[Early repolarisation. A dilemma of risk stratification]

More than 30 years of Brugada syndrome: a critical appraisal of achievements and open issues

Over the last three decades, what is referred to as Brugada syndrome (BrS) has developed from a clinical observation of initially a few cases of sudden cardiac death (SCD) in the absence of structural heart disease with ECG signs of "atypical right bundle brunch block" to a predominantly electrocardiographic, and to a lesser extent genetic, diagnosis. Today, BrS is diagnosed in patients without overt structural heart disease and a spontaneous Brugada type 1 ECG pattern regardless of symptoms. The diagnosis of BrS is less clear in those with an only transient or drug-induced type 1 Brugada pattern, but should be considered in the presence of an arrhythmic syncope, family history of BrS, or family history of sudden death. In addition to survived cardiac arrest, syncope is probably the single most decisive risk marker for future arrhythmias. For asymptomatic BrS, risk stratification remains challenging. General recommendations to lower the risk in BrS include avoidance of drugs/agents known to induce and/or increase right precordial ST-segment elevation, including treatment of fever with antipyretic drugs. Several ECG markers that have been associated with an increased risk of SCD have been incorporated into a recently published risk score for BrS. The aim of this article is to provide an overview of the status of risk stratification and to illustrate open issues und gaps in evidence in BrS.

[Indications for implantable loop recorders in patients with channelopathies and ventricular tachycardias]

Implantable loop recorders (ILR) do not play a pivotal role in the current guidelines on ventricular arrhythmias except in identifying rhythm-symptom correlations if ventricular arrhythmias are assumed. Before a decision for a pure diagnostic implantable device is made, a thorough arrhythmic risk assessment is of major importance due to the potential lethal outcome of ventricular arrhythmias. Nevertheless, some clinical circumstances exist where long-term monitoring by an ILR may add significant information in electrical heart diseases, in patients with ventricular arrhythmias, or structural heart diseases and a potential risk of ventricular arrhythmias. As medical therapy (β-blocker therapy) plays an important role in long QT syndrome (LQTS) and catecholaminergic polymorphic ventricular tachycardias (cpVT), the ILR can be used to control therapy in patients at risk. In electrical diseases without pharmacologic therapeutic options (e. g., Brugada syndrome), the ILR may be used in low-risk patients with atypical syncope as benign faints may occur without association to the underlying disease. Evidence on cardiomyopathies with preserved left ventricular function and nonsustained VT or premature ventricular complexes is scarce. The ILR may also add long-term information on the individual risk in these circumstances. In very rare diseases like infiltrative disease or muscular dystrophies, the ILR may also provide evidence on risk stratification. In summary, ILR in electrical heart diseases and in patients with ventricular tachycardia remains a very individual decision taking into account various clinical, electrocardiographic, and genetic parameters. The following review aims at highlighting possible indications and clinical scenarios for ILR in ventricular tachycardias and electrical heart diseases with-probably debatable-case presentations.

[The ECG of athletes]

INTRODUCTION

There has been a long standing controversy on the role of a resting electrocardiogram (ECG) in the preparticipation examination of athletes, as well as in children and adolescents, in leisure time and competitive athletes. Besides other arguments, this was due to the limited validity, which led to false positive and false negative findings.

METHODS

Recent studies from different research groups yielded a significant improvement in establishing ECG criteria in athletes to discriminate normal from abnormal or pathological findings in athletes. This is additionally supported and improved by a software-based ECG device considering the new Seattle criteria. These new criteria from the Seattle conference reliably discriminate normal from abnormal findings. Frequent ECG findings in athletes, especially in those engaged in endurance sports are sinus bradycardia, atrioventricular (AV) block and signs of left ventricular hypertrophy.

RESULTS

Abnormal findings are related to structural left ventricular alterations due to cardiomyopathy, mainly hypertrophic with or without outflow tract obstruction, arrhythmogenic right ventricular cardiomyopathy (ARVC) and dilated cardiomyopathy. The ECG findings suggestive of electrical conductance disorders are observed in channelopathies, Wolff-Parkinson-White (WPW) syndrome supraventricular arrhythmias or disturbances of cardiac conduction. The main diseases are long or short QT syndrome, Brugada syndrome and catecholaminergic polymorphic ventricular tachycardia. Atrial fibrillation, mostly paroxysmal, is also now more frequently observed especially in middle aged endurance athletes.

CONCLUSION

Interpretation of ECG in young and older athletes requires in-depth knowledge in cardiology and sports medicine. The interpretation can only be carried out by considering medical history, clinical examination and ethnicity. Profound and long-term experience of athlete's ECG interpretation is required to protect athletes and to prevent cardiac emergencies.