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5.19 Artefactual myocardial perfusion defects in right ventricular apical pacing
Journal of Nuclear Cardiology Volume 12, Number 4;S2-S13
Objective: To verify if the chronotrophic incompetence (CI) adds information to the ST- segment analysis in the detection of CAD in diabetic women without symptoms and to compare with the results of MPS. Methods: We analyzed, prospectively, 98 diabetic women who performed EST, MPS with dipyridamole and angiography (angio) within 2 months and without cardiac procedures between these studies. Angio was considered abnormal (abnl) at the presence of at least one coronary artery with obstruction greater than 50%. EST was considered abnl at the presence of ST-segment change equal to or greater than 1,5 mm at peak exercise in relation to rest. We calculate the CI by the standard equation: [peak heart rate (HR) - rest HR]/ [maximal age-predicted RH - rest HR] X 100. CI was defined as values ⬍ 80%. MPS was considered abnl if there were reversible defects after the stress phase. We correlated the obtained results with the angio.The statistic analysis was performed by chi-square and Fisher tests and differences were considered significant at p⬍0,05. Results: From the 98 women, 67 had abnl EST and from those, 20 had presented abnl angio (31,2%),p⫽0,150. Sexty-two women had IC and from those, 29 (47%) with abnl angio, p⫽0,087. Both abnl EST and CI were present in 42 women ans from those, 30 (71,4%) had abnl angio, p⬍0,05. In the 42 pts of the group with abnl MPS, 39 (93%) presented an abnormal cine. p⫽0,001. Conclusion: The obtained results may suggest that CI adds information to EST in order to identify CAD in non-symptomatic diabetic women, but pharmacological stress MPS has shown a better rate of CAD identification. 5.18 PACEMAKER RELATED MYOCARDIAL PERFUSION DEFECTS WORSEN DURING HIGHER PACING RATE AND CORONARY FLOW AUGMENTATION TJF ten Cate, FC Visser, NM Panhuyzen-Goedkoop, JF Verzijlbergen, NM van Hemel St. Antonius Hospital Nieuwegein Background: Asynchronous activation resulting from RVA pacing can adversely affect left ventricular function and myocardial perfusion despite normal coronary arteries. This troubles the detection of coronary heart disease in paced patients. Methods: Fourteen patients with permanent RVA pacing with angiographically normal coronary arteries underwent myocardial perfusion SPECT at rest with low and high pacing rate, and with pacing at low rates with adenosine. Data were analysed semi-quantitatively using a 20 segment scoring model and coded using a 4-point scoring system. Results: At rest, 23 of 42 (55%) coronary flow territories showed abnormal perfusion and 52 of 280 (19%) corresponding segments demonstrated abnormal perfusion; mean perfusion score 0.22. After high rate pacing, perfusion was abnormal in 31 of 42 (74%) flow territories and 122 of 280 (44%) segments: mean perfusion score 0.67. Adenosine infusion resulted in 28 of 42 (67%) abnormal flow territories and 90 of 280 (32%) abnormal segments; mean perfusion score 0.44. Perfusion defects were most often observed in close proximity to the origin of the pacing site. Conclusion: RVA pacing results in myocardial perfusion defects. The false-positive findings are present at rest and more outspoken with high rate pacing than during adenosine infusion. Detection of coronary artery disease should be carried out with caution in RVA paced patients because of the high number of perfusion defects in the absence of coronary artery disease.
Abstracts
S105
5.19 ARTEFACTUAL MYOCARDIAL PERFUSION DEFECTS IN RIGHT VENTRICULAR APICAL PACING TJF ten Cate, FC Visser, NM van Hemel, JF Verzijlbergen St. Antonius Hospital Nieuwegein Background: It is generally accepted that myocardial perfusion is diminished in patients with a right ventricular apical pacemaker. The regions affected are those with an abnormal contraction pattern. This study aims to assess the effects of abnormal contraction pattern on myocardial perfusion imaging. Methods: Eight patients with a permanent dual chamber pacemaker with a right ventricular apical lead for bradytachycardia syndrome were studied. All underwent myocardial perfusion SPECT at rest with technetium-99sestamibi. Technetium-99m-sestamibi was injected at rest during normal atrio-ventricular (AV) conduction. Myocardial SPECT was performed during AAI pacing with a rate of 5 above the resting heart rate and repeated in DDD pacing mode with the same heart rate. The first pacing mode of perfusion imaging was randomized. Results: Myocardial perfusion at rest with normal AV conduction was normal in 6 patients. The average summed rest score (SRS) was 0.875. During abnormal AV activation, myocardial perfusion was abnormal in 3 patients. The SRS increased to 3. The summed motion (SMS) and summed thickness scores (STS) also increased from 3 to 7 and from 0.875 to 3.5. Conclusion: During normal atrio-ventricular conduction normal perfusion is found in most patients. Subsequent DDD-pacing obviously results in new perfusion defects despite the fact that tracer distribution is not changed. The defects are strongly related to abnormal wall motion and thickening. Which suggests that these perfusion defects must be caused by partial volume effect.
