Safety and feasibility of atropine added in patients with sub-maximal heart rate during exercise myocardial perfusion SPECT.
BACKGROUND
Failure to reach 80% of maximal predicted heart rate (HR) during exercise may render a myocardial perfusion single photon emission computed tomography (SPECT) study non-diagnostic for ischemia detection. We sought to investigate the injection of atropine in patients who fail to achieve 80% of age-predicted HR during exercise performed for myocardial perfusion SPECT (MPS), defining its safety and efficacy to raise HR to adequate levels as well as its effect on MPS interpretation.


RESULTS
Between January 2002 and December 2004, we studied 3,150 consecutive patients (2,253 men and 897 women, mean age 55 +/- 6 years) who were referred to a single office-based nuclear cardiology laboratory for MPS using SPECT imaging. One milligram of atropine was administered to patients that were unable to continue because of fatigue before reaching minimal HR, without an ischemic response (group A, n = 397). The scintigraphic results for group A were compared with those of patients who spontaneously achieved target HR (group B, n = 2,753). In group A, mean HR before atropine injection was 119.5 +/- 13.6 beats per minute (bpm), and it increased up to 137.3 +/- 13.5 bpm after drug administration, with an incremental of 17.8 +/- 6.9 bpm (P < 0.0001). The mean percentage of age-related HR achieved in this group was 83.5 +/- 8.1%. In 302 of this patients (76.1%) more than 80% of their aged-related HR (86.9 +/- 5.1%) was attained. No major adverse effects occurred. When groups A and B were compared, baseline and peak HR, rate pressure product, and maximal metabolic equivalents achieved were higher in group B. There were no significant differences in the percentage of total positive perfusion studies between both groups: 210/397 patients (52.9%) in group A and 1,342/2,753 patients (48.7%) in group B (P = 0.39). Ischemia or ischemia plus scar was found in 112/397 patients (28.2%) in group A and in 923/2,753 patients (33.5%) of group B (P = 0.14).


CONCLUSIONS
Atropine added to exercise stress testing in patients who cannot achieve their 80% age-related HR is a safe, well-tolerated, and feasible method for MPS.
Sarullo
Filippo Maria
FM
Division of Cardiology, Buccheri La Ferla Fatebenefratelli Hospital, Via Salvatore Puglisi n.15, 90143 Palermo, Italy. fsarullo@neomedia.it
Ventimiglia
Corrado
C
Taormina
Andrea
A
Azzarello
Vincenzo
V
Felice
Filippo
F
Martino
Annamaria
A
Paterna
Salvatore
S
Di Pasquale
Pietro
P
D001145:Arrhythmias, Cardiac / Q000139:chemically induced; D001285:Atropine / Q000009:adverse effects; D001794:Blood Pressure / Q000187:drug effects; D018680:Cholinergic Antagonists / Q000009:adverse effects; D003326:Coronary Circulation / Q000187:drug effects*; D005080:Exercise Test / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000503:physiopathology; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D012107:Research Design; D012720:Severity of Illness Index; D015899:Tomography, Emission-Computed, Single-Photon
D018680:Cholinergic Antagonists; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C078700:technetium tc-99m tetrofosmin; D001285:Atropine