Mechanisms of Increased Ambulatory Blood Pressure in Patients With Intradialytic Hypertension

Inclusion Criteria (for Aims 1 and 2): * age more than 18 years * Hypertension defined as systolic blood pressure more than 140 mmHg before dialysis or more than 130 mmHg after dialysis * For case subjects with intradialytic hypertension: systolic blood pressure increase more than 10 mmHg from pre to post dialysis in at least 4 out of 6 screening treatments * For control subjects: systolic blood pressure decrease more than 10 mmHg from pre to post dialysis in at least 4 out of 6 screening treatments Inclusion criteria for Aim 3 includes the case subjects described above. Exclusion Criteria: For Aims 1 and 2: * Hemodialysis vintage less than 1 month * Amputated arm or leg * Presence of cardiac defibrillator or pacemaker * Presence of large metal prosthesis * Failure to achieve dry weight For Case subjects participating in Aim 3: * Patients with a specific indication for beta blocker therapy including systolic heart failure, history of myocardial infarction, history of tachyarrhythmia or angina being managed with beta blocker therapy. * Patients with contraindications to beta blockade including bradycardia (heart rate less than 60 beats per minute) while not on a pulse lowering drug, severe reactive airway disease, prior intolerance to beta blocker therapy * Prior intolerance to alpha blocker therapy