Electrocardiographic parameters effectively predict ventricular tachycardia/fibrillation in acute phase and abnormal cardiac function in chronic phase of ST-segment elevation myocardial infarction

Celastrol exerts antiarrhythmic effects in chronic heart failure via NLRP3/Caspase-1/IL-1β signaling pathway

OBJECTIVES

Celastrol has widespread therapeutic applications in various pathological conditions, including chronic inflammation. Previous studies have demonstrated the potent cardioprotective effects of celastrol. Nevertheless, limited attention has been given to its potential in reducing ventricular arrhythmias (VAs) following myocardial infarction (MI). Hence, this study aimed to elucidate the potential mechanisms underlying the regulatory effects of celastrol on VAs and cardiac electrophysiological parameters in rats after MI.

METHODS

Sprague-Dawley rats were divided at random: the sham, MI, and MI + celastrol groups. The left coronary artery was occluded in the MI and MI + Cel groups. Electrocardiogram, heart rate variability (HRV), ventricular electrophysiological parameters analysis, histology staining of ventricles, Enzyme-linked immunosorbent assay (ELISA), western blotting and Quantitative real-time polymerase chain reaction (qRT-PCR) were performed to elucidate the underlying mechanism of celastrol. Besides, H9c2 cells were subjected to hypoxic conditions to create an in vitro model of MI and then treated with celastrol for 24 hours. Nigericin was used to activate the NLRP3 inflammasome.

RESULTS

Compared with that MI group, cardiac electrophysiology instability was significantly alleviated in the MI + celastrol group. Additionally, celastrol improved HRV, upregulated the levels of Cx43, Kv.4.2, Kv4.3 and Cav1.2, mitigated myocardial fibrosis, and inhibited the NLRP3 inflammasome pathway. In vitro conditions also supported the regulatory effects of celastrol on the NLRP3 inflammasome pathway.

CONCLUSIONS

Celastrol could alleviate the adverse effects of VAs after MI partially by promoting autonomic nerve remodeling, ventricular electrical reconstruction and ion channel remodeling, and alleviating ventricular fibrosis and inflammatory responses partly by through inhibiting the NLRP3/Caspase-1/IL-1β pathway.

Tpeak-Tend ECG Marker in Obesity and Cardiovascular Diseases: A Comprehensive Review

Globally, cardiovascular diseases are still the leading cause of death. Numerous methods are used to diagnose cardiovascular pathologies; there is still a place for straightforward and noninvasive techniques, such as electrocardiogram (ECG). Depolarization and repolarization parameters, including QT interval and its derivatives, are well studied. However, the Tpeak-Tend interval is a novel and promising ECG marker with growing evidence for its potential role in predicting malignant arrhythmias. In this review, we discuss the association between the Tpeak-Tend interval and several cardiovascular diseases, including long QT syndrome, cardiomyopathies, heart failure, myocardial infarction, and obesity, which constitutes one of the risk factors for cardiovascular diseases.

The Effect of Obesity on Repolarization and Other ECG Parameters

Background: Overweight and obesity are important risk factors in the development of cardiovascular diseases. New repolarization markers, such as the Tpeak-Tend interval and JTpeak intervals, have not yet been profoundly studied in obese patients. The study aims to analyze whether, in patients with obesity and overweight, repolarization markers, including the Tpeak-Tend interval, are prolonged and simultaneously check the frequency of other ECG pathologies in a 12-lead ECG in this group of patients. Methods: A study group consisted of 181 adults (90 females and 91 males) with overweight and first-class obesity. The participants completed a questionnaire, and the ECG was performed and analyzed. Results: When analyzing the classic markers, only QT dispersion was significantly higher in obese people. The Tpeak-Tend parameter (97.08 ms ± 23.38 vs. 89.74 ms ± 12.88, respectively), its dispersion, and JTpeak-JTend parameters were statistically significantly longer in the obese group than in the controls. There were also substantial differences in P-wave, QRS duration, and P-wave dispersion, which were the highest in obese people. Tpeak-Tend was positively correlated with body mass and waist circumference, while JTpeak was with BMI, hip circumference, and WHR. Tpeak/JT was positively correlated with WHR and BMI. In backward stepwise multiple regression analysis for JTpeak-WHR, type 2 diabetes and smoking had the highest statistical significance. Conclusions: Only selected repolarization markers are significantly prolonged in patients with class 1 obesity and, additionally, in this group, we identified more pathologies of P wave as well as prolonged QRS duration.

