A rare and reversible cause of third-degree atrioventricular block: a case report

Background Cardiac involvement of Lyme disease (LD) typically results in atrioventricular (AV) conduction disturbance, mainly third-degree AV block. Case summary A 54-year-old patient presented to our emergency department due to recurrent syncope. Third-degree AV block with a ventricular escape rhythm (33 b.p.m.) was identified as the underlying rhythm. Transthoracic echocardiography (TTE) was normal. To rule out common reversible causes of complete AV block, a screening test for Lyme borreliosis was carried out. Elevated levels for borrelia IgG/IgM were found and confirmed by western blot analysis. Lyme carditis (LC) was postulated as the most likely cause of the third-degree AV block given the young age of the patient. Initiation of antibiotic therapy with ceftriaxone resulted in a gradual normalization of the AV conduction with stable first-degree AV block on Day 6 of therapy. The patient was changed on oral antibiotics (doxycycline) and discharged without a pacemaker. After 3 months, the AV conduction recovered to normal. Discussion Lyme carditis should always be considered, particularly in younger patients with new-onset AV block and without evidence of structural heart disease. Atrioventricular block recovers in the majority of cases after appropriate antibiotic treatment.

Severe secondary hyperkalemia and arrhythmia from drug interactions between calcium‐channel blocker and voriconazole: a case presentation

Background Patients with kidney disease may have concurrent hypertension and infection. Dihydropyridine calcium-channel blockers (CCB) are the most popular class of antihypertensive drugs used in clinical settings and can be metabolized by cytochrome P450 isoenzyme 3A4 (CYP3A4). Voriconazole is a commonly used antifungal treatment and a CYP3A4-inhibitor. Insufficient attention to drug interactions from the concomitant use of CCB and voriconazole may result in serious adverse reactions. Case presentation Here, we report a patient with acute kidney injury on stable anti-neutrophil cytoplasm antibody associated vasculitis who developed hyperkalemia resulting in sinus arrest with junctional escape rhythm attributed to drug interactions of CCB with voriconazole. This is a very rarely reported case and may be an under-recognized complication. After continuous renal replacement therapy and changing the anti-hypertensive drugs, symptoms, and laboratory abnormalities of the patient fully recovered. Conclusions This case warns us of severe consequences of drug interactions. Co-prescription of CYP3A4-inhibitors with calcium-channel blockers increases the risk of hypotension and acute kidney injury, which may further induce hyperkalemia and arrhythmia.

AV-node isolation in atrial fibrillation vs AV-node ablation by pace and ablate strategy

Funding Acknowledgements Type of funding sources: None. Introduction AV-node ablation (AVNA) is a common therapy option for rate control strategy of permanent atrial fibrillation. However, this therapy has numerous side-effects as bundle branch blocks and absence of escape rhythm. We have invented a new technique that isolates the AV node instead of ablation. Methods Our study includes 60 patients with 40 being treated with AVNA and 20 being treated with AV-node isolation (AVNI). In AVNI patient´s AV-node region was mapped using 3D navigation system. Ablation was performed around the previously mapped HIS-cloud regions isolating the atrium from the AV-node. In all cases in AVNI group ablation was performed with irrigated tip ablation catheter. Procedure time, ablation points, fluoroscopy time and total DAP, escape rhythm and delta QRS among other data were measured and compared in these two methods. Statistical analysis was performed by SPSS software 27.0. Results No complications appeared in this study. In the AVNI group more ablation points were used (p < 0.01) but there was no significant difference in total procedure time (p = 0.730). With AVNI highly significantly less fluoroscopy time (1.4 vs. 4.7 minutes) and total DAP (40.75 vs. 382.85 µGym²) was achieved (p < 0.01). Moreover, the median change in QRS width was 0 ms in the AVNI group vs. 26 ms in the AVNA group (p < 0.01). Immediately postoperative the escape rhythm of the AVNI group was significantly higher than in the AVNA group (MRang = 37.38 vs. MRang = 27.06, p = 0.023). Conclusion AV-node isolation using 3D navigation mapping system is a safe and effective alternative to classic AVNA procedure with less radiation exposure and potential preservation of escape rhythm, which is a major benefit in case of a pacemaker failure. Figure 1. 3D Navigation pictures after successful AVNI with NavX-System (left panel) and CARTO 3-System (right panel). His cloud with yellow points. The Tricuspid annulus could be defined with different color (green on the left panel) or with the tag points (white points on the right panel). Modified left lateral to posterior view. Abstract Figure.

Reversible acute Fontan circulation failure secondary to retrogradely conducted junctional rhythm: clinical echocardiographic correlation

Background Sequential atrioventricular activation plays a critical role in the physiology of Fontan circulation. Although bradycardia is usually well tolerated, retrogradely conducted junctional rhythm may acutely increase atrial pressure impairing cardiac output. Echocardiographic evaluation can reveal clues of this hemodynamic condition. The clinical impact of arrhythmic disturbance on the follow up of patients who had undergone total cavo-pulmonary connection is well recognized but the role of, transient periods of retrogradely conducted junctional rhythm on the immediate post-operative course is less defined. Case presentation We describe two cases of acute Fontan circulatory failure due to postoperative retrogradely conducted junctional escape rhythm despite an adequate heart rate and circadian variation. The patients rapidly improved after atrial pacing, allowing discharge with a minimal dose of diuretic. Conclusion In the absence of any hemodynamic target, hearth rhythm should be systematically checked after TCPC irrespective of adequacy of heart rate. Likewise, efficiency of temporary atrial pacing should be granted and surgeons should have a low threshold for epicardial lead implantation.

Cardiac Pacemaker in Pregnancy: How to Manage?

