No cupid, just an arrow: a penetrating injury into the interventricular septum.

BACKGROUND: Penetrating cardiac injuries are rare but often fatal, with 16-55% mortality. We report a patient who suffered a non-fatal occupational cardiac injury. CASE PRESENTATION: A 47-year-old man was operating an ironworker machine. A thin 3-cm metal fragment catapulted from the machine piercing the chest wall and the right ventricular outflow tract (RVOT), burrowing into the interventricular septum (IVS). The patient remained hemodynamically stable and walked to the nearest hospital. ECG-gated computed tomography revealed the exact location of the fragment within the IVS, allowing for detailed preoperative planning. The fragment was removed through a sternotomy and an incision through the RVOT. The postoperative course was uneventful. CONCLUSIONS: This case underscores the value of detailed preoperative imaging and the wide spectrum of clinical scenarios of penetrating cardiac injuries.

Postoperative Myocardial Injury and Inflammatory Biomarkers in Patients Undergoing Vascular Surgery: A Subanalysis of the Platelet Reactivity and Postoperative Myocardial Injury after Major Vascular Surgery (PROMISE) Study.

BACKGROUND: Postoperative myocardial injury (PMI) is associated with morbidity and mortality, but the aetiology remains unclear. We studied whether PMI is associated with perioperative systemic inflammation. The objective is the examination of the relationship between inflammatory biomarkers (Interleukin 6[IL-6], C-reactive protein [CRP]) and PMI, detected by elevated cardiac troponin (cTn), in patients undergoing elective open abdominal aortic surgery. METHODS: This prospective, single-center, observational cohort study included 54 patients undergoing elective open abdominal aortic surgery between March 2018 and April 2021. Patients were routinely treated with aspirin. IL-6 and CRP were measured preoperatively, directly after surgery, 24 hr and 48 hr postoperatively. The primary outcome was cTn release assessed by a fifth-generation high-sensitive cTn assay. Multivariable generalized linear regression models were used to evaluate the association between inflammatory biomarkers and cTn concentrations. RESULTS: Fifteen patients (27.8%) developed PMI. IL-6 directly and 24 hr postoperatively was associated with elevated cTn concentrations (1.28 [1.07-1.54], P = 0.009) and 1.75 [1.18-2.59], P = 0.006, respectively). Also, CRP directly and 24 hr postoperatively was associated with elevated cTn concentrations (1.25 [1.06-1.47], P = 0.009) and 1.61 [1.1-2.33], P = 0.013, respectively). No association was found between IL-6 or CRP and cTn concentrations when measured at 48 hr postsurgery. CONCLUSIONS: Biomarkers of inflammation are associated with elevated postoperative cTn concentrations in the early postoperative period in patients undergoing elective open abdominal aortic surgery.

Sex-related differences in non-ischemic myocardial injury in the emergency department: A real-world perspective.

BACKGROUND: Myocardial injury is associated with adverse outcomes. No data are reported about sex differences in incidence and factors associated with myocardial injury in an emergency department (ED) setting from a real-world perspective. We aimed to assess whether sex plays a major role in the diagnosis of myocardial injury in the ED. METHODS: In this subanalysis of a retrospective study, patients presenting at the ED with at least one high-sensitivity cardiac troponin T (hs-cTnT) value and without acute coronary syndromes diagnosis were compared. RESULTS: 31,383 patients were admitted to the ED, 4660 had one hs-cTnT value, and 3937 were enrolled: 1943 females (49.4%) and 1994 males (50.6%). The diagnosis of myocardial injury was higher among men (36.8% vs. 32.9%, p < 0.01). Male sex was independently associated with myocardial injury. An older age, an elevated NT-proB-type Natriuretic Peptide and a lower estimated glomerular filtrate rate were independently associated with myocardial injury in both sexes. CONCLUSIONS: In the ED, from a real-world perspective, myocardial injury occurred more frequently in males, and it was associated with older age and the presence of cardiac, lung, and kidney disease but not higher hs-cTnT values.

Accuracy of diagnostic tests in cardiac injury after blunt chest trauma: a systematic review and meta-analysis.

