ACCURACY OF EXERCISE-INDUCED LEFT AXIS QRS DEVIATION AS A SPECIFIC MARKER OF LEFT ANTERIOR DESCENDING CORONARY-ARTERY DISEASE

In this prospective study, we examined the diagnostic accuracy of exer cise-induced left QRS axis deviation as a marker of LAD coronary arter y stenosis. The mean frontal QRS axis of 66 consecutive patients with chest pain and exercise-induced ST segment depression referred for dia gnostic coronary angiography was analyzed and related to the angiograp hic findings. An exercise-induced leftward QRS axis deviation was foun d in 9/40 patients with and 0/26 patients without obstructive (greater than or equal to 70%) LAD disease (sensitivity 23%, specificity 100%, p = 0.025). In 7 of the 9 patients with left axis deviation, the lesi on was proximal to and in 2 in the region of the first septal perforat or. Inclusion of patients with 0 degrees exercise-induced QRS axis dev iation provided a more sensitive but less specific marker of LAD disea se [sensitivity 53% (21/40), specificity 81% (21/26), p = 0.015]. The findings were similar in patients with single and with multivessel cor onary artery disease. Grouping all patients in the present prospective and two previous retrospective studies (n = 165), the sensitivity was 29% and specificity 100% (p < 0.0001). Exercise-induced left QRS axis deviation was a highly specific marker of LAD coronary artery stenosi s.