5.20 COMBINED DIPYRIDAMOLE-EXERCISE TC-99M SESTAMIBI GATED SPECT MYOCARDIAL PERFUSION IMAGING: HOW DOES IT COMPARE TO STANDARD VASODILATOR OR EXERCISE STRESS IN RISK STRATIFICATION? J Thompsen, H Athar, V Sainani, D O’Sullivan, I Leka, GV Heller Hartford Hospital, Hartford, CT Background: The prognostic value of standard exercise (EX) and vasodilator (VASO) SPECT is well established. However, there are few data on the utility of combining both modes of stress. We compared gated SPECT variables, outcomes and risk stratification between patients undergoing EX, VASO, or dipyridamole-exercise (DIP-EX). Methods: After excluding patients who underwent PCI or CABG ⱕ60 days after gated SPECT, 10,718 consecutive patients who underwent EX (n⫽5683), VASO (n⫽3220), or DIP-EX (n⫽1815) with Tc-99m sestamibi MPI were evaluated. Selection of stress modality was based on the perceived ability to exercise. Follow-up was 86.3% complete over 29⫾18 months. The patients had an age of 61⫾14 years, 49.9% were female and 25.4% had a history of MI, PCI or CABG. Risk stratification was examined using the summed stress score (SSS) and post-stress ejection fraction (EF). Images were classified as normal (SSSⱕ3 and EFⱖ50%) or abnormal (SSS3 or EF⬍50%). Patients were followed for cardiac death (CD) or myocardial infarction (MI). Results: A significant increase in the incidence of abnormal perfusion or function and worsening of SSS and EF was found between modes of stress, the lowest with EX and highest with VASO. The cumulative event rate was 1.9%, 3% and 6.9% with EX, DIP-EX (p⬍0.01 versus EX) and VASO (p⬍0.001 versus EX and DIP-EX), respectively. With each mode of stress,
Objective: To verify if the chronotrophic incompetence (CI) adds information to the ST- segment analysis in the detection of CAD in diabetic women without symptoms and to compare with the results of MPS. Methods: We analyzed, prospectively, 98 diabetic women who performed EST, MPS with dipyridamole and angiography (angio) within 2 months and without cardiac procedures between these studies. Angio was considered abnormal (abnl) at the presence of at least one coronary artery with obstruction greater than 50%. EST was considered abnl at the presence of ST-segment change equal to or greater than 1,5 mm at peak exercise in relation to rest. We calculate the CI by the standard equation: [peak heart rate (HR) - rest HR]/ [maximal age-predicted RH - rest HR] X 100. CI was defined as values ⬍ 80%. MPS was considered abnl if there were reversible defects after the stress phase. We correlated the obtained results with the angio.The statistic analysis was performed by chi-square and Fisher tests and differences were considered significant at p⬍0,05. Results: From the 98 women, 67 had abnl EST and from those, 20 had presented abnl angio (31,2%),p⫽0,150. Sexty-two women had IC and from those, 29 (47%) with abnl angio, p⫽0,087. Both abnl EST and CI were present in 42 women ans from those, 30 (71,4%) had abnl angio, p⬍0,05. In the 42 pts of the group with abnl MPS, 39 (93%) presented an abnormal cine. p⫽0,001. Conclusion: The obtained results may suggest that CI adds information to EST in order to identify CAD in non-symptomatic diabetic women, but pharmacological stress MPS has shown a better rate of CAD identification. 5.18 PACEMAKER RELATED MYOCARDIAL PERFUSION DEFECTS WORSEN DURING HIGHER PACING RATE AND CORONARY FLOW AUGMENTATION TJF ten Cate, FC Visser, NM Panhuyzen-Goedkoop, JF Verzijlbergen, NM van Hemel St. Antonius Hospital Nieuwegein Background: Asynchronous activation resulting from RVA pacing can adversely affect left ventricular function and myocardial perfusion despite normal coronary arteries. This troubles the detection of coronary heart disease in paced patients. Methods: Fourteen patients with permanent RVA pacing with angiographically normal coronary arteries underwent myocardial perfusion SPECT at rest with low and high pacing rate, and with pacing at low rates with adenosine. Data were analysed semi-quantitatively using a 20 segment scoring model and coded using a 4-point scoring system. Results: At rest, 23 of 42 (55%) coronary flow territories showed abnormal perfusion and 52 of 280 (19%) corresponding segments demonstrated abnormal perfusion; mean perfusion score 0.22. After high rate pacing, perfusion was abnormal in 31 of 42 (74%) flow territories and 122 of 280 (44%) segments: mean perfusion score 0.67. Adenosine infusion resulted in 28 of 42 (67%) abnormal flow territories and 90 of 280 (32%) abnormal segments; mean perfusion score 0.44. Perfusion defects were most often observed in close proximity to the origin of the pacing site. Conclusion: RVA pacing results in myocardial perfusion defects. The false-positive findings are present at rest and more outspoken with high rate pacing than during adenosine infusion. Detection of coronary artery disease should be carried out with caution in RVA paced patients because of the high number of perfusion defects in the absence of coronary artery disease.
