Atypical bypass tracts or variants of ventricular pre-excitation are rare anatomic structures often with rate-dependent slowing in conduction, called decremental conduction. During sinus rhythm, electrocardiographic recognition of those structures may be difficult because unlike in the Wolff-Parkinson-White syndrome where usually overt ventricular pre-excitation is present, the electrocardiogram (ECG) often shows a subtle pre-excitation pattern because of less contribution to ventricular activation over the slow and decrementally conducting bypass. Following the structure described by Ivan Mahaim and Benatt corresponding to a fasciculoventricular pathway, several other new variants of ventricular pre-excitation were reported. In this review, we aim to discuss the electrocardiographic pattern of the different subtypes of variants of ventricular pre-excitation, including the atriofascicular pathway, long and short decrementally conducting atrioventricular pathways, fasciculoventricular pathway, the atrio-Hisian bypass tract, and nodoventricular and nodofascicular fibres. Emphasis will be on the ECG findings during sinus rhythm.

Since it was first reported in 1912, acute coronary syndrome (ACS) has become the leading cause of death in the Western world. Several improvements that have been made over the years in the pharmacological treatment of ACS have reduced the relative risk of death due to myocardial infarction from 35-45% previously to approximately 3.5% at present. Universities, websites, and educational videos commonly use a mnemonic for morphine, oxygen, nitrates, and aspirin (MONA) to refer to the adjuvant treatment used for the management of ACS.We review the scientific data pertaining to treatment strategies for the management of ACS and discuss whether MONA remains relevant in the present scenario.While using morphine and oxygen is associated with risks such as higher mortality and increase in the size of the infarct, respectively, several available drugs such as fibrinolytics, anticoagulants, beta-blockers, renin-angiotensin-aldosterone system inhibitors, P2Y12 inhibitors, and statins are known to be useful to treat ACS.MONA should be viewed as an obsolete teaching and learning aid, and therefore we recommend that its use be discontinued for the management of ACS.

Arrhythmogenic right ventricular dysplasia or cardiomyopathy (ARVD/C) is a pathologic condition where the right ventricle is partially or totally replaced by fatty and fibrous tissue. The electrocardiogram (ECG) has a central role for diagnosis since it comprises two major and two minor criteria in the diagnostic criteria published by the Task 1 Force, although it is not 100% necessary to make a final diagnosis, because around 10% of patients with ARVD/C present with a normal ECG. In this article, we review the 12-lead electrocardiographic findings of patients with ARVD/C. ECG criteria observed during depolarization [prolonged terminal activation duration, epsilon wave, partial right bundle branch block (RBBB) and advanced RBBB of peripheral origin with characteristic ECG patterns] and repolarization abnormalities, (negative T waves) are reviewed in detail. More common ventricular arrhythmias and risk of sudden death, and how to use the surface ECG to stratify the risk, are part of our final comments.

IntroductionPosteroseptal accessory pathways account for 34.5% of the total. Of these, 36% are located within the coronary sinus (CS). Its ablation requires technical alternatives to avoid damage to surrounding tissues, especially branches of the right coronary artery.Case reportA 22-year-old man was referred for re-do ablation of an accessory left septal-septal (PSE) pathway. Inside the CS, a precocity of 25 ms was found in the region of the median cardiac vein (VCM) (Fig. 2, panel A). Radiofrequency (RF) was administered with a non-irrigated bidirectional catheter within this vessel with resolution of the pre-excitation after 5 seconds. Immediately after, the patient presented chest pain and revealed a ST segment elevation of 1 mm in the inferior leads of ECG. Coronary angiography showed occlusion of the middle third of the posterior ventricular branch of the right coronary artery, with no signs of thrombus or dissection. Arterial angioplasty was performed with a bare metal stent, followed by TIMI III distal flow. Retrograde aortic mapping was performed and a precocity of 20 ms was found in the PSE region. The RF was applied followed by loss of pre-excitation after 1.5 seconds of application.ConclusionThis case demonstrates the risks involving delivering radiofrequency within the coronary sinus. We discuss some strategy that could help electrophysiologists in similar cases.