Stress cardiomyopathy in a Caucasian man

Abstract

Stress cardiomyopathy is increasingly being described as a form of reversible left ventricular systolic dysfunction, with a characteristic shape on left ventriculography. The acute clinical, electrocardiographic and laboratory abnormalities are reminiscent of acute coronary syndrome, with nonobstructive coronary arteries on angiography. Wall motion abnormalities typical of this disease exhibit apical akinesis with compensatory basal hyperkinesis, resulting in the characteristic systolic apical ballooning. Stress cardiomyopathy is much more common in women than men, especially postmenopausal women, and it is typically triggered by intense medical, emotional or physical stress. The pathogenesis of the disease is not well understood, with current evidence favouring catecholamine myocardial injury. Until prospective distinction can be made between stress car-diomyopathy and acute coronary syndrome, the diagnosis should be that of exclusion. In addition to long-term beta-blockers, angiotensin-converting enzyme inhibitors and diuretics as needed, treatment is generally supportive, with recovery of baseline left ventricular function within a few weeks to a month.

Stress cardiomyopathy occurs with a high predilection for women. Physical or emotional stress is common in the majority of reported cases, suggesting a central role for cate-cholamines in the pathogenesis of this transient left ventricular systolic dysfunction. Features of this unique cardiomyopathy include acute presentation with chest pain or shortness of breath, associated with electrocardiogram (ECG) changes of ischemia; positive biomarkers; and pathognomonic left ventricular wall motion abnormalities on ventriculography (apical ballooning), with nonobstructive coronary arteries on angiography. We present a unique case of stress cardiomyopa-thy in a Caucasian man. The pathophysiology, clinical presentation, diagnosis and prognosis of this unique and increasingly recognized syndrome is also reviewed.

CASE PRESENTATION

A 77-year-old Caucasian man who had a history of hypertension, coronary artery disease and mild congestive heart failure, with an estimated left ventricular ejection fraction of 45%, presented with worsening shortness of breath over the previous few days and chest pain on the day of admission. Before this, he had been functionally active and in his usual state of health, but admitted to being under intense emotional stress lately. Examination revealed that he had a temperature of 97.4°F, pulse rate of 101 beats/min, blood pressure of 139/73 mmHg and respiratory rate of 22 breaths/min. In addition, he had jugular venous distention, crackles up to his midchest, third heart sound gallop and 3+ bilateral pitting edema in the lower extremities.

An ECG showed sinus tachycardia with left bundle branch block (the baseline ECG was significant for intraventricular conduction defect). An echocardiogram demonstrated severe left ventricular systolic dysfunction, with an ejection fraction of 10%; global hypokinesia with akinetic septal, anterior and inferior walls; and moderate mitral and aortic regurgitation, with a restrictive pattern on mitral inflow (E wave of 1 m/s and A wave of 0.2 m/s) that was compatible with advanced diastolic dysfunction. Brain natriuretic peptide was elevated (830 ng/L, and troponin I was mildly elevated with a peak level of 0.13 μg/L. The patient underwent emergency cardiac catheterization in the setting of a presumed acute coronary syndrome. Angiography showed nonobstructive coronary arteries. The left ventriculogram (Figure 1) demonstrated large apical, anterolateral and inferior hypokinesis, as well as basal segment hyperkinesis, with apical ballooning suggestive of stress cardiomyopathy. The patient was maintained on beta-blockers, angiotensin-converting enzyme inhibitors and diuretics as needed. His symptoms improved, and repeat outpa-tient echocardiography two weeks after presentation revealed that he had recovered his baseline left ventricular ejection fraction of 45%, with resolution of the acute regional wall motion abnormalities and improvement of left ventricular filling pressure, evident by the new mitral inflow pattern shown in Figure 2 (E wave of 1.07 m/s and A wave of 0.8 m/s).

Figure 1.

End-diastolic (A) and end-systolic (B) frames from the left ventriculogram, showing anterolateral, apical and inferior wall hypoki-nesis with a hypercontractile base. The findings are characteristic of stress or takotsubo cardiomyopathy (transient left ventricular apical ballooning)

Figure 2.

