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Case report
Malignant mitral valve prolapse: an uncommon variation of a common condition
  1. Thomas Joyce1 and
  2. Sunita Ferns2
  1. 1School of Medicine, University of South Florida College of Medicine, Tampa, Florida, USA
  2. 2Department of Pediatrics, University of Florida Health Science Center Jacksonville, Jacksonville, Florida, USA
  1. Correspondence to Dr Sunita Ferns; sjulianaferns{at}gmail.com

Abstract

Mitral valve prolapse affects up to 3% of the population, with an annual risk of death of up to 2% a year. Presentation is often in the third to fourth decade of life. This report details an adolescent with mitral valve prolapse with non-specific symptoms but investigative findings of ventricular ectopy at higher heart rates. These patients warrant close surveillance to monitor for progressive arrhythmias and may progress to need an ICD.

  • general practice / family medicine
  • pacing and electrophysiology
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Background

Mitral valve prolapse (MVP) is a common cardiac abnormality that affects 2%–3% of the general population.1 It is characterised by mitral valve leaflets that billow or prolapse into the left atrium. MVP can be diagnosed by auscultation of a mid-systolic click and mid to late systolic murmur. It is confirmed by two-dimensional echocardiography showing 2 mm or more of leaflet prolapse into the left atrium in the long axis view.2 Although most cases of MVP are benign, a select subgroup may have life-threatening ventricular arrhythmias resulting in sudden cardiac death (SCD).3

Ventricular ectopy is another common cardiac abnormality that is largely asymptomatic, and 1%–4% of otherwise healthy adults can have frequent ectopic beats.4 However, some cases of ventricular ectopy can result in ventricular tachycardia or ventricular fibrillation, which can cause sudden death.

Recognising uncommon but potentially catastrophic consequences of these common abnormalities is important. This case highlights some of the high-risk features in MVP that may result in SCD.

Case presentation

A 17-year-old female patient was referred to cardiology clinic by her primary care physician for evaluation of a recently noted murmur. On questioning she admitted to mildly decreased exercise tolerance for the past year and occasional light-headedness, both at rest and with exercise, over the prior 5 years and had self-limited herself due to these symptoms. Of note, she had never fainted. Her medical history was unremarkable, and she denied use of alcohol, drugs or medications.

Family history was remarkable for her 40-year-old father having a history of atrial fibrillation and early-onset MVP with severe regurgitation in his 20s which required recent surgical repair. He was otherwise healthy with a body mass index of 22 and had no other risk factors for atrial fibrillation.

On presentation, the patient’s weight was 53 kg and her height was 1.575 m, with a body mass index of 21.5, pulse of 61 beats per minute, blood pressure of 110/64 and pulse oximetry of 98%. Cardiac auscultation revealed an intermittent mid-systolic click followed by a grade 1/6 systolic murmur at the cardiac apex when upright.

Investigations

A 12-lead ECG showed sinus rhythm with occasional premature ventricular contractions (PVCs) and T wave inversion in her inferior and lateral leads at baseline (figure 1). Her echocardiogram demonstrated MVP (figures 2 and 3) with very mild regurgitation, and mild tricuspid valve prolapse with trivial regurgitation.

Figure 1

A 12-lead ECG showed sinus rhythm and T wave inversion in the inferior and lateral leads.

Figure 2

Two-dimensional transthoracic echocardiography: apical four-chamber view mitral valve prolapse (A2 and P2 scallops). This image shows A2 and P2 prolapse.

Figure 3

Two-dimensional transthoracic echocardiography: apical four-chamber view showing mitral valve prolapse and mild mitral regurgitation.

Subsequent 24-hour Holter monitoring was remarkable for frequent premature ventricular complexes comprising 4% of the total QRS complexes. The ventricular ectopy occurred as isolated premature ventricular complexes and couplets and was seen at higher heart rates.

During her initial exercise stress test, she exercised for 6 min and 50 s on the Bruce protocol (METS: 8.20), but the test was stopped prematurely due to very frequent multifocal premature ventricular complexes with bidirectional couplets noted at higher heart rates (figure 4). The morphology of the ectopy suggested origin from a left posterior fasciculus characteristic of the type of ectopy noted in malignant MVP. There was T wave inversion noted in the inferior and lateral leads at baseline; however, no significant ST segment changes were noted throughout the duration of the test. Subsequent testing demonstrated a run of non-sustained ventricular tachycardia on ambulatory monitoring. A cardiac MRI was performed and showed no regions of delayed enhancement or fibrofatty changes. The mitral valve was noted to be myxomatous, but there was no evidence of mitral annular disjunction (MAD). Genetic testing included a cardiomyopathy, and arrhythmia panel was negative. The patient was offered an implantable loop recorder for closer monitoring of ventricular arrhythmias and was placed on a beta blocker.