INTRODUCTION: The diagnosis of cardiac contusion, caused by blunt chest trauma, remains a challenge due to the non-specific symptoms it causes and the lack of ideal tests to diagnose myocardial damage. A cardiac contusion can be life-threatening if not diagnosed and treated promptly. Several diagnostic tests have been used to evaluate the risk of cardiac complications, but the challenge of identifying patients with contusions nevertheless remains. AIM OF THE STUDY: To evaluate the accuracy of diagnostic tests for detecting blunt cardiac injury (BCI) and its complications, in patients with severe chest injuries, who are assessed in an emergency department or by any front-line emergency physician. METHODS: A targeted search strategy was performed using Ovid MEDLINE and Embase databases from 1993 up to October 2022. Data on at least one of the following diagnostic tests: electrocardiogram (ECG), serum creatinine phosphokinase-MB level (CPK-MB), echocardiography (Echo), Cardiac troponin I (cTnI) or Cardiac troponin T (cTnT). Diagnostic tests for cardiac contusion were evaluated for their accuracy in meta-analysis. Heterogeneity was assessed using the I2 and the QUADAS-2 tool was used to assess bias of the studies. RESULTS: This systematic review yielded 51 studies (n = 5,359). The weighted mean incidence of myocardial injuries after sustaining a blunt force trauma stood at 18.3% of cases. Overall weighted mean mortality among patients with blunt cardiac injury was 7.6% (1.4-36.4%). Initial ECG, cTnI, cTnT and transthoracic echocardiography TTE all showed high specificity (> 80%), but lower sensitivity (< 70%). TEE had a specificity of 72.1% (range 35.8-98.2%) and sensitivity of 86.7% (range 40-99.2%) in diagnosing cardiac contusion. CK-MB had the lowest diagnostic odds ratio of 3.598 (95% CI: 1.832-7.068). Normal ECG accompanied by normal cTnI showed a high sensitivity of 85% in ruling out cardiac injuries. CONCLUSION: Emergency physicians face great challenges in diagnosing cardiac injuries in patients following blunt trauma. In the majority of cases, joint use of ECG and cTnI was a pragmatic and cost-effective approach to rule out cardiac injuries. In addition, TEE may be highly accurate in identifying cardiac injuries in suspected cases.

Myocardial Injury Thresholds for 4 High-Sensitivity Troponin Assays in a Population-Based Sample of US Children and Adolescents.

BACKGROUND: Myocardial injury is an important pediatric diagnosis. Establishing normative data from a representative pediatric sample is vital to provide accurate upper reference limits (URLs) for defining myocardial injury using high-sensitivity cardiac troponin. METHODS: Among participants 1 to 18 years of age in the 1999-2004 National Health and Nutrition Examination Survey, we measured high-sensitivity troponin T using one assay (Roche) and high-sensitivity troponin I using 3 assays (Abbott, Siemens, and Ortho). In a strictly defined healthy subgroup, we estimated 97.5th and 99th percentile URLs for each assay using the recommended nonparametric method. RESULTS: Of 5695 pediatric participants, 4029 met criteria for the healthy subgroup (50% males; mean age 12.6 years). Our 99th percentile URL estimates for all 4 high-sensitivity troponin assays among children and adolescents were lower than the manufacturer-reported URLs (derived from adults). The 99th percentile URLs (95% CI) were 15 ng/L (95% CI, 12-17) for high-sensitivity troponin T, 16 ng/L (95% CI, 12-19) for high-sensitivity troponin I with the Abbott assay, 38 ng/L (95% CI, 25-46) for high-sensitivity troponin I with the Siemens assay, and 7 ng/L (95% CI, 5, 12) for high-sensitivity troponin I with the Ortho assay. The 95% CIs for age-, sex-, and race and ethnicity-specific 99th percentile URLs overlapped. However, the 97.5th percentile URL for each assay was measured with superior statistical precision (ie, tighter 95% CIs) and demonstrated differences by sex. For male compared with female children and adolescents, 97.5th percentile URLs were 11 ng/L (95% CI, 10-12) versus 6 ng/L (95% CI, 6-7) for high-sensitivity troponin T, 9 ng/L (95% CI, 7-10) versus 5 ng/L (95% CI, 4-6) for high-sensitivity troponin I with the Abbott assay, 21 ng/L (95% CI, 18-25) versus 11 ng/L (95% CI, 9-13) for high-sensitivity troponin I with the Siemens assay, and 4 ng/L (95% CI, 3-5) versus 2 ng/L (95% CI, 1-3) for high-sensitivity troponin I with the Ortho assay. In contrast to the 99th percentiles, the point estimates of 97.5th percentile pediatric URLs for high-sensitivity troponin were also much more stable to differences in the analytic approaches taken to estimate URLs. CONCLUSIONS: Because myocardial infarction is rare in children and adolescents, the use of statistically more precise and reliable sex-specific 97.5th percentile high-sensitivity troponin URLs might be considered to define pediatric myocardial injury.

