A new diastolic heart sound secondary to free pulmonary regurgitation

Abstract

Physical examination is recognised as a central pillar in a patient's initial clinical assessment and, in cardiovascular medicine, cardiac auscultation can yield a wealth of valuable information. The first and second heart sounds may be accompanied by a third (S3) or fourth (S4) sound (both diastolic) in various disease states, although S3 may be a normal finding in youth, athletes and the hyperdynamic circulation. These additional sounds do retain clinical relevance in modern practice — for example, the presence or absence of a S3 is commonly used to judge clinical response to treatment in the patient hospitalised due to decompensated heart failure. We report what we believe is the first description of a diastolic heart sound caused by severe regurgitation though a semilunar valve (pulmonary in this case) as opposed to forward flow through an atrioventricular valve. This new sound was detectable clinically, suspected echocardiographically and confirmed by phonocardiography. A 49 year old female was referred for specialist assessment after complaining of palpitations and increasing exertional breathlessness. She had undergone surgical repair of Fallot's tetralogy many years previously, but in a different country and the exact operation details were unavailable. She was not taking any regular medications at the time of referral. There was no known history of respiratory disease. On examination, she was in sinus rhythm with no signs of left ventricular failure. Cardiac auscultation revealed a normal second heart sound but with an additional diastolic sound and a prominent diastolic murmur loudest in the pulmonary region. The patient was thus referred for echocardiographic assessment. Transthoracic 2D-echocardiography demonstrated a moderately dilated right atrium and right ventricle (RV) with moderate tricuspid regurgitation and a dysplastic pulmonary valve with free pulmonary regurgitation (PR) on colour flow Doppler imaging. RV systolic function was only moderately impaired (S3 due to ventricular dysfunction is usually only seen in severe dysfunction). Spectral Doppler analysis revealed a non turbulent jet of laminar retrograde flow across the pulmonary valve with rapidly decaying velocity (due to diastolic equalization of PA and RV diastolic pressures) indicative of severe regurgitation. The additional diastolic sound appreciated on examination had the characteristics of a third heart sound but in fact, when phonocardiography was performed, it correlated precisely with the short and sharp peak retrograde PR velocity (Fig. 1). The patient's cardiac magnetic resonance (CMR) scan confirmed severe PR through a dysplastic pulmonary valve (Fig. 2). The patient subsequently underwent successful surgical pulmonary valve replacement and the additional sound is no longer audible. Patients who have previously undergone surgical repair of tetralogy of Fallot are at risk of developing significant pulmonary regurgitation as a late complication. This is associatedwith impaired exercise capacity [1] and an increased risk of ventricular arrhythmias and sudden death[2]. Echocardiography and CMR are both widely used in the non-invasive investigation of such patients following surgical repair[3]. A new heart sound has not been described for over one hundred years. Here, we present clinically detectable and echocardiographically confirmed evidence of an additional diastolic heart sound attributable to retrograde flow through a semilunar (pulmonary) valve as opposed to antegrade flow across an atrioventricular valve (S3and S4). A third heart sound may be seen in cases of severe atrioventricular valve (mitral or tricuspid) regurgitation but the conventional definition does not include regurgitation through the ventriculo-arterial valves (aortic and pulmonary). Therefore, the mechanism of this sound is not compatible with the current definitions of either the third or fourth heart sounds; hence we propose this is a new sound, which may be best termed a “pulmonary regurgitation sound”. We suggest that auscultation of this diastolic heart sound during routine clinical review should arouse suspicion of significant regurgitation and trigger referral for echocardiography to assess pulmonary valve function. The authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology (Shewan and Coats 2010;144:1–2).