Background and Objective: Occurrence of atrioventricular block due to arterial blood pressure or left ventricular systolic dysfunction in patients treated with beta-blockers, calcium channel blockers or Digoxin has been investigated throughout a number of studies. As determination of block level is particularly important in determining how to treat patients, this study was launched to evaluate the diagnostic accuracy of electrocardiography (ECG) in non-invasive determination of the block level in patients with atrioventricular block induced with the aforementioned drugs.

Materials and Methods: This analytic cross-sectional study was conducted on 42 patients with atrioventricular block treated with beta-blockers, calcium channel blockers or digoxin drugs referred to Rasht Dr. Heshmat hospital in 2014. After taking ECG from all patients, they underwent electrophysiology (EPS) and their block level was calculated. Diagnostic accuracy of ECG in determining the block level in comparison to EPS as a gold standard was investigated.

Results: Forty-two cases (16 male and 26 female with mean age of 74±4 years) were included. Beta blockers were the most frequent drugs used with atenolol as the prominent one (40.5%). The most frequent presentations were vertigo or light headache (28.6%). Many cases showed normal QRS complex morphology (38.1%). The mean duration of QRS complex was 117.7±29.9 ms and most of cases suffered from block grade III (76.2%). The ECG diagnostic accuracy in block level determination had 68% sensitivity, 85.7% specificity, 57% negative predictive value and 90.5% positive predictive value.

Conclusion: Results showed the high accuracy of ECG findings in determining block level. In this study, the sensitivity of ECG was higher in men, whereas in women the specificity was higher. Considering that ECG is a noninvasive method, it is recommended that in cases with limitations of using invasive methods, this method can be employed.