BJSM disease process, or may be a completely benign normal variant. PVCs are common in athletes with high vagal tone and resting bradycardia and may increase in frequency in parallel with physical fitness. A single PVC captured during a routine 12-lead ECG in an asymptomatic athlete does not require further evaluation, unless the athlete performs a high-intensity endurance sport (mainly cycling, triathlon, rowing or swimming). In this select group of high-intensity endurance athletes, a single PVC, especially if it has an LBBB morphology, may be a hallmark of ‘exercise-induced’ ARVC, and further evaluation should be considered.46–48 The Figure 20. ECG from a patient with pulmonary hypertension demonstrating evidence of right-axis deviation >120° (A), right ventricular hypertrophy (B), right atrial enlargement (C) and right ventricular strain (D). elevation or a markedly prolonged R0 ), or a RBBB in conjunction with other abnormal ECG findings should be further evaluated. Non-Specific intra-ventricular conduction delay IVCD is defined as a QRS complex >110 ms that does not have morphological features consistent with either LBBB or RBBB. IVCD has been documented among patients with cardiomyopathy, but is also frequently seen in healthy athletes. The physiology underlying IVCD in athletes remains incompletely understood but likely includes some combination of neurally mediated conduction fibre slowing and increased myocardial mass. Digital analysis of QRS duration can outperform standard visual measurement because the first onset and last offset in all of the leads can be considered.6 In asymptomatic athletes with an isolated IVCD with a QRS duration of 100– 139 ms, no further diagnostic evaluation is required. In contrast, athletes presenting with symptoms suggestive of cardiomyopathy, a family history of sudden death or suspected cardiomyopathy, an IVCD with marked QRS prolongation (≥140 ms) or an IVCD in tandem with other abnormal ECG findings should be further evaluated. Isolated premature ventricular contractions PVCs are electrical impulses that originate from myocardial tissue below the AV node. They are defined as QRS complexes >100 ms that are not preceded by a triggering pwave. PVCs may reflect pathological myocardial ‘irritability’ due to a cardiomyopathy, an underlying systemic 36 Sport & Geneeskunde | september 2013 | nummer 4 Pulmonary hypertension Pulmonary hypertension (PHT) is caused by a variety of aetiologies that result in elevation in the pulmonary artery pressure (mean pulmonary artery pressure greater than or equal to 25 mm Hg) and elevation in the pulmonary vascular resistance.89 presence of PVCs in an athlete with cardiovascular symptoms or a family history of sudden death or suspected cardiomyopathy should prompt further evaluation. In addition, multiple PVCs (2 or more) during a single ECG tracing (10 s), multifocal PVCs or PVCs found in tandem with other abnormal ECG findings should be further evaluated. As a result of the increased afterload on the right heart, patients are predisposed to develop right heart failure and are at risk for sudden death. PHT is a rare cause of sudden death in athletes but may be suggested by ECG abnormalities and thus a clinically relevant finding in the cardiovascular care of athletes. ECG findings in pulmonary hypertension The ECG findings in PHTare due to physiological and anatomic adaptions of the right heart as a result of elevated pulmonary artery pressures and/or pulmonary vascular resistance. Findings suggestive of PHT include right ventricular hypertrophy (RVH), right axis deviation, right ventricular strain and right atrial enlargement (figure 20).89–91 with idiopathic PHT, 87% demonstrated RVH and 79% demonstrated right axis deviation.89 However, in patients with PHT, the ECG remains an inadequate screening tool to completely rule out the presence of this disease.92 Right ventricular hypertrophy pattern RVH pattern is defined as an R wave in lead V1 plus S wave in V5 greater than 1.05 mV (10.5 mm at standard amplification) AND right axis deviation >120° (figure 20). Additional criteria for RVH associated with PHT include a tall R wave and small S wave with R/S ratio greater than 1 in lead In adults Pagina 35
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