Filtering electrocardiogram: Music, math, and ST-elevation myocardial infarction

Clinicians should have a basic understanding of the working principle of the instruments they use to avoid potential pitfalls caused by post-processing of the acquired biological signals. An electrocardiogram (ECG) is no exception; many different errors can arise during the acquisition or the processing of the ECG data, which may result in dangerous misdiagnoses. We present a case where the use of an inappropriate high-pass filter led to a false diagnosis of ST-elevation myocardial infarction. In addition, this report discusses the basic mechanisms of this frequently overlooked phenomenon and methods to avoid it

Macroscopic T-wave alternans in a patient presenting with hepatic encephalopathy

Macroscopic T-wave alternans (TWA) is the beat-to-beat variation in the amplitude or shape of the T wave on a surface electrocardiogram (ECG) and known to be a harbinger of impending malignant ventricular arrhythmias such as polymorphic ventricular tachycardia. We herein report a case with hepatic encephalopathy, who developed TWA, followed by polymorphic ventricular tachycardia

Prediction of mid-term outcome after cryo-balloon ablation of atrial fibrillation using post-procedure high-sensitivity troponin level

OBJECTIVE: High-sensitivity troponin I (hsTnI) assays lead to, among other things, improvement in the detection of myocardial injury and improved risk stratification of patients with atrial fibrillation (AF). The aim of this study was to investigate the association between post-procedure cardiac biomarkers and clinical outcome in patients undergoing cryo-balloon ablation (CA) for AF. METHODS: A total of 57 patients (mean age 55.1 ± 12.2 years, 50.9% female) with symptomatic paroxysmal AF underwent the CA procedure. Two hundred and twenty-eight pulmonary veins (PVs) were attempted for pulmonary vein isolation (PVI) with a second-generation cryo-balloon. hsTnI, CK-MB mass and myoglobin samples were prospectively obtained before and 24 hours after ablation. RESULT: At a mean follow up of 214.6 ± 24.3 days, the probability of being arrhythmia free after a single procedure was 86%. Post-ablation hsTnI (p = 0.001), left atrial (LA) diameter (p = 0.002), duration of AF (p = 0.002), mean minimal temperature of the left superior pulmonary vein (p = 0.005), and age (p = 0.021) were associated with increased AF recurrence rate. On multivariate analysis, lower hsTnI level was the only independent predictor for AF recurrence (p = 0.012). Post-ablation hsTnI levels lower than 4.40 ng/ml predicted AF recurrence during follow up, with a sensitivity of 86% and a specificity of 96%. CONCLUSION: It is well recognised that the PV antrum contributes to initiation and/or perpetuation of AF. A lower postablation hsTnI level may predict an increased AF recurrence rate, suggesting inadequate ablation of the PV antrum. This may be used as a non-invasive marker to predict the outcome of AF

Association between integrated backscatter and arrhythmia in patients with ischemic dilated cardiomyopathy

Background Ventricular scars due to myocardial infarction provide a substrate for ventricular arrhythmias, and cardiac magnetic resonance (CMR) is the golden standard for the quantification of scar tissue magnitude. CMR has still limitations with patients with ICD despite ICD's becoming MR-compatible. We investigated the association between calibrated integrated backscatter (cIBS) and arrhythmia frequency in patients with ICD

Association between integrated backscatter and arrhythmia in patients with ischemic dilated cardiomyopathy.

Background Ventricular scars due to myocardial infarction provide a substrate for ventricular arrhythmias, and cardiac magnetic resonance (CMR) is the golden standard for the quantification of scar tissue magnitude. CMR has still limitations with patients with ICD despite ICD's becoming MR-compatible. We investigated the association between calibrated integrated backscatter (cIBS) and arrhythmia frequency in patients with ICD