Regularly irregular tachycardia and QRS alternans? Think twice!
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ABSTRACT:
SUBMITTER: Grade Santos J
PROVIDER: S-EPMC10986392 | biostudies-literature | 2024 Apr
REPOSITORIES: biostudies-literature
Publications
Regularly irregular tachycardia and QRS alternans? Think twice!
Grade Santos João J Almeida Sofia S Brandão Luís L
European heart journal. Case reports 20240326 4
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Project description:BackgroundUhl's anomaly is a rare congenital heart disease characterized by 'Paper-like thinning of the right ventricular (RV) wall'. Since most patients with Uhl's anomaly die in infancy or childhood, the adult cases of this disorder have been limitedly reported and there were no past report describing this anomaly with ventricular tachycardia (VT), in which catheter ablation was successfully performed.Case summaryWe report the case of a 43-year-old man with a suggested Uhl's anomaly and VT. He underwent a catheter ablation of the recurrent VT. An electrophysiological study showed the VT (cycle length = 460 ms) with a right bundle branch block pattern and inferior axis represented QRS alternans. Concealed entrainment by pacing from the anterior right ventricle (RV) suggested the mechanism of this VT was re-entry and the QRS alternans was simultaneously reproduced during the pacing. Furthermore, the intracardiac electrograms exhibiting local conduction blocks were documented on the RV free wall near the apex. The electrograms seen in a 2:1 ratio were coincident with slurs in the initial QRS on the 12-lead electrocardiogram. Since the anterior RV wall was considered to be a part of the VT circuit, a linear ablation in that area was performed resulting in VT termination.DiscussionThe local conduction blocks near the RV apex were related to the mechanism of the QRS alternans during the VT in this case. That might be based on the variations in the myocardium lying in the RV, which is the specific feature of Uhl's anomaly.
| S-EPMC6439377 | biostudies-literature
Project description:BackgroundTo develop a new algorithm to differentiate ventricular tachycardia (VT) from preexcited tachycardia (pre-ET) according to left bundle branch block (LBBB) and right bundle branch block (RBBB) patterns.MethodsThis study included 67 electrocardiograms (ECGs) with VT and 63 ECGs with pre-ET, collected from our hospital and through PubMed. Of those, 64 were allocated to the derivation cohort and the rest to the validation cohort. The diagnoses of the ECGs were confirmed using an electrophysiological study. Parameters and classifiers from prior algorithms along with the propagation speeds in the early portion of the QRS complex (initial deflection index) in leads V1, V6, aVR, II, and III were manually measured. The performance of the new algorithm was compared with that of prior algorithms.ResultsThe initial deflection index in lead III was the strongest predictor of pre-ET in LBBB-pattern wide-QRS tachycardia (p = 0.003, AUC 0.805). The initial deflection index in lead V1 was the most powerful predictor of pre-ET in RBBB-pattern wide-QRS tachycardia (p = 0.001, AUC 0.848). Compared to earlier algorithms, those using the initial deflection indexes: lead III in LBBB patterns (cutoff value >0.3) and lead V1 in RBBB patterns (cutoff value ≤0.48), demonstrated superior performance in screening VT, with AUC values of 0.828. The initial deflection indexes proved effective as discriminators between VT and pre-ET in the validation cohort.ConclusionsIn LBBB-pattern wide-QRS tachycardia, the early propagation speed of pre-ET was faster than that in VT. Conversely, in RBBB-pattern wide-QRS tachycardia, it was slower.
| S-EPMC10943251 | biostudies-literature
Project description: Not available
| S-EPMC11628807 | biostudies-literature
Project description:BackgroundWide QRS complex tachycardia (WCT) differentiation into ventricular tachycardia (VT) and supraventricular wide complex tachycardia (SWCT) remains challenging despite numerous 12-lead electrocardiogram (ECG) criteria and algorithms. Automated solutions leveraging computerized ECG interpretation (CEI) measurements and engineered features offer practical ways to improve diagnostic accuracy. We propose automated algorithms based on (i) WCT QRS polarity direction (WCT Polarity Code [WCT-PC]) and (ii) QRS polarity shifts between WCT and baseline ECGs (QRS Polarity Shift [QRS-PS]).MethodsIn a three-part study, we derive and validate machine learning (ML) models-logistic regression (LR), artificial neural network (ANN), Random Forests (RF), support vector machine (SVM), and ensemble learning (EL)-using engineered (WCT-PC and QRS-PS) and previously established WCT differentiation features. Part 1 uses WCT ECG measurements alone, Part 2 pairs WCT and baseline ECG features, and Part 3 combines all features used in Parts 1 and 2 RESULTS: Among 235 WCT patients (158 SWCT, 77 VT), 103 had gold standard diagnoses. Part 1 models achieved AUCs of 0.86-0.88 using WCT ECG features alone. Part 2 improved accuracy with paired ECGs (AUCs 0.90-0.93). Part 3 showed variable results (AUC 0.72-0.93), with RF and SVM performing best.ConclusionsIncorporating engineered parameters related to QRS polarity direction and shifts can yield effective WCT differentiation, presenting a promising approach for automated CEI algorithms.
