal bradycardia in a single arm prospective study.

Cardioneuroablation (CNA) is currently considered as a promising treatment option for patients with symptomatic bradycardia caused by vagotonia. This study aims to further investigate its safety and efficacy in patients suffering from vagal bradycardia. A total of 60 patients with vagal bradycardia who underwent CNA in the First Affiliated Hospital of Xinjiang Medical University from November 2019 to June 2022. Preoperative atropine tests revealed abnormal vagal tone elevation in all patients. First, the electroanatomic structures of the left atrium was mapped out by using the Carto 3 system, according to the protocol of purely anatomy-guided and local fractionated intracardiac electrogram-guided CNA methods. The upper limit of ablation power of superior left ganglion (SLGP) and right anterior ganglion (RAGP) was not more than 45W with an ablation index of 450.Postoperative transesophageal cardiac electrophysiological examination was performed 1 to 3 months after surgery. The atropine test was conducted when appropriate. Twelve-lead electrocardiogram, Holter electrocardiogram, and skin sympathetic nerve activity were reviewed at 1, 3, 6 and 12 months after operation. Adverse events such as pacemaker implantation and other complications were also recorded to analyze the safety and efficacy of CNA in the treatment of vagus bradycardia. Sixty patients were enrolled in the study (38 males, mean age 36.67 ± 9.44, ranging from 18 to 50 years old). None of the patients had a vascular injury, thromboembolism, pericardial effusion, or other surgical complications. The mean heart rate, minimum heart rate, low frequency, low/high frequency, acceleration capacity of rate, and skin sympathetic nerve activity increased significantly after CNA. Conversely, SDNN, PNN50, rMSSD, high frequency, and deceleration capacity of rate values decreased after CNA (all P < 0.05). At 3 months after ablation, the average heart rate, maximum heart rate, and acceleration capacity of heart rate remained higher than those before ablation, and the deceleration capacity of heart rate remained lower than those before ablation and the above results continued to follow up for 12 months after ablation (all P < 0.05). There was no significant difference in other indicators compared with those before ablation (all P > 0.05). The remaining 81.67% (49/60) of the patients had good clinical results, with no episodes of arrhythmia during follow-up. CNA may be a safe and effective treatment for vagal-induced bradycardia, subject to confirmation by larger multicenter trials.

Unusual Tachycardia in a Patient With Chest Pain and Bradycardia.

This case report describes a patient in their 50s who presented with squeezing chest pain for 4 hours and an initial electrocardiogram showing acute inferior wall and right ventricular infarction with third-degree atrioventricular block.

Prognostic benefits of His-Purkinje capture in physiological pacemakers for bradycardia.

INTRODUCTION: Clinical outcomes of long-term ventricular septal pacing (VSP) without His-Purkinje capture remain unknown. This study evaluated the differences in clinical outcomes between conduction system pacing (CSP), VSP, and right ventricular pacing (RVP). METHODS: Consecutive patients with bradycardia indicated for pacing from 2016 to 2022 were prospectively followed for the clinical endpoints of heart failure (HF)-hospitalizations and all-cause mortality at 2 years. VSP was defined as septal pacing due to unsuccessful CSP implant or successful CSP followed by loss of His-Purkinje capture within 90 days. RESULTS: Among 1016 patients (age 73.9 ± 11.2 years, 47% female, 48% atrioventricular block), 612 received RVP, 335 received CSP and 69 received VSP. Paced QRS duration was similar between VSP and RVP, but both significantly longer than CSP (p < .05). HF-hospitalizations occurred in 130 (13%) patients (CSP 7% vs. RVP 16% vs. VSP 13%, p = .001), and all-cause mortality in 143 (14%) patients (CSP 7% vs. RVP 19% vs. VSP 9%, p < .001). The association of pacing modality with clinical events was limited to those with ventricular pacing (Vp) > 20% (pinteraction < .05). Adjusting for clinical risk factors among patients with Vp > 20%, VSP (adjusted hazard ratio [AHR]: 4.74, 95% confidence interval [CI]: 1.57-14.36) and RVP (AHR: 3.08, 95% CI: 1.44-6.60) were associated with increased hazard of HF-hospitalizations, and RVP (2.52, 95% CI: 1.19-5.35) with increased mortality, compared to CSP. Clinical endpoints did not differ between VSP and RVP with Vp > 20%, or amongst groups with Vp < 20%. CONCLUSION: Conduction system capture is associated with improved clinical outcomes. CSP should be preferred over VSP or RVP during pacing for bradycardia.

Newborns with congenital complete heart block: Advice for perinatal care providers.

