Does ST Elevation in Lead aVR Require an Emergent Trip to the Catheterization Laboratory?

This case report describes a patient in their 50s with hypertension, chronic obstructive pulmonary disease, heavy alcohol use, and tobacco use who presented to the emergency department with a 2-month history of nausea and vomiting.

Prognostic value of silent myocardial infarction in patients with chronic kidney disease after kidney transplantation.

We have shown that silent myocardial infarction (SMI) on 12-lead ECG is associated with increased cardiovascular disease (CVD) risk in patients awaiting renal transplantation (RT). In this study, we evaluated the prevalence of SMI in patients undergoing RT and their prognostic value after RT. MI was determined by automated analysis of ECG. SMI was defined as ECG evidence of MI without a history of clinical MI (CMI). The primary outcome was a composite of CVD death, non-fatal MI and coronary revascularization after RT. Of the 1189 patients who underwent RT, a 12-lead ECG was available in >99%. Of the entire cohort 6% had a history of CMI while 7% had SMI by ECG. During a median follow-up of 4.6 years, 147 (12%) experienced the primary outcome (8% CVD death, 4% MI, 4% coronary revascularization) and 12% died. Both SMI and CMI were associated with an increased risk of CVD events and all-cause deaths. In a multivariable adjusted Cox-regression model, both SMI (adjusted hazard ratio 2.03 [1.25-3.30], p = .004) and CMI (2.15 [1.24-3.74], p = .007) were independently associated with the primary outcome. SMI detected by ECG prior to RT is associated with increased risk of CVD events after RT.

Review of Published Cases of Syncope and Sudden Death in Patients With Severe Aortic Stenosis Documented by Electrocardiography.

The ECG findings during sudden collapse (syncope or sudden death) in severe aortic stenosis (AS) are not well defined. We conducted a comprehensive review of the literature for ECG data during sudden collapse in patients with AS and provided a case report of our own. There were 37 published cases of syncope or sudden death in patients with severe AS which were documented by ECG. Brady- or ventricular arrhythmias were documented in 34 cases (92%). Bradyarrhythmia (n = 24; 71%) was more common at the time of collapse than ventricular tachyarrhythmia (n = 10; 29%). There was slowing of the sinus rate before bradyarrhythmia in the vast majority of patients with bradyarrhythmia but not in those presenting with ventricular tachyarrhythmia (75% vs 0%; p <0.001). ECG evidence of ischemia (ST-segment depression or elevation) was present in most patients with bradyarrhythmia but not in those with ventricular tachyarrhythmia (75% vs 0%; p = 0.011). In conclusion, our findings suggest that left ventricular baroreceptor activation plays a dominant role in the pathophysiology of sudden collapse in patients with severe AS and suggest that ischemia may play a role as well.

Eccentric Activation Patterns in the Left Ventricular Outflow Tract during Idiopathic Ventricular Arrhythmias Originating From the Left Ventricular Summit: A Pitfall for Predicting the Sites of Ventricular Arrhythmia Origins.

BACKGROUND: Idiopathic ventricular arrhythmias (VAs) originating from the left ventricular summit (LVS) can be ablated from the great cardiac vein and remote endocardial sites. The ablation sites are determined by mapping in the great cardiac vein and left ventricular outflow tract. This study investigated whether that mapping could accurately predict the sites of LVS-VA origins. METHODS: We studied 26 consecutive patients with idiopathic LVS-VA origins that were identified in the basal and apical LVS in 15 and 11 patients, respectively. RESULTS: Radiofrequency catheter ablation of the apical LVS-VAs was successful in the great cardiac vein in 9 patients and in the apical LV outflow tract in 2. That of the basal LVS-VAs was successful in the aortomitral continuity in 9 patients, at the junction of the left and right coronary cusps in 4, and in the left coronary cusp in 2. Three apical LVS-VAs exhibited an eccentric endocardial activation pattern that was from the basal to apical LV outflow tract. In 11 basal LVS-VAs, the activation pattern was eccentric because the ventricular activation within the great cardiac vein in the apical LVS was earlier than that in the basal LV outflow tract. In 2 basal LVS-VAs, the activation pattern was eccentric because a relatively early ventricular activation was recorded at multiple sites away from the successful ablation site. CONCLUSIONS: Eccentric activation patterns often occurred during idiopathic LVS-VAs, which could mislead the catheter ablation of those VAs. Understanding such eccentric activation patterns was suggested to be able to improve the outcomes of the catheter ablation of those VAs by the anatomic approach.

Subclinical atrial fibrillation detection with a floating atrial sensing dipole in single lead implantable cardioverter-defibrillator systems: Results of the SENSE trial.

