QT interval: metric for cardiac prognosis?

Predicting QT interval prolongation in patients diagnosed with the 2019 novel coronavirus infection

INTRODUCTION

2019 novel coronavirus (COVID-19) patients frequently develop QT interval prolongation that predisposes them to Torsades de Pointes and sudden cardiac death. Continuous cardiac monitoring has been recommended for any COVID-19 patient with a Tisdale Score of seven or more. This recommendation, however, has not been validated.

METHODS

We included 178 COVID-19 patients admitted to a non-intensive care unit setting of a tertiary academic medical center. A receiver operating characteristics curve was plotted to determine the accuracy of the Tisdale Score to predict QT interval prolongation. Multivariable analysis was performed to identify additional predictors.

RESULTS

The area under the curve of the Tisdale Score was 0.60 (CI 95%, 0.46-0.75). Using the cutoff of seven to stratify COVID-19, patients had a sensitivity of 85.7% and a specificity of 7.6%. Risk factors independently associated with QT interval prolongation included a history of end-stage renal disease (ESRD) (OR, 6.42; CI 95%, 1.28-32.13), QTc ≥450 ms on admission (OR, 5.90; CI 95%, 1.62-21.50), and serum potassium ≤3.5 mmol/L during hospitalization (OR, 4.97; CI 95%, 1.51-16.36).

CONCLUSION

The Tisdale Score is not a useful tool to stratify hospitalized non-critical COVID-19 patients based on their risks of developing QT interval prolongation. Clinicians should initiate continuous cardiac monitoring for patients who present with a history of ESRD, QTc ≥450 ms on admission or serum potassium ≤3.5 mmol/L.

Pediatric cirrhotic cardiomyopathy: Impact on liver transplant outcomes

In adults, cirrhotic cardiomyopathy (CCM) has a significant incidence and impact on liver transplantation. For pediatric liver transplantation (pLT), data on liver-induced cardiac changes are scarce, and in particular, the comparison between cirrhotic and noncirrhotic liver disease has not been investigated. We retrospectively evaluated cardiac changes associated with CCM by echocardiography and 12-lead electrocardiogram in 198 pLT-candidates (median age 4.1 years) 4.2 before and 12 months after pLT. Results were correlated with the stage of liver fibrosis and cholestasis before transplantation. The left ventricular end-diastolic diameter (LVIDd) z score, left ventricular mass z score, and left ventricular mass index were significantly higher in cirrhotic patients (-0.10 versus 0.98, P < 0.001; -1.55 versus -0.42, P = 0.001; 78.99 versus 125.64 g/m² , P = 0.001, respectively) compared with children with noncirrhotic liver disease. Pathological z scores (>2SDS) for the LVIDd occurred more frequently in cirrhotic patients compared with patients with noncirrhotic liver disease (31/169 versus 1/29; P = 0.03) and were significantly associated with cholestasis. All observed cardiac changes were reversible 1 year after pLT. Pathological LVIDd z scores correlated highly with intensive care unit (ICU) stay (9.6 days versus 17.1 days, respectively, P = 0.002) but not with patient survival pre-LT or post-LT. In contrast to other studies, prolonged QTc time was not associated with liver cirrhosis in our patients. In conclusion, CCM-associated cardiac changes in pLT candidates with cirrhotic liver disease are frequent, mild, and associated with cholestasis and reversible after pLT. They may impact peritransplant care and posttransplant hospitalization time. Further prospective evaluation is warranted. In particular, for QTc time prolongation etiological factors, possible protective effects of ursodeoxycholic acid treatment and the use as a screening parameter for CCM should be verified. Liver Transplantation 24 820-830 2018 AASLD.

A detailed description and assessment of outcomes of patients with hospital recorded QTc prolongation

Corrected QT (QTc) interval prolongation has been shown to be an independent predictor of mortality in many clinical settings and is a common finding in hospitalized patients. The causes and outcomes of patients with extreme QTc interval prolongation during a hospital admission are poorly described. The aim of this study was to prospectively identify patients with automated readings of QTc intervals >550 ms at 1 academic tertiary hospital. One hundred seventy-two patients with dramatic QTc interval prolongation (574 ± 53 ms) were identified (mean age 67.6 ± 15.1 years, 48% women). Most patients had underlying heart disease (60%), predominantly ischemic cardiomyopathy (43%). At lease 1 credible and presumed reversible cause associated with QTc interval prolongation was identified in 98% of patients. The most common culprits were QTc interval-prolonging medications, which were deemed most responsible in 48% of patients, with 25% of these patients taking ≥2 offending drugs. Two patients were diagnosed with congenital long-QT syndrome. Patients with electrocardiograms available before and after hospital admission demonstrated significantly lower preadmission and postdischarge QTc intervals compared with the QTc intervals recorded in the hospital. In conclusion, in-hospital mortality was high in the study population (29%), with only 4% of patients experiencing arrhythmic deaths, all of which were attributed to secondary causes.

Short- and long-term prognostic value of the corrected QT interval in the non–ST-elevation acute coronary syndrome

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 > or =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 > or =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 > or =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.