Serum Copeptin in Cardiooncology Practice: Review of Pathophysiological and Clinical Implications.

In cardiooncology practice, "early cardiotoxicity" refers to an emerging subclinical myocardial dysfunction/injury in response to certain chemotherapeutic regimens. This condition can progress to overt cardiotoxicity in time and hence warrants proper and timely diagnostic and preventive strategies. Current diagnostic strategies for "early cardiotoxicity" are largely based on conventional biomarkers and certain echocardiographic indices. However, a significant gap still exists in this setting, warranting further strategies to improve diagnosis and overall prognosis in cancer survivors. Copeptin (surrogate marker of the arginine vasopressine axis) might serve as a promising adjunctive guide for the timely detection, risk stratification, and management of early cardiotoxicity on top of conventional strategies largely due to its multifaceted pathophysiological implications in the clinical setting. This work aims to focus on serum copeptin as a marker of "early cardiotoxicity" and its general clinical implications in patients with cancer.

Deep learning augmented ECG analysis to identify biomarker-defined myocardial injury.

Chest pain is a common clinical complaint for which myocardial injury is the primary concern and is associated with significant morbidity and mortality. To aid providers' decision-making, we aimed to analyze the electrocardiogram (ECG) using a deep convolutional neural network (CNN) to predict serum troponin I (TnI) from ECGs. We developed a CNN using 64,728 ECGs from 32,479 patients who underwent ECG within 2 h prior to a serum TnI laboratory result at the University of California, San Francisco (UCSF). In our primary analysis, we classified patients into groups of TnI < 0.02 or ≥ 0.02 µg/L using 12-lead ECGs. This was repeated with an alternative threshold of 1.0 µg/L and with single-lead ECG inputs. We also performed multiclass prediction for a set of serum troponin ranges. Finally, we tested the CNN in a cohort of patients selected for coronary angiography, including 3038 ECGs from 672 patients. Cohort patients were 49.0% female, 42.8% white, and 59.3% (19,283) never had a positive TnI value (≥ 0.02 µg/L). CNNs accurately predicted elevated TnI, both at a threshold of 0.02 µg/L (AUC = 0.783, 95% CI 0.780-0.786) and at a threshold of 1.0 µg/L (AUC = 0.802, 0.795-0.809). Models using single-lead ECG data achieved significantly lower accuracy, with AUCs ranging from 0.740 to 0.773 with variation by lead. Accuracy of the multi-class model was lower for intermediate TnI value-ranges. Our models performed similarly on the cohort of patients who underwent coronary angiography. Biomarker-defined myocardial injury can be predicted by CNNs from 12-lead and single-lead ECGs.

Managing blunt cardiac injury.

Blunt cardiac injury (BCI) encompasses a spectrum of pathologies ranging from clinically silent, transient arrhythmias to deadly cardiac wall rupture. Of diagnosed BCIs, cardiac contusion is most common. Suggestive symptoms may be unrelated to BCI, while some injuries may be clinically asymptomatic. Cardiac rupture is the most devastating complication of BCI. Most patients who sustain rupture of a heart chamber do not reach the emergency department alive. The incidence of BCI following blunt thoracic trauma remains variable and no gold standard exists to either diagnose cardiac injury or provide management. Diagnostic tests should be limited to identifying those patients who are at risk of developing cardiac complications as a result of cardiac in jury. Therapeutic interventions should be directed to treat the complications of cardiac injury. Prompt, appropriate and well-orchestrated surgical treatment is invaluable in the management of the unstable patients.

Catheter-Induced Left Ventricular Perforation and Cardiac Tamponade During Left Heart Catheterization.

