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D H Spodick

Publications and source records attributed to D H Spodick.

At least 379 records · Page 21Linked to original sources
PubMed1978

Effects of recording speed on precision of time-based polycardiographic measurements. Optimal paper speeds for measuring points and intervals.

Optimal paper speeds have not been established for all time-based measurements of the cardiac cycle by appropriately designed observer performance studies. In 10 subjects (5 normals and 5 cardiac patients) carotid pulse, phonocardiogram, and electrocardiogram were recorded on magnetic tape for measurement of all fiducial points for systolic time intervals, the systolic time intervals themselves, the pulse transmission time, cycle length (RR), qR time, and R-to-point versus q-to-point measurements at recording speeds of 25, 50, 75, 100, and 200 mm/s. Tracings were coded numerically and randomised. Three observers measured all points and calculated intervals in a sequence determined by individual tables of random numbers. Left ventricular ejection time was the only calculation that could be made at 25 mm/s statistically equally well as at all other speeds. The smallest numerical observer differences occurred uniformly at 100 mm/s paper speed when all recording speeds were considered. However, after excluding the 25 mm/s speed there were no significant differences among point measurements. Measurements of points from R (rather than q) reduced observer variability. We conclude that for point measurements, for systolic time intervals, pulse transmission time, and RR interval, recording speed between 50 and 200 mm/s showed no statistical differences, though smallest numerical differences occurred at 100 mm/s. For LVET, 25 mm/s was satisfactory.

Adult↗
PubMed1978

Cardiac response during uninterrupted treadmill exercise and recovery: measurement by systolic time intervals.

In 12 normal subjects, use of ear densitography permitted measurement of systolic time intervals (STI) during uninterrupted treadmill exercise to over 90 percent maximal heart rate on a modified Bruce protocol. Results for control (sitting leads to standing) leads to end-exercise at 18 minutes leads to 10 minutes' sitting recovery were--heart rate (HR): (77 leads to 861 leads to 171 leads to 98 beats per minute; preejection period (PEP): (106 leads to 111) leads to 49 leads to 110 msec; ejection time index (ETI) (351 leads to 330) leads to 380 leads to 366 msec; PEP/LVET (0.42 leads to 0.49) leads to 0.29 leads to 0.45. Heart rate increased steadily to 18 minutes. In contrast, the PEP/LVET decrease was almost complete by three minutes and both ETI and PEP responses were bimodal with respective plateaus between three and six minutes and three and nine minutes. All STI and HR curves showed rapid restitution during early recovery. The changes during treadmill exercise were numerically comparable to those during bicycle exercise at a common heart rate. The results indicate that it is technically feasible to measure systolic time intervals with precision during uninterrupted treadmill exercise; responses to treadmill exercise were in the direction expected and quantitatively comparable to bicycle exercise at comparable stress level. These obervations provide the technical and physiologic bases for applying this method in clinical treadmill exercise testing.

Adult↗