Gate-keeper to coronary angiography: comparison of exercise testing, myocardial perfusion SPECT and individually tailored approach for risk stratification.

We aimed to evaluate the differences between exercise testing (ET), myocardial perfusion SPECT (MPS) and a combination of ET and MPS based risk assessment as outlined by the guidelines with respect to their "gate-keeper" role to coronary angiography (cath) and the associated diagnostic procedural costs if prognostic considerations, as those proposed by the current guidelines and the recent literature, were taken into account. The Duke-score and the summed difference score (SDS; extent of ischemia) were assessed in 955 consecutive patients referred for MPS combined with ET. According to the guidelines and the available literature, three different algorithms for risk stratification were retrospectively applied: (1) ET based risk stratification and cath if intermediate or high risk Duke-score; (2) MPS based risk stratification and cath if SDS ≥ 8; (3) combined approach with ET as first step and MPS in case of intermediate risk Duke-score. A cath would have been suggested in every patient with either high risk Duke-score or SDS ≥ 8 in patients with intermediate risk Duke-score. The referral rate to cath was 27% according to the ET alone, 13% using MPS, and finally 12% applying the combined risk stratification. The cost of the diagnostic work-up including cath were: 615€, 1,299€, and 598€ per patient, respectively. The coronary angiography referral rate widely depends on the diagnostic modality used for risk stratification and according to the referral criteria provided by the guidelines. In the present study, the use of a stress imaging modality (MPS) and published prognostic data was associated with a lower referral rate to cath as compared to exercise testing alone and thus underlines the advantage of a risk based approach applying stress imaging in patients with intermediate risk Duke-score.

Interrelation of ST-segment depression during bicycle ergometry and extent of myocardial ischaemia by myocardial perfusion SPECT.

PURPOSE: The aim of this study was to compare ST-segment depression (STD) during bicycle ergometry and extent of myocardial ischaemia assessed by myocardial perfusion SPECT (MPS) in a large patient cohort. METHODS: Consecutive patients (n = 955) referred for MPS with bicycle ergometry and interpretable stress ECG were evaluated with respect to ECG and MPS findings of ischaemia. The maximal STD was recorded and exercise ECG was considered ischaemic if STD was horizontal or downsloping (>or=1 mm). MPS was interpreted using a 20-segment model with a scale of 0 to 4. A summed stress (SSS), summed rest (SRS) and summed difference score (SDS = SSS-SRS, e.g. extent of ischaemia) were derived. Ischaemia was defined as an SDS >or= 2. RESULTS: An exercise-induced STD was present in 215 patients (22%) and myocardial ischaemia on MPS was present in 366 patients (38%). The extent of ST-segment depression and the number of ECG leads with significant STD were each strongly and significantly associated with increasing severity of ischaemia and the number of coronary territories involved (p < 0.01 for all correlations). CONCLUSION: These data demonstrate a strong correlation between the extent of STD, number of ischaemic leads and severity of myocardial ischaemia as assessed by MPS during bicycle ergometry.

Value of VDD-pacing systems in patients with atrioventricular block: experience over a decade.

BACKGROUND: Even though current guidelines suggest the use of VDD pacemakers in patients with AV block and normal sinus node function, a DDD system is often preferred for fear of either long-term atrial undersensing or late sinus node dysfunction and the resultant need for system upgrades. METHODS: We evaluated the long-term follow-up of all VDD pacemakers implanted in our center between 1992 and 2001 regarding atrial sensing, maintenance of AV synchrony, incidence of atrial fibrillation (AF), or the need for system upgrade, respectively. RESULTS: 320 consecutive patients (56% men, age 75+/-13 years) received a VDD pacemaker for the following indications: third-degree AV block 54%, second-degree AV block 34%, fascicular block with first-degree AV block and syncope 6%, others 6%. 138 patients (43%) died during follow-up, 3.8+/-2.3 years after implantation. Follow-up duration was 6.1+/-2.5 years in the remaining patients. At the last follow-up, 268 pacemakers (84%) were programmed to the VDD mode, 47 pacemakers (15%) were permanently programmed to the VVI mode (AF 36, undersensing 7, others 4, respectively). In five patients a DDD upgrade was necessary for sinus node dysfunction (3) or lead defect (2). Lead revision was performed in 19 patients (6%) (ventricular lead dislocation 7, atrial undersensing 6, lead fracture 3, others 2, respectively). CONCLUSION: VDD pacemakers have an excellent long-term performance in patients with AV block. They have a very low incidence of lead revisions for atrial undersensing (2%) and DDD upgrades for secondary sinus node dysfunction (1%).