Abstracts
S105
5.19 ARTEFACTUAL MYOCARDIAL PERFUSION DEFECTS IN RIGHT VENTRICULAR APICAL PACING TJF ten Cate, FC Visser, NM van Hemel, JF Verzijlbergen St. Antonius Hospital Nieuwegein Background: It is generally accepted that myocardial perfusion is diminished in patients with a right ventricular apical pacemaker. The regions affected are those with an abnormal contraction pattern. This study aims to assess the effects of abnormal contraction pattern on myocardial perfusion imaging. Methods: Eight patients with a permanent dual chamber pacemaker with a right ventricular apical lead for bradytachycardia syndrome were studied. All underwent myocardial perfusion SPECT at rest with technetium-99sestamibi. Technetium-99m-sestamibi was injected at rest during normal atrio-ventricular (AV) conduction. Myocardial SPECT was performed during AAI pacing with a rate of 5 above the resting heart rate and repeated in DDD pacing mode with the same heart rate. The first pacing mode of perfusion imaging was randomized. Results: Myocardial perfusion at rest with normal AV conduction was normal in 6 patients. The average summed rest score (SRS) was 0.875. During abnormal AV activation, myocardial perfusion was abnormal in 3 patients. The SRS increased to 3. The summed motion (SMS) and summed thickness scores (STS) also increased from 3 to 7 and from 0.875 to 3.5. Conclusion: During normal atrio-ventricular conduction normal perfusion is found in most patients. Subsequent DDD-pacing obviously results in new perfusion defects despite the fact that tracer distribution is not changed. The defects are strongly related to abnormal wall motion and thickening. Which suggests that these perfusion defects must be caused by partial volume effect.
5.20 COMBINED DIPYRIDAMOLE-EXERCISE TC-99M SESTAMIBI GATED SPECT MYOCARDIAL PERFUSION IMAGING: HOW DOES IT COMPARE TO STANDARD VASODILATOR OR EXERCISE STRESS IN RISK STRATIFICATION? J Thompsen, H Athar, V Sainani, D O’Sullivan, I Leka, GV Heller Hartford Hospital, Hartford, CT Background: The prognostic value of standard exercise (EX) and vasodilator (VASO) SPECT is well established. However, there are few data on the utility of combining both modes of stress. We compared gated SPECT variables, outcomes and risk stratification between patients undergoing EX, VASO, or dipyridamole-exercise (DIP-EX). Methods: After excluding patients who underwent PCI or CABG ⱕ60 days after gated SPECT, 10,718 consecutive patients who underwent EX (n⫽5683), VASO (n⫽3220), or DIP-EX (n⫽1815) with Tc-99m sestamibi MPI were evaluated. Selection of stress modality was based on the perceived ability to exercise. Follow-up was 86.3% complete over 29⫾18 months. The patients had an age of 61⫾14 years, 49.9% were female and 25.4% had a history of MI, PCI or CABG. Risk stratification was examined using the summed stress score (SSS) and post-stress ejection fraction (EF). Images were classified as normal (SSSⱕ3 and EFⱖ50%) or abnormal (SSS3 or EF⬍50%). Patients were followed for cardiac death (CD) or myocardial infarction (MI). Results: A significant increase in the incidence of abnormal perfusion or function and worsening of SSS and EF was found between modes of stress, the lowest with EX and highest with VASO. The cumulative event rate was 1.9%, 3% and 6.9% with EX, DIP-EX (p⬍0.01 versus EX) and VASO (p⬍0.001 versus EX and DIP-EX), respectively. With each mode of stress,