Search

Background: Prolonged repolarization duration is a significant total mortality (TM) predictor in post-myocardial infarction patients.Aim: We examined the clinical significance of QT interval that was extracted from a Short Resting Holter ECG (SRH ECG - 30-min duration) as a TM predictor in heart failure (HF) patients.Methods: One hundred forty-five HF patients (male = 84%, mean age = 64 ± 12 years, mean LVEF = 33 ± 10%) underwent an SRH ECG recording for 30 min. These high-resolution ECG signals were analyzed and the QT interval was calculated and corrected according to the Fridericia formula. After 42.1 months, 26 patients died.Results: Univariate analysis for Deceased and Living groups: QTc:455 ± 33 ms vs 441 ± 32 ms (p = 0.04), LVEF:32 ± 10% vs 34 ± 9% (p < 0.5), Mean Heart Rate: 73 ± 11 bpm vs 69 ± 12 bpm (p = 0.2), SDNN/HRV: 45 ± 42 ms vs 41 ± 29 ms (p = 0.4), QRS: 123 ± 26 ms vs 119 ± 29 ms (p = 0.5). Multivariate Cox regression analysis with model adjusted for QTc, Mean Heart Rate, LVEF, QRS, revealed that QTc-Fridericia interval was an independent TM predictor (H.R.:1.017, 95% C.I.: 1.003-1.030, p = 0.01). The cut-off point of 490 ms (90th percentile) in the same model presented HR: 2.9 for TM (95%C.I.: 1.066-7.882, p = 0.03). Kaplan Meier curves depicted a clear difference in survival between the two patients' groups (QTc Group≥490 ms vs QTc Group <490 ms). The curve diverge was important (log-rank, p = 0.02).Conclusion: A fast risk stratification approach with SRH ECG recording is an efficient method for flash evaluation of mortality risk in HF patients. [ABSTRACT FROM AUTHOR]

Background: Minimizing direct patient contact among healthcare personnel is crucial for mitigating infectious risk during the coronavirus disease 2019 (COVID-19) pandemic. The use of remote cardiac telemetry as an alternative to 12‑lead electrocardiography (ECG) for continuous QTc monitoring may facilitate this strategy, but its application has not yet been validated or implemented.Methods: In the validation component of this two-part prospective cohort study, a total of 65 hospitalized patients with simultaneous ECG and telemetry were identified. QTc obtained via remote telemetry as measured by 3 independent, blinded operators were compared with ECG as assessed by 2 board-certified electrophysiologists as the gold-standard. Pearson correlation coefficients were calculated to measure the strength of linear correlation between the two methods. In a separate cohort comprised of 68 COVID-19 patients treated with combined hydroxychloroquine and azithromycin, telemetry-based QTc values were compared at serial time points after medication administration using Friedman rank-sum test of repeated measures.Results: Telemetry-based QTc measurements highly correlated with QTc values derived from ECG, with correlation coefficients of 0.74, 0.79, 0.85 (individual operators), and 0.84 (mean of all operators). Among the COVID-19 cohort, treatment led to a median QTc increase of 15 milliseconds between baseline and following the 9th dose (p = 0.002), with 8 (12%) patients exhibiting an increase in QTc ≥ 60 milliseconds and 4 (6%) developing QTc ≥ 500 milliseconds.Conclusions: Cardiac telemetry is a validated clinical tool for QTc monitoring that may serve an expanding role during the COVID-19 pandemic strengthened by its remote and continuous monitoring capability and ubiquitous presence throughout hospitals. [ABSTRACT FROM AUTHOR]

