QT dispersion. Is it an independent risk factor for in-hospital mortality in patients with intracerebral hemorrhage?

Association between electrolyte levels at presentation and hematoma expansion and outcome in spontaneous intracerebral hemorrhage: A systematic review

PURPOSE

To assess the association between specific electrolyte levels (sodium, potassium, calcium, magnesium, and phosphorus) on presentation and hematoma expansion (HE) and outcome in intracerebral hemorrhage (ICH).

METHODS

This review was conducted in accordance with the PRISMA statement recommendations. Three databases were searched (Pubmed, Scopus, and Cochrane). Risk of bias was computed using the Newcastle-Ottawa Scale tool.

RESULTS

18 full-text articles were included in this systematic review including 10,385 ICH patients. Hypocalcemia was associated with worse short-term outcome in four studies, and two other studies were neutral. All studies investigating HE in hypocalcemia (n = 5) reported an association between low calcium level and HE. Hyponatremia (Na < 135 mEq/L) was shown to correlate with worse short-term outcome in two studies, and worse long-term outcome in one. There was one report showing no association between sodium level and HE. Hypomagnesemia was shown to be associated with worse short-term outcome in one study, while other reports were neutral. Studies evaluating hypophosphatemia or hypokalemia in ICH were limited, with no demonstrable significant effect on outcome.

CONCLUSION

This review suggests a significant association between hypocalcemia, hyponatremia and, of lesser degree, hypomagnesemia on admission and HE or worse outcome in ICH.

QT interval prolongation in patients with acute ischemic stroke: a report in northwest China

Aims

QT interval prolongation is common in patients with stroke and increases the risk of malignant arrhythmia and sudden death. Our aim was to analyze differences in the QT interval and electrocardiogram abnormalities between acute ischemic stroke patients and controls.

Methods

We retrospectively collected data from 273 patients with acute ischemic stroke from the neurological intensive care unit and 495 controls from other departments. A standard 12-lead electrocardiogram was recorded within 24 hours of hospitalization. Clinical information, the QT interval corrected for heart rate (QTc), and the incidence of electrocardiogram abnormalities were compared between groups.

Results

There was no difference in age, sex, or the prevalence of hypertension or diabetes mellitus between the acute ischemic stroke group and controls. Acute ischemic stroke patients showed a significantly longer QTc and a higher incidence of both sinus bradycardia and ST-T changes compared with controls. We also showed that the changes in electrocardiogram results observed in acute ischemic stroke might be transient.

Conclusion

Acute ischemic stroke patients may have a longer QT interval and a higher incidence of electrocardiogram abnormalities. In clinical practice, careful attention should be paid to acute ischemic stroke patients to prevent malignant arrhythmia.

Does the Magnitude of the Electrocardiogram QT Interval Dispersion Predict Stroke Outcome?

BACKGROUND

QT dispersion, maximal interlead difference in QT interval on 12-lead electrocardiogram (ECG), measures cardiac repolarization abnormalities. Data are conflicting whether QT dispersion predicts adverse outcome in acute ischemic stroke (AIS) patients. Our objective is to determine if QT dispersion predicts: (1) short-term clinical outcome in AIS, and (2) stroke location (insular versus noninsular cortex).

METHODS

Admission ECGs from 412 consecutive patients with acute stroke symptoms from 2 university-based stroke centers were reviewed. QT dispersion was measured. A neuroradiologist reviewed brain imaging for insular cortex involvement. Favorable clinical outcomes at discharge were modified Rankin Scale (mRS) score of 0-1, discharge National Institutes of Health Stroke Scale (NIHSS) score less than 2, and discharge to home. Multiple logistic regressions were performed for each outcome measure and to determine the association between insular infarct and QT dispersion.

RESULTS

Of 145 subjects in the final analysis, median age was 65 years (interquartile range [IQR] 56-75), male patients were 38%, black patients were 68%, median QT dispersion was 78 milliseconds (IQR 59-98), and median admission NIHSS score was 4 (IQR 2-6). QT dispersion did not predict short-term clinical outcome for mRS score (odds ratio [OR] = 1.001, 95% confidence interval [CI] .99-1.01, P = .85), NIHSS at discharge (OR = .994, 95% CI .98-1.01, P = .30), or discharge disposition (OR = 1.001, 95% CI .99-1.01, P = .81). Insular cortex involvement did not correlate with QT dispersion magnitude (OR = 1.009, 95% CI .99-1.02, P = .45).