| S-EPMC11688452 | biostudies-literature
Project description:Differential diagnosis of wide QRS tachycardia (WQRST) on the electrocardiogram remains a challenging exercise. Correct diagnosis is important for prescribing appropriate therapy and determining prognosis. Differential diagnosis of wide QRS tachycardia revolves around differentiation between supraventricular tachycardia with aberrant conduction and ventricular tachycardia. Observations such as clinical history, findings of physical examination during tachycardia, AV dissociation, QRS morphology in lead V1 and lead V6, precordial concordance, RS complexes in precordial leads, contralateral bundle branch block during wide QRS tachycardia, R wave morphologies in lead aVR, and ventricular initial/terminal velocity of conduction ratio can help arrive at the correct diagnosis with reasonable accuracy. The observations described here can help arrive at the correct diagnosis of WQRST with both reasonable accuracy and confidence.
| S-EPMC8485819 | biostudies-literature
Project description:Background Action potential alternans can induce ventricular tachyarrhythmias and manifest on the surface ECG as T-wave alternans (TWA) and QRS alternans (QRSA). We sought to evaluate microvolt QRSA in cardiomyopathy patients in relation to TWA and ventricular tachyarrhythmia outcomes. Methods and Results Prospectively enrolled cardiomyopathy patients (n=100) with prophylactic defibrillators had 12-lead ECGs recorded during ventricular pacing from 100 to 120 beats/min. QRSA and TWA were quantified in moving 128-beat segments using the spectral method. Segments were categorized as QRSA positive (QRSA+) and/or TWA positive (TWA+) based on ≥2 precordial leads having alternans magnitude >0 and signal:noise >3. Patients were similarly categorized based on having ≥3 consecutive segments with alternans. TWA+ and QRSA+ occurred together in 31% of patients and alone in 18% and 14% of patients, respectively. Although TWA magnitude (1.4±0.4 versus 4.7±1.0 µV, P<0.01) and proportion of TWA+ studies (16% versus 46%, P<0.01) increased with rate, QRSA did not change. QRS duration was longer in QRSA+ than QRSA-negative patients (138±23 versus 113±26 ms, P<0.01). At 3.5 years follow-up, appropriate defibrillator therapy or sustained ventricular tachyarrhythmia was greater in QRSA+ than QRSA-negative patients (30% versus 8%, P=0.02) but similar in TWA+ and TWA-negative patients. Among QRSA+ patients, the event rate was greater in those without TWA (62% versus 21%, P=0.02). Multivariable Cox analysis revealed QRSA+ (hazard ratio [HR], 4.6; 95% CI, 1.5-14; P=0.009) and QRS duration >120 ms (HR, 4.1; 95% CI, 1.3-12; P=0.014) to predict events. Conclusions Microvolt QRSA is novel phenomenon in cardiomyopathy patients that can exist without TWA and is associated with QRS prolongation. QRSA increases the risk of ventricular tachyarrhythmia 4-fold, which merits further study as a risk stratifier.
