Specially Programmed
Pacemaker Eliminates Syncope
by Alfonso
Estrada , M.D.
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Patients with neurocardiogenic syncope can have one of three types of response to upright tilting: a cardioinhibitory response in which an inappropriate heart rate drop occurs; a vasodepressor response in which a sustained blood pressure drop occurs; or a mixed response in which both inappropriate bradycardia and hypotension occur.
M.M. was initially
only treated for a bradycardic response with insertion of a standard dual
chamber pacemaker. But during tilt
table testing, symptomatic hypotension, not prevented by low rate pacing,
occurred and he continued to be plagued by recurrent aggravating symptoms.
(See Case Study)
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Case
Study
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Patient: M.M., 44-year-old male from Glenview History: Evaluated by PCP for chronic weakness and recurrent syncope. Diagnosed with Sick Sinus Syndrome and a dual chamber pacer was inserted to treat bradycardia Symptoms: Intermittent episodes of weakness, dizziness and syncope persisted after pacer insertion Tests: Tilt table test Diagnosis: Neurocardiogenic syncope Treatment: Special pacemaker pro-gramming with “positive hysteresis” |
Standard medical treatment for this form of neurocardiogenic syncope, including beta-blocking drugs and aminophylline, were tried but were not tolerated due to adverse side effects.
Because of the complexity of this electro-physiologic and hemodynamic problem, the patient was referred to the author for further management. Unbeknownst to many cardiologists, M.M.’s type of pace-maker had a special capacity called “posi-tive hysteresis” that, when programmed on, solved his problem.
With “positive hysteresis,” the pacemaker senses for a sudden drop in the patient’s heart rate and, when it occurs, the pacer turns on at a higher rate (i.e. 90-100 bpm) than its usual preset rate (i.e. 60 or 70 bpm). (See Figure 1.)
Figure 1:
Pacemaker telemetry of an aborted syncopal event.
Even though the majority of syncope patients have an underlying cardiac disorder, it’s sometimes difficult to imagine in a man as young as M.M., especially with no family history of heart disease or previous symptoms.
But whether or not there’s a personal or family history, or other signs, there’s a high statistical likelihood that syncopal episodes are cardiovascular in origin.
Since his pacemaker was reprogrammed, M.M. has done well and remains under the care of his personal physician. He has experienced some occasional weakness, but no syncopal episodes, and enjoys a much-improved quality of life. He is followed in the author’s pacemaker clinic every six months. The use of such a highly specialized pacemaker with a “positive hysteresis” feature is routine for physicians with long involvement in the field of cardiac pacing.
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