CONCLUSIONS

We could not demonstrate that QT dispersion is useful in predicting short-term clinical outcome at discharge in AIS. Further, the magnitude of QT dispersion did not predict insular cortical stroke location.

The dispersion of myocardial repolarization in ischemic stroke and intracranial hemorrhage

BACKGROUND

Markers of dispersion of myocardial repolarization have been proposed to identify the patients at higher risk of malignant arrhythmic events. The aim of the present study is to assess a possible association of the electrocardiografic (ECG) markers of the dispersion of repolarization with the type of stroke, involvement of insula, neurological severity (National Institutes of Health Stroke Scale, NIHSS score), and disability (modified Rankin Scale, mRS score) in patients with a cerebrovascular event.

METHODS

We conducted a retrospective analysis based on data prospectively collected from consecutive patients with a cerebrovascular event who underwent 12‑lead ECG at admission to the Verona Stroke Unit.

RESULTS

Of the 63 patients included in the study, 55 had ischemic stroke and 8 intracranial hemorrhage. TpTe (time between the peak and the end of the T wave) and TpTe/QTc (TpTe/corrected time between the start of the Q wave and the end of the T wave) in lead V5 were higher in intracranial hemorrhage than in ischemic stroke (p = 0.03 and p = 0.04, respectively) and QT max (the longest QT calculated in the 12 leads) was higher in patients with involvement of insula (p ≤ 0.01). A correlation was found between QTc max and NIHSS score at admission (p = 0.02), QT max and NIHSS score at discharge (p = 0.05), and QT max and mRS score at discharge (p = 0.02).

CONCLUSIONS

TpTe and TpTe/QTc in V5 lead were associated with intracranial hemorrhage and QT max was associated with involvement of insula. The prolongation of QT was correlated with neurological severity and disability.

The evaluation of a new marker of transmyocardial repolarization parameters in ischemic stroke patients; T peak-T end (T p-e), T p-e/QTc

The cardiovascular manifestations of acute ischemic stroke have been well known. Several electrocardiography (ECG) abnormalities have been reported in patients following acute stroke, including QT interval prolongation, ST segment deviation and T-wave changes. This study aimed to investigate the changes in transmyocardial repolarization parameters, in ischemic stroke patients. The study is a prospective, blind, and controlled clinical study. The patients without cardiac disease who received ischemic stroke diagnoses were included in the study. ECG was received from the patients in the first hour and 72 h. The P, QT, T _p-e, T _p-e dispersion, and the T _p-e/QT ratio were calculated. Moreover, fifty-five stroke patients and 35 control subjects were included to the study. All dispersion values and T _p-e/QT_c ratio in patients group were higher than those of control group (p < 0.05 for all values). When evaluated between ECGs' on first and third days, it was found that decreasing on all dispersion values and T _p-e/QT_c ratio in ECGs on third day than ECGs on first day (p < 0.05 for all values). QT, QT_c, and T _p-e dispersions values in patients who have insular lobe involvement were higher than those of patients who do not have insular lobe involvement (p < 0.001 for all values). In this study, we showed that acute stroke increases that P _d, QT_d, QT_cd and new repolarization markers T _p-e and T _p-e/QT_c, during first 24 and 72 h in acute stroke patients without cardiovascular disease compared with the control group. The physicians should be aware about ventricular dysrhythmias in patients with ischemic stroke and these patients closely observed with cardiac monitoring, especially within first 24 h, and especially patients with insular lobe involvement.

Vectorcardiography identifies patients with electrocardiographically concealed long QT syndrome

BACKGROUND

Long QT syndrome (LQTS) and genotypic subtypes are associated with distinctive T-wave patterns, arrhythmogenic triggers, and corrected QT (QTc) interval risk associations. Twenty percent of patients with LQTS have normal QTc values, defined as electrographically concealed LQTS (ecLQTS). Vectorcardiography (VCG) has value for sudden cardiac death risk assessment.

OBJECTIVE

The purpose of this study was to determine the use of VCG to identify patients with ecLQTS.