Early prediction of ventricular fibrillation using electrocardiographic characteristics in prehospital suspected ST-segment elevation myocardial infarction: a case-control study

PURPOSE

Our objective was to determine characteristics of electrocardiograms (ECG) that predict ventricular fibrillation (VF) among prehospital patients with suspected ST-segment elevation myocardial infarction (STEMI) in Québec.

METHODS

We performed a matched case-control study of prehospital adult suspected with STEMI. Patients in case group (STEMI/VF+) were matched with controls (STEMI/VF-) for age and sex and then compared for ECG characteristics, including ST-segment elevations (STE) and depressions (STD), duration of interval complexes, general characteristics, and several calculated variables. Logistic regression was used to measure the association between ECG characteristics and VF development.

RESULTS

Overall, 310 prehospital patients with suspected STEMI were included in the analysis (case group, n = 155; control group, n = 155). We confirmed that the presence of TW-pattern complex (OR 7.0, 95% CI 1.55-31.58), premature ventricular contraction (PVC) (OR 5.5, 95% CI 2.04-14.82), and STE in V2-V6 (OR 3.8, 95% CI 1.21-11.74) were electrocardiographic predictors of VF. We also observed that STD in V3-V5 (OR 6.5, 95% CI 1.42-29.39), atrial fibrillation (AF) ≥ 100 beats per minute (bpm) (OR 6.3, 95% CI 1.80-21.90), the combination of STE in V4 and V5, and STD in II, III and aVF (OR 4.8, 95% CI 1.01-22.35), and the presence of STD in ≥ 6 leads (OR 4.2, 95% CI 1.33-13.13) were also associated with VF development. Finally, simultaneous association of 2 (OR 2.3, 95% CI 1.13-4.06) and 3 (OR 11.6, 95% CI 3.22-41.66) predictors showed significant association with VF.

CONCLUSIONS

In addition to some already known predictors, we have identified several ECG findings associated with the development of VF in patients with suspected STEMI. Early identification of patients with STEMI at increased risk of VF should help EMS providers anticipate adverse events and encourage use of defibrillation pads.

Effect of reperfusion strategy on QT dispersion in patients with acute myocardial infarction: Impact on in-hospital arrhythmia

BACKGROUND

Myocardial ischemia and ST-elevation myocardial infarction (STEMI) increase QT dispersion (QTD) and corrected QT dispersion (QTcD), and are also associated with ventricular arrhythmia.

AIM

To evaluate the effects of reperfusion strategy [primary percutaneous coronary intervention (PPCI) or fibrinolytic therapy] on QTD and QTcD in STEMI patients and assess the impact of the chosen strategy on the occurrence of in-hospital arrhythmia.

METHODS

This prospective, observational, multicenter study included 240 patients admitted with STEMI who were treated with either PPCI (group I) or fibrinolytic therapy (group II). QTD and QTcD were measured on admission and 24 hr after reperfusion, and patients were observed to detect in-hospital arrhythmia.

RESULTS

There were significant reductions in QTD and QTcD from admission to 24 hr in both group I and group II patients. QTD and QTcD were found to be shorter in group I patients at 24 hr than those in group II (53 ± 19 msec vs 60 ± 18 msec, P = 0.005 and 60 ± 21 msec vs 69+22 msec, P = 0.003, respectively). The occurrence of in-hospital arrhythmia was significantly more frequent in group II than in group I (25 patients, 20.8% vs 8 patients, 6.7%, P = 0.001). Furthermore, QTD and QTcD were higher in patients with in-hospital arrhythmia than those without (P = 0.001 and P = 0.02, respectively).

CONCLUSION

In STEMI patients, PPCI and fibrinolytic therapy effectively reduced QTD and QTcD, with a higher observed reduction using PPCI. PPCI was associated with a lower incidence of in-hospital arrhythmia than fibrinolytic therapy. In addition, QTD and QTcD were shorter in patients not experiencing in-hospital arrhythmia than those with arrhythmia.

Association of a simple SACAF score with bystander witnessed sudden death due to ventricular tachyarrhythmias in a multicenter cohort

