Pacemaker-related myocardial perfusion defects worsen during higher pacing rate and coronary flow augmentation.
BACKGROUND
Asynchronous activation resulting from right ventricular apical (RVA) pacing can adversely affect left ventricular function and myocardial perfusion despite normal coronary arteries. This situation makes detection of coronary heart disease in paced patients difficult.


OBJECTIVE
The purpose of this study was to assess the distribution, extent, and severity of myocardial perfusion defects with RVA pacing at low and high rates and increased coronary blood flow with adenosine.


METHODS
Fourteen patients with permanent RVA pacing and angiographically normal coronary arteries underwent myocardial perfusion single-photon emission computed tomography at rest at low and high pacing rates and with pacing at low rates with adenosine. Data were analyzed semi-quantitatively using a 20-segment scoring model and coded using a four-point scoring system.


RESULTS
At rest, 23 (55%) of 42 coronary flow territories showed abnormal perfusion and 52 (19%) of 280 corresponding segments demonstrated abnormal perfusion; mean perfusion score was 0.22. After high-rate pacing, perfusion was abnormal in 31 (74%) of 42 flow territories and 122 (44%) of 280 segments; mean perfusion score was 0.67. Adenosine infusion resulted in 28 (67%) of 42 abnormal flow territories and 90 (32%) of 280 abnormal segments; mean perfusion score was 0.44. Perfusion defects were observed most often in close proximity to the origin of the pacing site.


CONCLUSIONS
RVA pacing results in myocardial perfusion defects. The false-positive findings are present at rest and more obvious with high-rate pacing than during adenosine infusion. Detection of coronary artery disease should be performed with caution in RVA paced patients because of the high number of perfusion defects observed in the absence of coronary artery disease.
ten Cate
Tim J F
TJ
Department of Nuclear Medicine, St. Antonius Hospital Nieuwegein, Nieuwegein, The Netherlands.
Visser
Frans C
FC
Panhuyzen-Goedkoop
Nicole M
NM
Verzijlbergen
J Fred
JF
van Hemel
Norbert M
NM
D000241:Adenosine / Q000008:administration & dosage; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002304:Cardiac Pacing, Artificial; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006352:Heart Ventricles / Q000187:drug effects / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D007431:Intraoperative Complications / Q000209:etiology / Q000503:physiopathology; D015428:Myocardial Reperfusion Injury / Q000209:etiology* / Q000503:physiopathology; D010138:Pacemaker, Artificial / Q000009:adverse effects*
D000889:Anti-Arrhythmia Agents; D000241:Adenosine