Congenital complete heart block (CCHB) is a rare, but a potentially life-threatening manifestation of autoimmune diseases in neonates. Bradycardia in CCHB can be misdiagnosed as foetal distress in utero and thus precipitating a Caesarean section. We report a case series of three neonates with bradycardia without any electrolyte abnormalities and structurally normal hearts with favourable outcomes.

Bradycardia risk stratification with implantable loop recorder after unexplained syncope.

BACKGROUND: An implantable loop recorder is an effective tool for diagnosing unexplained syncope. However, after a first episode in non-high-risk patients, the usefulness of implantable loop recorder implantation remains unclear. AIMS: To analyse relevant risk factors for significant bradycardia in order to identify patients who do or do not benefit from implantable loop recorder implantation. Also, to study whether implantable loop recorder implantation with remote monitoring is associated with less recurrence of traumatic syncope. METHODS: This was a retrospective monocentric study including patients with implantable loop recorder implantation after unexplained syncope, using remote monitoring and iterative consultations. RESULTS: Two hundred and thirty-seven patients were implanted for unexplained syncope. Significant bradycardia occurred in 53 patients (22.4%): 23 (43.4%) caused by paroxysmal atrioventricular block and 30 (56.6%) caused by sinus node dysfunction, leading to permanent pacemaker implantation in 48 patients. Compared with younger patients, there was a 3.46-fold increase (95% confidence interval 1.92-6.23; P<0.0001) in the risk of significant bradycardia in patients aged≥60 years. Based on multivariable analysis, only "typical syncope" was associated with significant bradycardia occurrence (hazard ratio 3.14, 95% confidence interval 1.75-5.65; P=0.0001). There was no recurrence of significant bradycardia with traumatic complications among patients implanted for traumatic syncope. CONCLUSIONS: This study shows that: (1) implantable loop recorders identify more significant bradycardia in patients aged≥60 presenting with a first non-high-risk typical syncope, suggesting that an implantable loop recorder should be implanted after a first episode of unexplained syncope in such conditions; and (2) after traumatic syncope, implantable loop recorder implantation is safe, and is associated with little or no recurrence of traumatic syncope.

Comparison of clinical outcomes between transthoracic echocardiography- and X-ray-guided left bundle branch pacing for bradycardia: A randomized controlled trial.

INTRODUCTION: Left bundle branch pacing (LBBP) is a physiological pacing modality. However, the long procedure and fluoroscopy time of LBBP is still a problem. This study aims to compare the clinical outcomes between transthoracic echocardiography (TTE)- and X-ray-guided LBBP. METHODS: This is a single-center, prospective, randomized controlled study. Consecutive patients who underwent LBBP in our team from June 2022 to November 2022 were enrolled. Procedure and fluoroscopy time, pacing parameters, electrophysiological and echocardiographic characteristics, as well as complications were recorded at implantation and during follow-up. RESULTS: In this study, 60 patients were enrolled and divided into two groups: 30 patients were allocated to the X-ray group and the remaining 30 to the TTE group. There was no significant difference in the success rate between the two groups (86.7% vs. 76.7%, p = .317). The procedure time of TTE group was comparable to that of the X-ray group (9.0 vs. 12.0 min, p = .063). However, the fluoroscopy time in the TTE group was significantly lower than that of the X-ray group (2.5 vs. 5.0 min, p = .002). There were no statistically significant differences in pacing parameters, electrophysiological and echocardiographic characteristics, or complications between the two groups at implantation and during follow-up. CONCLUSION: TTE-guided LBBP is a feasible and safe method. Compared with X-ray, TTE showed a comparable success rate and procedure time, but it could significantly reduce the fluoroscopy time of LBBP.

BRASH syndrome with a complete heart block- a case report.

INTRODUCTION: BRASH syndrome (Bradycardia, Renal failure, Atrioventricular (AV) nodal blocking agent, Shock and Hyperkalemia) is a recently emerging diagnosis that describes the profound bradycardia seen in patients on AV nodal blockers who present with acute kidney injury (AKI) and hyperkalemia. CASE PRESENTATION: We present a case of a 68 years old female patient with past history of hypertension taking atenolol and Enalapril presented to emergency department with the complaint of loss of consciousness of 02 hours duration. She had 03 days history of fatigue, poor oral intake, decreased urine output, appetite loss, vertigo and global headache. Her vital signs were blood pressure of 60/40 mmHg, absent radial pulse and temperature of 36.4 °C. Her systemic examination was remarkable for dry buccal mucosa; apical heart rate was 22 beats per minute. Glasgow Coma Scale was 13/15. Her laboratory tests showed creatinine of 1.83 mg/dL, blood urea nitrogen of 89 mg/dL and potassium elevated to the level of 6.39 mEq/dL. ECG revealed complete heart block with a normal QT interval and T waves and no U waves with ventricular rate of 22 beats per minute. Her previous medications were discontinued and the patient was resuscitated with intravenous (IV) fluids. She was given 03 doses of 1 mg atropine every 5 minutes but there was no increment in heart rate. She was given 50% dextrose with 10 international units of regular insulin, 1 g of calcium gluconate and Intravenous perfusion of norepinephrine and dopamine. Subsequently, after 14 hours of ICU admission the patient had a cardiac arrest with asystole and resuscitation was attempted but she couldn't survive. CONCLUSION: BRASH syndrome is largely an under-recognized life threatening clinical diagnosis. Physicians should have high index of suspicion for BRASH when they encounter patients with bradycardia, hyperkalemia, and renal failure, as timely diagnosis is crucial in the management.

