J. Endocrinol. Invest. 13: 943-947,1990
CASE REPORT
Pheochromocytoma associated ventricular tachycardia blocked with atenolol 1 R. D. Michaels*, J. H. Hays*, J. T. O'Brian*, and K. M. M. Shakir* *Division of Endocrinology, Department of Internal Medicine, National Naval Medical Center, Bethesda, Maryland 20889-5000, USA ABSTRACT. Ventricular tachycardia in patients with pheochromocytoma is rare. We report a patient with a norepinephrine-secreting extra-adrenal pheochromocytoma who had exercise induced ventricular tachycardia. Prior to diagnosis, the patient was treated with a selective ß1 blocker, atenolol, wh ich resulted in suppression of the dys-
rhythmia and amelioration of the hypertension. This is the first reported case of selective ß blockade suppressing ventricular tachycardia in a patient with a pheochromocytoma. Electrocardiographie abnormalities described in patients with pheochromocytoma are reviewed.
INTRODUCTION Pheochromocytomas are rare tumorS which secrete excess catecholamines resulting in persistent or episodic clinical features of headache, palpitations, pallor, perspiration and hypertension. Treatment with nonselective beta blockers alone in pheochromocytomas is considered by many to be contraindicated due to the hypertensive crisis that can be induced (1). Although cardiac dysrythmias are stated to be common in patients with pheochromocytoma, exercise-induced ventricular tachycardia has not previously been reported. We describe a patient with a pheochromocytoma and exercise-induced ventricular tachycardia in whom the dysrhythmia was suppressed by a BI selective antagonist.
dizziness had chest pain and left arm numbness when metoprolol was added to his medication regimen. Records indicate a blood pressure of 160/92 and a pulse of 64 per minute at that time. The metoprolol was discontinued and enalapril 5 mg daily was added to a daily dose of hydrochlorothiazide/triamterene. He continued to be lightheaded and have nausea and headache after exercise. He had numerous acute care visits with complaints of chest pain prompting his physician to schedule an exercise stress test (Bruce protocol). He was noted intermittently to have hypertension with an otherwise normal physical examination and normal resting electrocardiogram. Six months before referral, an exercise stress test was remarkable for an 8 beat run of nonsustained ventricular tachycardia one minute following completion of the test along with the previously described symptoms which occurred after exercise. A 24 hour Holter monitor and an echocardiogram were normal. The patient subsequently underwent coronary angiographic evaluation, which was normal. Atenolol 100 mg per day was added to his treatment regimen and a followup exercise stress test showed no dysrhythmias. One month later, all medications were discontinued and electrophysiologic studies were performed at that facility. No inducible dysrhythmias were found. The exercise stress test was repeated off all medications and numerous episodes of exercise induced ventricular tachycardia were again docu-
CASE REPORT Two years prior to evaluation at our clinic a 28 year old white male with a five year history of hypertension and exercise induced nausea, vomiting and Key-words: Pheochromocytoma. ventricular tachycardia. atenolol. metoprolol Correspondence: Michaels R.D .. M.D .. Division of Endocrinology. Department of Internal Medicine. National Naval Medical Center. Bethesda. Maryland 20889 - 5000. USA. Received April 26. 1990; accepted September 13. 1990. 'The opinions and assertions contained herein are the private on es 01 the authors and are not to be construed as otficial or as reflecting the views of the Navy Department or the Naval service at large.
943
RD. Michaels, J.H. Hays, J. T O'Brian, et al.
Table 1 - Urinary levels ot VMA, metanephrines and catecholamines. Posl-op
Pre-op 10/21/88 2750 15.0
Dale Volume (mi) Crealinine üLmol/24h) VMA (mmol/24h) Melanephrines (nmol/24h) Epinephrine (nmol/24h) Norepinephrine ((nmol/24h)
14.0 55 2435
2/28/89 3650 17.7 82 24.5 < 27. 1578
4/30/89 1800 19.4 -~--
2.5 27. 212
Normal range for VMA is 10-51 mmol/24h. Normal range for melanephrines 0-11 nmol/24h, epinephrine < 55 nmol/24h, and norepinephrine< 590 nmol/24h. To converl VMA from mmol 10 mg divide by 5.06. To converl from nmol 10 I'g/dl for epinephrine divide by 5.5 and for melanephrines divide by 5.44 10 converl nmol 10 mg. To converl norepinephrine from nmol 10 I'g/ dl divide by 5.91.