Mitral inflow pulsed-wave Doppler recording on follow-up echocardiography two weeks after presentation, showing improvement in left ventricular filling pressure with an E velocity of 1.07 m/s and an A velocity of 0.8 m/s, compared with values of 1.0 m/s and 0.2 m/s, respectively, on presentation

DISCUSSION

Acute stress cardiomyopathy is increasingly being described as a form of reversible left ventricular systolic dysfunction in the absence of coronary artery disease (1,2). It was first described in Japan, hence the name takotsubo cardiomyopathy (Japanese for octopus trap [tako-tsubo], which the balloon shape of the apex during systole in this syndrome resembles). However, the syndrome now has a more global distribution (3), and other nomenclatures used for describing this syndrome are apical ballooning syndrome, ampulla cardiomyopa-thy and ‘broken heart’ syndrome (1-4). Because left ventricular dysfunction is not always confined to the apex, with less common variations involving the basal, midportion and lateral wall of the ventricle, the term stress cardiomyopa-thy may be preferable to other nomenclatures (5).

The pathogenesis of stress cardiomyopathy is not well understood. It is much more common in women than men, with a mean age of 62 to 75 years at presentation. Onset is typically triggered by either intense emotional or physical stress, or acute medical illness, with the most common presenting symptoms being chest pain or shortness of breath, shock and ECG changes of myocardial ischemia (1,2). Postulated mechanisms can be summarized into three main categories: catecholamine-induced ventricular dysfunction, which is best supported by the available evidence (including the significantly higher plasma catecholamine levels in patients with stress cardiomyopathy than in patients with a similar degree of ischemic cardiomyopathy [6], and the similarity to transient left ventricular dysfunction in patients with acute brain injury [7]); multivessel coronary vasospasm, which has been rarely reported in Western cases (1) but is as high as 30% of patients in the Japanese literature (spontaneous or provoked multivessel vasospasm) (8); and dynamic left ventricular outflow tract obstruction, with apical systolic dysfunction related to catecholamine excess.

In addition to left ventricular apical dysfunction, right ventricular involvement, present in approximately 26% of patients, seems to be associated with a more severe impairment of left ventricular systolic dysfunction, which may be suspected by the presence of pleural effusion (9).

Features distinguishing stress cardiomyopathy from left anterior descending coronary artery territory infarction are summarized below (1-4,6-10).

• ECG abnormalities are the most common findings, along with ST-segment elevation or depression, T wave inversion and, rarely, Q waves.

• Cardiac biomarkers are frequently elevated, but elevations are mild and inconsistent with the severity of hemodynamic compromise (total creatine kinase less than 400 U).

• Wall motion abnormalities on echocardiography or left ventricular angiogram span a larger perfusion territory than can be accounted for by one coronary artery, with reduced overall left ventricular systolic function (showing the characteristic apical ballooning in most cases).

• Lack of delayed hyperenhancement on magnetic resonance imaging with gadolinium.

• Recovery of baseline left ventricular systolic function within one to four weeks, with a relatively low mortality rate ranging from 0% to 8%.

Diagnosis of stress cardiomyopathy is determined mainly by exclusion of acute coronary syndrome. Suspicion of stress car-diomyopathy is not a sufficient reason to withhold acute therapy for acute coronary syndrome, because the majority of patients presenting with acute chest symptoms and ECG changes (mainly those with ST elevation) have a critical coronary lesion; therefore, diagnosis of stress cardiomyopathy is established by the presence of all four criteria shown in Table 1 (1,2).

TABLE 1.

Diagnostic criteria for stress cardiomyopathy

Transient akinesis or dyskinesis of the apical and midventricular segments in association with regional wall motion abnormalities that extend beyond the distribution of a single epicardial vessel Absence on angiography of obstructive coronary artery disease or evidence of acute plaque rupture New ST-segment elevation or T wave inversion on the electrocardiogram Absence of recent significant head trauma, intracranial bleeding, pheochromocytoma, myocarditis or hypertrophic cardiomyopathy

CONCLUSIONS

Stress cardiomyopathy should be suspected whenever the acute ischemic ECG and echocardiographic abnormalities exceed the biomarker evidence for myocardial necrosis with nonob-structive coronary arteries on angiography. Conservative treatment involving stress alleviation, supportive therapy, and use of (despite the absence of controlled clinical trials) beta-blockers, angiotensin-converting enzyme inhibitors and diuretics (taken as needed for fluid overload) are advised (1). The in-hospital mortality rate, as well as the risk of recurrence, is low, with patients typically recovering baseline left ventricular systolic function within one month (2,3,6).