Dynamic left ventricular outflow tract obstruction in a patient with pheochromocytoma

Malignant Left Ventricular Outflow Tract Obstruction: A Reason to Operate?

A 57-year-old man with high-grade synovial sarcoma was found to have cardiac involvement of his malignancy. Intracardiac tumor resulted in dynamic left ventricular outflow tract obstruction and severe mitral regurgitation. He underwent mitral valve replacement and had no cardiovascular symptoms at 1-year follow-up. (Level of Difficulty: Intermediate.).

Catecholamine-Induced Cardiomyopathy in Pheochromocytoma: How to Manage a Rare Complication in a Rare Disease?

Pheochromocytomas and paragangliomas (PHEOs) are rare neuroendocrine tumors. Clinical manifestations include different cardiovascular signs and symptoms, which are related to excessive secretion of catecholamines. Catecholamine-induced cardiomyopathy in PHEO (CICMPP) is a rare but dreaded complication of PHEO. Once patient is diagnosed with this condition, the prognosis is worse and a surgical risk is much higher than expected. This article focuses on how catecholamines affect the heart and the pathophysiologic mechanism of CICMPP. The cardiovascular responses to catecholamine depend mostly on which catecholamine is released as well as the amount of catecholamine that is released. The acute release of norepinephrine and epinephrine from PHEO increases heart rate, systemic vascular resistance, myocardial contractility, and reduces venous compliance. The excessive adrenergic stimulation by catecholamine results in severe vasoconstriction and coronary vasospasm, myocardial ischemia, and subsequently damage, and necrosis. Chronically elevated catecholamine levels lead to significant desensitization of cardiac β-adrenoceptors. The increased levels of the enzyme β-adrenoceptors kinase (βARK) in the heart seems to mediate these biochemical and physiological changes that are consistently correlated with attenuated responsiveness to catecholamine stimulation. Through these mechanisms different types of cardiomyopathy (CMP) can be formed. This review discusses extensively the 3 types of cardiomyopathies that can be present in a PHEO patient. It also provides the clinical presentation and diagnostic and therapeutic algorithm in managing patients with CICMPP.

Stress induced hypertensive response: should it be evaluated more carefully?

Various diagnostic methods have been used to evaluate hypertensive patients under physical and pharmacological stress. Several studies have shown that exercise hypertension has an independent, adverse impact on outcome; however, other prognostic studies have shown that exercise hypertension is a favorable prognostic indicator and associated with good outcome. Exercise hypertension may be encountered as a warning signal of hypertension at rest and future hypertensive left ventricular hypertrophy. The results of diagnostic stress tests support that hypertensive response to exercise is frequently associated with high rate-pressure product in hypertensives. In addition to the observations on high rate-pressure product and enhanced ventricular contractility in patients with hypertension, evaluation of myocardial contractility by Doppler tissue imaging has shown hyperdynamic myocardial function under pharmacological stress. These recent quantitative data in hypertensives suggest that hyperdynamic myocardial function and high rate-pressure product response to stress may be related to exaggerated hypertension, which may have more importance than that it has been already given in clinical practice.

Stress-induced regional features of left ventricle is related to pathogenesis of clinical conditions with both acute and chronic stress

Tako-tsubo cardiomyopathy is a relatively newly described acute and reversible left ventricular (LV) dysfunction triggered by emotional stress. The disease is associated with excessive sympathetic stimulation, microvascular dysfunction and abnormal myocardial tissue metabolism. Recently, we have pointed out that tako-tsubo cardiomyopathy may be associated with particular LV features which are also described by quantitative echocardiographic methods in hypertensive heart disease. The patients with acute or chronic stress can be presented clinically by stress-induced LV hypercontractility of LV base, relevant LV outflow tract obstruction and narrowed cavity. Recent observations also have confirmed the possibility of association of both acute and chronic conditions in a clinical presentation of the patients. Therefore, we believe that the presence of both resistance and hypercontractile response of LV base to stress induction compared with midapical region in clinical conditions with acute or chronic stress is important in the disease process.

Standing position alone or in combination with exercise as a stress test to provoke left ventricular outflow tract gradient in hypertrophic cardiomyopathy and other conditions

Measuring left ventricular outflow tract (LVOT) gradient by echocardiography in decubitus position, which is used in routine clinical practice, does not reflect the pathophysiology of this dynamic abnormality during daily activities, which trigger the symptoms. LVOT obstruction is dynamic and greatly dependent upon the left ventricular cavity size, geometric configuration of hypertrophy, load, contractility and mitral apparatus abnormalities, including systolic anterior motion of mitral leaflet. Importantly, LVOT gradient may develop not only in hypertrophic cardiomyopathy, but also in other heart diseases. Recent studies show that LVOT gradient should be measured both in a standing position and during exercise.

Takotsubo cardiomyopathy may be associated with cardiac geometric features as observed in hypertensive heart disease

Takotsubo cardiomyopathy is a clinical entity with a relatively new described acute and reversible left ventricular (LV) dysfunction triggered by emotional stress. Different observations have represented that takotsubo cardiomyopathy may be associated with similar LV myocardial geometry as described by novel quantitative echocardiographic methods in hypertensive heart disease. Therefore, acute emotional stress in takotsubo cardiomyopathy or chronic stress by increased afterload in hypertension possibly represents similar morphologic and functional features on the basis of heart.

Catecholamine therapy inducing dynamic left ventricular outflow tract obstruction

Hypertrophic obstructive cardiomyopathy with significant hypertrophy of the basal septum is the most frequently reported cause of left ventricular outflow tract (LVOT) obstruction. Additionally, other conditions such as dehydration, sepsis, vasodilatation, or mitral valve repair have been associated with LVOT obstruction. In this report, we present a case of a patient without hypertrophy who developed severe dynamic left ventricular outflow tract obstruction during catecholamine stimulation for shock that complicated severe pancreatitis. The present case serves as a reminder that hypovolemia together with a hyperdynamic state resulting from catecholamine administration may result in the development of dynamic LVOT obstruction even if baseline cardiac evaluation is unremarkable. Early detection and intensive efforts to reverse the underlying conditions, including cessation of catecholamine therapy and correction of hypovolemia are essential.