Despite the increasing use of permanent cardiac pacemakers in a younger patient population, there are little data related to pregnancy. Normal physiologic alterations of pregnancy need to be taken into account in the management of the pregnant woman with a pacemaker in place. Similarly, gestational events including the potential for surgical intervention require a basic knowledge of pacemaker technology and monitoring. We present a case of a patient with junctional escape rhythm and was implanted pacemaker during pregnancy. A 24 years old women referred from obstetric outpatient clinic with asymptomatic bradycardia and cryptogenic stroke 2 years earlier. ECG shows sinus arrest with junctional escape rhythm. After multi-disciplinary discussion, team decided to implant double chamber pacemaker implantation. The pacemaker setting is adjusted to prepare caesarean section at 39 weeks gestation with delivery of an aterm infant. The postoperative course was uneventful. Pre-pregnancy pacemaker settings were re-established after the postpartum period. The current literature on managing pregnant patients with pacemakers is quite limited. Such patients require a multidisciplinary approach to care. Electromagnetic Interference (EMI) should be noticed.

Reversible complete heart block due to hypercalcaemia

A 65-year-old woman presented to the emergency room with a syncope. An ECG done revealed complete heart block with a narrow QRS escape rhythm and a normal QT interval. Further investigation revealed severe hypercalcaemia and elevated parathormone levels. Her heart block disappeared on correction of the hypercalcaemia. A right inferior parathyroid adenoma was found and surgically removed. Thus, hypercalcaemia may lead to reversible complete heart block without QT interval shortening.

Recurrent seizures in a young woman: when video-EEG diagnoses a cardiac cause: a case report

Background While transient loss of consciousness is a frequent presenting symptom, differential diagnosis between syncope and epilepsy can be challenging. Misdiagnosis of epilepsy leads to important psychosocial consequences and eliminates the opportunity to treat patient’s true condition. Case summary A 39-year-old woman presenting with recurrent seizures since her childhood was referred to neurological consultation. Electroencephalograms (EEGs) and magnetic resonance imaging previously performed were normal. A sleep-deprived video-EEG was performed and highlighted after 12 h of sleep deprivation a progressive dropping of the heart rate followed by a complete heart block without ventricular escape rhythm and asystole for about 30 s. Her EEG recording later showed diffuse slow waves traducing a global cerebral dysfunction and suffering. The diagnosis of vaso-vagal syncope with predominant cardioinhibitory response was made and a dual-chamber pacemaker with rate-drop response algorithm was implanted. After a 2 years of follow-up, the patient remained free of syncope. Discussion Patients presenting with loss of consciousness and convulsion are often diagnosed with epilepsy despite normal EEGs. In patients presenting with recurrent seizures with unclear diagnosis of epilepsy or in a situation of drug-resistant epilepsy, syncope diagnosis should always be considered and a risk stratification is necessary. The benefit of pacemaker implantation in patients with recurrent vaso-vagal syncope is still very controversial. Only patients presenting with spontaneous asystole should be considered for pacemaker implantation in case of recurrent vaso-vagal syncope.

Sudden Cardiac Arrest in a Patient With Myxedema Coma and COVID-19

SARS-CoV-2 infection is associated with significant lung and cardiac morbidity but there is a limited understanding of the endocrine manifestations of coronavirus disease 2019 (COVID-19). Although thyrotoxicosis due to subacute thyroiditis has been reported in COVID-19, it is unknown whether SARS-CoV-2 infection can also lead to decompensated hypothyroidism. We present the first case of myxedema coma (MC) in COVID-19 and we discuss how SARS-CoV-2 may have precipitated multiorgan damage and sudden cardiac arrest in our patient. A 69-year-old woman with a history of small cell lung cancer presented with hypothermia, hypotension, decreased respiratory rate, and a Glasgow Coma Scale score of 5. The patient was intubated and administered vasopressors. Laboratory investigation showed elevated thyrotropin, very low free thyroxine, elevated thyroid peroxidase antibody, and markedly elevated inflammatory markers. SARS-CoV-2 test was positive. Computed tomography showed pulmonary embolism and peripheral ground-glass opacities in the lungs. The patient was diagnosed with myxedema coma with concomitant COVID-19. While treatment with intravenous hydrocortisone and levothyroxine were begun the patient developed a junctional escape rhythm. Eight minutes later, the patient became pulseless and was eventually resuscitated. Echocardiogram following the arrest showed evidence of right heart dysfunction. She died 2 days later of multiorgan failure. This is the first report of SARS-CoV-2 infection with MC. Sudden cardiac arrest likely resulted from the presence of viral pneumonia, cardiac arrhythmia, pulmonary emboli, and MC—all of which were associated with the patient’s SARS-CoV-2 infection.

Successful transcutaneous pacing following ventricular standstill during anaesthetic induction in a dog with third-degree atrioventricular block

Third-degree atrioventricular block is a haemodynamically unstable bradycardia frequently resulting in signs of lethargy, weakness and collapse. In this reported case, a four year-four month-old male neutered Cavalier King Charles spaniel diagnosed with third-degree atrioventricular block was referred for transvenous permanent pacemaker implantation. During induction of general anaesthesia, the dog suffered cardiac arrest consistent with ventricular standstill, as indicated by cessation of ventricular electrical activity on the ECG monitor and the absence of a peripheral pulse. The prior placement of transthoracic pacing pads under sedation allowed for rapid commencement of temporary transcutaneous pacing and proved effective in achieving ventricular capture with re-establishment of cardiac output. The subsequent general anaesthesia for implantation of a permanent pacemaker was uneventful. This report considers the possible causes of ventricular escape rhythm suppression and highlights the importance of ensuring availability of a temporary pacing method from the outset when anaesthetising animals with unstable and symptomatic bradycardias.