Adrenal pheochromocytoma associated with dramatic cyclic hemodynamic fluctuations.

A 52-year-old woman with a right adrenal pheochromocytoma had repetitive attacks of symptomatic hypotension/shock with systolic blood pressure (SBP)<50 mmHg followed by hypertension/hypertensive crises with SBP>300 mmHg. A non-invasive recording of beat-to-beat SBP, diastolic blood pressure (DBP), heart rate (HR), stroke volume (SV), cardiac output (CO) and total peripheral resistance (TPR) was collected for 346 min. Twenty hemodynamic cycles occurred during this time, lasting 17 min on average, with the most dramatic changes of TPR. The ratio of the highest to the lowest observed values was nearly 12:1 for TPR, over 6:1 for both SBP and DBP, over 4:1 for CO, and nearly 4:1 for SV and 2:1 for HR. The fluctuations of TPR preceded changes of all other hemodynamic variables.