Effect of Transcutaneous Magnetic Stimulation in Patients With Ventricular Tachycardia Storm: A Randomized Clinical Trial

IMPORTANCE

Autonomic neuromodulation provides therapeutic benefit in ventricular tachycardia (VT) storm. Transcutaneous magnetic stimulation (TcMS) can noninvasively and nondestructively modulate a patient's nervous system activity and may reduce VT burden in patients with VT storm.

OBJECTIVE

To evaluate the safety and efficacy of TcMS of the left stellate ganglion for patients with VT storm.

DESIGN, SETTING, AND PARTICIPANTS

This double-blind, sham-controlled randomized clinical trial took place at a single tertiary referral center between August 2019 and July 2021. The study included 26 adult patients with 3 or more episodes of VT in 24 hours.

INTERVENTIONS

Patients were randomly assigned to receive a single session of either TcMS that targeted the left stellate ganglion (n = 14) or sham stimulation (n = 12).

MAIN OUTCOMES AND MEASURES

The primary outcome was freedom from VT in the 24-hour period following randomization. Key secondary outcomes included safety of TcMS on cardiac implantable electronic devices, as well as burden of VT in the 72-hour period following randomization.

RESULTS

Among 26 patients (mean [SD] age, 64 [13] years; 20 [77%] male), a mean (SD) of 12.7 (10.3) episodes of VT occurred within the 24 hours preceding randomization. Patients had recurrent VT despite taking a mean (SD) of 2.0 (0.6) antiarrhythmic drugs (AADs), and 11 patients (42%) required mechanical hemodynamic support at the time of randomization. In the 24-hour period after randomization, VT recurred in 4 of 14 patients (29% [SD 47%]) in the TcMS group vs 7 of 12 patients (58% [SD 51%]) in the sham group (P = .20). In the 72-hour period after randomization, patients in the TcMS group had a mean (SD) of 4.5 (7.2) episodes of VT vs 10.7 (13.8) in the sham group (incidence rate ratio, 0.42; P < .001). Patients in the TcMS group were taking fewer AADs 24 hours after randomization compared with baseline (mean [SD], 0.9 [0.8] vs 1.8 [0.4]; P = .001), whereas there was no difference in the number of AADs taken for the sham group (mean [SD], 2.3 [0.8] vs 1.9 [0.5]; P = .20). None of the 7 patients in the TcMS group with a cardiac implantable electronic device had clinically significant effects on device function.

CONCLUSIONS AND RELEVANCE

In this randomized clinical trial, findings support the potential for TcMS to safely reduce the burden of VT in the setting of VT storm in patients with and without cardiac implantable electronic devices and inform the design of future trials to further investigate this novel treatment approach.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04043312.

Longitudinal Electrocardiographic Assessment in the Brugada Syndrome

Background

The type 1 electrocardiographic (ECG) pattern diagnostic of Brugada syndrome (BrS) can be dynamic. Limited studies have rigorously evaluated the temporal stability of the Brugada ECG pattern.

Objective

We sought to evaluate fluctuations of the Brugada pattern in serial resting ECGs from BrS patients managed within a large health care system.

Methods

In our cohort of BrS patients with at least 2 standard, resting ECGs recorded on separate clinical encounters, we evaluated serial changes in the Brugada pattern and categorized patients into 1 of 3 groups: dynamic was defined as the presence of both type 1 and non–type 1 patterns in available ECGs; the provoked-only group was defined as having a non–type 1 Brugada pattern across resting ECGs; and the persistent group was defined as having a type 1 pattern on all ECGs. We also evaluated the clinical risk in this cohort according to the Shanghai risk score.