Figure 4

Multifocal premature ventricular complexes (PVC) with bidirectional couplets (CPLT) noted at higher heart rates on exercise stress testing.

Treatment

The patient was offered an implantable loop recorder for closer monitoring of ventricular arrhythmias and was placed on a beta blocker. Risks and benefits of a targeted ablation were also discussed with the patient, which she declined. As this patient had not sustained a syncopal or life-threatening episode and her ventricular ectopy was effectively suppressed with a beta blocker, an implantable cardiac defibrillator(ICD) was not indicated or offered. However, we did stress the importance of reporting back to us immediately with concerning symptoms and sending in regular transmissions from her implantable loop recorder.

Outcome and follow-up

The patient was seen at 6 monthly intervals over the last 18 months. She has self-restricted exercise and continues to do well clinically. Monitoring data to date show evidence of isolated PVCs but no ventricular tachycardia (VT). A repeat exercise stress test shows suppression of ectopy on the beta blocker.

Discussion

Arrhythmogenic or malignant MVP is identified through a combination of clinical findings. The most common electrocardiographic finding in patients with the condition is an inverted T wave in the lateral leads.5 Another common finding in patients with arrhythmogenic MVP is ventricular ectopy, especially at higher heart rates. Imaging features that may point to a diagnosis of malignant MVP include prolapse of both leaflets of the mitral valve (bileaflet MVP), MAD, systolic curling of the leaflets and left ventricular fibrosis.3 6–8 Mitral regurgitation is usually mild and rarely severe.3 MVP is considered the classic form if the degree of anterior leaflet redundancy or thickening is ≥5 mm. Without this thickening, MVP is labelled non-classic.

Although the association of SCD with MVP has been described, the underlying pathophysiology is less well understood. In a recent large database registry study, ventricular fibrillation (VF) was the common arrhythmia, and when documented most cases of VT were triggered by PVCs. Cardiac arrest in these patients is usually precipitated by periods of stress.9 Autopsy series have shown an increased incidence of diffuse and focal fibrosis in the left ventricle (LV), suggesting that these may provide the substrate for ventricular arrhythmias.8 The median age is about 30 years and presentation in children and adolescents is uncommon.3

What is unique about this case is the evidence of malignant MVP in an adolescent patient and the relatively non-specific findings in her clinical history. She had self-limited her activities prior to seeing a cardiologist due to symptoms of light-headedness and palpitations. Inverted T waves in the inferolateral leads and the relatively high burden of ectopy at baseline were an indication to pursue further testing in this patient. The nature of the ventricular ectopy with a right bundle branch block pattern in V1, positive R waves across the precordial leads, positive R waves in lead II, and aVL and S wave in a VF suggests a left posterior fascicular origin for the ectopy noted in malignant MVP. Like other patients with malignant MVP, there was evidence of bileaflet mitral valve involvement with redundancy and prolapse.3 The mitral regurgitation was only mild, which is also in keeping with previously reported literature.3 Cardiac MRI confirmed the myxomatous appearance of the mitral valve noted on echocardiography; however, no MAD was noted. This is especially important as MAD may have an impact on local myocardial function and papillary muscle fibrosis.7 The utility of programmed ventricular stimulation in these patients is questionable, and a negative study or absence of proof of an inducible arrhythmia is not necessary proof of absence of the risk of SCD. These patients should have close cardiac follow-up with serial monitoring to screen for progression of ventricular dysrhythmia. This may include the use of an an implantable loop recorder, as was recommended in our patient. In patients with life-threatening ventricular ectopy, an implantable cardioverter-defibrillator is indicated.

Patient’s perspective

I was never a very athletic kid and no one ever thought anything of it. I would feel my heart flutter when I was at gym and I didn’t like the feeling so I stopped doing the things that would make me uncomfortable. It wasn’t until I started feeling lightheaded that I heard I should see a cardiologist. My Dad was seeing a cardiologist as well but we didn’t expect to find that I had mitral valve prolapse, the same as my Dad. My cardiologist thought I should see an electrophysiologist and I underwent a bunch of tests. I finally started feeling better after I started my beta blockers. I know MVP can affect people in different ways but am reassured that the bad rhythms were recognized early enough to treat in me.

Learning points

  • Malignant ventricular arrhythmias are a rare but life-threatening consequence in patients with mitral valve prolapse.

  • Early recognition of significant clinical, electrocardiographic and imaging parameters may help risk-stratify patients at risk of sudden cardiac death.

  • Newer modalities of monitoring such as an implantable loop recorder may be used to identify high-risk patients who may benefit from an implantable defibrillator.

References

View Abstract

Footnotes

  • Contributors TJ contributed to the acquisition of patient information, drafting of the work and final approval of the version to be published. SF contributed to the conception and design of the work, analysis of reports and critically revising the content, and approved of the version to be published.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Parental/guardian consent obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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