INTRODUCTION: Subclinical atrial fibrillation (AF), in the form of cardiac implantable device-detected atrial high rate episodes (AHREs), has been associated with increased thromboembolism. An implantable cardioverter-defibrillator (ICD) lead with a floating atrial dipole may permit a single lead (DX) ICD system to detect AHREs. We sought to assess the utility of the DX ICD system for subclinical AF detection in patients, with a prospective multicenter, cohort-controlled trial. METHODS AND RESULTS: One hundred fifty patients without prior history of AF (age 59 ± 13 years; 108 [72%] male) were enrolled into the DX cohort and implanted with a Biotronik DX ICD system at eight centers. Age-, sex-, and left ventricular ejection fraction-matched single- and dual-chamber ICD cohorts were derived from a Cornell database and from the IMPACT trial, respectively. The primary endpoint were AHRE detection at 12 months. During median 12 months follow-up, AHREs were detected in 19 (13%) patients in the DX, 8 (5.3%) in the single-chamber, and 19 (13%) in the dual-chamber cohorts. The rate of AHRE detection was significantly higher in the DX cohort compared to the single-chamber cohort (P = .026), but not significantly different compared to the dual-chamber cohort. There were no inappropriate ICD therapies in the DX cohort. At 12 months, only 3.0% of patients in the DX cohort had sensed atrial amplitudes less than 1.0 mV. CONCLUSION: Use of a DX ICD lead allows subclinical AF detection with a single lead DX system that is superior to that of a conventional single-chamber ICD system.

New atrial fibrillation diagnosed by 30-day rhythm monitoring.

BACKGROUND: Recent studies of patients with pacemakers and implantable cardioverter/defibrillators have shown that subclinical atrial fibrillation (AF) is common and is associated with thromboembolic risk. We sought to evaluate the frequency, characteristics, and impact of new AF diagnosed by ambulatory 30-day rhythm monitoring. METHODS: The 30-day rhythm monitoring data from January 2010 to August 2015 at our institution were reviewed. Medical record review was performed on patients that had a new or preexisting diagnosis of AF. RESULTS: Of 2,326 patients without a previous diagnosis of AF, 78 had a new diagnosis of AF (3.4%) during 30-day monitoring. Patients with a new diagnosis of AF (mean age of 68.5 years, 56% female) had a mean CHA2DS2-VASc score of 3.2 (±1.8). The median time to diagnosis was 6 days, and 86% were diagnosed within 14 days. In 31 patients (40%), AF was exclusively detected automatically by the monitor. Of 46 patients that had manually activated the monitor, 34 also had automatically detected AF. Each patient had a median of 7 episodes, with the median duration of the longest episode being approximately 2 hours. Following the diagnosis of AF, 37 (47%) were started on anticoagulation and 9 (12%) were prescribed aspirin. CONCLUSIONS: A total of 3.4% of patients who underwent 30-day rhythm monitoring for any indication were found to have a new diagnosis of AF (402 per 1000 patient-years). Most of these episodes were detected automatically, corresponding to device-detected subclinical AF. The most common intervention following diagnosis of AF was initiation of oral anticoagulation.

Incidence of atrioventricular block with vasodilator stress SPECT: A meta-analysis.

BACKGROUND: Adenosine or regadenoson are often used with pharmacologic stress testing. Adenosine may trigger atrioventricular block (AVB). Despite its higher selectivity, regadenoson has also been associated with AVB. We studied the incidence of de novo AVB with these agents. METHODS: A comprehensive search of SCOPUS was performed from inception to March 2016. Studies of at least 10 patients, using adenosine and/or regadenoson with SPECT-MPI, reporting rates of AVB were selected for further review. RESULTS: Thirty four studies were pooled including 22,957 patients. Adenosine was used in 21 studies and regadenoson in 15. Both were administered in two studies. The estimated incidence of overall and high-grade AVB was 3.81% (95% CI 1.99%-6.19%) and 1.93% (95% CI 0.77%-3.59%), respectively. The incidence of AVB (8.58%; 95% CI 5.55%-12.21% vs 0.30%; 95% CI 0.04%-0.82%, respectively, P < .001) and high-grade AVB (5.21%; 95% CI 2.81%-8.30% vs 0.05%; 95% CI < .001%-0.19% respectively, P < .001) were higher with adenosine compared to regadenoson. CONCLUSION: AVB is seen in about 4% of patients undergoing vasodilator stress test. Both overall and high-grade AVB are more frequent with adenosine compared to regadenoson.

Acute Hemodynamic Effects of Biventricular Pacing After Left Ventricular Assist Device.

