Current Cardiology Reviews - Volume 17, Issue 1, 2021

Lyme carditis (LC) is an early-disseminated manifestation of Lyme disease, most commonly presenting as a high-degree atrioventricular block (AVB). The degree of AVB can fluctuate rapidly within minutes, and progression to third-degree AVB is potentially fatal if not recognized and managed promptly. However, the AVB in LC is often transient and usually resolves with appropriate antibiotic therapy. LC should be on the differential diagnosis in young patients presenting with new high-degree AVB and factors that increase the index of suspicion for Lyme disease. The Suspicious Index in Lyme Carditis (SILC) score helps clinicians risk-stratify for LC. A systematic approach to the diagnosis and treatment of LC minimizes the unnecessary implantation of permanent pacemakers.

Medicine has many great pioneers, and in 1899, one such pioneer - Karel Frederik Wenckebach made a discovery which, even to this day, remains one of the fundamental concepts within electrophysiology. Since the Wenckebach Phenomenon was first described, the field of electrophysiology has developed at a rapid pace, allowing us to observe this behaviour, and its complexities, in many new ways. In a similar way, this chapter will illustrate Wenckebach behaviour across a spectrum of modalities from the 12 lead ECG, through to the intra-cardiac recordings from both electrophysiological studies and implantable cardiac devices. In doing so, we continue to shed light on the phenomenon first identified through Wenckebach’s meticulous attention to detail some 120 years ago.

Revision of the Task Force diagnostic criteria (TFC) for arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D), in 2010, has increased the sensitivity for the diagnosis of early and familial forms of the disease. Epsilon wave (EW) is a major diagnostic criterion in the context of ARVC/D, however, it remains unquantifiable and therefore, may leave room for substantial subjective interpretation, thus, explaining the existing high inter-observer variability in the assessment of EW. EW, when present, coexists with other disease characteristics, which are sufficient for ARVC/D diagnosis, making EW generally not required for ARVC/D diagnosis. Nevertheless, EW remains an important part of the electrocardiographic phenotype of ARVC/D that may be useful in planning diagnostic work-up, which needs to be recognized.

RBBB, a pattern seen on the 12-lead ECG, results when normal electrical activity in the His-Purkinje system is interrupted for some reason. The normal sequence of activation is altered in RBBB, with a resultant characteristic appearance on the ECG manifest by a widened QRS complex and changes in the directional vectors of the R and S waves. This ECG pattern is often seen in clinical practice and generally regarded as benign. The anatomy, epidemiology, causes, symptoms, ECG findings and diagnosis, differential diagnosis in ECG, treatment, complications, prognosis, with respect to RBBB are outlined here, demonstrating some typical ECGs of RBBB.

Many advances in the knowledge of medical science are due to the observation of an unknown phenomenon that remains an open question. A plausible hypothesis must be demonstrated and proved through a scientific method in order to be accepted by the scientific community and the same results must be reached by following either the same or different techniques. The original case described by Rosenbaum MB et al., in this review triggered a series of anatomic and physiologic investigations with clinical and experimental observations that supported the trifascicular nature of the intraventricular conduction system of the heart and the concept of hemiblocks. The recognition and description of the left fascicular blocks made by the Argentinian School of Electrocardiology bridged an important gap in electrocardiography and many electrocardiograms that could not be explained until that moment could finally be understood. This review intends to redefine reliable criteria for the electrocardiographic and vectorcardiographic diagnosis of left fascicular blocks [hemiblocks]. The anatomy of the left bundle branch is also discussed to better understand the incidence, prevalence, clinical significance and main causes of left anterior and left posterior hemiblock either isolated or associated with right bundle branch block. This review offers the reader a reappraisal of the trifascicular nature of the intraventricular conduction system regarding the anatomy of the left bundle branch system and its pathophysiological and clinical significance.

ST-elevation myocardial (STEMI) is frequently associated with conduction disorders. Regional myocardial ischemia or injury may affect the cardiac conduction system at various locations, and neural reflexes or changes in the balance of the autonomous nervous system may be involved. Sinoatrial and atrioventricular blocks are more frequent in inferior than anterior STEMI, while new left anterior fascicular block and right bundle branch block indicate proximal occlusion of the left anterior descending coronary artery. New left bundle branch block is associated with multi-vessel disease. Most conduction disorders associated with STEMI are reversible with reperfusion therapy, but they may still impair prognosis because they indicate a large area at risk, extensive myocardial infarction or severe coronary artery disease. Acute STEMI recognition is possible in patients with a fascicular or right bundle branch block, but future studies need to define the cut-off values for ST depression in the leads V1-V3 in inferolateral MI and for ST elevation in the same leads in anterior STEMI. In the left bundle branch block, concordant ST elevation is a specific sign of acute coronary artery occlusion, but the ECG feature has low sensitivity.