METHODS

We performed a retrospective analysis in patients with ecLQTS with resting QTc values <440 ms. Computerized derivation of the spatial mean and peak QRS-T angles, QTpeak, Tpeak-Tend (angle between QRS and T-wave peak amplitudes in 3-dimensional space), and T-wave eigenvalues (TwEVs; amplitudes [in microvolts] for each of the first 4 TwEVs were derived from the 12-lead electrocardiogram) was performed. The results were compared with those for healthy controls. Intergenotype differences were analyzed.

RESULTS

Of 610 patients with LQTS, 169 patients (28%) had ecLQTS (86 (51%) men; mean age 22 ± 16 years; mean QTc interval 422 ± 14 ms). There were 519 healthy controls (44% men; mean age 19.8 ± 13.8 years) with a mean QTc interval of 426 ± 28 ms. Among VCG parameters, QTpeak and TwEVs significantly differentiated patients with ecLQTS from controls (P ≤ .01 for each) as well as differentiated KCNQ1-encoded type 1 LQTS (ecLQT1), KCNH2-encoded type 2 LQTS (ecLQT2), and SCN5A-encoded type 3 LQTS (ecLQT3) from controls (P < .01). ecLQT3 was differentiated from controls and ecLQT1 and ecLQT2 by the fourth TwEV (P < .01 for each). The fourth TwEV differentiated symptomatic patients with ecLQTS from asymptomatic patients with ecLQTS (P < .01).

CONCLUSION

ecLQTS can be distinguished from controls using QTpeak. ecLQT3 was best differentiated by the fourth TwEV. VCG may facilitate familial diagnostic anticipation of LQTS status before the completion of mutation-specific genetic testing even with normal resting QTc values.

Relationship between QT interval dispersion in acute stroke and stroke prognosis: a systematic review

BACKGROUND

QT dispersion (QTd) has been proposed as an indirect electrocardiography (ECG) measure of heterogeneity of ventricular repolarization. The predictive value of QTd in acute stroke remains controversial. We aimed to clarify the relationship between QTd and acute stroke and stroke prognosis.

METHODS

A systematic review of the literature was performed using prespecified medical subjects heading terms, Boolean logic, and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Eligible studies included ischemic or hemorrhagic stroke and provided QTd measurements.

RESULTS

Two independent reviewers identified 553 publications. Sixteen articles were included in the final analysis. There were a total of 888 stroke patients: 59% ischemic and 41% hemorrhagic. There was considerable heterogeneity in study design, stroke subtypes, ECG assessment time, control groups, and comparison groups. Nine studies reported a significant association between acute stroke and baseline QTd. Two studies reported that QTd increases are specifically related to hemorrhagic strokes, involvement of the insular cortex, right-side lesions, larger strokes, and increases in 3,4-dihydroxyphenylethylene glycol in hemorrhagic stroke. Three studies reported QTd to be an independent predictor of stroke mortality. One study each reported increases in QTd in stroke patients who developed ventricular arrhythmias and cardiorespiratory compromise.

CONCLUSIONS

There are few well-designed studies and considerable variability in study design in addressing the significance of QTd in acute stroke. Available data suggest that stroke is likely to be associated with increased QTd. Although some evidence suggests a possible prognostic role of QTd in stroke, larger and well-designed studies need to confirm these findings.

Electrocardiographic abnormalities and elevated cTNT at admission for intracerebral hemorrhage: predictors for survival?

BACKGROUND

Cerebrovascular lesions are often associated with electrocardiographic (ECG) abnormalities. The main purpose of this work was to investigate the prognostic value of ECG abnormalities and/or elevated cardiac troponin (cTNT) on admission in patients with nontraumatic intracerebral hemorrhage (ICH).

METHODS

Ninety-seven consecutive patients with ICH were included. The predictive value of ECG abnormalities and increased TNT on survival were evaluated using Cox proportional hazard model.

RESULTS

The most frequently observed ECG abnormalities were the presence of a Q wave (39.6%), followed by prolonged QTc (>0.44 s; 35.4%), which was an independent predictor for long-term mortality (P = 0.019). No difference in QTc was observed between patients with right versus left ICH. Increased cTNT levels at admission had no prognostic value.

CONCLUSION

Various ECG changes were common in patients presenting with an ICH, but only prolonged QTc was found to be an independent predictor of poor survival during follow-up after ICH.

