John P. Higgins

Caffeine reduces myocardial blood flow during exercise.

Caffeine consumption has been receiving increased interest from both the medical and lay press, especially given the increased amounts now available in energy products. Acute ingestion of caffeine usually increases cardiac work; however, caffeine impairs the expected proportional increase in myocardial blood flow to match this increased work of the heart, most notably during exercise. This appears to be mainly due to caffeines effect on blocking adenosine-induced vasodilatation in the coronary arteries in normal healthy subjects. This review summarizes the available medical literature specifically relating to pure caffeine tablet ingestion and reduced exercise coronary blood flow, and suggests possible mechanisms. Further studies are needed to evaluate this effect for other common caffeine-delivery systems, including coffee, energy beverages, and energy gels, which are often used for exercise performance enhancement, especially in teenagers and young athletes.

Chlamydia pneumoniae and Coronary Artery Disease: The Antibiotic Trials

Parallel with the mounting evidence that atherosclerosis has a major inflammatory component, provoking agents that may initiate and drive this process have been sought. Infectious agents such as Chlamydia pneumoniae have been alleged to be activators of inflammation that may contribute to atherosclerosis and thus coronary artery disease (CAD) and its associated complications. A logical pneumoniae extension of this theory whether treating C pneumoniae infection with antibiotics and/or modulating inflammatory processes can affect CAD and its sequelae. This article discusses the potential role of C pneumoniae in atherosclerosis, its detection, and the rationale for antibiotics. Additionally, it summarizes the current randomized clinical trials of antichlamydial antibiotics in patients with CAD and draws conclusions based on the results.

Stress-induced abnormalities in myocardial perfusion imaging that are not related to perfusion but are of diagnostic and prognostic importance

IntroductionCertain stress-induced ancillary findings on myocardial perfusion scintigraphy increase the likelihood that the patient has coronary artery disease (CAD); furthermore, among CAD patients, they indicate more severe and extensive disease, placing these patients at higher risk for future cardiac events. Indeed, in studies with no obvious perfusion defect yet with serious CAD—for example, balanced ischemia—it can be these high-risk findings that necessitate invasive intervention.DiscussionBesides reversible perfusion defects, such findings include increased pulmonary radiotracer uptake, transient cavity dilatation, increased end-diastolic or end-systolic volume, decreased post-stress ejection fraction, and increased right ventricular tracer uptake on stress images. The pathophysiology underlying these findings is clearly different as they do not always occur together, and each independently predicts more severe and extensive CAD. In the current review, these findings are defined and their significance in diagnosing patients with suspected or known CAD is discussed.

Normal resting electrocardiographic variants in young athletes.

Abstract With a growing awareness of the tragedy of sudden cardiac arrest (SCA) in young athletes, more extensive pre-participation examinations are being performed prior to competitive sport participation. In addition to a history and physical, young athletes often have a 12-lead resting electrocardiogram (ECG) to better identify heart disease associated with SCA. Complicating this process is that certain “abnormal” resting ECG findings are considered normal variants in healthy children and young adults. The ability to recognize these normal variants is often useful in preventing excessive referral of patients to cardiologists for evaluation of resting ECGs that are benign variations of normal and in making sound decisions regarding appropriate clearance to exercise. This review describes these normal variants.

Androgen abuse and increased cardiac risk.

Abstract The objectives of this article were to review the anabolic androgen steroids, specifically the direct and indirect effects on the cardiovascular system of the individuals who use them, and to summarize the evidence regarding the effects of androgens on the cardiovascular system. A search of the English-language scientific literature from 1976 to March 2012 was performed primarily by searching the MEDLINE and Embase databases and Google. Anabolic androgenic steroids are associated with direct effects such as cardiac muscle hypertrophy and myocardial fibrosis and indirect effects, including dyslipidemia, hypertension, arrhythmia, and myocardial infarction. It is likely that chronic exposure to these agents can result in significant alterations in the cardiovascular system, and their safety has not been fully established.

