Abstract Objective: To review the relevant literature on the use of atrioventricular node ablation and pacing in patients with heart failure and atrial fibrillation. Methods: A PubMed/MEDLINE and SCOPUS search was performed in order to assess the clinical outcomes of atrioventricular node ablation and pacemaker implantation, as well as the complications that may occur. Results: Several clinical trials, observational analyses and meta-analyses have shown that “pace and ablate” strategy not only improves symptoms but also can enhance cardiac performance in patients with heart failure and atrial fibrillation. Although this procedure is effective and safe, some complications may occur including worsening of heart failure, permanent fibrillation, arrhythmias and sudden death. Regarding the implantation of pacemaker, cardiac resynchronization therapy is shown to be the optimal choice compared to right ventricle apical pacing. His bundle pacing is a promising alternative to cardiac resynchronization therapy and has shown beneficial effects, while left bundle brunch pacing is an innovative modality. Conclusions: Atrioventricular node ablation and implantation of pacemaker is shown to have beneficial effects on clinical outcomes of patients with atrial fibrillation ± heart failure who do not respond or are intolerant to medical treatment. Cardiac resynchronization therapy is the treatment of choice and His bundle pacing seems to be an effective alternative way of pacing in these patients.

Coronavirus 2019 (COVID-19) is an infectious disease that is becoming a pandemic. Hydroxychloroquine in combination with azythromycin are among drugs currently in use to eradicate COVID-19. Despite concerns due to its potential cardiac toxicity, hydroxychloroquine is widely accepted in mild and moderate COVID-19 pneumonia. In this case report, we report a case of a young Indonesian adult male with suspected COVID-19 pneumonia who received hydroxychloroquine and azythromycin therapies and during 24 hour experienced deterioration of atrioventricular block.

Lyme carditis (LC) is a manifestation of the early disseminated stage of Lyme disease and often presents as high-degree atrioventricular (AV) block. High-degree AV block in LC can be treated with antibiotics, usually resolving with highly favourable prognosis, thus preventing the unnecessary implantation of permanent pacemakers. We present a systematic approach to the diagnosis and management of LC that implements the Suspicious Index in Lyme Carditis (SILC) risk stratification score.

Although first described in the final decade of the 19th century, the axis responsible for atrioventricular conduction has long been the source of multiple controversies. Some of these continue to reverberate. When first described by His, for example, many doubted the existence of the bundle we now name in his honour, while Kent suggested that multiple pathways crossed the atrioventricular junctions in the normal heart. It was Tawara who clarified the situation, although many of his key definitions have not universally been accepted. In key studies in the third decade of the 20th century, Mahaim then suggested the presence of ubiquitous connections that provided "paraspecific" pathways for atrioventricular conduction. In this review, we show the validity of these original investigations, based on our own experience with a large number of datasets from human hearts prepared by serial histological sectioning. Using our own reconstructions, we show how the atrioventricular conduction axis can be placed back within the heart. We emphasise that newly emerging techniques will be key in providing the resolution to map cellular detail to the gross evidence provided by the serial sections

Those using the mouse for the purposes of electrophysiological research presume that the morphology of the conduction axis is comparable with the human arrangement. As yet, however, to the best of our knowledge, no direct comparison has been made between the species. By comparing our extensive histological findings in the human heart with comparable serially-sectioned datasets prepared from adult murine hearts, we aimed to provide this information. When comparing the gross anatomy, we used three-dimensional datasets of neonatal mice hearts prepared using episcopic microscopy. The overall cardiac architecture is comparable, although the mouse has a persistent left superior caval vein draining via the coronary sinus. An inferior pyramidal space, and an infero-septal recess, are both present in the murine heart, although not as well developed as in the human heart. The overall arrangement of the conduction axis is similarly comparable, albeit with subtle differences reflecting the incomplete wedging of the subaortic outflow tract in the murine heart. Most significantly, the findings in both species reveal the presence of extensive superior septal pathways, which perhaps explain the finding of base-to-apex activation of the ventricular mass known to occur in the murine heart.

Clinical and analytical differences between adult patients monoinfected with Borrelia burgdorferi sensu lato (s.l.) and patients infected with B. burgdorferi s.l. who also had IgG antibodies against Babesia divergens have not been reported so far. Both Lyme disease caused by B. burgdorferi and babesiosis caused by B. divergens, endemic in Asturias, Northwestern Spain, are transmitted by Ixodes tick bites. Clinical, laboratory and other diagnostic tests characteristics (imaging, electro-cardiographic-ECG) of 120 residents of Asturias with confirmed B. burgdorferi s.l. infection, di-agnosed during 2015-2017, of whom 47 (39.2%) had B. divergens IgG antibodies, were retrospec-tively compared. Cardiorespiratory symptoms were reported in 9/47 (19.2%) patients with Lyme disease and B. divergens IgG antibodies compared to 4/73 (5.5%) patients with B. burgdorferi s.l. monoinfection (P=0.02). Dyspnea was recorded in 4/47 (8.5%) patients with Lyme disease and B. divergens IgG antibodies compared to 1/73 (1.4%) monoinfected (P=0.07). In addition ECG atri-oventricular (AV) block, mostly 1st degree, was detected in 5/47 (15.6%) patients with Lyme dis-ease and B. divergens IgG antibodies compared to 1/73 (2.6%) B. burgdorferi s.l. monoinfected (P=0.09). No other clinical, laboratory or other tests differences were observed between B. burgdorferi and B. divergens IgG antibodies carriers and B. burgdorferi monoinfected. We con-cluded that patients with Lyme disease and B. divergens IgG antibodies had more frequent car-diorespiratory symptoms, mainly dyspnea, compared to B. burgdorferi monoinfected patients. These symptoms were unrelated to anemia. ECG AV block, perhaps induced by summative myo-cardial damage due to either infections or B. divergens induced lung microcirculation slow-ing-down, might play a role in the cardiorespiratory dysfunction.

Fetuses of pregnant women affected by anti-Ro/anti La antibodies are at risk to develop complete atrioventricular heart block (CAVB) and other potentially life-threatening cardiac affections. CAVB can develop in less than 24 hours. Treatment with anti-inflammatory drugs and immuno-globulins (IVIG) can restore normal rhythm if applied in the transition period. Routine weekly echocardiography as often recommended will seldomly detect emergent AVB. Surveillance of these pregnancies is controversial. To obtain an overview of the current practice in Germany we have developed a web-based survey sent by the DEGUM (German Society of Ultrasound in Med-icine) to ultrasound specialists. Home-monitoring by hand-held Doppler is a promising new approach. With the intention to evaluate practicability, we instructed pregnant women at risk to use hand-held Doppler in the vulnerable period between 18-26 weeks at our university center.