| S-EPMC7660784 | biostudies-literature
Project description:BackgroundThe incidence of sudden arrhythmic death is markedly increased in diabetics.ObjectiveThe purpose of this study was to develop a mouse model for postmyocardial infarction (post-MI) ventricular tachycardia (VT) in the diabetic heart and determine the mechanism of an antiarrhythmic effect of statins.MethodsECG transmitters were implanted in wild-type (WT), placebo, and pravastatin-treated type I diabetic Akita mice. MIs were induced by coronary ligation, and Ca2+ transients were studied by optical mapping, and Ca2+ transients and sparks in left ventricular myocytes (VM) by the Ionoptix system and confocal microscopy.ResultsBurst pacing of Akita mouse hearts resulted in rate-related QRS/T-wave alternans, which was attenuated in pravastatin-treated mice. Post-MI Akita mice developed QRS/T-wave alternans and VT at 2820 ± 879 beats per mouse, which decreased to 343 ± 115 in pravastatin-treated mice (n = 13, P <.05). Optical mapping demonstrated pacing-induced VT originating in the peri-infarction zone and Ca2+ alternans, both attenuated in hearts of statin-treated mice. Akita VM displayed Ca2+ alternans, and triggered activity as well as increased Ca2+ transient decay time (Tau), Ca2+ sparks, and cytosolic Ca2+ and decreased SR Ca2+ stores all of which were in part reversed in cells from statin treated mice. Homogenates of Akita ventricles demonstrated decreased SERCA2a/PLB ratio and increased ratio of protein phosphatase (PP-1) to the PP-1 inhibitor PPI-1 which were reversed in homogenates of pravastatin-treated Akita mice.ConclusionPravastatin decreased the incidence of post-MI VT and Ca2+ alternans in Akita mouse hearts in part by revering abnormalities of Ca2+ handling via the PP-1/PPI-1 pathway.
| S-EPMC5713915 | biostudies-literature
Project description:Hyper-realistic manipulations of audio-visual content, i.e., deepfakes, present new challenges for establishing the veracity of online content. Research on the human impact of deepfakes remains sparse. In a pre-registered behavioral experiment (N = 210), we show that (1) people cannot reliably detect deepfakes and (2) neither raising awareness nor introducing financial incentives improves their detection accuracy. Zeroing in on the underlying cognitive processes, we find that (3) people are biased toward mistaking deepfakes as authentic videos (rather than vice versa) and (4) they overestimate their own detection abilities. Together, these results suggest that people adopt a "seeing-is-believing" heuristic for deepfake detection while being overconfident in their (low) detection abilities. The combination renders people particularly susceptible to be influenced by deepfake content.
| S-EPMC8602050 | biostudies-literature
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| S-EPMC7498522 | biostudies-literature
Project description:Background Unlike T-wave alternans (TWA), the relation between QRS alternans (QRSA) and ventricular arrhythmia (VA) risk has not been evaluated in hypertrophic cardiomyopathy (HCM). We assessed microvolt QRSA/TWA in relation to HCM risk factors and late VA outcomes in HCM. Methods and Results Prospectively enrolled patients with HCM (n=130) with prophylactic implantable cardioverter-defibrillators underwent digital 12-lead ECG recordings during ventricular pacing (100-120 beats/min). QRSA/TWA was quantified using the spectral method. Patients were categorized as QRSA+ and/or TWA+ if sustained alternans was present in ≥2 precordial leads. The VA end point was appropriate implantable cardioverter-defibrillator therapy over 5 years of follow-up. QRSA+ and TWA+ occurred together in 28% of patients and alone in 7% and 7% of patients, respectively. QRSA magnitude increased with pacing rate (1.9±0.6 versus 6.2±2.0 µV; P=0.006). Left ventricular thickness was greater in QRSA+ than in QRSA- patients (22±7 versus 20±6 mm; P=0.035). Over 5 years follow-up, 17% of patients had VA. The annual VA rate was greater in QRSA+ versus QRSA- patients (5.8% versus 2.0%; P=0.006), with the QRSA+/TWA- subgroup having the greatest rate (13.3% versus 2.6%; P<0.001). In those with <2 risk factors, QRSA- patients had a low annual VA rate compared QRSA+ patients (0.58% versus 7.1%; P=0.001). Separate Cox models revealed QRSA+ (hazard ratio [HR], 2.9 [95% CI, 1.2-7.0]; P=0.019) and QRSA+/TWA- (HR, 7.9 [95% CI, 2.9-21.7]; P<0.001) as the most significant VA predictors. TWA and HCM risk factors did not predict VA. Conclusions In HCM, microvolt QRSA is a novel, rate-dependent phenomenon that can exist without TWA and is associated with greater left ventricular thickness. QRSA increases VA risk 3-fold in all patients, whereas the absence of QRSA confers low VA risk in patients with <2 risk factors. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02560844.
| S-EPMC9075383 | biostudies-literature