Until the mid-1980s, it was believed that the vectorcardiogram (VCG) presented a greater specificity, sensitivity and accuracy in comparison to the 12-lead electrocardiogram (ECG), in the cardiology diagnosis. Currently, the VCG still is superior to the ECG in specific situations, such as in the evaluation of myocardial infarctions when associated with intraventricular conduction disturbances, in the identification and location of accessory pathways in ventricular preexcitation, in the differential diagnosis of patterns varying from normal of electrical axis deviation, in the evaluation of particular aspects of Brugada syndrome, Brugada phenocopies, concealed form of arrhythmogenic right ventricular cardiomyopathy and zonal or fascicular blocks of the right bundle branch on right ventricular free wall.VCG allows us to analyze the presence of left septal fascicular block more accurately than ECG and in the diagnosis of the interatrial blocks and severity of some chambers enlargements. The three-dimensional spatial orientation of both the atrial and the ventricular activity provides a far more complete observation tool than the linear ECG. We believe that the ECG/VCG binomial simultaneously obtained by the technique called electro-vectorcardiography (ECG/VCG) brought a significant gain for the differential diagnosis of several pathologies. Finally, in the field of education and research, VCG provided a better and more rational tridimensional insight into the electrical phenomena that occurs spatially, and represented an important impact on the progress of electrocardiography.

Asymptomatic bradyarrhythmias involving sinus node dysfunction and atrioventicular blocks are frequently noted in clinical practice. Its prevalence is expected to rise as devices that are developed for monitoring cardiac rhythm for longer duration become more widely available. Episodes of bradyarrhythmia that are asymptomatic are considered to have a benign course compared with those that cause symptoms and do not necessitate further treatment. However, in certain cases, they can be a harbinger of future symptoms or cardiac manifestations of systemic diseases. The evaluation and risk stratification of individuals presenting with asymptomatic bradyarrhythmias is important not only for preventing implantation of unnecessary permanent pacing devices but also for reducing significant morbidity by implementing proper treatment as required. In this article, we will review the current evidence on the pathophysiology, diagnosis, evaluation and management of patients with asymptomatic bradyarrhythmias.

Atrial conduction disorders result from impaired propagation of cardiac impulses from the sinoatrial node through the atrial conduction pathways. Disorders affecting interatrial conduction alter P-wave characteristics on the surface electrocardiogram. A variety of P-wave indices reflecting derangements in atrial conduction have been described and have been associated with an increased risk of atrial fibrillation (AF) and stroke. Interatrial block (IAB) is the most well-known of the different P-wave indices and is important clinically due to its ability to predict patients who are at risk of the development of AF and other supraventricular tachycardias. P-Wave Axis is a measure of the net direction of atrial depolarization and is determined by calculating the net vector of the P-wave electrical activation in the six limb-leads using the hexaxial reference system. It has been associated with stroke and it has been proposed that this variable be added to the existing CHA2DS2-VASc score to create a P2-CHA2DS2-VASc score to improve stroke prediction. P-Terminal Force in V1 is thought to be an epiphenomenon of advanced atrial fibrotic disease and has been shown to be associated with a higher risk of death, cardiac death, and congestive heart failure as well as an increased risk of AF. P-wave Dispersion is defined as the difference between the shortest and longest P-wave duration recorded on multiple concurrent surface ECG leads on a standard 12-lead ECG and has also been associated with the development of AF and AF recurrence. Pwave voltage in lead I (PVL1) is thought to be an electrocardiographic representation of cardiac conductive properties and, therefore, the extent of atrial fibrosis relative to myocardial mass. Reduced PVL1 has been demonstrated to be associated with new-onset AF in patients with coronary artery disease and may be useful for predicting AF. Recently a risk score (the MVP risk score) has been developed using IAB and PVL1 to predict atrial fibrillation and has shown a good predictive ability to determine patients at high risk of developing atrial fibrillation. The MVP risk score is currently undergoing validation in other populations. This section reviews the different P-wave indices in-depth, reflecting atrial conduction abnormalities.

Since its outbreak in China at the end of 2019, the new coronavirus disease (COVID-19) was characterized by both easy spreading and high mortality. The latter proved to be way more elevated in the North of Italy -with a peak of 18.4% in region Lombardia and even 31% in the city of Bergamo and surrounding county- than in the rest of the world. In an attempt to conceptualize the reasons for such a dramatic situation, four key elements have been identified: COVID-19 itself, old age, lung disease, and heart failure. Their harmful combination has been named “The deadly quartet”. The underlying risk factors, among which a lot of them are distinctive features of the population in northern Italy, have been summarized as “unmodifiable”, “partially modifiable”, and “modifiable”, for the sake of clarity. Up-to-date scientific evidence in this field has been described in the form of a narrative and easy-to-read review.