Results

In 72 patients with BrS (mean age 46 ± 15 years, 69% male), 828 standard, resting ECGs were recorded over a median duration of 30.2 (interquartile range 6.3–68.1) months. The dynamic group comprised 50 (69% of the cohort) patients, the provoked-only group consisted of 17 patients (24% of the cohort), and the persistent group included 5 patients. No significant differences were detected in the total number of ECGs evaluated during the follow-up period between any of the groups. Only sinus node dysfunction and a prior cardiac arrest were associated with the persistent type 1 group. The majority of patients had a low annualized risk of lethal arrhythmic events.

Conclusion

Most BrS patients have a dynamic Brugada pattern noted on longitudinal, resting ECGs. Expert consensus statements should provide clarity on the frequency of obtaining resting ECGs in patients suspected of having BrS during follow-up.

Substrate Characterization and Outcome of Catheter Ablation of Ventricular Tachycardia in Patients With Nonischemic Cardiomyopathy and Isolated Epicardial Scar

BACKGROUND

The substrate for ventricular tachycardia (VT) in left ventricular (LV) nonischemic cardiomyopathy may be epicardial. We assessed the prevalence, location, endocardial electrograms, and VT ablation outcomes in LV nonischemic cardiomyopathy with isolated epicardial substrate.

METHODS

Forty-seven of 531 (9%) patients with LV nonischemic cardiomyopathy and VT demonstrated normal endocardial (>1.5 mV)/abnormal epicardial bipolar low-voltage area (LVA, <1.0 mV and signal abnormality). Abnormal endocardial unipolar LVA (≤8.3 mV) and endocardial bipolar split electrograms and predictors of ablation success were assessed.

RESULTS

Epicardial bipolar LVA (27.3 cm² [interquartile range, 15.8-50.0]) localized to basal (40), mid (8), and apical (3) LV with basal inferolateral LV most common (28/47, 60%). Of 44 endocardial maps available, 40 (91%) had endocardial unipolar LVA (24.5 cm² [interquartile range, 9.4-68.5]) and 29 (67%) had characteristic normal amplitude endocardial split electrograms opposite the epicardial LVA. At mean of 34 months, the VT-free survival was 55% after one and 72% after multiple procedures. Greater endocardial unipolar LVA than epicardial bipolar LVA (hazard ratio, 10.66 [CI, 2.63-43.12], P=0.001) and number of inducible VTs (hazard ratio, 1.96 [CI, 1.27-3.00], P=0.002) were associated with VT recurrence.

CONCLUSIONS

In patients with LV nonischemic cardiomyopathy and VT, the substrate may be confined to epicardial and commonly basal inferolateral. LV endocardial unipolar LVA and normal amplitude bipolar split electrograms identify epicardial LVA. Ablation targeting epicardial VT and substrate achieves good long-term VT-free survival. Greater endocardial unipolar than epicardial bipolar LVA and more inducible VTs predict VT recurrence.

Persistent Opioid Use After Cardiac Implantable Electronic Device Procedures

BACKGROUND

Prescription opioids are a major contributor to the ongoing epidemic of persistent opioid use (POU). The incidence of POU among opioid-naïve patients after cardiac implantable electronic device (CIED) procedures is unknown.

METHODS

This retrospective cohort study used data from a national administrative claims database from 2004 to 2018 of patients undergoing CIED procedures. Adult patients were included if they were opioid-naïve during the 180-day period before the procedure and did not undergo another procedure with anesthesia in the next 180 days. POU was defined by filling an additional opioid prescription >30 days after the CIED procedure.

RESULTS

Of the 143 400 patients who met the inclusion criteria, 15 316 (11%) filled an opioid prescription within 14 days of surgery. Among these patients, POU occurred in 1901 (12.4%) patients 30 to 180 days after surgery. The likelihood of developing POU was increased for patients who had a history of drug abuse (odds ratio, 1.52; P=0.005), preoperative muscle relaxant (odds ratio, 1.52; P<0.001) or benzodiazepine (odds ratio, 1.23; P=0.001) use, or opioid use in the previous 5 years (OR, 1.76; P<0.0001). POU did not differ after subcutaneous implantable cardioverter defibrillator or other CIED procedures (11.1 versus 12.4%; P=0.5). In a sensitivity analysis excluding high-risk patients who were discharged to a facility or who had a history of drug abuse or previous opioid, benzodiazepine, or muscle relaxant use, 8.9% of the remaining cohort had POU. Patients prescribed >135 mg of oral morphine equivalents had a significantly increased risk of POU.

