Journal of electrocardiology
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Review Case Reports
Arrythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) and cathecholaminergic polymorphic ventricular tachycardia (CPVT): A phenotypic spectrum seen in same patient.
ARVD/C and CPVT are rare inheritable sudden cardiac death syndromes predominantly expressed in younger individuals. ARVD/C is characterized by a progressive fibrofatty replacement of the myocardium that predisposes to ventricular tachycardia while CPVT is characterized by exercise induced bidirectional/polymorphic ventricular tachycardia (VT) and a structurally normal heart. A mutation in different genes causes these syndromes but recently, mutation in a common gene RYR2 has been associated with both disorders and it has been suggested that CPVT and ARVD/C represent a phenotypic spectrum. We present a case unique in expressing both these phenotypes.
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The J-wave pattern on 12-lead ECG is traditionally defined as a positive deflection at junction between the end of the QRS and the beginning of the ST-segment. This pattern has recently been associated with increased risk for idiopathic ventricular fibrillation in the absence of cardiovascular disease. The interest for the clinical significance of J-wave pattern as a potential ECG hallmark of high risk for cardiac arrest has recently been reinforced by the growing practice of ECG screening, such as occurs in large population of young competitive athletes. ⋯ Furthermore the J-wave pattern has been demonstrated to be a dynamic phenomenon related to the training status, with the larger prominence at the peak of training and with an inverse relation between magnitude of J-wave and heart rate. In addition the J-wave pattern is usually associated with other ECG changes, such as increased QRS voltages and ST-segment elevation, as well as LV remodeling, suggesting that it likely represents another expression of the physiologic athlete's heart. Finally the scientific data available demonstrated that during a medium follow-up period the J-wave pattern does not convey risk for adverse cardiac events, including sudden death or ventricular tachyarrhythmias.
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Review Comparative Study
Development of three methods for extracting respiration from the surface ECG: a review.
Respiration rate (RR) is a critical vital sign that can be monitored to detect acute changes in patient condition (e.g., apnea) and potentially provide an early warning of impending life-threatening deterioration. Monitoring respiration signals is also critical for detecting sleep disordered breathing such as sleep apnea. Additionally, analyzing a respiration signal can enhance the quality of medical images by gating image acquisition based on the same phase of the patient's respiratory cycle. Although many methods exist for measuring respiration, in this review we focus on three ECG-derived respiration techniques we developed to obtain respiration from an ECG signal. ⋯ Over the last five years, we have performed six studies using the above methods: 1) In 1907 sleep lab patients with >1.5M 30-second epochs, EDR achieved an apnea detection accuracy of 79%. 2) In 24 adult polysomnograms, use of EDR and chest belts for RR computation was compared to airflow RR; mean RR error was EDR: 1.8±2.7 and belts: 0.8±2.1. 3) During cardiac MRI, a comparison of EMGDR breath locations to the reference abdominal belt signal yielded sensitivity/PPV of 94/95%. 4) Another comparison study for breath detection during MRI yielded sensitivity/PPV pairs of EDR: 99/97, RSA: 79/78, and EMGDR: 89/86%. 5) We tested EMGDR performance in the presence of simulated respiratory disease using CPAP to produce PEEP. For 10 patients, no false breath waveforms were generated with mild PEEP, but they appeared in 2 subjects at high PEEP. 6) A patient monitoring study compared RR computation from EDR to impedance-derived RR, and showed that EDR provides a near equivalent RR measurement with reduced hardware circuitry requirements.
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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.
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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.