A previously asymptomatic 37-yr-old man presented to the hospital with acute hypertension of 220/120 mm Hg and unstable ventricular tachycardia requiring cardioversion. A transthoracic echocardiogram (TTE) 1 yr earlier had shown mitral valve prolapse with moderate mitral regurgitation (MR), normal left ventricular (LV) size and function and mild right ventricular (RV) dilation. His TTE after admission revealed dilated, hypokinetic RV with mild tricuspid regurgitation and flattening of the interventricular septum (IVS) (Video Clip 1; please see video clip available at www.anesthesia-analgesia.org). The estimated LV ejection fraction (EF) was 55% with moderate MR. The rest of the TTE was unremarkable.
Further workup revealed elevated urine catecholamine levels and a 5 × 6 cm right adrenal mass. The patient was started on phenoxybenzamine and labetalol and was scheduled for adrenalectomy. A repeat, preoperative TTE 1 wk after admission demonstrated a deteriorated LVEF of 30% and an otherwise unchanged examination. Consequently, the diagnosis of pheochromocytoma and catecholamine-induced cardiomyopathy was made. A biventricular assist device was on standby in anticipation of intraoperative cardiac deterioration. Intraoperative transesophageal echocardiography (TEE) demonstrated a massively dilated and severely hypokinetic RV distorting the normal cardiac anatomy. Systolic and diastolic IVS flattening was present (Fig. 1, Video Clip 2; please see video clip available at www.anesthesia-analgesia.org). The right atrium was enlarged and tricuspid regurgitation remained mild. The LV was also significantly dilated with an estimated EF of 25%–30% (Video 1). The mitral valve annulus was widened at 5.1 cm. Mitral valve prolapse with severe, eccentric MR (vena contracta width >1 cm) was visualized (Video Clip 3; please see video clip available at www.anesthesia-analgesia.org).
The intraoperative anesthetic management was based on the stage of surgery, hemodynamic changes and TEE findings. His measured pulmonary artery pressures were mildly elevated with episodic increases to 80/40 mm Hg. The cardiac index was 2.6 L/m2 and the systemic vascular resistance was 1500 dynes s · cm−5.
Sodium nitroprusside, esmolol, and phentolamine were titrated to effect for intermittent hypertension of up to 240/130 mm Hg. Severe hypotension to 60/30mm Hg (cardiac index 3.2 L/m2, systemic vascular resistance 500 dynes · s · cm−5) followed adrenalectomy requiring treatment with epinephrine, norepinephrine, arginine vasopressin, and volume expansion. His arterial blood pressure slowly improved to 90/60 mm Hg. The estimated LVEF improved to 35% and ventricular assist device placement was deemed unnecessary. The patient had an uncomplicated postoperative course.
TTE 1 mo later showed normalization of LV size and function. The mitral valve annulus was less dilated (4.2 cm) and the MR was moderate (vena contracta width of 0.55 cm). RV function improved slightly with less dilation and minimal IVS flattening (Video 1).
Pheochromocytoma, a catecholamine-secreting tumor, may present with tachycardia, hypertension or cardiomyopathy. Wall motion abnormalities and biventricular dilation are common in catecholamine-induced cardiomyopathy.1,2 Similar ventricular dysfunction extending beyond a single coronary distribution has been described in Takotsubo or “stress” cardiomyopathy.1 Both catecholamine-induced cardiomyopathy and Takotsubo cardiomyopathy may be caused by coronary vasospasm, increased vascular resistance, tachycardia or direct catecholamine-mediated myocyte injury.1 Rapid cardiac deterioration has been documented echocardiographically in catecholamine-induced cardiomyopathy.2
Ventricular interdependence is a complex phenomenon that may influence the configuration and motion of the IVS.3 In this case TEE showed severe RV > LV dysfunction leading to IVS flattening. Conversely, IVS and LV dysfunction may lead to a decline in RV contractile force based on the anatomic coupling of the ventricles.3 The normal circular shape of the IVS, with its convexity towards the RV, is a result of a positive left-to-right transseptal pressure gradient.4 A decrease in this transseptal pressure gradient, associated with increases in RV and/or decreases in LV pressure or volume, shifts the septum towards a neutral flat position. In an unloaded heart, the normal IVS configuration is relatively flat.4
Systolic septal flattening may be partly due to increased myocardial stiffness during ventricular contraction, which is enough to counterbalance increasing systolic left-to-right forces tending to push the IVS towards the RV.4 RV pressure overload leads to IVS flattening during the entire cardiac cycle with maximum septal flattening at end-systole5,6 (Table 1). Conversely, RV volume overload produces diastolic, but not systolic IVS flattening. In retrospect, we used the eccentricity index to quantify the degree of IVS flattening5 (Fig. 2). A higher index represents greater septal flattening, whereas an index of 1 describes a round LV.5 The eccentricity index indicated worse IVS flattening preoperatively and during systole when compared to the intraoperative images. Only minimal flattening was present postoperatively. One possible explanation is that RV hypertension was greatest preoperatively and that medical and surgical therapy reduced RV pressure and thus IVS flattening. Another explanation is that worsening LV function and dilation augmented LV diastolic pressures, which reduced the transseptal pressure gradient.
Improvement or reversal of catecholamine-induced cardiomyopathy weeks after surgical resection is a well-known phenomenon.1 This patient had less RV dilation and mildly improved RV function 1 mo postoperatively. IVS motion, LV size, and systolic function had normalized. The MR was less severe, most likely due to a decreased mitral valve annular diameter.
In summary, we present echocardiographic findings in a case of cardiomyopathy in a patient with pheochromocytoma. The observations of deterioration of preoperartive biventricular function that improved significantly postadenalectomy support the diagnosis of catecholamine-induced cardiomyopathy.
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