Adaptive Rate Pacing Controlled by Right Ventricular Preejection Interval for Severe Refractory Orthostatic Hypotension

Abstract

A 72-year-old African-American man with frequent recurrent syncope was found to have severe refractory orthostatic hypotension with concomitant supine hypertension. Pharmacotherapy was successful in controlling his supine hypertension but was unable to resolve his severe orthostatic hypotension. Temporary fixed rate tachypacing was only minimally effective in preventing syncope during upright tilt, while variable rate pacing based on degree of blood pressure fall was far superior. Following these observations, an adaptive rate pacing system controlled by right ventricular preejection interval was implanted (Precept DR Model 1200). The system adequately sensed the patient's fall in blood pressure when sitting or standing and augmented its rate accordingly, thus preventing syncope. While supine, the pacing rate fell to 60 ppm, thereby, avoiding an exacerbation of his concomitant supine hypertension. Over a 3-month follow-up period, he has had no further orthostatic or syncopal episodes. We conclude that adaptive rate pacing using right ventricular preejection interval may be an effective treatment for severe refractory orthostatic hypotension.

Pacing does not improve hypotension in patients with severe orthostatic hypotension

“…As seen in Table 5, however, the stroke volume also drops with tilting and pacing requiring even faster pacing rates. Some of the studies that showed a benefit with tachypacing paced at rates of 125 bpm [6]. With faster heart rates,however,the stroke volume may be lower due to reduced diastolic filling time thereby making the strategy potentially self defeating.…”

“…Abe et al [1] describe two cases in which tachypacing at 100 beats per minute prevented syncope. Grubb et al [6] describe another case of an elderly man with severe refractory orthostatic hypotension and supine hypertension who benefited from adaptive tachypacing. Other authors have reported similar findings [5,7,12].…”

Effective Pacing Therapy for Syncope with Severe Orthostatic Hypotension and Chronotropic Incompetence

“…This patient could not appropriately respond to fall the BP at the time of postural change so syncope or presyncopal state is exhibited. There have been some reports of attempting atrial-pacing therapy to increase heart rate and thereby increase cardiac output in order to improve hypotension in OH patients [3][4][5][6]. A mechanism of OH improvement by atrial overdrive pacing has not been made clear.…”

“…Severe OH patients with chronotropic incompetence have no adequate response of HR, when the BP falls during postural change. There have been a few reports of cardiac pacing therapy effectively providing good clinical result for drug-refractory OH [3][4][5][6]. In the small group study, rate response pacing is effective to keep BP and HR during postural change for OH patients with chronotropic incompetence.…”

Permanent cardiac pacing as primary therapy for neurocardiogenic (reflex) syncope

“…The development of novel sensor technologies that would permit either direct or indirect measurement of blood pressure would allow for the onset of pacing at a much earlier point in the syncopal event providing a greater likelihood of altering or aborting its progression. Early reports of sensors using right ventricular or transthoracic impedance have been encouraging [27], as have other systems still in development [28].…”