Automatic wide complex tachycardia differentiation using mathematically synthesized vectorcardiogram signals.

BACKGROUND: Automated wide complex tachycardia (WCT) differentiation into ventricular tachycardia (VT) and supraventricular wide complex tachycardia (SWCT) may be accomplished using novel calculations that quantify the extent of mean electrical vector changes between the WCT and baseline electrocardiogram (ECG). At present, it is unknown whether quantifying mean electrical vector changes within three orthogonal vectorcardiogram (VCG) leads (X, Y, and Z leads) can improve automated VT and SWCT classification. METHODS: A derivation cohort of paired WCT and baseline ECGs was used to derive five logistic regression models: (i) one novel WCT differentiation model (i.e., VCG Model), (ii) three previously developed WCT differentiation models (i.e., WCT Formula, VT Prediction Model, and WCT Formula II), and (iii) one "all-inclusive" model (i.e., Hybrid Model). A separate validation cohort of paired WCT and baseline ECGs was used to trial and compare each model's performance. RESULTS: The VCG Model, composed of WCT QRS duration, baseline QRS duration, absolute change in QRS duration, X-lead QRS amplitude change, Y-lead QRS amplitude change, and Z-lead QRS amplitude change, demonstrated effective WCT differentiation (area under the curve [AUC] 0.94) for the derivation cohort. For the validation cohort, the diagnostic performance of the VCG Model (AUC 0.94) was similar to that achieved by the WCT Formula (AUC 0.95), VT Prediction Model (AUC 0.91), WCT Formula II (AUC 0.94), and Hybrid Model (AUC 0.95). CONCLUSION: Custom calculations derived from mathematically synthesized VCG signals may be used to formulate an effective means to differentiate WCTs automatically.

Conceptual and literature basis for wide complex tachycardia and baseline ECG comparison.

Accurate wide QRS complex tachycardia (WCT) differentiation into either ventricular tachycardia or supraventricular wide complex tachycardia using 12­lead electrocardiogram (ECG) interpretation is essential for diagnostic, therapeutic, and prognostic reasons. There is an ever-expanding variety of WCT differentiation methods and criteria available to clinicians. However, only a few make use of the diagnostic value of comparing the ECG during WCT to that of the patient's baseline ECG. Therefore, we highlight the conceptual rationale and scientific literature supporting the diagnostic value of WCT and baseline ECG comparison.

Increased risk of hematoma with uninterrupted warfarin in patients undergoing implantation of subcutaneous implantable cardioverter defibrillator.

BACKGROUND: The perioperative management of anticoagulation with the use of subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation is still evolving. OBJECTIVE: The purpose of this study was to assess whether it is safe to perform S-ICD implantation with uninterrupted warfarin. METHODS: This is a multi-center retrospective review of patients undergoing S-ICD implantation between October 1, 2012 and June 30, 2017. Forty-eight patients underwent successful S-ICD implantation during the study period. The most common indication for implantation was primary prevention of sudden cardiac death. In 23 (47.9%) patients, warfarin was continued without any interruption. In 25 (52.1%) patients, warfarin was interrupted prior to implantation. The incidence of clinically significant lateral pocket hematoma was compared in the two groups. RESULTS: The mean international normalized ratio was 2.0 ± 0.4 in the uninterrupted group and 1.4 ± 0.4 for the interrupted group. A total of seven patients developed a hematoma at the lateral pocket. No patient developed a hematoma at the parasternal pockets. Six patients in the uninterrupted group (26.1%) and one patient in the interrupted group (0.04%) developed a significant lateral pocket hematoma (P = .04). The concomitant use of dual antiplatelet therapy did not increase the risk of hematoma. There was no significant difference between HASBLED and CHA2 DS2 VASc scores between the groups. None of the patients with a hematoma developed infection or required hematoma evacuation. CONCLUSIONS: The uninterrupted use of warfarin in the perioperative period of S-ICD implantation is associated with an increased risk of lateral pocket hematoma.

Differentiating wide complex tachycardias: A historical perspective.