BACKGROUND: Despite cardiac resynchronization therapy (CRT), some patients with heart failure progress and undergo left ventricular assist device (LVAD) implantation. Management of CRT after LVAD implantation has not been well studied. The purpose of this study was to determine whether RV pacing or biventricular pacing measurably affects acute hemodynamics in patients with an LVAD and a CRT device. METHODS AND RESULTS: Seven patients with CRT and LVAD underwent right heart catheterization. Pressures and oximetry were measured and LVAD parameters were recorded during 3 different conditions: RV pacing alone, biventricular pacing, and intrinsic atrioventricular conduction. Paired t tests were used to evaluate changes within subjects. There were no significant changes in right atrial pressure, pulmonary arterial pressures, pulmonary capillary wedge pressure, cardiac index, or any LVAD parameter (P > .05). CONCLUSIONS: Our data suggest that CRT probably has no acute hemodynamic effect in patients with LVADs, but further study is needed.

Idiopathic Ventricular Arrhythmias Originating From the Infundibular Muscles: Prevalence, Electrocardiographic and Electrophysiological Characteristics, and Outcome of Catheter Ablation.

BACKGROUND: This study investigated the prevalence, electrocardiographic and electrophysiological characteristics, and ablation outcome of idiopathic ventricular arrhythmias (VAs) originating from the infundibular muscles (IFMs) in the right ventricle consisting of the parietal band (PB) and septal band (SB). METHODS AND RESULTS: We studied 19 patients with idiopathic VA origins in the PB in 14 and SB in 5 among 294 consecutive patients with VA origins in the right ventricle. PB and SB VAs exhibited left bundle branch block with a left inferior (n=12) or superior (n=2) axis and left (n=4) or right inferior (n=1) axis pattern, respectively. In lead I, all PB VAs exhibited R waves while SB VAs often exhibited S waves. A QS pattern in lead aVR and the presence of a notch in the mid-QRS were common in all IFMs VAs. During IFMs VAs, a far-field ventricular electrogram with an early activation was always recorded in the His bundle region regardless of the location of the VA origins. With 9.2±6.9 radiofrequency applications and a duration of 972±946 seconds, catheter ablation was successful in 15 patients. VAs recurred in 4 during a follow-up period of 43±24 months. A change in the QRS morphology was observed spontaneously in 5 patients, immediately after ablation in 4, and at the time of the VA recurrence in 2. CONCLUSIONS: Idiopathic VAs originating from the IFMs are rare (PB>SB). Catheter ablation of these IFMs VAs was challenging, requiring a large amount of the radiofrequency energy delivery for a successful ablation with a relatively high recurrence rate.

Prognostic value of silent myocardial infarction in patients with chronic kidney disease being evaluated for kidney transplantation.

BACKGROUND: Patients with advanced chronic kidney disease (CKD) have increased risk of myocardial infarction (MI). Silent MIs (SMIs) are common in CKD patients and carry increased mortality risk. The prevalence and prognostic value of SMI in advanced CKD has not been evaluated. METHODS: We identified consecutive patients with advanced CKD who were evaluated for renal transplantation at the University of Alabama at Birmingham between June 2004 and January 2006. Clinical MI (CMI) was determined by review of medical records. SMI was defined as ECG evidence of MI without clinical history of MI. The primary end-point was a composite of death, MI, or coronary revascularization censored at time of renal transplantation. RESULTS: The cohort included 1007 patients with advanced CKD aged 48±12years (58% men, 43% diabetes, 75% on dialysis). The prevalence of SMI and CMI was 10.7% and 6.7%, respectively. The only independent predictor of SMI was older age (odds ratio for age ≥50yrs. 2.32, p<0.001). During a median follow-up of 28months, 376 (37%) patients experienced the primary outcome (33% death, 2% MI, 5% coronary revascularization). In a multivariable adjusted Cox-regression model, both SMI (adjusted HR 1.58, [1.13-2.20], p=0.007) and CMI (adjusted HR 1.67 [1.15-2.43], p=0.007) were independently associated with the primary outcome. Further, both SMI (HR 2.37 [1.15-4.88], p=0.02) and CMI (HR 4.02 [1.80-8.98], p=0.001) were associated with increased risk after renal transplantation. CONCLUSIONS: SMI is more common than CMI in patients with advanced CKD. Both SMI and CMI are associated with increased risk of future cardiovascular events.

Idiopathic Ventricular Arrhythmias Originating From the Parietal Band: Electrocardiographic and Electrophysiological Characteristics and Outcome of Catheter Ablation.