Ischemic-appearing electrocardiographic changes predict myocardial injury in patients with intracerebral hemorrhage

OBJECTIVES

Myocardial injury is common among patients with intracerebral hemorrhage (ICH). However, it is challenging for emergency physicians to recognize acute myocardial injury in this population, as electrocardiographic (ECG) abnormalities are common in this setting. Our objective is to examine whether ischemic-appearing ECG changes predict subsequent myocardial injury in the context of ICH.

METHODS

Consecutive patients with primary ICH presenting to a single academic center were prospectively enrolled. Electrocardiograms were retrospectively reviewed by 3 independent readers. Anatomical areas of ischemia were defined as I and aVL; II, III, and aVF; V(1) to V(4); and V(5) and V(6). Medical record review identified myocardial injury, defined as troponin I or T elevation (cutoff 1.5 and 0.1 ng/mL, respectively), within 30 days.

RESULTS

Between 1998 and 2004, 218 patients presented directly to our emergency department and did not have a do-not-resuscitate/do-not-intubate order; arrival ECGs and troponin levels were available for 206 patients. Ischemic-appearing changes were noted in 41% of patients, and myocardial injury was noted in 12% of patients. Ischemic-appearing changes were more common in patients with subsequent injury (64% vs 37%; P = .02). After multivariable analysis controlling for age and cardiac risk factors, ischemic-appearing ECG changes independently predicted myocardial injury (odds ratio, 3.2; 95% confidence interval, 1.3-8.2). In an exploratory analysis, ischemic-appearing ECG changes in leads I and aVL as well as V(5) and V(6) were more specific for myocardial injury (P = .002 and P = .03, respectively).

CONCLUSION

In conclusion, although a range of ECG abnormalities can occur after ICH, the finding of ischemic-appearing changes in an anatomical distribution can help predict which patients are having true myocardial injury.

Changes in QT dispersion after thrombolysis for stroke

BACKGROUND

QT dispersion (QTD) reflects heterogeneity of myocardial repolarization, which is modulated by the central nervous system. Although largely studied in patients with cardiovascular disease, QTD is increased in acute stroke and this finding is an independent predictor of functional outcome and mortality following acute neurological events.

HYPOTHESIS

The hypothesis of this study was to determine whether changes in QTD in patients presenting with ischemic stroke parallel changes in neurologic function.

METHODS

We retrospectively studied 30 consecutive patients (76+/-9 years, 50% male) who received thrombolytic therapy for acute ischemic stroke between September 1996 and August 2002, and had multiple electrocardiograms (ECGs). QTD was calculated from the admission ECG and the last available ECG (median 3 days) during hospital admission as the absolute difference between the maximum and minimum QT intervals in at least 11 of 12 leads. The National Institute of Health Stroke Scale (NIHSS) was used to assess neurological status on admission and discharge. DeltaQTD was calculated as the absolute difference between QTD measured on admission and on the last available ECG. Absolute changes in heart rate corrected QTD (DeltaQTDc) and NIHSS scores (DeltaNIHSS) were also calculated.

RESULTS

DeltaQTD was significantly higher in the 27% of patients who died as compared to the survivors (44+/-26 ms vs. -2+/-21 ms, p<.001). DeltaNIHSS correlated directly with DeltaQTD (r=0.57, p<0.001) and with DeltaQTDc (r=0.60, p<0.001). The NIHSS score changed in the same direction 3.1 units (95% CI: 2.0, 4.2) for every 10 ms change in QTD.

CONCLUSION

DeltaQTD are associated with changes in neurological function in patients treated with thrombolytic therapy for acute ischemic stroke.

QTc dispersion as a prognostic factor in intracerebral hemorrhage

QTc dispersion in the electrocardiogram (ECG) is a new important prognostic factor for many diseases, but its role in intracerebral hemorrhage (ICH) is not clear. This study was performed to investigate the prognostic significance of QTc dispersion in the acute ICH patients. We studied the differences of QTc dispersion from the initial ECG in the ED between the survival to discharge and nonsurvival patients retrospectively. We found that the patients had lesser chance to survival to discharge if they had increased QTc dispersion, longer maximal QTc interval, lower Glasgow Coma Scale (GCS), and brainstem involvement in the univariate analyses. The QTc dispersion and GCS were the statistically significant independent predictors in the multiple logistic analyses. Increased QTc dispersion in the initial ED electrocardiograph is an important prognostic factor for ICH patients. More attention to the disposition and intensive care should be given for these patients.