D-lactic acidosis or D-lactate encephalopathy is a rare condition that occurs primarily in individuals who have a history of short bowel syndrome. The unabsorbed carbohydrates act as a substrate for colonic bacteria to form D-lactic acid among other organic acids. The acidic pH generated as a result of D-lactate production further propagates production of D-lactic acid, hence giving rise to a vicious cycle. D-lactic acid accumulation in the blood can cause neurologic symptoms such as delirium, ataxia, and slurred speech. Diagnosis is made by a combination of clinical and laboratory data including special assays for D-lactate. Treatment includes correcting the acidosis and decreasing substrate for D-lactate such as carbohydrates in meals. In addition, antibiotics can be used to clear colonic flora. Although newer techniques for diagnosis and treatment are being developed, clinical diagnosis still holds paramount importance, as there can be many confounders in the diagnosis as will be discussed subsequently.

Interatrial block (IAB; P-wave duration ≥ 110 ms), which represents a delay in the conduction between the atria, is a pandemic conduction abnormality that is frequently underappreciated in clinical practice. Despite its comprehensive documentation in the medical literature, it has still not received adequate attention and also not adequately described and discussed in most cardiology textbooks. IAB can be of varying degrees and classified based on the degree of P-duration and its morphology. It can transform into a higher degree block and can also manifest transiently. IAB may be a preceding or causative risk factor for various atrial arrhythmias (esp. atrial fibrillation) and also be associated with various other clinical abnormalities ranging from left atrial dilation and thromboembolism including embolic stroke and mesenteric ischemia. IAB certainly deserves more attention and prospective studies are needed to formulate a standard consensus regarding appropriate management strategies.

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Hydroxychloroquine, initially used as an antimalarial, is used as an immunomodulatory and antiinflammatory agent for the management of autoimmune and rheumatic diseases such as systemic lupus erythematosus. Lately, there has been interest in its potential efficacy against severe acute respiratory syndrome coronavirus 2, with several speculated mechanisms. The purpose of this review is to elaborate on the mechanisms surrounding hydroxychloroquine. The review is an in-depth analysis of the antimalarial, immunomodulatory, and antiviral mechanisms of hydroxychloroquine, with detailed and novel pictorial explanations. The mechanisms of hydroxychloroquine are related to potential cardiotoxic manifestations and demonstrate potential adverse effects when used for coronavirus disease 2019 (COVID-19). Finally, current literature associated with hydroxychloroquine and COVID-19 has been analyzed to interrelate the mechanisms, adverse effects, and use of hydroxychloroquine in the current pandemic. Currently, there is insufficient evidence about the efficacy and safety of hydroxychloroquine in COVID-19. KEY MESSAGES 1. HCQ, initially an antimalarial agent, is used as an immunomodulatory agent for managing several autoimmune diseases, for which its efficacy is linked to inhibiting lysosomal antigen processing, MHC-II antigen presentation, and TLR functions. 2. HCQ is generally well-tolerated although severe life-threatening adverse effects including cardiomyopathy and conduction defects have been reported. 3. HCQ use in COVID-19 should be discouraged outside clinical trials under strict medical supervision.

Type-2 diabetes mellitus (T2DM) plays a central role in the development of cardiovascular disease (CVD). However, its relationship to epicardial adipose tissue (EAT) and pericardial adipose tissue (PAT) in particular is important in the pathophysiology of coronary artery disease. Owing to its close proximity to the heart and coronary vasculature, EAT exerts a direct metabolic impact by secreting proinflammatory adipokines and free fatty acids, which promote CVD locally. In this review, we have discussed the relationship between T2DM and cardiac fat deposits, particularly EAT and PAT, which together exert a big impact on the cardiovascular health.

A B S T R A C T Background:The correlation between vertical P-wave axis (P-axis > 60°) and pulmonary emphysema was investigated on a very large controlled series to see if P-axis verticalisation as lone criterion can be effectively used to screen emphysema in general population. Correlation between degrees of P-axis verticalisation and the severity of the obstructive lung disease (as per global initiative for chronic obstructive lung disease [GOLD] criteria) was also studied to see if this criterion can be used for gross quantification of the chronic obstructive pulmonary disease (COPD) in routine clinical practice. Materials and methods:Around 6500 unselected, routine electrocardiograms (ECGs) were reviewed which yielded 600 ECGs with vertical P-axis in sinus rhythm. 635 ECGs from the same continuum were selected with P-axis ≤60° matched for patient's age and sex serving as controls. Charts were reviewed for the diagnosis of COPD and emphysema based on medical history, pulmonary function tests, and imaging studies.Results: Prevalence of emphysema in patients with vertical P-axis was strikingly higher than in the control group: 85% vs 4.4%. The sensitivity and specificity of vertical P-axis for diagnosing emphysema was 94.76% and 86.47%, respectively. Vertical P-axis and forced expiratory volume (FEV1) were inversely correlated (Pearson correlation coefficient = -0.683). Prevalence of severe COPD was strikingly higher in patients with P-axis > 75° as compared to the group with P-axis 60°-75°: 96.3% vs 4.6%. Close to 80% of the emphysema patients with P-axis > 85° had very severe disease (FEV1 < 30%).Conclusion: P-axis verticalisation is highly effective for screening emphysema and degree of verticalisation provides a gross quantification of the disease.

Pericardial decompression syndrome (PDS) is an infrequent, life-threatening complication following pericardial drainage for cardiac tamponade physiology. PDS usually develops after initial clinical improvement following pericardiocentesis and is significantly underreported and may be overlooked in the clinical practice. Although the precise mechanisms resulting in PDS are not well understood, this seems to be highly associated with patients who have some underlying ventricular dysfunction. Physicians performing pericardial drainage should be mindful of the risk factors associated with the procedure including the rare potential for the development of PDS.

Anaphylaxis rarely manifests as a vasospastic acute coronary syndrome with or without the presence of underlying coronary artery disease. The variability in the underlying pathogenesis produces a wide clinical spectrum of this syndrome. We present three cases of anaphylactic acute coronary syndrome that display different clinical variants of this phenomenon. The main pathophysiological mechanism of the allergic anginal syndromes is the inflammatory mediators released during a hypersensitivity reaction triggered by food, insect bites, or drugs. It is important to appropriately recognize and treat Kounis syndrome in patients with exposure to a documented allergen.