Catheter Ablation of Idiopathic Left Ventricular Tachycardia Associated with a False Tendon

A 36-year-old man was referred for recurrent episodes of wide QRS tachycardia occurring both spontaneously and provoked by exertion. Echocardiogram and coronary angiography were reportedly normal. At prior electrophysiology (EP) study, sustained monomorphic ventricular tachycardia [VT] was induced with burst pacing during isoproterenol infusion. Attempts to map the tachycardia for radiofrequency (RF) catheter ablation were thwarted when the tachycardia terminated dnring the mapping procedure and could not be reinitiated. During sinus rhythm pacing at an inferoapical site on the left ventricular [LV) septum reproduced the VT QRS morphology. RF energy was delivered at this site and VT remained noninducible. Several days later, VT recurred and the patient was referred for a second attempt at ablation.

Can angiotensin-converting enzyme inhibitors reverse atherosclerosis?

Angiotensin II, a potent vasoconstrictor, is mainly present in the vascular endothelium. Multiple studies have confirmed that angiotensin-converting enzyme (ACE) inhibitors, which block the formation of angiotensin II, lower blood pressure and also improve heart failure. These agents not only have beneficial hemodynamic effects but also bestow additional benefits on vascular function and prevent clinical cardiovascular events in patients at risk for coronary artery disease. These latter benefits may represent effects of ACE inhibitors on local endocrine pathways, inflammatory processes, and atherosclerosis taking place within the arterial wall. Current evidence suggests that, although ACE inhibitors may not substantially reverse atherosclerotic plaque already present, they may slow the progression of such atherosclerotic lesions. In addition, by modulating inflammatory pathways within and adjacent to the atherosclerotic lesion, they may stabilize an unstable plaque and therefore decrease the risk of plaque rupture and its complications.

Sudden cardiac death in young athletes: preparticipation screening for underlying cardiovascular abnormalities and approaches to prevention

Abstract The study of sudden cardiac death (SCD) in athletes has received more interest in the medical and lay press over the past few years. Professional athletes represent ideals of fitness and health, and the sudden death of prominent athletes can come as a shock. Underlying occult cardiovascular disorders are the most common cause of SCD in athletes. Unfortunately, because these disorders rarely present clinically, their initial manifestation is often a fatal event. Due to this, much attention has turned to both primary and secondary prevention. Primary prevention includes preparticipation screening and secondary prevention includes having automatic external defibrillators available at sporting events. This article summarizes the most common causes of athletic-related cardiac arrest and evaluates the screening methods used to screen for these conditions. The general sentiment is that we need to more effectively identify athletes who are at risk for SCD, but how to do so using an efficient screening system and in a cost-effective manner have not been determined.

Sudden cardiac death in the soccer field: a retrospective study in young soccer players from 2000 to 2013.

Abstract Soccer is the most popular sport in the world, with over 200 million active players. Sudden cardiac death (SCD) represents the most striking as well as the most common cause of death in the soccer field. Underlying cardiovascular pathologies predispose to life threatening ventricular arrhythmias and SCD in soccer players. Up to thousands to hundred thousands players might have an underlying condition that predisposes them for SCD. After several media striking SCD events in soccer players the Fédération Internationale de Football Association (FIFA) has made screening recommendations that are more thorough than the ones recommended for the American Heart Association and the European Society of Cardiology. We present a retrospective search through Internet databases that resulted in 54 soccer players with SCD events from 2000 until 2013. In this article, we will describe and discuss the conditions of those cases of SCD in order to provide more knowledge of the factors that may precipitate SCD in young soccer players.

Chlamydia pneumoniae and coronary artery disease: legitimized linkages?

Chlamydia pneumoniae (Cp) infection in early life may accelerate atherosclerosis over ensuing decades, leading to cardiovascular complications. Cp promotes endothelial dysfunction and may modulate inflammation underlying atherosclerosis. It represents a biologically plausible candidate for the causation of atherosclerosis. Other infections simultaneously occurring with Cp may result in a synergistic effect to promote atherosclerosis. Studies on the treatment of Cp with antibiotics indicates decreased rates of infection, modulation of inflammation and in some settings, fewer cardiovascular complications.