Electrocardiogram shows normal sinus rhythm (NSR), rightward axis, RV strain pattern, increased voltage and left atrial enlargement (LAE) criteria for left ventricular hypertrophy (LVH).

Echocardiography shows the following (Fig. 10.2a, b):

Basic auscultation features of FML include severe MR with decrescendo, mixed frequency murmur and eccentric radiation.

The murmur is classically holosystolic, extending from S1 through to S2. It can also be early systolic, mid systolic or late systolic.

Soft S1 heart sounds may be heard and the click associated with MVP may disappear.

S2 splitting due to early A2 is frequently heard.

Occasionally, an early to mid diastolic murmur is present due to increased mitral flow or MV pre-closure.

FML classically radiates to the axilla or left intrascapular region, but the jet direction can influence murmur radiation [1].

In an observational study conducted by the Mayo clinic of 229 patients with isolated MR due to FML, 87 % had grade 3 or 4 murmur, classified as severe MR. Therefore, auscultation findings consistent with severe MR are often used to help diagnosis FML [2].

Auscultation examples of severe MR.

Aortic Stenosis (AS): In a posterior chordae rupture leading to a flail posterior cusp, the stream of regurgitation may strike the atrial septum in such a way that mimics the shape and radiation into the carotids typical of AS. Radiation of a posterior chordae rupture may be better heard into the lower back opposed to the neck. Rarely, anterior chordae ruptures may also mimic AS. The reason is unknown, but anterior chordal rupture may radiate along the spine and to the top of the head [3].

Tricuspid Regurgitation (TR): TR, another holosystolic murmur, is heard best along the left sternal border and is augmented by inspiration. It presents with a prominent v wave and y descent in the JVP [3].

Gallavardin Phenomenon: Gallavardin phenomenon is an aortic ejection murmur seen in elderly patients with calcific aortic stenosis. The aortic valve will lack commissural fusion, allowing the cusps to vibrate and produce pure frequencies. The musical sounding murmur is prominent in the apex with high frequency components, suggestive for MR. However, Gallavardin phenomenon does not radiate to the left axilla like FML and is accentuated by a slowing of the heart rate while MR does not change with a slowed heart rate [3].

Ventricular Septal Defects (VSD): MR usually radiates best to the axilla and to the left posterior intrascapular area of the chest. If loud enough, MR radiates to the right, but to a lesser degree. Conversely, VSD murmur from ventricular septal rupture will be loudest near the apex [3, 4].

Corrected Transposition of Great Vessels: Corrected transposition of the great vessels may mimic severe MR if the tricuspid valve becomes regurgitant, for example in Ebstein’s anomaly (downward displacement of a deformed tricuspid valve). This is not uncommon in corrected transpositions. Additionally, anomalous insertion of chordae into the left tricuspid valve has also been found to be a cause and likewise mimics MR [3].

In addition to the auscultation features listed above, clues of severe MR may help identify FML:

Because the majority of patients with FML present with signs of severe MR, bedside maneuvers that augment or decrease the intensity of MR murmurs will aid in differentiating mitral flail from other conditions that present with systolic murmurs. Specifically, the maneuvers listed below were found to be particularly helpful in the diagnosis of MR.

Isometric Handgrip Exercise: augmented the murmurs of MR with 68 % sensitivity and 92 % specificity. This maneuver is helpful in distinguishing MR from the murmurs of aortic stenosis, hypertrophic cardiomyopathy and to a lesser degree, right-sided murmurs where the majority of cases showed no change or a decrease in murmur intensity. However, a parallel increase in murmur intensity was seen with VSD and therefore the MR murmurs could not be distinguished from VSD solely on the basis of the response to handgrip [1].

Transient Arterial Occlusion: augmented the murmurs of mitral regurgitation with 78 % sensitivity and 100 % specificity. This augmentation was also seen with the murmurs of VSD. The majority of all other systolic murmurs did not change or decreased in intensity with transient arterial occlusion [1].