4.1Pacemakers for Tilt testing

StudyParticipantsinterventions
Ammirati 2001 (SYDIT)
RCT; study held in Italy. Funding: None stated
TLoC population: selected patients with NM syncope. Prior tests: All patients had 1 prior test. Extensive prior tests to exclude other causes (12-lead ECG, exercise, echo, 24h ECG, CSM, EEG plus CT, MRI, EP as necessary) and positive tilt test. Tilt test: all positive on head up tilt; 60 deg for 30 min; then isosorbide dinitrate 1.25mg for 15 min; 56% had ISD. All patients had TLoC during tilt test.
Patient characteristics:
  • age: Pacemaker 61(SD 13) years; drug 55 (SD 15) years; age >35 years
  • sex: 43% and 37% male;
  • cardioinhibitory NM syncope: some patients (60.2% patients had syncope in association with > asystole 3s (mean 16 (SD18) pace; 18 (11) drug))
  • comorbidities: not stated, but study excluded cardiac, neurological or metabolic disease and no-one had need for concomitant chronic pharmacological treatment.
History of TLoC: median 7 (range 3–130) events; median 2 (1–20) and 2(1–12) in 6 months prior to enrollment
Other study comments: Trial terminated early. Syncope witnessed in 57% of events and 29% other events associated with minor injuries (i.e. 86% independently verified). Inclusion criteria: Recurrent vasovagal syncope plus age > 35 y + at least 3 syncopal spells in previous 2 years, with last episode within 6 mo of enrollment. Plus positive response to tilt test with syncope in association with relative bradycardia (< 60 bpm).
Exclusion criteria: Syncope of cause other than vasovagal known or suspected. Any historical, clinical, laboratory evidence of cardiac, neurological or metabolic disease. Need for concomitant chronic pharmacological treatment for any cause. Definition of TLoC: Sudden transient loss of consciousness with inability to maintain postural tone and spontaneous recovery.
Intervention 1: Dual chamber pacemaker (DDD) with rate drop response pacing: (syncope + trough heart rate < 60 bpm) programmed on basis of heart rate behaviour on tilt test plus lower rate 40bpm and minimum AV delay of 200 ms; time: median 390 days (IQR 360–420) time to 1st recurrence (n=46)
Comparator: Atenolol 50 mg once per day, then titrated up to 100 mg/day within 2–3 days; time: median 135 days (IQR 15–250) time to 1st recurrence (n=47).
Connolly 2003 (VPS II)
RCT; study held in Canada, Australia, US, Colombia.
Funding: study co-funded by Medtronic Inc (pacemaker manufacturer) and lead author had honorarium from them.
TLoC population: selected patients with NM syncope.
Prior tests: Unclear or Not stated. Typical history of recurrent vasovagal syncope and positive tilt test: syncope/presyncope + heart rate × bp < 6000 mm Hg/min
All positive on head up tilt; 60–80 deg for 15–30 min; then isoproterenol 1–5 mcg for 5–15 min (44% DDD & 56% ODO IPN). 60% DDD & 71% for ODO had TLoC during tilt test. Patient characteristics: History of TLoC: median 15 (IQR 8–50) DDD and 20 (8–50); median 4 (3–12) DDD and 4 (2–15) events in past year; median 1 month since last event
Other study comments: Concomitant pharmacological therapy used during follow up: beta-blockers 12% ODO, 19% DDD; fludrocortisone 10% vs 2%; SSRI 12% vs 13%. Syncope witnessed in 12/16 (75%) (DDD) and 12/22 (55%) (ODO).
Inclusion criteria: Older than 19 years; typical history of recurrent vasovagal syncope with at least 6 episodes ever or 3 in 2 years before enrollment.
Positive head up tilt result with heart rate × bp < 6000 mm Hg/min
Exclusion criteria: Any other cause of syncope; patients with important valvular, coronary artery, or myocardial disease; ECG abnormality; any major noncardiovascular disease.
Definition of TLoC: Transient loss of consciousness with prompt spontaneous recovery.
Intervention 1: Dual chamber pacemaker (DDD) with rate drop response pacing: drop size 20 beats, drop rate 70/min and intervention rate of 100/min for 2 min; time: 6 months (n=48)
Comparator: Dual chamber pacemaker set to sensing only (ODO); time: 6 months (n=52).
Connolly 1999 (VPS)
RCT; study held in Canada and USA.
Funding: none stated
TLoC population: selected patients with NM syncope.
Prior tests: All patients had 1 prior test. History of recurrent syncope and positive tilt test (syncope/presyncope + trough heart rate <60bpm or see inclusion criteria). Other causes of TLoC excluded (arrhythmias, carotid sinus syndrome, seizures)
Tilt test: all positive on head up tilt; passive then isoproterenol phase; 78% pacemaker and 67% no PM had IPN. 77% in the pacemaker group and 63% in the no PM group had TLoC during tilt test; rest had presyncope
Patient characteristics: History of TLoC: TLoC history: median 14 (IQR 8–35) PM and 35 (20–100) lifetime events; median 3 (2–12) and 6 (3–40) in previous year; mean 92 days (SD 126) and 63 (SD 130) from most recent episode to randomisation.
Other study comments: Trial terminated early. Syncope witnessed in 50% of PM events & 32% no PM; 0% & 21% events associated with minor injuries. 7% in each group received a beta-blocker and 1/27 in the no PM group had disopyramide.
Adjusted analysis same.
Inclusion criteria: At least 6 lifetime syncopal spells plus positive tilt test with syncope or presyncope and with relative bradycardia (trough heart rate of <60 bpm if no isoproterenol used, <70 if up to 2 mcg/min IPN used or <80 if over 2 mcg/min used). Exclusion criteria: Important valvular, coronary, myocardial/conduction abnormality; previous pacemaker therapy; contraindication to insertion of pacemaker, a major chronic noncardiovascular disease.
Definition of TLoC: Transient state of unconsciousness characterised by spontaneous recovery.
Intervention 1: Dual chamber pacemaker (DDD) with rate drop response pacing: drop 5 to 15 bpm over 20–40 beats, drop rate 60/min and intervention rate of 100/min for 2 min] + usual care (none required); time: mean 112days (n=27)
Comparator: usual care medical or nonmedical at discretion of physician (none required); time: mean 54 days (n=27).

From: Appendix D1, Included studies characteristics

Cover of Transient Loss of Consciousness (‘Blackouts’) Management in Adults and Young People
Transient Loss of Consciousness (‘Blackouts’) Management in Adults and Young People [Internet].
NICE Clinical Guidelines, No. 109.
National Clinical Guideline Centre for Acute and Chronic Conditions (UK).
Copyright © National Clinical Guideline Centre for Acute and Chronic Conditions, 2010.

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