The aim of this study was to assess the utility, safety and prognostic value of echocardiographic stress test (EST) in non-invasive diagnosis of ischemic heart disease in patients (pts) with implanted pacemaker, with and without left ventricle hypertrophy.
Material and methods: EST was performed in 40 patients (mean age 60+/-10 years, from 43 to 78) with pacemaker. Using external programming system heart rate was accelerated by 10 beats in every 3 minute till reaching maximal heart rate. The examination was conducted only in patients with physiological stimulation of right atrium by AAI mode. Angiographically significant coronary artery stenosis size was accepted as over 50% artery diameter. Mean duration time of performed examination was 13+/-4 min.
Results: No adverse events were observed. The quality of stress echo visualization was good in every case. Heart rate at rest and at maximal stimulation were respectively 68+/-8 and 132+/-13 per minute (p<0.0001) and systolic blood pressure pressure 140+/-13 and 142+/-13 mmHg (ns). In 10 (25%) pts the result was positive, in 24 (60%) negative, and in 6 (15%) - non-diagnostic. Non-diagnostic result of the test was due to pacemaker limitation (1 pts), and achieving Wenckebach point (5 pts). Test specificity was 95%, sensitivity 69%, accuracy - 85%. Significant occlusion in coronary angiography were observed in 40% pts (including 1-vessel disease - 12,5%). In left ventricle hypertrophy group (n=19), the EST accuracy was 87% (without significant difference with non-hypertrophy group). In the group with beta blockers therapy (n=16) the observed accuracy was 93%. The follow-up time was 963+/-497 days. The prognostic value of positive EST result for cardiac events was 80%, and for negative - 100%. None of the pts with negative stress echo result suffered any cardiac event.
Conclusions: EST is a safe, short lasting examination with good quality of echo visualization. This method seems to be of important value in diagnosing the ischaemic heart disease in pts with pacemaker, also with left ventricle hypertrophy and obligatory beta blockers medication.