Apical ballooning (takotsubo cardiomyopathy) in mid-ventricular obstructive hypertrophic cardiomyopathy

Abstract

Background

The conventional view holds that left ventricular (LV) apical ballooning in stress cardiomyopathy is caused by a hyperadrenergic state related to emotional or physical stress. However, some suggest ballooning also occurs in obstructive hypertrophic cardiomyopathy (HCM) when obstruction becomes severe. Nearly all cases of apical ballooning in HCM were reported in patients with LV outflow tract obstruction. Herein, we present a case due to mid-ventricular obstruction.

Case Summary

A 52-year-old woman presented with dyspnoea and chest pain. She denied any recent emotional or physical stress. Physical examination was notable for a Grade 2/6 systolic murmur along the left sternal border. The peak high-sensitivity troponin level was 315 ng/L (normal < 6 ng/L). Coronary angiography was unremarkable. Echocardiography revealed LV apical ballooning with severely reduced LV ejection fraction. In addition, there was severe septal hypertrophy with mid-cavity obstruction. Continuous-wave Doppler interrogation across the obstruction revealed a bifid (‘lobster claw’) configuration with a characteristic abrupt early systolic drop in flow velocity. The patient was treated with beta-blockers. Follow-up examination revealed resolution of apical ballooning.

Discussion

We believe apical ballooning in our patient with HCM resulted from severe afterload mismatch (produced by mid-cavity obstruction) and supply–demand ischaemia, as well as the limited contractile reserve that characterizes myopathic muscle. This is supported by the rapid decline in early systolic flow velocity seen with Doppler interrogation (lobster claw configuration) across the obstruction.

Learning points.

• Obstructive hypertrophic cardiomyopathy with mid-ventricular obstruction can cause left ventricular apical ballooning (takotsubo cardiomyopathy) when latent obstruction is severe and unrelenting.

• Ballooning represents the combined effects of afterload mismatch, supply–demand ischaemia, and limited myocardial reserve.

Introduction

Apical ballooning in stress cardiomyopathy (takotsubo syndrome) is thought to be related to the catecholamine excess that attends emotional or physical stress.¹ It has however been suggested that ballooning may also occur in the setting of obstructive hypertrophic cardiomyopathy (HCM), where it is presumably caused by afterload mismatch and supply–demand ischaemia when latent obstruction becomes severe and unrelenting.^2,3 Virtually, all such cases have been reported in patients with obstruction of the left ventricular (LV) outflow tract (OT). Herein, we present a novel case of apical ballooning with obstruction at the level of the mid-ventricle.

Summary figure

The panel on the left shows the site of mid-cavity obstruction in a patient with hypertrophic cardiomyopathy. The continuous-wave Doppler tracing on the right, obtained across the obstruction, demonstrates a bifid (lobster claw) appearance. The abrupt drop in velocity during early systole (arrows) reflects the effects of afterload mismatch, supply–demand ischaemia and limited myocardial contractile reserve. Restoration of intracavitary flow occurs as the left ventricle relaxes and the obstruction is relieved allowing blood previously ‘trapped’ in the apex during systole to flow (paradoxically) towards the left ventricular base (yellow arrow).

Case presentation

A 52-year-old woman presented with exertional dyspnoea and intermittent non-exertional chest pain for several days. She denied any complaint of syncope or any recent emotional or physical stress. There was a history of atrial flutter for which she underwent cardioversion 4 years earlier without recurrence. The patient’s history was also notable for hypertension and hyperlipidaemia for which she was prescribed medication that she did not take. On examination, the blood pressure measured 101/67 mmHg and the pulse was 98 b.p.m. The heart sounds were unremarkable. There was a Grade 2/6 systolic murmur along the left sternal border. There were no gallops, rubs or clicks. The lungs were clear, and there was no lower extremity oedema. A 12-lead electrocardiogram revealed sinus tachycardia at 108 b.p.m. with 1 mm of ST-segment elevation and T-wave inversion in Leads I, II, aVL, aVF, and V2–V6 (Figure 1). An electrocardiogram performed 4 years earlier showed rapid atrial flutter with LV hypertrophy and secondary ST-T changes (Figure 2). The maximum high-sensitivity troponin-T level was 315 ng/L (normal < 6 ng/L).

Figure 1.