Iatrogenic ventricular perforation of the myocardial wall is a rare but life-threatening complication. It has been described using pulmonary artery catheter, pigtail catheter, and Judkins catheter. Straight wires and catheters can be used to cross the aortic valve for left ventriculogram; however, the risk of perforation is higher compared with J-tip wires. Prompt recognition of cardiac tamponade and pericardial drain insertion is vital, but surgical patch repair may be required for definitive treatment. This case highlights the importance of increased vigilance and prompt management of cardiac tamponade with the use of high-risk equipment during cardiac catheterization.

Left Ventricular Septal Avulsion in the Setting of Blunt Cardiac Injury.

A 23-year-old man sustained blunt cardiac injury after a motor vehicle collision resulting in left ventricular septal avulsion, ruptured chordae tendineae, and moderate to severe tricuspid regurgitation that necessitated operative intervention. The patient underwent successful resection of a prolapsed avulsed septal wall segment and concomitant tricuspid valve repair.

Relationship Between Preprocedural Lipid Levels and Periprocedural Myocardial Injury in Patients Undergoing Elective Percutaneous Coronary Intervention.

BACKGROUND: Periprocedural myocardial injury is a predictor of cardiovascular morbidity and mortality after percutaneous coronary intervention. METHODS: The authors examined the effects of preprocedural lipid levels (low-density lipoprotein, high-density lipoprotein, and triglycerides) in 977 patients with coronary artery disease who underwent elective percutaneous coronary intervention. RESULTS: Elevated cardiac troponin I level (≥5× the upper limit of normal) was used to indicate periprocedural myocardial injury. Serum lipid samples were collected 12 hours preprocedurally. Cardiac troponin I was collected 1, 6, and 12 hours postprocedurally. Correlations between preprocedural lipid levels and postprocedural cardiac troponin I were studied. Low-density lipoprotein levels were less than 70 mg/dL in 70% of patients and greater than 100 mg/dL in only 7.4% of patients; 13% had triglyceride levels greater than or equal to 150 mg/dL, and 96% had high-density lipoprotein levels less than 40 mg/dL. Patients with elevated cardiac troponin I had significantly lower left ventricular ejection fraction than did those with cardiac troponin I levels less than 5× the upper limit of normal (P = .01). Double-and triple-vessel disease were more common in patients with elevated cardiac troponin I (P < .002). Multivariable logistic and linear regression analyses revealed no statistically significant associations between lipid levels and postprocedural cardiac troponin I elevation, possibly because such large proportions of included patients had low levels of low-density lipoprotein (70%) and a history of statin intake (86%). CONCLUSION: The authors found no association between lipid profile and periprocedural myocardial injury.

Thoracic Penetrating Wounds with Cardiac Injury: A Single-Center Experience.

Background: Management protocols for patients with penetrating cardiac injury have undergone a dramatic transition during the last decades. However, even today cardiac trauma remains a major medical problem. Methods: Retrospective single-center case series study, 41 patients with precordial wounds hospitalized at the Institute of Emergency Medicine, Chisinau, period 2005-2020. Mean age - 45.8 Ã+- 8.9 years, M:F/19.5:1. Traumatic event: stabbing (82.9%,n=34) or gunshot wound (17.1%,n=7). Preoperative paraclinical examinations: electrocardiography, chest X-ray, FAST, pleurotomy, pericardial puncture, and thoracoscopy. Results: 36 (87.8%) patients were hemodynamically unstable on hospitalization, and 19 (52.8%) were immediately transferred to the operating room. Preferred surgical access: left anterolateral thoracotomy - 26 (63.4%), right anterolateral thoracotomy - 13 (31.7%), and left posterolateral thoracotomy - 2 (4.9%). Non-penetrating lesions were discovered in 5 (12.2%) while penetrating trauma in other 36 (87.8%) cases, most frequently the right ventricle being injured. Additional intrathoracic lesions discovered in 29 (70.7%) patients: pulmonary parenchyma rupture - 25 (86.2%), internal mammary artery injury - 3 (10.3%), and intercostal artery injury - 1 (3.5%). The average length of stay was 13.2 Ã+- 4 days, including stay in the Intensive Care Unit - 2.9 Ã+- 1.2. Mortality rate -17.1% (n=7). Conclusions: Successful cardiac suture determined the survival rate of 82.9%. Lethality increases proportionally to the severity of the cardiac injury, the volume of blood loss, and damage to the right vs left heart chambers.

Technical considerations in the management of penetrating cardiac injury.