Out-of-hospital cardiac arrest (OHCA) remains a major threat to public health worldwide. OHCA patients presenting initial shockable ventricular tachycardia/ventricular fibrillation (VT/VF) rhythm have a better survival rate. We sought to develop a simple SACAF score to discriminate VT/VF from non-VT/VF OHCAs based on the Taiwan multicenter hospital-based registry database. We analyzed the in- and pre-hospital data, including demographics, baseline comorbidities, response times, automated external defibrillator information, and the 12-lead ECG recording closest to the OHCA event in bystander-witnessed OHCA patients. Among the 461 study patients, male sex (OR 2.54, 95% CI = 1.32–4.88, P = 0.005), age ≤ 65 years (OR 2.78, 95% CI = 1.64–4.70, P < 0.001), cardiovascular diseases (OR 2.97, 95% CI = 1.73–5.11, P < 0.001), and atrial fibrillation (AF) (OR 2.36, 95% CI = 1.17–4.76, P = 0.017) were independent risk factors for VT/VF OHCA (n = 81) compared with non-VT/VF OHCA (n = 380). A composite SACAF score was developed (male Sex, Age ≤ 65 years, Cardiovascular diseases, and AF) and compared with the performance of a modified CHA₂DS₂-VASc score (Cardiovascular diseases, Hypertension, Age ≥ 75 years, Diabetes, previous Stroke, Vascular disease, Age 65–74 years, female Sex category). The area under the receiver operating characteristic curve (AUC) of the SACAF was 0.739 (95% CI = 0.681–0.797, P < 0.001), whereas the AUC of the modified CHA₂DS₂-VASc was 0.474 (95% CI = 0.408–0.541, P = 0.464). A SACAF score of ≥ 2 was useful in discriminating VT/VF from non-VT/VF OHCAs with a sensitivity of 0.75 and a specificity of 0.60. In conclusion, the simple SACAF score appears to be useful in discriminating VT/VF from non-VT/VF bystander-witnessed OHCAs and the findings may also shed light on future mechanistic evaluation.

Increased QT Dispersion and High Risk of Ventricular Arrhythmias is Associated with Hyperuricemia in Individuals with Normal Renal Function

Background and aim: Uric acid elevation has been shown to be an important risk factor for cardiovascular and cerebrobascular disease. QT dispersion (QTd) is a parameter that shows the heterogeneity of ventricular repolarization and can be calculated noninvasively from surface electrocardiography. Increased QTd has been associated with severe arrhythmia and risk of sudden death in many patients and disease groups. In this context, we aimed to investigate the effect of uric acid levels on QTd and the effects of decrease in uric acid levels on QTd.

Methods: A total of 225 patients with normal renal function were included in the study; 133 of these patients were hyperuricemic (>7 mg/dL), and the remaining 72 patients were normouricemic (Group 1). The hyperuricemic patients were randomly divided into 2 groups, one group (n = 67) was given placebo (Group 2) for 4 months, and the remaining 66 patients were given allopurinol 300 mg/day (Group 3).

Results: Hyperuricemic patients had higher hsCRP and QTd and lower eGFR values compared to the normouricemic control group. After 4 months of treatment, 66 patients treated with allopurinol showed a significant decrease in serum uric acid, systolic and diastolic blood pressure, and hsCRP levels, and a significant increase in eGFR. Although the QTd values in the treatment group did not decrease to the same levels as in the normouricemic control group, a statistically significant decrease was found compared to their baseline values. In hyperuricemic control and normouricemic control patients, there were no differences in the levels of uric acid, hsCRP, eGFR, systolic and diastolic blood pressure, and QTd values compared to baseline values.

Conclusions: There was a significant association between elevated serum uric acid and QTd, as well as with inflammatory biomarkers. Also, patients who had received hypouricemic therapy during the follow-up period presented a significant decrease in inflammatory markers as well as QTd. This indicates the beneficial effects of decreasing uric acid levels in decreasing the risk for future major adverse events related to ventricular arrhythmias.

Association of T-wave abnormalities with major cardiovascular events in diabetes: the ACCORD trial

AIMS/HYPOTHESIS

T-wave abnormalities (TWA) are often found on ECG and signify abnormal ventricular repolarisation. While TWA have been shown to be associated with subclinical atherosclerosis, the relationship between TWA and hard cardiovascular endpoints is less clear and may differ in the presence of diabetes, so we sought to explore these associations in participants from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial.

METHODS

TWA were operationally defined as the presence of any Minnesota Codes 5-1 through 5-4 in any lead distribution. Multivariable Cox proportional hazards models were constructed to examine relationships between TWA and clinical cardiovascular events. Secondary analyses explored the risks conferred by major vs minor TWA, differential effects of TWA by anatomic localisation (anterolateral, inferior or anterior lead distributions), and differing associations in those with or without prevalent CVD.