A 12-lead electrocardiogram obtained at the time of admission.

Figure 2.

A 12-lead electrocardiogram obtained 4 years prior to admission showing rapid atrial flutter and LV hypertrophy with secondary ST-T changes.

Transthoracic echocardiographic examination revealed akinesis of the mid and apical LV segments with preserved basal contractility (Movie S1). The overall LV ejection fraction was severely reduced. Maximal septal thickness (mid-inferoseptum) at end-diastole measured 2.1 cm. Mid-ventricular obstruction was apparent from the convergence zone seen with colour flow Doppler imaging (Figure 3). Continuous-wave Doppler interrogation across the obstruction revealed a bifid (‘lobster claw’) spectral tracing shown in Figure 4. The first deflection of this tracing reached a peak velocity of 2.9 m/s in early systole corresponding to a gradient across the obstruction of 34 mmHg. The second deflection, which peaked in late systole, persisted through the isovolumetric relaxation period. The two deflections are separated by a markedly low mid-systolic velocity nadir.

Figure 3.

Mid-ventricular obstruction. (A) Four-chamber systolic frame with mid-cavity obstruction. (B) Simultaneous colour flow Doppler image reveals a convergence zone overlying the obstruction (arrows).

Figure 4.

Continuous-wave Doppler interrogation across the mid-ventricular obstruction shows a peak velocity across the obstruction of 2.9 m/s (peak gradient of 34 mmHg). Note the rapid decline in early systolic velocity (green arrows). This is followed by a markedly low mid-systolic velocity nadir (asterisk). When flow resumes, it continues through the end of the isovolumetric period (onset of the transmitral E-wave) due to movement of sequestered blood out of the apical ‘chamber’ towards the LV base (yellow arrow).

There was mild mitral and trivial tricuspid regurgitation, and the estimated pulmonary artery systolic pressure was 22 mmHg. The left and right atria were normal in size. Right ventricular size and systolic function were normal. The patient underwent coronary angiography that revealed no evidence of coronary artery disease. She was prescribed metoprolol tartrate 50 mg daily and was instructed to continue after discharge. A follow-up study performed 6 weeks later revealed resolution of apical ballooning with no significant change in septal wall thickness.

Discussion

The conventional view holds that stress cardiomyopathy occurs in the setting of extreme emotional or physical stress. These are thought to trigger a hyperadrenergic response, which exerts toxic effects on the myocardium or causes microvascular spasm resulting in regional LV dysfunction usually involving the mid and apical segments.¹ Some suggest that apical ballooning may also occur in patients with obstructive HCM.^2,3 In this respect, one study found phenotypic features of HCM (increased septal thickness, increased anterior mitral leaflet length, and anteriorly displaced mitral coaptation) in 30% of unselected patients with apical ballooning.⁴ Apical ballooning in obstructive HCM is thought to be caused by afterload mismatch and supply–demand ischaemia. Reduced myocardial oxygen supply results from decreased diastolic blood pressure and small vessel disease, whereas increased myocardial oxygen demand is caused by elevated wall stress due to increased LV systolic pressure.^3,5 The role of afterload mismatch and supply–demand ischaemia in the pathogenesis of apical ballooning is supported by its reversal following interventions that alleviate LVOT obstruction, including beta-adrenergic blocker and vasoconstrictor therapy, and in intractable cases of cardiogenic shock, by emergent surgical myectomy.^2,3 The effects of afterload mismatch and supply–demand ischaemia on myocardial contractility are further aggravated by the abnormal energetics that characterize myopathic muscle. Even without superimposed afterload mismatch and ischaemia, the myocardium in HCM exhibits inadequate energy reserves (adenosine triphosphate) to sustain high energy consuming cellular processes such as actin–myosin coupling.⁵ This has been demonstrated with metabolic cardiac magnetic resonance imaging in patients with HCM as well as relatives who have HCM-associated variants but who have not yet developed hypertrophy.⁵ The limited myocardial contractile reserve that characterizes obstructive HCM is also suggested by the so-called lobster claw abnormality seen with Doppler imaging (Figure 5). This abnormality was first described by Sherrid et al.⁷ who observed that when pulsed wave Doppler interrogation is performed upstream of the point of mitral leaflet–septal contact in patients with frank afterload excess (LVOT gradient > 50 mmHg), Doppler recordings display a shape similar to that of a lobster’s claw (Figure 5). It has been suggested that the rapid fall in early systolic velocity observed in such tracings results from inadequate myocardial contraction (due to limited contractile reserve) in the face of excessive afterload and that these abnormalities culminate in frank contractile failure and ballooning.^6–9 Finally, a close inspection of the lobster claw tracing reveals that it is not until later in systole, when LV pressure, and hence LVOT obstruction, decrease that Doppler flow velocity rises and forward flow into the LVOT resumes (Figure 5).