Penetrating cardiac injuries require rapid diagnosis, efficient exposure and nuanced technical approaches, within a framework of highly coordinated and integrated multidisciplinary care. Acute care surgeons, with both strategic and technical expertise, are ideally positioned to address the potentially devastating consequences of these injuries. The aim of this narrative review is to offer a technical approach to the rapid evaluation, exposure, operative repair and postoperative care of penetrating cardiac injuries. A comprehensive review of the cardiac trauma literature, dating back to 1970, has provided a detailed toolbox of approaches to subxiphoid pericardial windows, resuscitative thoracotomy, median sternotomy, pericardiotomy, aortic clamping, cardiac hemorrhage control, cardiac repair, coronary artery injuries, pericardial closure, drain placement, chest wall closures, damage control thoracic procedures and immediate postoperative cardiac care, all based on fundamental physiological principles and anatomical considerations.

Cardiac contusions in the acute care setting: Historical background, evaluation and management.

INTRODUCTION: Albeit described since 1763, cardiac contusions is still an under-recognised clinical condition in the acute care setting. This evidence-based review aims to provide an overview of the topic by focusing on etiopathogenesis, classification and clinical presentation of patients with cardiac contusions, as well as on the diagnostic work-up and therapy options available for this subset population in the acute care setting. METHODS: A targeted research strategy was performed using PubMed, MEDLINE, Embase and Cochrane Central databases up to June 2022. The literature search was conducted using the following keywords (in Title and/or Abstract): ("cardiac" OR "heart" OR "myocardial") AND ("contusion"). All available high-quality resources written in English and containing information on epidemiology, etiopathogenesis, clinical findings, diagnosis and management of cardiac contusions were included in our research. RESULTS: Biochemical samples of cardiac troponins together with a 12­lead ECG appear to be sufficient screening tools in hemodynamically stable subjects, while cardiac ultrasound provides a further diagnostic clue for patients with hemodynamic instability or those more likely to have a significant cardiac contusion. CONCLUSIONS: The management of patients with suspected cardiac contusion remains a challenge in clinical practice. For this kind of patients a comprehensive diagnostic approach and a prompt emergency response are required, taking into consideration the degree of severity and clinical impairment of associated traumatic injuries.

Treatment of penetrating cardiac wounds for the general surgeon on call.

ABSTRACT: "Scoop and run" approaches for severely injured patients have been adopted by emergency medical services over the past 40 years. This has resulted in more patients with severe injuries including penetrating cardiac wounds arriving at trauma centers and other acute care hospitals. General surgery trauma teams and general surgeons taking trauma call are the first responders for diagnosis, resuscitation, and operative management of injured patients. By natural selection, 96% to 98% of patients with signs of life on arrival to the trauma center after sustaining a penetrating cardiac wound have injuries that are amenable to repair by a general surgeon, fellow, or senior surgical resident without the need for a cardiothoracic surgeon or cardiopulmonary bypass.This literature and experience-based review summarizes the diagnostic and operative approaches that should be known by all trauma teams and general surgeons taking trauma call. In addition, it describes when a cardiothoracic surgeon should be consulted and briefly reviews how complex penetrating cardiac injuries are repaired.

Use and Prognostic Implications of Cardiac Troponin in COVID-19.

Myocardial injury is common in patients with COVID-19 and is associated with an adverse prognosis. Cardiac troponin (cTn) is used to detect myocardial injury and assist with risk stratification in this population. SARS-CoV-2 infection can play a role in the pathogenesis of acute myocardial injury due to both direct and indirect damage to the cardiovascular system. Despite the initial concerns about an increased incidence of acute myocardial infarction (MI), most cTn increases are related to chronic myocardial injury due to comorbidities and/or acute nonischemic myocardial injury. This review will discuss the latest findings on this topic.

Predictors and Prognostic Implications of Myocardial Injury After Transcatheter Aortic Valve Replacement.

