The prognostic value of dispersion of repolarization in stress cardiomyopathy.

INTRODUCTION: Although abnormalities of ventricular repolarization are a hallmark of SC, their clinical impact on management remains to be determined. This study sought to evaluate the prognostic value of dispersion of repolarization in stress cardiomyopathy (SC) with regards to major cardiac events (MCE), recovery time, and recurrence. METHODS: This study analyzed data from258 patients with SC, from January 2009 to January 2018. Standard 12 lead ECG recordings during the acute, subacute, and recovery phases were collected for each eligible patient. Logistic regression was used to identify independent predictors of MCE, a composite of 30 day all-cause mortality, cardiogenic shock, life-threatening ventricular arrhythmias, and stroke. RESULTS: Among the 101 eligible patients (80.2% females, mean age 45.8 ± 11.5 years) in the study cohort, MCE occurred in 16 patients (15.8%). Cox regression analysis identified two independent predictors of MCE: increased ΔQT dispersion ≥ 40 ms (HR 1.31, 95% CI 1.05-9.77, p = 0.029) and increased Δnegative T wave amplitude dispersion ≤ -2.0 mV (HR 1.25, 95% CI 1.11-11.93, p = 0.018) during the subacute phase. The final regression model had good accuracy (sensitivity 81.3%, specificity 96.5%) and discriminative power (AUC 0.89, 95% CI 0.83-0.95). Kaplan-Meier analysis revealed that there was increasing MCE in patients with zero, one, or two predictors (log rank p < 0.001). In addition, patients with increased dispersion also had a significantly longer time to achieve complete recovery (21.4 ± 6.8 vs. 8.5 ± 4.3 days, p = 0.012) and a higher incidence of recurrence (31.3% vs. 2.4%, p = 0.011) of SC. CONCLUSION: Evaluation of dynamic changes of dispersion of repolarization is a simple bed-side tool with high predictive accuracy for prognostication of short term adverse outcomes, delayed recovery, and recurrence in patients with SC.

Fragmented QRS on electrocardiography as a predictor of myocardial scar in patients with hypertrophic cardiomyopathy.

Background: Fragmented QRS (fQRS) and Q waves are ECG findings in patients with myocardial scar. fQRS is more sensitive than pathological Q waves in detecting myocardial fibrosis in patients with coronary artery disease (CAD). Cardiac magnetic resonance (CMR) imaging is used for the diagnosis and for quantifying scar tissue in patients with HCM. Our aim was to correlate ECG parameters like fQRS and Q waves with the presence of late gadolinium enhancement (LGE) assessed by contrast CMR imaging to elucidate ECG markers which might predict scar tissue in HCM.Methods: This study is a retrospective analysis which included 39 patients who were diagnosed/suspected to have HCM on echocardiography and referred for contrast CMR imaging at our centre between 2010 and 2016. Presence of fQRS was correlated with scar demonstrated by LGE on CMR.Results: Twenty four (66.67%) patients had asymmetrical septal hypertrophy, 7 (19.44%) patients had apical involvement while 5 (13.89%) had concentric pattern. Only 4 (11.11%) patients had pathological Q waves in contiguous leads on surface ECG while fQRS in two contiguous leads was present in 23 (63.89%) patients. Presence of fQRS was more in patients with LGE on CMR than those without (84.61 versus 10%, p<.001). When presence of LGE in specific segments (anterior, lateral and inferior) was correlated with corresponding ECG leads, all the three segments showed significant correlation. The overall sensitivity, specificity, PPV and NPV of fQRS for predicting scar tissue were 84.6, 90.0, 95.6 and 69.2%, respectively.Conclusion: fQRS on surface ECG can be used as an indirect marker to predict the presence of fibrosis in HCM.

A novel prediction model for risk stratification in patients with a type 1 Brugada ECG pattern.

BACKGROUND: Risk stratification in Brugada syndrome remains a controversial and unresolved clinical problem, especially in asymptomatic patients with a type 1 ECG pattern. The purpose of this study is to derive and validate a prediction model based on clinical and ECG parameters to effectively identify patients with a type 1 ECG pattern who are at high risk of major arrhythmic events (MAE) during follow-up. METHODS: This study analysed data from 103 consecutive patients with Brugada Type 1 ECG pattern and no history of previous cardiac arrest. The prediction model was derived using logistic regression with MAE as the primary outcome, and patient demographic and electrocardiographic parameters as potential predictor variables. The model was externally validated in an independent cohort of 42 patients. RESULTS: The final model (Brugada Risk Stratification [BRS] score) consisted of 4 independent predictors (1 point each) of MAE during follow-up (median 85.3 months): spontaneous type 1 pattern, QRS fragments in inferior leads≥3,S wave upslope duration ratio ≥ 0.8, and T peak - T end ≥ 100 ms. The BRS score (AUC = 0.95,95% CI 0.0.92-0.98) stratifies patients with a type 1 ECG pattern into low (BRS score ≤ 2) and high (BRS score ≥ 3) risk classes, with a class specific risk of MAE of 0-1.1% and 92.3-100% across the derivation and validation cohorts, respectively. CONCLUSIONS: The BRS score is a simple bed-side tool with high predictive accuracy, for risk stratification of patients with a Brugada Type 1 ECG pattern. Prospective validation of the prediction model is necessary before this score can be implemented in clinical practice.

Familial atrioventricular nodal re-entrant tachycardia: A case seriers and a systematic review.

Multiple reports of familial clustering suggest that genetic factors may contribute in the pathogenesis of atrioventricular nodal re-entrant tachycardia (AVNRT). We report three cases of AVNRT in a father and his two sons along with a review of literature of other similar cases. Electrophysiological studies induced typical AVNRT, which was successfully eliminated by radiofrequency ablation in all of them. Of the 22 reported cases, 96% had typical (slow-fast) variant of AVNRT. The predominant pattern of inheritance appears to be autosomal dominant, though other patterns may exist. Further research is needed to understand the genetic influence of AVNRT and its pathophysiology.

An unusual type of accessory pathway in tricuspid atresia.

The occurrence of pre-excitation in tricuspid atresia (TA) is slightly more common than that in normal children. The accessory pathway (AP), when it occurs in the setting of congenital atrioventricular valvar disease, is usually ipsilateral to the side of the abnormal valve. This report describes a patient with TA who had pre-excitation due to a left-sided AP that masked and modified the typical electrocardiographic features. The electrophysiological study confirmed an epicardial left posterior AP that was successfully ablated with radiofrequency energy, through the coronary sinus. Left-sided APs including epicardial ones may rarely be seen in TA and can potentially cause difficulties due to lack of vascular access to the heart after the Fontan surgery if arrhythmias occur. They are amenable to successful radiofrequency ablation and need to be dressed prior to Fontan surgery. .