Figure 5.

Pulsed wave Doppler recording obtained within the LV cavity in a patient with obstructive HCM and LVOT obstruction. Note the rapid deceleration after peak velocity is reached (green arrows). When flow resumes, it continues until end-systole (yellow arrow). Reproduced with permission from Silbiger.⁶

LV hypertrophy at the level of the mid-ventricle is seen in ∼10% of HCM patients.¹⁰ Obstruction in these patients results when the protruding mid-septum and lateral wall contract around the papillary muscles resulting in a characteristic hourglass appearance. We believe the ballooning observed in our patient is the result of afterload mismatch caused by mid-ventricular obstruction. Moreover, the continuous-wave Doppler signal we obtained across the obstruction (Figure 4) revealed a lobster claw shape. The rapid fall in early systolic velocity we observed is consistent with the brittle contractility of the left ventricle labouring against the mid-cavity obstruction. It is not until later in systole, as the ventricle begins to relax and the obstruction is relieved, that Doppler flow velocity increases. Notably, this flow proceeds from the LV apex to its base indicating that blood has been ‘trapped’ by the obstruction, only emerging from the apex in diastole. It is worth noting that the lobster claw tracing observed with LVOT obstruction is entirely confined to systole (Figure 5), whereas that in our case continues through the isovolumetric relaxation period (Figure 4), indicating trapped blood in the apex. It is noteworthy that the peak early systolic velocity measured across the obstruction in our patient measured 2.9 m/s. Using the modified Bernoulli equation suggests that the degree of obstruction is relatively mild (peak gradient = 34 mmHg) and unlikely to precipitate afterload mismatch. However, it is important to note that gradients measured at the level of the mid-ventricle have been shown to be significantly underestimated by the modified Bernoulli equation likely due to the abrupt cessation of mid-ventricular flow caused by obstruction.¹¹ In fact, one study of patients with mid-ventricular obstruction found that invasively measured mid-ventricular gradients average 81 ± 31 mmHg, whereas those derived by Doppler echocardiography average 45 ± 38 mmHg (P = 0.0002).¹¹

Four cases of LV apical ballooning after development of acute mid-LV obstruction were reported by Merli et al. from St. George’s Hospital in London in 2006.¹² In contrast to our case, no lobster claw abnormality was observed in these patients likely because echocardiography was performed after the most severe afterload excess and ischaemia had abate.

The differential diagnosis of the wall motion abnormalities seen in this case includes thrombotic myocardial infarction, MINOCA (myocardial infarction with normal coronary arteries), and myocarditis. These entities can be confirmed by their characteristic distribution of fibrosis assessed by late gadolinium enhancement using cardiac magnetic resonance imaging. While magnetic resonance imaging was not performed in our patient, the non-coronary distribution of the wall motion abnormalities and their subsequent resolution suggest mid-LV obstruction was the underlying cause.

Lead author biography

Jeffrey J. Silbiger, MD, is Professor of Medicine at the Icahn School of Medicine at Mount Sinai and serves as the Director of the Echocardiography Laboratory at NYC Health + Hospitals/Elmhurst in New York. His clinical interests include mitral valve disease and echocardiography.

Supplementary material

Supplementary material is available at European Heart Journal – Case Reports online.

Author contributions

Jeffrey J Silbiger (Conceptualization, Writing—review & editing [lead]), Richa Patel (Writing—original draft [equal]), Priya Panday (Writing—original draft [equal]), Kateryna Taranik (Methodology [lead], Writing—original draft [supporting]), and Mark V. Sherrid (Conceptualization [equal], Writing—review & editing [supporting])

Consent: Written, informed was obtained in accordance with COPE guidelines.

Funding

There were no governmental, not-for-profit or private funding sources for this work.

Data availability

The data underlying this article are available in the article and in its online Supplementary material.