[Diagnostic value and safety of stress echocardiography protocol based on rapid pacing in patients with implanted...

Assessment of safety and diagnostic value of stress echocardiography protocol based on rapid pacing in patients with implanted permanent pacemakers operating in AAI/DDD and VVI modes.

88 rapid pacing stress echo tests were performed in 60 patients (39M, 21F, aged 47-79, mean 64 +/- 9 years), utilizing permanent pacemakers. Left ventricular segmental contractility was assessed at rest and during 100/min and 85% of predicted maximal heart rate. Each pacing stage lasted for 3minutes. The test was performed with the use of AAI/DDD or VVI pacing mode and then repeated with WV mode in pts with DDD pacemaker. Coronary stenosis of at least 50% was considered significant. Mean duration of the test was 9.9 +/- 1.7 min, including 6.7 +/- 1.4 min of pacing.

No severe adverse effects were observed. Among 88 tests performed, AAI/DDD modes were used in 41 and VVI mode in 47 were as significant increase of the heart rate comparing to baseline was achieved - 68 vs 129/min; p<0.0001, including patients treated with beta-blockers - 69 vs 128/min; p < 0.0001. No significant differences in systolic blood pressure were found between rest and stress (126 vs 126 mm Hg). In 58 patients (66%) the test was considered positive for ischemia, in 29 (33%), negative and in 1 (1%) nondiagnostic. Sensitivity, specificity, accuracy, positive and negative predictive values were respectively: 92%, 66%, 79%, 78% i 86%. For AAI/ DDD modes the above values calculated for the entire group were: 95%, 75%, 85%, 79%, 94%, while for VVI mode they were: 90%, 56%, 73%, 76%, 77% (NS). In the presence of left ventricular hypertrophy the accuracy was 79% for AAI/DDD and 71% for VVI mode, and in patients without hypertrophy 92% and 74% respectively.

A stress echo protocol using permanent pacemaker for rapid pacing is a brief and safe diagnostic technique. Accuracy of the test is similar regardless of the pacing mode used. The test can be utilized as a technique of choice for noninvasive diagnostics of coronary disease in patients with permanent pacemakers.