One of the most critical and challenging skills is the distinction of wide complex tachycardias into ventricular tachycardia or supraventricular wide complex tachycardia. Prompt and accurate differentiation of wide complex tachycardias naturally influences short- and long-term management decisions and may directly affect patient outcomes. Currently, there are many useful electrocardiographic criteria and algorithms designed to distinguish ventricular tachycardia and supraventricular wide complex tachycardia accurately; however, no single approach guarantees diagnostic certainty. In this review, we offer an in-depth analysis of available methods to differentiate wide complex tachycardias by retrospectively examining its rich literature base - one that spans several decades.

Perioperative management of oral anticoagulation in patients undergoing implantation of subcutaneous implantable cardioverter-defibrillator.

BACKGROUND: The perioperative anticoagulation management during subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation is still evolving. OBJECTIVE: The purpose of this study was to assess whether it is safe to perform S-ICD implantation with uninterrupted warfarin. METHODS: This is a single-center retrospective review of patients undergoing S-ICD implantation between October 1, 2012 and June 30, 2017. One hundred thirty-seven patients underwent successful S-ICD implantation during the study period. The most common indication for implantation was primary prevention of sudden cardiac death. In 24 (17.5%) patients, warfarin was continued without any interruption (warfarin group). In 113 (82.5%) patients, no warfarin was used in the perioperative period (nonwarfarin group). The incidence of clinically significant lateral pocket hematoma was compared in the 2 groups. RESULTS: The mean international normalized ratio was 1.83 ± 0.47 in the warfarin group and 1.09 ± 0.18 in the nonwarfarin group. A total of 8 patients developed a hematoma at the lateral pocket. No patient developed a hematoma at the parasternal pockets. Six patients (25%) in the warfarin group and 2 (1.5%) in the nonwarfarin group developed a significant lateral pocket hematoma (P = .001). The mean length of stay was longer in the warfarin group (1.23 ± 0.46 days) than in the nonwarfarin group (1.02 ± 0.18 days) (P = .0008). An international normalized ratio of >1.8 predicted the risk of hematoma. The concomitant use of dual antiplatelet therapy did not increase the risk of hematoma. None of the patients with a hematoma developed infection or required hematoma evacuation. CONCLUSION: Uninterrupted warfarin in the perioperative period during S-ICD implantation is associated with an increased risk of significant lateral pocket hematoma that results in prolonged hospital stay.

Role of exercise electrocardiogram to screen for T-wave oversensing after implantation of subcutaneous implantable cardioverter-defibrillator.

BACKGROUND: During early experience with subcutaneous implantable cardioverter-defibrillators (S-ICD), several patients had inappropriate shocks from T-wave oversensing (TWOS) during exercise. This prompted some operators to perform routine treadmill exercise tests after implantation of S-ICD to screen for TWOS. Meanwhile, improvements have been made in the detection algorithms by the manufacturer. OBJECTIVE: To assess whether routine treadmill exercise post S-ICD implantation is warranted. METHODS: Patients undergoing S-ICD implantation from October 2012 to December 2016 who were able to complete a treadmill exercise were included in the study. The amplitude of R and T waves as assessed by the device programmer at rest and peak exercise was calculated and incidence of TWOS recorded. RESULTS: Eighty-seven patients with complete treadmill exercise test data were included in the final analysis. The majority of the patients received S-ICD for primary prevention. Nine percent of the included patients had hypertrophic obstructive cardiomyopathy. During treadmill exercise, there was significant increase in the heart rate from rest (77 ± 14 beats per minute) to peak exercise (133 ± 14 beats per minute; P < .0001). There was no significant difference between R-wave amplitude at rest (2 ± 0.77 mV) and peak exercise (1.88 ± 0.94 mV; P = .36). Similarly, there was no significant difference between T-wave amplitude at rest (0.27 ± 0.19 mV) and peak exercise (0.33 ± 0.23 mV; P = .06). The incidence of TWOS during exercise was zero. CONCLUSIONS: With current screening and detection algorithms for S-ICD, routine treadmill exercise does not result in additional discrimination of patients susceptible to TWOS.