Validation of electrocardiographic criteria for identifying left ventricular dysfunction in patients with previous myocardial infarction.

BACKGROUND: Eleven criteria correlating electrocardiogram (ECG) findings with reduced left ventricular ejection fraction (LVEF) have been previously published. These have not been compared head-to-head in a single study. We studied their value as a screening test to identify patients with reduced LVEF estimated by cardiac magnetic resonance (CMR) imaging. METHODS: ECGs and CMR from 548 patients (age 61 + 11 years, 79% male) with previous myocardial infarction (MI), from the DETERMINE and PRE-DETERMINE studies, were analyzed. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of each criterion for identifying patients with LVEF ≤ 30% and ≤ 40% were studied. A useful screening test should have high sensitivity and NPV. RESULTS: Mean LVEF was 40% (SD = 11%); 264 patients (48.2%) had LVEF ≤ 40%, and 96 patients (17.5%) had LVEF ≤ 30%. Six of 11 criteria were associated with a significant lower LVEF, but had poor sensitivity to identify LVEF ≤ 30% (range 2.1%-55.2%) or LVEF ≤ 40% (1.1%-51.1%); NPVs were good for LVEF ≤ 30% (range 82.8%-85.9%) but not for LVEF ≤ 40% (range 52.1%-60.6%). Goldberger's third criterion (RV4/SV4 < 1) and combinations of maximal QRS duration > 124 ms + either Goldberger's third criterion or Goldberger's first criterion (SV1 or SV2 + RV5 or RV6 ≥ 3.5 mV) had high specificity (95.4%-100%) for LVEF ≤ 40%, although seen in only 48 (8.8%) patients; predictive values were similar on subgroup analysis. CONCLUSIONS: None of the ECG criteria qualified as a good screening test. Three criteria had high specificity for LVEF ≤ 40%, although seen in < 9% of patients. Whether other ECG criteria can better identify LV dysfunction remains to be determined.

A Rare Case Report of Flecainide-Induced Left Bundle Branch Block (LBBB) and Transient Cardiomyopathy.

Flecainide is an antiarrhythmic agent that has been reported to have numerous cardiotoxic effects, including the development of arrhythmias and the reduction of left ventricular ejection fraction (LVEF). However, it is not commonly reported as a cause for left bundle branch block and cardiomyopathy. In this case report, we present the case of a 67-year-old female patient who developed transient cardiomyopathy and left bundle branch block (LBBB) secondary to flecainide therapy. The patient's condition improved upon cessation of flecainide.

The effect of head-upright tilt table testing for vasovagal syncope on P-wave duration.

Fluid shifts in vasovagal syncope may be reflected in electrocardiographic P-wave duration. We examined the effect of head-upright tilt-table testing (HUT) on P-wave duration among patients with positive or negative HUT. P-wave duration was measured at baseline and several post-HUT time points. In patients with a positive HUT, the test was immediately discontinued. P-wave duration measurements obtained at the completion of the test or when symptoms occurred were compared to baseline measurements. The P-wave duration among patients with a positive HUT was significantly reduced at the onset of symptoms as compared to baseline (-14.0 ms, P = .0054) and 2-minute tilt measurements (-11.3 ms, P = .0246). P-wave duration measurements were not reduced in patients experiencing a negative HUT at any follow-up time. We showed a significant reduction in P-wave duration among patients experiencing positive HUT that suggests a dynamic relationship between atrial volume and P-wave duration.