Noninvasive assessment of left ventricular performance in patients with ischemic heart disease: Ear densitographic study during uninterrupted treadmill exercise

Among 738 consecutive patients with chest pain referred for exercise testing, only 17 men fulfilled strict criteria for this pilot study: (1) achievement of at least 90 percent of age-predicted maximal heart rate or etectrocardtographic criteria for a positive test; (2) subsequent coronary anglography; (3) exclusion of prior heart disease; and (4) absence of medication. Measurements of systolic time intervals obtained with ear densitography during early exercise differentiated 10 patients with coronary artery disease (Group 1) from 17 men (7 patients plus 10 normal volunteers) with normal coronary arteries (Group 2). Despite nearly identical heart rate and blood pressure responses In both groups, men In Group 1 had a significantly greater reduction of preelection period (PEP) at 1 minute and 4 minutes as well as a greater decrease hi PEP/LVET (left ventricular ejection time) ratio. Differences were most significant when expressed as percent change of $\text{PEP}\text{LVET}$ ratio from control value (p <0.001 at both 1 minute and 4 minutes). After 4 minutes, men in Group 1 had no further decrease in $\text{PEP}\text{LVET}$ ratio and in 8 of the 10 men $\text{PEP}\text{LVET}$ ratio then increased to peak exercise. By contrast, $\text{PEP}\text{LVET}$ ratio continued to decrease to peak exercise in men In Group 2. The early floor in $\text{PEP}\text{LVET}$ ratio In Group 1 represents limited functional reserve and the subsequent increase suggests functional deterioration. Thus, densHographic systolic time interval measurements during uninterrupted exercise in unmedlcated subjects appear to improve the sensitivity and specificity of the conventional treadmill test.