RESULTS

Among 8176 eligible participants (mean 62.1 ± 6.3 SD years, 61.4% male), there were 3759 cardiovascular events, including 1430 deaths (473 of a cardiovascular aetiology), 474 heart failure events, 1452 major CHD events and 403 strokes. Participants with TWA had increased risks of all-cause mortality (HR 1.45 [95% CI 1.30, 1.62], p < 0.0001), cardiovascular mortality (HR 1.93 [1.59, 2.34], p = 0.0001), congestive heart failure (HR 2.04 [1.69, 2.48], p < 0.0001) and major CHD (HR 1.40 [1.26, 1.57], p < 0.0001), but no increased risk of stroke (HR 0.99 [0.80, 1.23], p = 0.95). Major TWA conferred a higher risk than minor TWA. When TWA were added to the UK Prospective Diabetes Study risk engine, there was improved discrimination for incident CHD events, but only for those with prevalent CVD (area under the receiver operating characteristic curve 0.5744 and 0.6030 with p = 0.0067). Adding TWA to the risk engine yielded improvements in reclassification that were of greater magnitude in those with prevalent CVD (net reclassification improvement [NRI] 0.24 [95% CI 0.16, 0.32] in those with prevalent CVD, NRI 0.14 [95% CI 0.07, 0.22] in those without prevalent CVD).

CONCLUSIONS/INTERPRETATION

The presence and magnitude of TWA are associated with increased risk of clinical cardiovascular events and mortality in individuals with diabetes and may have value in refining risk, particularly in those with prevalent CVD. Graphical abstract.

Heart Rate Dependency and Inter-Lead Variability of the T Peak - T End Intervals

The electrocardiographic (ECG) assessment of the T peak–T end (Tpe) intervals has been used in many clinical studies, but several related physiological aspects have not been reported. Specifically, the sources of the Tpe differences between different ECG leads have not been systematically researched, the relationship of Tpe duration to underlying heart rate has not been firmly established, and little is known about the mutual correspondence of Tpe intervals measured in different ECG leads. This study evaluated 796,620 10-s 12-lead ECGs obtained from long-term Holters recorded in 639 healthy subjects (311 female) aged 33.8 ± 9.4 years. For each ECG, transformation to orthogonal XYZ lead was used to measure Tpe in the orthogonal vector magnitude (used as a reference for lead-to-lead comparisons) and to construct a three-dimensional T wave loop. The loop roundness was expressed by a ratio between its circumference and length. These ratios were significantly related to the standard deviation of Tpe durations in different ECG leads. At the underlying heart rate of 60 beats per minute, Tpe intervals were shorter in female than in male individuals (82.5 ± 5.6 vs 90.0 ± 6.5 ms, p < 0.0001). When studying linear slopes between Tpe intervals measured in different leads and the underlying heart rate, we found only minimal heart rate dependency, which was not systematic across the ECG leads and/or across the population. For any ECG lead, positive Tpe/RR slope was found in some subjects (e.g., 79 and 25% of subjects for V2 and V4 measurements, respectively) and a negative Tpe/RR slope in other subjects (e.g., 40 and 65% for V6 and V5, respectively). The steepest positive and negative Tpe/RR slopes were found for measurements in lead V2 and V4, respectively. In all leads, the Tpe/RR slope values were close to zero, indicating, on average, Tpe changes well below 2 ms for RR interval changes of 100 ms. On average, longest Tpe intervals were measured in lead V2, the shortest in lead III. The study concludes that the Tpe intervals measured in different leads cannot be combined. Irrespective of the measured ECG lead, the Tpe interval is not systematically heart rate dependent, and no heart rate correction should be used in clinical Tpe investigations.

ECG markers of local but not global increase in dispersion of ventricular repolarization (simulation study)

BACKGROUND

An increase in local dispersion of repolarization (DOR) may contribute more to arrhythmogenesis as compared to changes of global DOR. The aim of this simulation study was to find ECG markers of local increase in DOR in conditions where global DOR remains normal.

METHODS

In the framework of van Oosterom and Oostendorp ECGSIM model, the local DOR was increased in 10 different ventricular locations by (1) action potential duration (APD) shortening/lengthening both on epi- and endocardium, (2) epicardial APD shortening, and (3) endocardial APD shortening. The simulation cases where the increase in local DOR was accompanied by increase in global DOR were excluded from consideration. T-wave parameters were analyzed in the simulated precordial and anatomically ordered limb leads.

RESULTS

The increase in local DOR resulted in increased lead-to‑lead differences in Tpeak and Tend instants in 28 out of 32 simulated scenarios, and in an increased dispersion of Tpeak-Tend interval throughout 12 standard leads in 8 out of 32 simulated scenarios. In all simulations, the global DOR measured as a difference between earliest and latest repolarization times and standard APD deviation was the same.