Background and Objectives: Electrical risk score (ERS) has been proposed as easy, inexpensive test to stratify of sudden cardiac death (SCD) risk in subjects with normal left ventricular function. Potentially, aging, gender and drugs can influence ERS affecting two on six electrical markers, particularly, those based on the repolarization. Aim of this study was to establish aging, gender and drug therapy possible influences on ERS and mortality in elderly patients.Method: 237 consecutive, low SCD risk-outpatients with asymptomatic and treated cardiovascular risk factors were analyzed. Six simple ECG markers composed ERS: heart rate (>75 bpm); left ventricular hypertrophy (Sokolow-Lyon criteria); delayed QRS transition zone (≥V4), frontal QRS-T angle (>90°), long QTBazett; long T peak to T end interval (Tp-e). We obtained ERS in 237 outpatients, grouped according age (<40 ys, ≥40 to <60 ys and ≥60 ys), gender and drug therapy with or without possible influence on the repolarization phase.Results: Two-hundred-thirty-seven patients were grouped respectively in the following age classes: <40 years old; ≥40 to <60 years old and ≥60 years old. ERS (p < 0.05), QTBazett (p < 0.001), Tp-e (p < 0.001) were higher in older subjects independently from gender, drug therapy and cardiovascular comorbidity. After two years we reported a 7.3% of mortality in the older groups; age (deceased versus survivors: 80 ± 4 versus 73 ± 7 years, p < 0.05) and Tp-e (deceased versus survivors: 117 ± 15 versus 93 ± 21 ms, p < 0.05) were significantly lower in survivors, multivariable logistic regression analysis selected only the Tp-e as significant risk factor for total mortality (odd ratio 1.06, 95% CI: 1.01-1.12, p < 0.05).Conclusion: Aging was associated to the ERS and repolarization phase derangement. Tp-e should be considered a marker of total mortality rather than SCD in the over sixty years old patients. [ABSTRACT FROM AUTHOR]

Introduction: Prolongation of the corrected QT interval (QTc) can lead to torsades de pointes. This study is designed to determine the validity of the continuous QTc (cQTc) measurement in critically ill patients.Methods: In a retrospective cohort study, QTc analysis was performed with manual measurements on a single selected lead from a 12-lead ECG and cQTc measurement obtained at the same time. In addition, automated QTc measurement from the 12-lead ECG was also included in the study. Validation was performed by calculating intraclass correlation coefficient (ICC), Pearson's correlation and Bland-Altman plot.Results: 119 patients with QRS<120 ms were included with a mean cQTc of 468 ms (standard deviation (SD) 37) and mean manually measured QTc of 449 ms (SD 41) (p<0.001). Pearson's correlation was 0.65 (p<0.01), ICC was 0.65 (95% CI: 0.53-0.74). Bland-Altman plot shows a mean difference of 19.5 ms (limits of agreement (LOA) -44.6 to 83.7). For cQTc compared to automated QTc from the 12-lead ECG the intraclass correlation coefficient was 0.77 (95% CI: 0.68-0.83, p<0.001) and the Bland-Altman plot shows a mean difference of 7.8 ms (LOA -40.2 to 55.8).Conclusion: cQTc measurement in critically ill patients with a QRS duration shorter than 120 ms shows an acceptable accuracy to be used in routine care. [ABSTRACT FROM AUTHOR]

Abstract: Background and purpose: Myocardial ischemia prolongs the QTc interval. Very little data exists about its prognostic implications in the non–ST-elevation acute coronary syndromes (NST-ACS). Methods: This is and observational and prospective study in which we evaluated the prognostic implications of the QTc obtained at admission (AQTc) in the short- and long-term of the NST-ACS. The median of the follow-up was 17 months. Results: AQTc correlated adequately with the incidence of adverse events in the short- and long-term (P < .001), with the best cut-off point in 450 milliseconds. Patients with AQTc ≥450 presented higher frequency of in-hospital death: 8.8% vs 1.2%; P = .001, and MACE (death, recurrent ischemia, or urgent coronary revascularization): 72% vs 25%; P < .001. In a Cox regression analysis, we found 3 independent predictors of cardiovascular death after discharge: AQTc ≥450 (14.7% vs 2.1%; P < .0001), age >65 years and left ventricular ejection fraction <40%. Coronary revascularization reduced the risk of posthospitalary cardiovascular death in AQTc ≥450 milliseconds (5% vs 24%; P < .0001) but had no significant effect in AQTc<450 milliseconds. Conclusion: These findings provide a new evidence supporting the prognostic value of the AQTc in predicting unfavorable events in the short- and long-term of the NST-ACS. [Copyright &y& Elsevier]

We assessed the feasibility of AliveCor tracings for QTC assessment in patients receiving dofetilide. Five patients with persistent AF underwent the two-handed measurement (mimicks Lead I). On the ECG, Lead I or II was used. There was no significant difference between the AliveCor-QTC and ECG-QTC (all ± 20 msec). The AliveCor device can be used to monitor the QTC in these patients. [ABSTRACT FROM AUTHOR]