[Historical development of diagnosis of bradyarrhythmias : The early years of clinical electrophysiology in Germany]. / Historische Entwicklung der Diagnostik der bradykarden Rhythmusstörungen : Die frühen Jahre der Klinischen Elektrophysiologie in Deutschland.

The introduction of His bundle electrography by Benjamin Scherlag (New York) in 1969, together with programmed stimulation of the heart by Philip Coumel (Paris) in 1967, and Hein Wellens (Amsterdam) in 1972, were decisive turning points on the way to invasive electrophysiology and the development of an independent, now distinctly interventional subspecialty of cardiology. The main topic of the 1970s was bradycardic arrhythmias, promoted by pacemaker therapy, which had been introduced just over 10 years earlier. The recording of the potentials of the bundle of His and other recording locations in the atria and ventricles allowed a differentiated assessment of the excitation process and the refractory periods. High-rate atrial stimulation to determine sinus node recovery time and premature stimulation to determine sinoatrial conduction time were developed to analyze sinoatrial node function. This article describes the introduction of His bundle electrography in a gradually increasing number of centers in Germany and their scientific contribution.

Atrioventricular synchronous leadless pacing: Micra AV.

Since the arrival of leadless pacemakers (LPs), they have become a cornerstone in remedial treatment of bradycardia and atrioventricular (AV) conduction disorders, as an alternative to transvenous pacemakers. Even though clinical trials and case reports show indisputable benefits of LP therapy, they also bring some doubts. Together with the positive results of the MARVEL trials, AV synchronization has become widely available in LPs, presenting a significant development in leadless technology. This review presents the Micra AV (MAV), describes major clinical trials, and introduces the basics of AV synchronicity obtained with the MAV and its unique programming options.

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.

Tachy-brady syndrome: Electrophysiology and evolving principles of management.

Sudden alterations in the heart rate may be associated with diverse symptoms. Sinus node dysfunction (SND), also known as sick sinus syndrome, is a sinoatrial (SA) node disorder. SND is primarily caused by the dysfunction of the pacemaker, as well as impaired impulse transmission resulting in a multitude of abnormalities in the heart rhythms, such as bradycardia-tachycardia, atrial bradyarrhythmias, and atrial tachyarrhythmias. The transition from bradycardia to tachycardia is generally referred to as "tachy-brady syndrome" (TBS). Although TBS is etiologically variable, the manifestations remain consistent throughout. Abnormal heart rhythms have the propensity to limit tissue perfusion resulting in palpitations, fatigue, lightheadedness, presyncope, and syncope. In this review, we examine the physiology of tachy-brady syndrome, the practical approach to its diagnosis and management, and the role of adenosine in treating SND.

Pulse Methylprednisolone-Induced Sinus Bradycardia: A Case Report.

Corticosteroids have a wide range of uses. The most commonadverse side effectsofhigh-dosepulse steroids are hyperglycemia, gastrointestinal intolerance, and psychiatric symptoms. Cardiac arrhythmias have been reported in patients who receive high-dose steroid therapy. Bradycardia is a rare adverse side effect of pulse steroid therapy. We present the case of a 57-year-old male patient who developed symptomatic sinus bradycardia after he received pulse methylprednisolone therapy as treatment for graft-versushost disease. The patient's pulse steroid therapy was discontinued, and the dose of methylprednisolone was reduced to 100 mg/day. He was treated conservatively and with close observation; the patient's heart rate increased to 68 beats/min after 1 day, and then to 78 beats/min. The diagnosis of methylprednisolone-induced bradycardia was made after exclusion of other common etiologies of sinus bradycardia. This case report demonstrates the importance of careful cardiovascular monitoring in patients who receive high-dose methylprednisolone because of dose-related cardiovascular risks.