CONCLUSIONS

The local increase in DOR was expressed in increased lead-to‑lead differences in Tpeak and Tend instants between adjacent anatomically ordered standard leads (aVL, I, aVR(-), II, aVF, III, and V1-V6), even if global DOR, Tpeak-Tend interval and Tpeak-Tend dispersion were within a normal range.

Arrhythmic Risk in Elderly Patients Candidates to Transcatheter Aortic Valve Replacement: Predictive Role of Repolarization Temporal Dispersion

Background/Aim

Degenerative aortic valve stenosis (AS) is associated to ventricular arrhythmias and sudden cardiac death, as well as mental stress in specific patients. In such a context, substrate, autonomic imbalance as well as repolarization dispersion abnormalities play an undoubted role. Aim of the study was to evaluate the increase of premature ventricular contractions (PVC) and complex ventricular arrhythmias during mental stress in elderly patients candidate to the transcatheter aortic valve replacement (TAVR).

Methods

In eighty-one elderly patients with AS we calculated several short-period RR- and QT-derived variables at rest, during controlled breathing and during mild mental stress, the latter being represented by a mini-mental state evaluation (MMSE).

Results

All the myocardial repolarization dispersion markers worsened during mental stress (p < 0.05). Furthermore, during MMSE, low frequency component of the RR variability increased significantly both as absolute power (LF_RR) and normalized units (LF_{RRN U}) (p < 0.05) as well as the low-high frequency ratio (LF_RR/HF_RR) (p < 0.05). Eventually, twenty-four (30%) and twelve (15%) patients increased significantly PVC and, respectively, complex ventricular arrhythmias during the MMSE administration. At multivariate logistic regression analysis, the standard deviation of QTend (QTe_sd), obtained at rest, was predictive of increased PVC (odd ratio: 1.54, 95% CI 1.14-2.08; p = 0.005) and complex ventricular arrhythmias (odd ratio: 2.31, 95% CI 1.40-3.83; p = 0.001) during MMSE. The QTe_sd showed the widest sensitive-specificity area under the curve for the increase of PVC (AUC: 0.699, 95% CI: 0.576-0.822, p < 0.05) and complex ventricular arrhythmias (AUC: 0.801, 95% CI: 0.648-0.954, p < 0.05).

Conclusion

In elderly with AS ventricular arrhythmias worsened during a simple cognitive assessment, this events being a possible further burden on the outcome of TAVR. QTe_sd might be useful to identify those patients with the highest risk of ventricular arrhythmias. Whether the TAVR could led to a QTe_sd reduction and, hence, to a reduction of the arrhythmic burden in this setting of patients is worthy to be investigated.

Electrocardiographic measures of ventricular repolarization dispersion and arrhythmic outcomes among ST elevation myocardial infarction patients with pre-infarction angina undergoing primary percutaneous coronary intervention

BACKGROUND

Arrhythmias are considered one of the major causes of death in ST elevation myocardial infarction (STEMI), particularly in the early in-hospital phase. Pre-infarction angina (PIA) has been suggested to have a protective role.

OBJECTIVES

To study the difference in acute electrocardiographic findings between STEMI patients with and without PIA and to assess the in-hospital arrhythmias in both groups.

MATERIAL AND METHODS

We prospectively enrolled 238 consecutive patients with STEMI. Patients were divided into two groups: those with or without PIA. ECG data recorded and analyzed included ST-segment resolution (STR) at 90 min, corrected QT interval (QTc) and dispersion (QTD), T-peak-to-T-end interval (Tp-Te), and dispersion and Tp-Te/QT ratio. In-hospital ventricular arrhythmias encountered in both groups were recorded. Predictors of in-hospital arrhythmias were assessed among different clinical and electrocardiographic parameters.

RESULTS

Of the 238 patients included, 42 (17%) had PIA and 196 (83%) had no PIA. Patients with PIA had higher rates of STR (p < 0.0001), while patients with no PIA had higher values of QTc (p = 0.006), QTD (p = 0.001), Tp-Te interval (p = 0.001), Tp-Te dispersion (p < 0.0001), and Tp-Te/QT ratio (p = 0.01) compared to those with angina preceding their incident infarction (PIA). This was reflected into significantly higher rates of in-hospital arrhythmias among patients with no PIA (20% vs. 7%, p = 0.04). Furthermore, longer Tp-Te interval and higher Tp-Te/QT ratio independently predicted in-hospital ventricular arrhythmias.

CONCLUSION

Pre-infarction angina patients had better electrocardiographic measures of repolarization dispersion and encountered significantly less arrhythmic events compared to patients who did not experience PIA.