Seismocardiographic changes associated with obstruction of coronary blood flow during balloon angioplasty.
Seismocardiography, a new noninvasive technique, detects low-frequency cardiac vibrations on the chest wall during ventricular contraction and during both early and late ventricular filling. To evaluate the ability of seismocardiography to detect ischemia caused by decreased coronary blood flow, 35 patients were studied during coronary angioplasty. Seismocardiograms and electrocardiograms were recorded twice at baseline, with the catheter across the lesion before first inflation (n = 15), every 30 seconds during the first inflation, 1 and 2 minutes after the first inflation and greater than or equal to 5 minutes after the final inflation. For comparison, sequential seismocardiograms were also obtained from 15 healthy volunteers. Electrocardiograms were blindly scored for ST change from baseline (0 = none, 1 = 0.5 mm ST depression, 2 = greater than or equal to 1.0 mm ST depression, 3 = ST elevation). Seismocardiograms were blindly scored for change from baseline (0 = none, 1 = mild, 2 = moderate, 3 = marked) for both the systolic and diastolic waves. The average maximal systolic seismocardiographic score was 2.5 +/- 0.8 for patients who had undergone angioplasty and 1.0 +/- 0.9 for volunteers (p less than 0.001). The average maximal diastolic seismocardiographic score was 2.3 +/- 0.8 for angioplasty patients and 0.7 +/- 0.9 for volunteers (p less than 0.001). The percentage of angioplasty patients with electrocardiographic, systolic and diastolic seismocardiographic scores greater than or equal to 2 was, respectively: 0, 11 and 14% at second baseline; 23, 67 and 53% with catheter across the lesion; 44, 75 and 59% after 30 seconds of inflation; 42, 71 and 61% after 60 seconds of inflation; 23, 74 and 61% after 1 minute of deflation; and 0, 71 and 47% 5 minutes after final inflation.(ABSTRACT TRUNCATED AT 250 WORDS)