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. Author manuscript; available in PMC: 2012 Jun 1.

Published in final edited form as: Circ Arrhythm Electrophysiol. 2011 Mar 23;4(3):407–417. doi: 10.1161/CIRCEP.109.934208

Body surface versus intracardiac alternans detection. (A) Probability that a body surface lead is positive for RA given that the corresponding intracardiac lead is positive for RA, for each of the RV, CS, LV, EPI, and triangular RV-CS far-field intracardiac lead configurations. Error bars define 95% confidence intervals. (B) Probability that a body surface lead is positive for RA given a specified number of far-field intracardiac leads is positive for RA. The greater the number of positive for RA far-field intracardiac lead configurations, the greater the probability that RA is seen on the body surface. (C) Probability that an intracardiac lead configuration is positive for RA given that RA is seen on the body surface, for each of the RV, CS, LV, EPI, and triangular RV-CS far-field intracardiac lead configurations (N=7225, overall sample size). The RV-CS positive percentage was significantly larger than for the CS configuration (p=0.006, χ₁²=7.58, MO), and trended toward statistical significance for RV-CS vs. RV (p=0.090, χ₁²=2.87, MO), RV-CS vs. LV (p=0.056, χ₁²=3.64, MO), and RV-CS vs. EPI (p=0.154, χ₁²=2.03, MO) comparisons. (D) Probability that at least X far-field intracardiac leads are positive for RA given that RA is seen on the body surface, where X = 1, 2, 3, 4, or all intracardiac leads. (E) Probability that a far-field bipolar intracardiac lead is positive for RA, given that at least one intracardiac far-field lead is positive for RA, for each of the RV, CS, LV, EPI, and triangular RV-CS far-field intracardiac lead configurations. The RV-CS positive percentage was significantly larger than for the RV configuration (p=0.040, χ₁²=4.23, MO), the CS configuration (p=0.004, χ₁²=8.16, MO), and the LV configuration (p=0.035, χ₁²=4.46, MO), but not for the EPI configuration (p=0.270, χ₁²=1.22, MO). Statistically significant comparisons are marked by an *.

Body surface versus intracardiac alternans detection. (A) Probability that a body surface lead is positive for RA given that the corresponding intracardiac lead is positive for RA, for each of the RV, CS, LV, EPI, and triangular RV-CS far-field intracardiac lead configurations. Error bars define 95% confidence intervals. (B) Probability that a body surface lead is positive for RA given a specified number of far-field intracardiac leads is positive for RA. The greater the number of positive for RA far-field intracardiac lead configurations, the greater the probability that RA is seen on the body surface. (C) Probability that an intracardiac lead configuration is positive for RA given that RA is seen on the body surface, for each of the RV, CS, LV, EPI, and triangular RV-CS far-field intracardiac lead configurations (N=7225, overall sample size). The RV-CS positive percentage was significantly larger than for the CS configuration (p=0.006, χ₁²=7.58, MO), and trended toward statistical significance for RV-CS vs. RV (p=0.090, χ₁²=2.87, MO), RV-CS vs. LV (p=0.056, χ₁²=3.64, MO), and RV-CS vs. EPI (p=0.154, χ₁²=2.03, MO) comparisons. (D) Probability that at least X far-field intracardiac leads are positive for RA given that RA is seen on the body surface, where X = 1, 2, 3, 4, or all intracardiac leads. (E) Probability that a far-field bipolar intracardiac lead is positive for RA, given that at least one intracardiac far-field lead is positive for RA, for each of the RV, CS, LV, EPI, and triangular RV-CS far-field intracardiac lead configurations. The RV-CS positive percentage was significantly larger than for the RV configuration (p=0.040, χ₁²=4.23, MO), the CS configuration (p=0.004, χ₁²=8.16, MO), and the LV configuration (p=0.035, χ₁²=4.46, MO), but not for the EPI configuration (p=0.270, χ₁²=1.22, MO). Statistically significant comparisons are marked by an *.