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Preserved diagnostic utility of dobutamine stress echocardiography in pacemaker-dependent patients with absolute
H Oral1, W F Armstrong, D S Bach
1Division of Cardiology, Department of Medicine, University of Michigan, USA.
Insights
Dobutamine stress echocardiography (DSE) remains a valuable tool for diagnosing and predicting cardiac events in pacemaker-dependent patients with absolute chronotropic incompetence, even without heart rate increases.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Clinical Medicine
Background:
- Dobutamine stress echocardiography (DSE) mechanism involves chronotropy and inotropy.
- Limited data exist on DSE efficacy in pacemaker patients with absolute chronotropic incompetence (ACI).
- Pacemaker dependency and ACI can affect heart rate response during stress testing.
Purpose of the Study:
- To evaluate the diagnostic and prognostic utility of DSE.
- To assess DSE in patients with fixed-rate pacemakers and ACI.
- To determine if DSE can identify inducible ischemia despite lack of HR increase.
Main Methods:
- Retrospective analysis of 22 pacemaker-dependent patients with fixed heart rates during DSE (1990-1997).
- Review of myocardial perfusion SPECT and coronary angiography when available.
- Clinical follow-up for adverse ischemic cardiac events.
Main Results:
- 50% of patients showed inducible ischemia on DSE despite ACI.
- DSE demonstrated 100% sensitivity and 60% specificity for detecting coronary artery disease.
- No adverse ischemic events occurred in patients with negative DSE findings during follow-up.
Conclusions:
- DSE retains diagnostic value in pacemaker-dependent patients with ACI.
- DSE provides prognostic information regarding ischemic cardiac events.
- The study supports the use of DSE in this challenging patient population.
Background:
The mechanism by which dobutamine induces ischemia is thought to depend on both increased chronotropy and inotropy. No data have been reported on the diagnostic power of dobutamine stress echocardiography (DSE) among patients with fixed-rate pacemakers and absolute chronotropic incompetence. The purpose of this study was to determine the diagnostic and prognostic utility of DSE in patients with fixed-rate, demand ventricular pacing who had no heart rate (HR) increase during DSE.
Methods:
From 1990 to 1997, 22 patients remained pacemaker dependent with a fixed HR (69.7 +/- 5.7 beats/min) throughout DSE. Myocardial perfusion single-photon emission computed tomography and coronary angiographic studies were reviewed when available. Clinical follow-up was determined for all patients at 15.4 +/- 7.7 months.
Results:
In spite of absolute chronotropic incompetence during DSE, 11 (50%) of 22 patients had test results consistent with inducible ischemia. Coronary artery disease was confirmed in 6 (75%) of 8 who had coronary angiograms. Three of 11 patients with negative DSE underwent coronary angiography that confirmed the absence of significant coronary artery disease. DSE had a sensitivity of 100% and specificity of 60% in pacemaker-dependent patients with absolute chronotropic incompetence. At the time of clinical follow-up, none of the patients with no inducible ischemia on DSE had an adverse ischemic cardiac event.
Conclusions:
This study suggests that DSE has preserved diagnostic and prognostic utility in pacemaker-dependent patients with absolute chronotropic incompetence.