Myocardial injury (MI) is not unusual after transcatheter aortic valve replacement (TAVR). To determine precipitating factors and prognostic outcomes of MI after TAVR, we retrospectively investigated relationships between MI after TAVR and aortic root dimensions, baseline patient characteristics, echocardiographic findings, and procedural features. Of 474 patients who underwent transfemoral TAVR for severe aortic stenosis in our tertiary center from June 2011 through June 2018, 188 (mean age, 77.7 ± 7.7 yr; 96 women [51%]) met the study inclusion criteria. Patients were divided into postprocedural MI (PMI) (n=74) and no-PMI (n=114) groups, in accordance with high-sensitivity troponin T levels. We found that MI risk was associated with older age (odds ratio [OR]=1.054; 95% CI, 1.013-1.098; P=0.01), transcatheter heart valve type (OR=10.207; 95% CI, 2.861-36.463; P=0.001), distances from the aortic annulus to the right coronary artery ostium (OR=0.853; 95% CI, 0.731-0.995; P=0.04) and the left main coronary artery ostium (OR=0.747; 95% CI, 0.616-0.906; P=0.003), and baseline glomerular filtration rate (OR=0.985; 95% CI, 0.970-1.000; P=0.04). Moreover, the PMI group had a longer time to hospital discharge (P=0.001) and a higher permanent pacemaker implantation rate (P=0.04) than did the no-PMI group. Our findings may enable better estimation of which patients are at higher risk of MI after TAVR and thus improve the planning and course of clinical care.

Incidence, Treatment, and Outcomes of Coronary Artery Perforation During Percutaneous Coronary Intervention.

OBJECTIVES: To examine the incidence, treatment and outcomes of perforation during percutaneous coronary intervention (PCI). BACKGROUND: Coronary perforation is a potentially life-threatening PCI complication. METHODS: We examined the clinical, angiographic, and procedural characteristics, management, and outcomes of coronary perforation at a tertiary care institution. RESULTS: Between 2014 and 2019, perforation occurred in 70 of 10,278 PCIs (0.7%). Patient age was 71 ± 12 years, 66% were men, and 30% had prior coronary artery bypass graft surgery. Among perforation cases, the prevalence of chronic total occlusions was 33%, moderate/severe calcification was 66% and moderate/severe tortuosity was 41%. The frequency of Ellis class 1, 2, and 3 perforations was 14%, 50%, and 36%, respectively. Most (n = 51; 73%) were large vessel perforations, 16 (23%) were distal vessel perforations and 3 (4%) were collateral vessel perforations (1 septal and 2 epicardial). Hypotension occurred in 26%, pericardial effusion in 36% and tamponade in 13%; 47% of perforations did not have clinical consequences. Perforations were most often treated with prolonged balloon inflation (63%), reversal of anticoagulation (39%), and covered stent implantation (33%). Technical and procedural success were 73% and 60%, respectively, and major periprocedural adverse cardiac events occurred in 21% of the patients. Three patients (4%) required emergent CABG surgery and four (6%) died. CONCLUSIONS: Coronary perforation is an infrequent complication of PCI. Most perforations are large vessel perforations and often require further intervention. The incidence of death or emergent cardiac surgery is low.

Impact of cryoballoon contact angle and acute myocardial injury on pulmonary vein reconnection.

At present, it remains unclear whether the effect on cryoinjury can be strongly exerted by contact of the balloon with the pulmonary vein (PV) ostium. The present study included 204 paroxysmal atrial fibrillation (PAF) patients who underwent an initial pulmonary vein isolation (PVI) using a cryoballoon from the Osaka Rosai Atrial Fibrillation ablation (ORAF) registry. The total balloon contact angle was measured from the equator line (sum of the angles of the upper side and bottom side in all PVs) under fluoroscopic imaging. The patients were stratified into three tertile groups according to the total balloon contact angle. We evaluated the relationship between the total balloon contact angle and clinical outcomes, including the value of acute myocardial injury marker (high-sensitive cardiac troponin I [hs-TnI]), arrhythmia recurrence, and PV reconnections in the repeated ablation. The total balloon contact angle was significantly associated with the hs-TnI value among the tertile groups (p < 0.001) and a multiple regression analysis showed that the total balloon contact angle significantly correlated with the hs-TnI value (standardized beta-coefficient = 0.572, p < 0.001). The balloon contact angle in PVs with PV reconnections was significantly lower than in those without (p = 0.044), while no significant differences in the recurrence of atrial fibrillation among the tertile groups were observed in the enrolled patients. The total balloon contact angle was significantly associated with the acute myocardial injury marker, hs-TnI. The total balloon contact angle was significantly associated with PV reconnections after cryoballoon ablation in patients who underwent a repeat ablation.