CONCLUSIONS

POU is common after CIED procedures, and 12% of patients continued to use opioids >30 days after surgery. Higher initially prescribed oral morphine equivalent doses were associated with developing POU.

Sex Differences in Ablation Strategy, Lesion Sets, and Complications of Catheter Ablation for Atrial Fibrillation: An Analysis From the GWTG-AFIB Registry

BACKGROUND

When presenting for atrial fibrillation (AF) ablation, women, compared with men, tend to have more nonpulmonary vein triggers and advanced atrial disease. Whether this informs differences in AF ablation strategy is not well described. We aimed to characterize ablation strategy and complications by sex, using the Get With The Guidelines-AF registry.

METHODS

From the Get With The Guidelines-AF registry ablation feature, we included patients who underwent initial AF ablation procedure between January 7, 2016, and December 27, 2019. Patients were stratified based on AF type (paroxysmal versus nonparoxysmal) and sex. We compared patient demographics, ablation strategy, and complications by sex.

RESULTS

Among 5356 patients from 31 sites who underwent AF ablation, 1969 were women (36.8%). Women, compared with men, were older (66.8±9.6 versus 63.4±10.6, P<0.0001) and were more likely to have paroxysmal AF (59.4% versus 49.5%, P<0.0001). In women with nonparoxysmal AF, left atrial linear ablation was more frequent (roof line: 53.9% versus 45.3%, P=0.0002; inferior mitral isthmus line: 10.2% versus 7.0%, P=0.01; floor line: 46.1% versus 40.6%, P=0.02) than in men. In multivariable analysis, the association between patient sex and complications from ablation was not statistically significant.

CONCLUSIONS

In this US wide AF ablation quality improvement registry, women with nonparoxysmal AF were more likely to receive adjunctive lesion sets compared with men. These findings suggest that patient sex may inform ablation strategy in ways that may not be strongly supported by evidence and emphasize the need to clarify optimal ablation strategies by sex.

Pacing-Induced Cardiomyopathy

Right ventricular (RV) pacing-induced cardiomyopathy (PICM) is typically defined as left ventricular systolic dysfunction resulting from electrical and mechanical dyssynchrony caused by RV pacing. RV PICM is common, occurring in 10-20% of individuals exposed to frequent RV pacing. Multiple risk factors for PICM have been identified, including male sex, wider native and paced QRS durations, and higher RV pacing percentage, but the ability to predict which individuals will develop PICM remains modest. Biventricular and conduction system pacing, which better preserve electrical and mechanical synchrony, typically prevent the development of PICM and reverse left ventricular systolic dysfunction after PICM has occurred.

Sinus rhythm QRS amplitude and fractionation in patients with nonischemic cardiomyopathy to identify ventricular tachycardia substrate and location

BACKGROUND

Ventricular tachycardia (VT) substrate in left ventricular (LV) nonischemic cardiomyopathy (NICM) consists of fibrosis with surviving myocardium.

OBJECTIVE

The purpose of this study was to determine whether, in patients with LV NICM and sustained VT, reduced QRS amplitude and QRSf during sinus rhythm can identify the presence and location of abnormal septal (S-NICM) and/or free-wall (FW-NICM) VT substrate.

METHODS

We compared patients with NICM and VT (group 1) with electroanatomic mapping septal (S-NICM; n = 21) or free-wall (FW-NICM; n = 20) VT substrate to a 38-patient reference cohort (group 2) with cardiac magnetic resonance imaging (cMRI) and NICM but no VT referred for primary prevention implantable cardioverter-defibrillator (26 [68.4%] with late gadolinium enhancement).