mented, the longest run lasting 22 seconds. His blood pressure was noted to be 250/110 at this time. Atenolol 100 mg per day was restarted and a repeat exercise stress test was normal. Reevaluation at a third institution included another exercise stress test off all medications and revealed the same findings. As an outpatient while on a daily regimen of 100 mg atenolol and 5 mg enalapril his physician suspected a pheachromocytoma. A 24 hour urine collection revealed an elevated metanephrine level of 14.0 nmol (normal range 0-11 nmol/24h) and he was referred to our institution for further evaluation. On presentation, he was without complaints, blood pressure was 118/68 mmHg and the pulse rate was 68 per minute while supine, with no orthostatic change. HEENT examination was normal. There was no jugular venous distension. 8 1 and 8 2 were normal with an early systolic ejection click. The abdomen was normal with no palpable masses. There was no peripheral edema and neurological examination was normal. The patient was admitted for continuous electrocardiographic ambulatory monitoring while medi-
cations were discontinued. Twenty-four hour urine collections for metanephrines, vanillylmandelic acid (VMA), and fractionated catecholamines along with a clonidine suppression test (2) were performed after the patient was off medications for seven days. The results are shown in Tables 1 and 2. The baseline plasma norepinephrine level was elevated and did not decrease during the three hour clonidine suppression test, consistent with a pheochromocytoma (2). A computerized tomographic scan of the abdomen showed a retroperitoneal soft tissue mass 4.7 x 4.2 cm located medial to the inferior pole of the left kidney, adjacent to the bifurcation of the aorta. A 1311-metaiodobenzylguanidine (MIBG) scan was positive in the same area, and as shown in Figure 1, the MRI scan confirmed a mass in the same location with enhancement on T2 vs T 1 weighted images, consistent with a pheochromocytoma. Other normal laboratory values included: a CBC, electrolytes, renal and liver function tests. Chest x-ray and electrocardiogram were normal. The patient was prepared for surgery with phenoxybenzamine, increased gradually over two weeks to 20 mg bid,
Table 2 - Clonidine suppression test tor pre- and postoperative plasma catecholamine levels. Time (h) 0 1 2 3
PRE-OP
POST-OP
Norepinephrine (nmol/l)
Epinephrine (pmol/l)
Norepinephrine (nmol/l)
Epinephrine (pmol/I)
5.45 6.76 10.21 6.19
388 655 699 524
0.97 0.57 0.37 1.11
< 55
CASE REPORT
Pheochromocytoma associated ventricular tachycardia blocked with atenolol 1 R. D. Michaels*, J. H. Hays*, J. T. O'Brian*, and K. M. M. Shakir* *Division of Endocrinology, Department of Internal Medicine, National Naval Medical Center, Bethesda, Maryland 20889-5000, USA ABSTRACT. Ventricular tachycardia in patients with pheochromocytoma is rare. We report a patient with a norepinephrine-secreting extra-adrenal pheochromocytoma who had exercise induced ventricular tachycardia. Prior to diagnosis, the patient was treated with a selective ß1 blocker, atenolol, wh ich resulted in suppression of the dys-
rhythmia and amelioration of the hypertension. This is the first reported case of selective ß blockade suppressing ventricular tachycardia in a patient with a pheochromocytoma. Electrocardiographie abnormalities described in patients with pheochromocytoma are reviewed.
INTRODUCTION Pheochromocytomas are rare tumorS which secrete excess catecholamines resulting in persistent or episodic clinical features of headache, palpitations, pallor, perspiration and hypertension. Treatment with nonselective beta blockers alone in pheochromocytomas is considered by many to be contraindicated due to the hypertensive crisis that can be induced (1). Although cardiac dysrythmias are stated to be common in patients with pheochromocytoma, exercise-induced ventricular tachycardia has not previously been reported. We describe a patient with a pheochromocytoma and exercise-induced ventricular tachycardia in whom the dysrhythmia was suppressed by a BI selective antagonist.
