Journal of electrocardiology
-
An 83-year-old woman with chronic left bundle branch block and remote history of pacemaker implantation for intermittent AV block was hospitalized for fatigue and leg swelling. She had no cardiac complaints. Routine 12-lead electrocardiogram showed sinus rhythm with left bundle branch block. ⋯ The electrocardiographic changes were consistent with cardiac memory. This case is unique because cardiac memory in patients with intermittent left bundle branch block typically occurs when the QRS complexes normalize and not during left bundle branch block itself. Our findings indicate that memory Ts can develop not only after normalization of wide complex rhythms but also with alternating wide complex rhythms as in the presented case where a ventricular paced rhythm was replaced by left bundle branch block.
-
Pre-hospital 12-lead ECG interpretation is important because pre-hospital activation of the coronary catheterization laboratory reduces ST-segment elevation myocardial infarction (STEMI) discovery-to-treatment time. In addition, some ECG features indicate higher risk in STEMI such as proximal left anterior descending (LAD) culprit lesion location. The challenging nature of the pre-hospital environment can lead to noisier ECGs which make automated STEMI detection difficult. We describe an automated system to classify lesion location as proximal LAD, LAD, right coronary artery (RCA) and left circumflex (LCx) and test the performance on pre-hospital 12-lead ECG. ⋯ Although our test database is not large, algorithm performance suggests culprit lesion location can be reliably determined from pre-hospital ECG. Further research is needed however to evaluate the impact of automated culprit lesion location on patient treatment and outcomes.
-
Left ventricular hypertrophy (LVH) induces changes in the depolarization and repolarization of the heart that alter the resting electrocardiogram (ECG). These changes include widening of the QRS duration, an increase in the QRS amplitude and secondary changes in the ST segment and T waves. Typically, there is ST segment depression and T wave inversion (or biphasic T waves) in the lateral leads and ST segment elevation (STE) in the precordial leads V1-V3. ⋯ These changes may vary over time and may not necessarily reflect acute ischemia. The ST-T changes secondary to LVH interfere with ECG interpretation and may affect our accuracy in diagnosing STEMI and other forms of active ischemia. The current guidelines specify thresholds for STE in patients without LVH for whom acute reperfusion therapy is indicated; however, there are no such thresholds for patients with LVH.
-
Takotsubo cardiomyopathy (TC) is a recently recognized novel cardiac syndrome characterized by transient left ventricular dysfunction without obstructive coronary disease, electrocardiographic (ECG) changes (ST-segment elevation and/or negative T wave) or elevated cardiac enzymes. Because the clinical features and ECG findings of TC mimic those of anterior acute myocardial infarction (AMI) with occlusion of the left anterior descending coronary artery, differential diagnosis has an important role in selecting the most appropriate treatment strategy. ⋯ Although it has been suggested that ECG does not allow reliable differentiation between TC and anterior AMI, several ECG criteria distinguishing TC from anterior AMI have been proposed. In this review, we discuss ECG findings of TC, especially in the acute phase, compare them with those of anterior AMI, and identify ECG features that may facilitate early recognition of this disease.
-
Cornell product criteria, Sokolow-Lyon voltage criteria and electrocardiographic (ECG) strain (secondary ST-T abnormalities) are markers for left ventricular hypertrophy (LVH) and adverse prognosis in population studies. However, the relationship of regression of ECG LVH and strain during antihypertensive therapy to cardiovascular (CV) risk was unclear before the Losartan Intervention for Endpoint Reduction in Hypertension (LIFE) study. We reviewed findings on ECG LVH regression and strain over time in 9193 hypertensive patients with ECG LVH at baseline enrolled in the LIFE study. ⋯ After controlling for treatment with losartan or atenolol, for baseline Framingham risk score, Cornell product, and Sokolow-Lyon voltage, and for baseline and in-treatment systolic and diastolic blood pressure, 1 standard deviation (SD) lower in-treatment Cornell product was associated with a 14.5% decrease in the composite endpoint (HR. 0.86, 95% CI [0.82-0.90]). In a parallel analysis, 1 SD lower in-treatment Sokolow-Lyon voltage was associated with a 16.6% decrease in the composite endpoint (HR. 0.83, 95% CI [0.78-0.88]). The LIFE study shows that evaluation of both baseline and in-study ECG LVH defined by Cornell product criteria, Sokolow-Lyon voltage criteria or ECG strain improves prediction of CV events and that regression of ECG LVH during antihypertensive treatment is associated with better outcome, independent of blood pressure reduction.