RESULTS

Group 1 had lower QRS amplitude in leads II (0.60 ± 0.22 vs 0.86 ± 0.35, P <.001), aVR (0.60 ± 0.24 vs 0.75 ± 0.31, P = .002), aVF (0.48 ± 0.20 vs 0.70 ± 0.28, P <.001), and V₂ (1.09 ± 0.52 vs 1.38 ± 0.55, P = .001) than group 2. QRS <0.55 mV in lead aVF identified VT and accompanying substrate with sensitivity 70% and specificity 71%. Most group 1 and group 2 patients had 12-lead ECG QRS fractionation (QRSf) in ≥2 contiguous leads (78% vs 63.2%, P = .14). Sensitivity and specificity for ≥2 QRSf leads identifying respective regional electroanatomic or cMRI abnormalities were 76% and 50% for inferior, 44% and 87% for lateral, and 21% and 89% for anterior leads.

CONCLUSION

In LV NICM, low frontal plane QRS (<0.55 mV in aVF) is associated with VT substrate. Although multilead QRS fractionation is associated with the presence and location of VT substrate, it is frequently identified in patients without VT with cMRI abnormalities.

Interatrial septal tachycardias following atrial fibrillation ablation or cardiac surgery: Electrophysiological features and ablation outcomes

BACKGROUND

Interatrial septal tachycardias (IAS-ATs) following atrial fibrillation (AF) ablation or cardiac surgery are rare, and their management is challenging.

OBJECTIVE

The purpose of this study was to investigate the electrophysiological features and outcomes associated with catheter ablation of IAS-AT.

METHODS

We screened 338 patients undergoing catheter ablation of ATs following AF ablation or cardiac surgery. Diagnosis of IAS-AT was based on activation mapping and analysis of response to atrial overdrive pacing.

RESULTS

Twenty-nine patients (9%) had IAS-AT (cycle length [CL] 311 ± 104 ms); 16 (55%) had prior AF ablation procedures (median 3; range 1-5), 3 (10%) had prior surgical maze, and 12 (41%) had prior cardiac surgery (including atrial septal defect surgical repair in 5 and left atrial myxoma resection in 1). IAS substrate abnormalities were documented in all patients. Activation mapping always demonstrated a diffuse early IAS breakout with centrifugal biatrial activation, and atrial overdrive pacing showed a good postpacing interval (equal or within 25 ms of the AT CL) only at 1 or 2 anatomically opposite IAS sites in all cases. Ablation was acutely successful in 27 patients (93%) (from only the right IAS in 2, only the left IAS in 9, both IAS sides with sequential ablation in 13, and both IAS sides with bipolar ablation in 3). After median follow-up of 15 (6-52) months, 17 patients (59%) remained free from recurrent arrhythmias.

CONCLUSION

IAS-ATs are rare and typically occur in patients with evidence of IAS substrate abnormalities and prior cardiac surgery. Catheter ablation can be challenging and may require sequential unipolar ablation or bipolar ablation.

Stroke, Timing of Atrial Fibrillation Diagnosis, and Risk of Death

OBJECTIVE

To evaluate the prognosis of patients with ischemic stroke according to the timing of an atrial fibrillation (AF) diagnosis, we created an inception cohort of incident stroke events and compared the risk of death between patients with stroke with (1) sinus rhythm, (2) known AF (KAF), and (3) AF diagnosed after stroke (AFDAS).

METHODS

We used the Penn AF Free study to create an inception cohort of patients with incident stroke. Mortality events were identified after linkage with the National Death Index through June 30, 2017. We also evaluated initiation of anticoagulants and antiplatelets across the study duration. Cox proportional hazards models evaluated associations between stroke subtypes and death.