BACKGROUNDS: The parietal band is one of the muscle bands in the right ventricle. This study investigated the electrocardiographic and electrophysiological characteristics and ablation outcome of idiopathic ventricular arrhythmias (VAs) originating from the parietal band. METHODS AND RESULTS: We studied 14 patients with idiopathic VA origins in the parietal band among 294 consecutive patients with VA origins in the right ventricle. The QRS morphologies of the parietal band VAs were characterized by a left bundle branch block and left inferior (n=12) or superior (n=2) axis pattern with the presence of a notch in the middle of the QRS in all cases, precordial transition at ≤lead V3 in 7 patients, and a slow QRS onset in 4 patients. During parietal band VAs, a far-field ventricular electrogram with an early activation was always recorded in the His bundle region, regardless of the location of the VA origins. During the catheter ablation, a mean number of 10.4±7.4 radiofrequency applications with a duration of 1099±1034 seconds were delivered. Catheter ablation was successful in 10 patients, and VAs recurred in 4 during a mean follow-up period of 41±24 months. A change in the QRS morphology was observed spontaneously in 4 patients, immediately after the ablation in 4, and at the time of a VA recurrence in 2. CONCLUSIONS: Idiopathic VAs rarely originated from the parietal band. The catheter ablation of the parietal band VAs was always challenging, requiring a large amount of the radiofrequency energy delivery for a successful ablation with a relatively high recurrence rate.

Safety and Efficacy of Uninterrupted Apixaban Therapy Versus Warfarin During Atrial Fibrillation Ablation.

Thromboembolic cerebrovascular accident remains a rare but potentially devastating complication of catheter-based atrial fibrillation (AF) ablation. Uninterrupted oral anticoagulant therapy with warfarin has become the standard of care when performing catheter-based AF ablation. Compared with warfarin, apixaban, a factor Xa inhibitor, has been shown to reduce the risk of stroke and major bleeding in nonvalvular AF. With an increase in apixaban use for stroke prophylaxis in patients with AF, there is an increased interest in the safety and efficacy of uninterrupted apixaban therapy during AF ablation. We compared the safety and efficacy of uninterrupted OA therapy with either warfarin or apixaban in all patients who underwent catheter-based AF ablation at the University of Alabama at Birmingham and at Augusta University Medical Center from January 7, 2013, to February 25, 2016. All patients underwent a transesophageal echocardiogram on the day of their ablation to assess for the presence of intracardiac thrombi. All complications were identified and classified as bleeding, thromboembolic events, or other. A total of 627 patients were analyzed as described earlier. There were 310 patients in the warfarin group and 317 patients in the apixaban group. There were 8 complications in the warfarin group and 5 complications in the apixaban group (p = 0.38). There were no thromboembolic complications in either group. In conclusion, the use of apixaban is as safe and effective as warfarin for uninterrupted OA therapy during catheter-based ablation of AF.

Efficacy of an Anatomical Approach in Radiofrequency Catheter Ablation of Idiopathic Ventricular Arrhythmias Originating From the Left Ventricular Outflow Tract.

BACKGROUND: When anatomic obstacles preclude radiofrequency catheter ablation of idiopathic ventricular arrhythmias (VAs) originating from the left ventricular outflow tract (LVOT), an alternative approach from the anatomically opposite side (endocardial versus epicardial or above versus below the aortic valve) may be considered (anatomic ablation). The purpose of this study was to investigate the efficacy of an anatomic ablation in idiopathic LVOT VAs. METHODS AND RESULTS: We studied 229 consecutive patients with idiopathic LVOT VAs. Radiofrequency ablation from the first suitable site was successful in 190 patients, and in the remaining 39 patients, it was unsuccessful or had to be abandoned because of anatomic obstacles. In 22 of these 39 patients, an anatomic ablation was successful, and the VA origins were located in the intramural LVOT in 17 patients, basal left ventricular summit in 4, and LVOT septum near the His bundle in 1. The anatomic ablation was highly successful for idiopathic VAs originating from the intramural LVOT (>75%) and lateral LVOT, whereas it was unlikely to be successful for idiopathic VAs originating from the basal left ventricular summit (25%) and sepal LVOT. CONCLUSIONS: When a standard catheter ablation targeting the best electrophysiological measure of idiopathic LVOT VAs was unsuccessful or had to be abandoned because of anatomic obstacles, an anatomic ablation was moderately successful. These idiopathic LVOT VAs with a successful anatomic ablation commonly arose from the intramural LVOT among the left coronary cusp, aortomitral continuity, and epicardium, occasionally the basal left ventricular summit, and rarely the LVOT septum near the His bundle.