It is widely known that liver cirrhosis, regardless of the etiologies is accompanied by severe hemodynamic changes. The principal pathophysiological mechanisms are the hyperdynamic circulation with increased cardiac output, heart rate along with reduced systemic vascular resistance. Thus, counteractive mechanisms may develop that eventually lead to systolic as well as diastolic dysfunction and rhythm disturbances, in order to keep a steady homeostasis in the human body. Literally, blunted contractile responsiveness to physical or pharmacological stress, impaired diastolic relaxation and electrophysiological changes, primarily QT interval prolongation, do occur progressively in a cirrhotic patient with no known preexisting cardiac disease. This condition is identified as cirrhotic cardiomyopathy (CCM), an entity different from that seen in alcoholic cardiac muscle disease. For the past decades, clinicians did study and attempt to understand the pathophysiology and clinical significance of this process. Indeed, various factors have been identified acting at the molecular and cellular level. Electrocardiography, echocardiography and various serum biomarkers are the main tools that help healthcare practitioners to point to the correct diagnosis. Noteworthy, the subjects that suffer from cirrhotic cardiomyopathy may progress to heart failure during invasive procedures such as surgery, insertion of a transjugular intrahepatic portosystemic shunting (TIPS) and liver transplantation. Besides, several studies have illustrated that CCM is a contributing factor, or even a precipitant, of hepatorenal syndrome (HRS), a conceivable reversible kidney failure in patients with liver cirrhosis and ascites. The treatment is the same as it is in the patients with liver cirrhosis and heart failure and there is no particular treatment for cirrhotic cardiomyopathy. Hence, it is of utmost importance to clearly comprehend the pathophysiology of this disease in order to design more accurate diagnostic tools and definitive treatments in a way to prevent the complications of cirrhosis and overt heart failure. The objective of this review is to describe in a comprehensive way the pathological alterations that occur in the cardiovascular system of cirrhotic patients. It will also point the limitations that remain in the diagnosis and treatment strategies and more importantly, this review will alert the clinicians in the modern era to further observe and record additional pathological changes in this subset of patients.

The fervency for advancement and evolution in percutaneous coronary intervention has revolutionised the treatment of coronary artery disease. Historically, the focus of the interventional cardiologist was directed at the restoration of luminal patency of the major epicardial coronary arteries, yet whilst this approach is evolving with much greater utilisation of physiological assessment, it often neglects consideration of the role of the coronary microcirculation, which has been shown to clearly influence prognosis. In this review, we explore the narrative of the coronary circulation as more than just a simple conduit for blood but an organ with functional significance. We review organisation and physiology of the coronary circulation, as well as the current methods and techniques used to examine it. We discuss the studies exploring coronary artery endothelial function, appreciating that coronary artery disease occurs on a spectrum of disorder and that percutaneous coronary intervention has a latent effect on the coronary circulation with long-term consequences. It is concluded that greater recognition of the coronary artery endothelium and mechanisms of the coronary circulation should further guide revascularisation strategies.

Background: Pericardial Decompression Syndrome (PDS) is defined as paradoxical hemodynamic deterioration and/or pulmonary edema, commonly associated with ventricular dysfunction. This phenomenon was first described by Vandyke in 1983. PDS is a rare but formidable complication of pericardiocentesis, which, if not managed appropriately, is fatal. PDS, as an entity, has discrete literature; this review is to understand its epidemiology, presentation, and management. Methodology: Medline, Science Direct and Google Scholar databases were utilized to do a systemic literature search. PRISMA protocol was employed. Abstracts, case reports, case series and clinical studies were identified from 1983 to 2019. A total of 6508 articles were reviewed, out of which, 210 were short-listed, and after removal of duplicates, 49 manuscripts were included in this review. For statistical analysis, patient data was tabulated in SPSS version 20. Cases were divided into two categories surgical and percutaneous groups. t-test was conducted for continuous variable and chi-square test was conducted for categorical data used for analysis. Results: A total of 42 full-length case reports, 2 poster abstracts, 3 case series of 2 patients, 1 case series of 4 patients and 1 case series of 5 patients were included in the study. A total of 59 cases were included in this manuscript. Our data had 45.8% (n=27) males and 54.2% (n=32) females. The mean age of patients was 48.04 ± 17 years. Pericardiocentesis was performed in 52.5% (n=31) cases, and pericardiostomy was performed in 45.8% (n=27). The most common identifiable cause of pericardial effusion was found to be malignancy in 35.6% (n=21). Twenty-three 23 cases reported pre-procedural ejection fraction, which ranged from 20% -75% with a mean of 55.8 ± 14.6% , while 26 cases reported post-procedural ejection fraction which ranged from 10% -65% with a mean of 30% ± 15.1% . Data was further divided into two categories, namely, pericardiocentesis and pericardiostomy. The outcome as death was significant in the pericardiostomy arm with a p-value of < 0.00. The use of inotropic agents for the treatment of PDS was more common in needle pericardiocentesis with a p-value of 0.04. Lastly, the computed recovery time did not yield any significance with a p-value of 0.275. Conclusion: Pericardial decompression syndrome is a rare condition with high mortality. Operators performing pericardial drainage should be aware of this complication following drainage of cardiac tamponade, since early recognition and expeditious supportive care are the only therapeutic modalities available for adequate management of this complication.

N-Butyl cyanoacrylate embolization of peripheral pulmonary artery aneurysms has rarely been performed. This report presents a young woman with a history of patent ductus arteriosus and massive hemoptysis secondary to pulmonary artery aneurysm, successfully managed by embolotherapy using n-Butyl cyanoacrylate. This is the first report of n-Butyl cyanoacrylate embolization treatment of a bleeding pulmonary artery aneurysm in the setting of patent ductus arteriosus. The pertinent literature has been reviewed and the clinical background and the procedure have been explained.