RESULTS

We identified 1,489 individuals who developed an incident ischemic stroke event: 985 did not develop AF at any point during the study period, 215 had KAF before stroke, 160 had AF detected ≤6 months after stroke, and 129 had AF detected >6 months after stroke. After a median follow-up of 4.9 years (interquartile range 1.9-6.8), 686 deaths occurred. The annualized mortality rate was 8.8% in the stroke, no AF group; 12.2% in the KAF group; 15.8% in the AFDAS ≤6 months group; and 12.7% in the AFDAS >6 months group. Patients in the AFDAS ≤6 months group had the highest independent risk of all-cause mortality even after multivariable adjustment for demographics, clinical risk factors, and the use of antithrombotic therapies (hazard ratio 1.62 [1.22-2.14]). Compared to the stroke, no AF group, those with KAF had a higher mortality risk that was rendered nonsignificant after adjustment.

CONCLUSIONS

The AFDAS group had the highest risk of death, which was not explained by comorbidities or use of antithrombotic therapies.

ICE-Derived Left Atrial and Left Ventricular Endocardial and Myocardial Speckle Tracking Strain Patterns in Atrial Fibrillation at the Time of Radiofrequency Ablation

Objectives

Intracardiac echocardiography(ICE) has excellent imaging resolution and border recognition which increase strain measurement accuracy. We hypothesized that left atrial(LA) substrate and functional impairment can be detected by measuring LA strain deformation in patients with persistent and paroxysmal atrial fibrillation(AF), as compared to those with no AF. Strain deformation changes in LA and left ventricle(LV) can also be assessed post-ablation to determine its effect.

Methods

ICE-derived speckle tracking strain(STS) was prospectively performed in 96 patients, including 62 patients with AF(31 persistent and 31 paroxysmal AF) pre-/post-ablation, and 34 patients with no AF. We measured major strain parameters including longitudinal segmental(endo/myocardial) "average peak overall strain of all segments"(PkAll), peak strain rate(SR),and different time-to-peak strain in LA and LV images.

Results

At baseline, persistent AF patients had significantly lower(p<0.01) LA endocardial(4.3±2.5 vs. 20.3±8.9 and 25.5±12.9 %) and myocardial PkAll(4.4±2.6 vs. 15.7±7.2 and 20.9±9.2 %), endocardial(0.9±0.4 vs. 1.8±0.7 and 2.2±0.6 1/s) and myocardial peak SR(0.7±0.4 vs. 1.5±0.6 and 1.9±0.5 1/s), as compared to paroxysmal AF and no AF patients. After successful ablation, endo-/myocardial LA PkAll and peak SR were significantly improved, most dramatically in patients with persistent AF. LV endocardial/myocardial strain and SR also improved in AF patients post-ablation.

Conclusion

LA longitudinal strain(%)/SR(1/s) parameters in AF patients are more abnormal than those with no AF, suggesting LA substrate/functional damage. AF ablation improved LA strains/SR but with values in paroxysmal > persistent AF suggesting background LA damage in persistent AF.

Racial/Ethnic and Socioeconomic Disparities in Management of Incident Paroxysmal Atrial Fibrillation

IMPORTANCE

In patients with paroxysmal atrial fibrillation (AF), rhythm control with either antiarrhythmic drugs (AADs) or catheter ablation has been associated with decreased symptoms, prevention of adverse remodeling, and improved cardiovascular outcomes. Adoption of advanced cardiovascular therapeutics, however, is often slower among patients from racial/ethnic minority groups and those with lower income.

OBJECTIVE

To ascertain the cumulative rates of AAD and catheter ablation use for the management of paroxysmal AF and to investigate for the presence of inequities in AF management by evaluating the association of race/ethnicity and socioeconomic status with their use in the United States.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study obtained inpatient, outpatient, and pharmacy claims data from the Optum Clinformatics Data Mart between October 1, 2015, and June 30, 2019. Adult patients (aged ≥18 years) in the database with a diagnosis of incident paroxysmal AF were identified. Patients were excluded if they did not have continuous insurance enrollment for at least 1 year before and at least 6 months after study entry.

