Publications

AIMS

First-degree atrioventricular block (AVB) has traditionally been considered a benign electrocardiographic finding in healthy individuals. However, the clinical significance of first-degree AVB has not been evaluated in patients with stable coronary heart disease. We investigated whether first-degree AVB is associated with heart failure (HF) and mortality in a prospective cohort study of outpatients with stable coronary artery disease (CAD).

METHODS AND RESULTS

We measured the P-R interval in 938 patients with stable CAD and classified them into those with (P-R interval ≥ 220 ms) and without (P-R interval <220 ms) first-degree AVB. Hazard ratios (HRs) and 95% confidence intervals were calculated for HF hospitalization and all-cause mortality. During 5 years of follow-up, there were 123 hospitalizations for HF and 285 deaths. Compared with patients who had normal atrioventricular conduction, those with first-degree AVB were at increased risk for HF hospitalization (age-adjusted HR 2.33: 95% CI 1.49-3.65; P= 0.0002), mortality [age-adjusted HR 1.58; 95% CI (1.13-2.20); P = 0.008], cardiovascular (CV) mortality [age-adjusted HR 2.33; 95% CI (1.28-4.22); P= 0.005], and the combined endpoint of HF hospitalization or CV mortality (age-adjusted HR 2.43: 95% CI 1.64-3.61; P ≤ 0.0001). These associations persisted after multivariable adjustment for heart rate, medication use, ischaemic burden, and QRS duration. Adjustment for left ventricular systolic and diastolic function partially attenuated the effect, but first-degree AVB remained associated with the combined endpoint of HF or CV death (HR 1.61, CI 1.02-2.54; P= 0.04).

CONCLUSION

In a large cohort of patients with stable coronary artery disease, first-degree AVB is associated with HF and death.

BACKGROUND

An unusual 12-lead electrocardiographic pattern may be present in patients with cavotricuspid isthmus (CTI)-dependent flutter.

OBJECTIVE

 Using baseline patient characteristics and echocardiography, we sought to study predictors of unusual electrocardiogram (ECG) characteristics in patients with CTI-dependent atrial flutter.

METHODS

 This was a dual-center, retrospective cohort study of 147 patients undergoing electrophysiology study and ablation for CTI-dependent atrial flutter.

RESULTS

Among this cohort, 23 patients (16%) had unusual 12-lead ECG characteristics. Using multivariate logistic regression, we found two clinical predictors for having an unusual ECG pattern. A clockwise (CW) pattern at time of electrophysiology study was the strongest predictor of an unusual ECG pattern (odds ratio 15.3, 95% confidence interval [CI] 4.0-59.4, P < 0.005). In addition, patients with decreased systolic function had a 3.5 greater odds (95% CI 1.1-11.5, P = 0.037) of having an unusual ECG pattern.

CONCLUSIONS

Our data demonstrate that among patients suffering from CTI-dependent atrial flutter who are referred for ablation, 16% will have unusual ECG patterns. Patients with CW atrial activation and left ventricle dysfunction have greater odds of manifesting unusual patterns by surface electrocardiogram.