dizziness had chest pain and left arm numbness when metoprolol was added to his medication regimen. Records indicate a blood pressure of 160/92 and a pulse of 64 per minute at that time. The metoprolol was discontinued and enalapril 5 mg daily was added to a daily dose of hydrochlorothiazide/triamterene. He continued to be lightheaded and have nausea and headache after exercise. He had numerous acute care visits with complaints of chest pain prompting his physician to schedule an exercise stress test (Bruce protocol). He was noted intermittently to have hypertension with an otherwise normal physical examination and normal resting electrocardiogram. Six months before referral, an exercise stress test was remarkable for an 8 beat run of nonsustained ventricular tachycardia one minute following completion of the test along with the previously described symptoms which occurred after exercise. A 24 hour Holter monitor and an echocardiogram were normal. The patient subsequently underwent coronary angiographic evaluation, which was normal. Atenolol 100 mg per day was added to his treatment regimen and a followup exercise stress test showed no dysrhythmias. One month later, all medications were discontinued and electrophysiologic studies were performed at that facility. No inducible dysrhythmias were found. The exercise stress test was repeated off all medications and numerous episodes of exercise induced ventricular tachycardia were again docu-
CASE REPORT Two years prior to evaluation at our clinic a 28 year old white male with a five year history of hypertension and exercise induced nausea, vomiting and Key-words: Pheochromocytoma. ventricular tachycardia. atenolol. metoprolol Correspondence: Michaels R.D .. M.D .. Division of Endocrinology. Department of Internal Medicine. National Naval Medical Center. Bethesda. Maryland 20889 - 5000. USA. Received April 26. 1990; accepted September 13. 1990. 'The opinions and assertions contained herein are the private on es 01 the authors and are not to be construed as otficial or as reflecting the views of the Navy Department or the Naval service at large.
943
RD. Michaels, J.H. Hays, J. T O'Brian, et al.
Table 1 - Urinary levels ot VMA, metanephrines and catecholamines. Posl-op
Pre-op 10/21/88 2750 15.0
Dale Volume (mi) Crealinine üLmol/24h) VMA (mmol/24h) Melanephrines (nmol/24h) Epinephrine (nmol/24h) Norepinephrine ((nmol/24h)
14.0 55 2435
2/28/89 3650 17.7 82 24.5 < 27. 1578
4/30/89 1800 19.4 -~--
2.5 27. 212
Normal range for VMA is 10-51 mmol/24h. Normal range for melanephrines 0-11 nmol/24h, epinephrine < 55 nmol/24h, and norepinephrine< 590 nmol/24h. To converl VMA from mmol 10 mg divide by 5.06. To converl from nmol 10 I'g/dl for epinephrine divide by 5.5 and for melanephrines divide by 5.44 10 converl nmol 10 mg. To converl norepinephrine from nmol 10 I'g/ dl divide by 5.91.
mented, the longest run lasting 22 seconds. His blood pressure was noted to be 250/110 at this time. Atenolol 100 mg per day was restarted and a repeat exercise stress test was normal. Reevaluation at a third institution included another exercise stress test off all medications and revealed the same findings. As an outpatient while on a daily regimen of 100 mg atenolol and 5 mg enalapril his physician suspected a pheachromocytoma. A 24 hour urine collection revealed an elevated metanephrine level of 14.0 nmol (normal range 0-11 nmol/24h) and he was referred to our institution for further evaluation. On presentation, he was without complaints, blood pressure was 118/68 mmHg and the pulse rate was 68 per minute while supine, with no orthostatic change. HEENT examination was normal. There was no jugular venous distension. 8 1 and 8 2 were normal with an early systolic ejection click. The abdomen was normal with no palpable masses. There was no peripheral edema and neurological examination was normal. The patient was admitted for continuous electrocardiographic ambulatory monitoring while medi-
cations were discontinued. Twenty-four hour urine collections for metanephrines, vanillylmandelic acid (VMA), and fractionated catecholamines along with a clonidine suppression test (2) were performed after the patient was off medications for seven days. The results are shown in Tables 1 and 2. The baseline plasma norepinephrine level was elevated and did not decrease during the three hour clonidine suppression test, consistent with a pheochromocytoma (2). A computerized tomographic scan of the abdomen showed a retroperitoneal soft tissue mass 4.7 x 4.2 cm located medial to the inferior pole of the left kidney, adjacent to the bifurcation of the aorta. A 1311-metaiodobenzylguanidine (MIBG) scan was positive in the same area, and as shown in Figure 1, the MRI scan confirmed a mass in the same location with enhancement on T2 vs T 1 weighted images, consistent with a pheochromocytoma. Other normal laboratory values included: a CBC, electrolytes, renal and liver function tests. Chest x-ray and electrocardiogram were normal. The patient was prepared for surgery with phenoxybenzamine, increased gradually over two weeks to 20 mg bid,
Table 2 - Clonidine suppression test tor pre- and postoperative plasma catecholamine levels. Time (h) 0 1 2 3
PRE-OP
POST-OP
Norepinephrine (nmol/l)
Epinephrine (pmol/l)
Norepinephrine (nmol/l)
Epinephrine (pmol/I)
5.45 6.76 10.21 6.19
388 655 699 524
0.97 0.57 0.37 1.11
< 55