EXPOSURES

Race/ethnicity and zip code-linked median household income.

MAIN OUTCOMES AND MEASURES

Treatment with a rhythm control strategy, and catheter ablation specifically, among those who received rhythm control. Multivariable logistic regression models were used to assess the association of race/ethnicity and zip code-linked median household income with a rhythm control strategy (AADs or catheter ablation) vs a rate control strategy as well as with catheter ablation vs AADs among those receiving rhythm control.

RESULTS

Of the 109 221 patients who met the inclusion criteria, 55 185 were men (50.5%) and 73 523 were White (67.3%), with a median (interquartile range) age of 75 (68-82) years. A total of 86 359 patients (79.1%) were treated with rate control, 19 362 patients (17.7%) with AADs, and 3500 (3.2%) with catheter ablation. Between 2016 and 2019, the cumulative percentage of patients treated with catheter ablation increased from 1.6% to 3.8%. In multivariable analyses, Black race (adjusted odds ratio [aOR], 0.89; 95% CI, 0.83-0.94; P < .001) and lower zip code-linked median household income (aOR for <$50 000: 0.83 [95% CI, 0.79-0.87; P < .001]; aOR for $50 000-$99 999: 0.92 [95% CI, 0.88-0.96; P = <.001] compared with ≥$100 000) were independently associated with lower use of rhythm control. Latinx ethnicity (aOR, 0.73; 95% CI, 0.60-0.89; P = .002) and lower zip code-linked median household income (aOR for <$50 000: 0.61 [95% CI, 0.54-0.69; P < .001]; aOR for $50 000-$99 999: 0.81 [95% CI, 0.72-0.90; P < .001] compared with ≥$100 000) were independently associated with lower catheter ablation use among those receiving rhythm control.

CONCLUSIONS AND RELEVANCE

This study found that despite increased use of rhythm control strategies for treatment of paroxysmal AF, catheter ablation use remained low and patients from racial/ethnic minority groups and those with lower income were less likely to receive rhythm control treatment, especially catheter ablation. These findings highlight inequities in paroxysmal AF management based on race/ethnicity and socioeconomic status.

Oral anticoagulant use in patients with atrial fibrillation and mitral valve repair

BACKGROUND

Patients with atrial fibrillation (AF) who have undergone mitral valve repair are at risk for thromboembolic strokes. Prior to 2019, only vitamin K antagonists were recommended for patients with AF who had undergone mitral valve repair despite the introduction of direct oral anticoagulants (DOAC) in 2010.

OBJECTIVE

To characterize the use of anticoagulants in patients with AF who underwent surgical mitral valve repair (sMVR) or transcatheter mitral valve repair (tMVR).

METHODS

We performed a retrospective cohort analysis of patients with AF undergoing sMVR or tMVR between 04/2014 and 12/2018 using Optum's de-identified Clinformatics® Data Mart Database. We identified anticoagulants prescribed within 90 days of discharge from hospitalization.

RESULTS

Overall, 1997 patients with AF underwent valve repair: 1560 underwent sMVR, and 437 underwent tMVR. The mean CHA₂DS₂-VASc score among all patients was 4.1 (SD 1.9). The overall use of anticoagulation was unchanged between 2014 (72.2%) and 2018 (70.0%) (P = .49). Among patients who underwent sMVR or tMVR between April 2014 and December 2018, the use of VKA therapy decreased from 62.9% to 32.1% (P < .01 for trend) and the use of DOACs increased from 12.4% to 37.3% (P < .01 for trend).

CONCLUSIONS

Among patients with AF who underwent sMVR or tMVR between 2014 and 2018, roughly 30% of patients were not treated with any anticoagulant within 90 days of discharge, despite an elevated stroke risk in the cohort. The rate of DOAC use increased steadily over the study period but did not significantly increase the rate of overall anticoagulant use in this high-risk cohort.