The prognostic value of artificial intelligence to predict cardiac amyloidosis in patients with severe aortic stenosis undergoing transcatheter aortic valve replacement.

Aims: Cardiac amyloidosis (CA) is common in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR). Cardiac amyloidosis has poor outcomes, and its assessment in all TAVR patients is costly and challenging. Electrocardiogram (ECG) artificial intelligence (AI) algorithms that screen for CA may be useful to identify at-risk patients. Methods and results: In this retrospective analysis of our institutional National Cardiovascular Disease Registry (NCDR)-TAVR database, patients undergoing TAVR between January 2012 and December 2018 were included. Pre-TAVR CA probability was analysed by an ECG AI predictive model, with >50% risk defined as high probability for CA. Univariable and propensity score covariate adjustment analyses using Cox regression were performed to compare clinical outcomes between patients with high CA probability vs. those with low probability at 1-year follow-up after TAVR. Of 1426 patients who underwent TAVR (mean age 81.0 ± 8.5 years, 57.6% male), 349 (24.4%) had high CA probability on pre-procedure ECG. Only 17 (1.2%) had a clinical diagnosis of CA. After multivariable adjustment, high probability of CA by ECG AI algorithm was significantly associated with increased all-cause mortality [hazard ratio (HR) 1.40, 95% confidence interval (CI) 1.01-1.96, P = 0.046] and higher rates of major adverse cardiovascular events (transient ischaemic attack (TIA)/stroke, myocardial infarction, and heart failure hospitalizations] (HR 1.36, 95% CI 1.01-1.82, P = 0.041), driven primarily by heart failure hospitalizations (HR 1.58, 95% CI 1.13-2.20, P = 0.008) at 1-year follow-up. There were no significant differences in TIA/stroke or myocardial infarction. Conclusion: Artificial intelligence applied to pre-TAVR ECGs identifies a subgroup at higher risk of clinical events. These targeted patients may benefit from further diagnostic evaluation for CA.

Electrical storm after left ventricular assist device (LVAD) implantation.

INTRODUCTION: Ventricular tachycardia storm or electrical storm (ES) is a common complication following left ventricular assist device (LVAD) implantation. The factors contributing to ES and outcomes are less studied. The study aimed to determine the factors associated with ES and the probability of survival in patients undergoing LVAD in three tertiary centers over a span of 15 years. METHODS: We performed a retrospective cohort study on all patients who underwent LVAD implantation at the Mayo Clinic (Rochester, Phoenix, and Jacksonville) from January 1, 2006 to December 31, 2020. ES was defined as ≥3 episodes of sustained ventricular tachycardia over a period of 24 h with no identifiable reversible cause. Detailed chart reviews of the electronic health records within the Mayo Clinic and outside medical records were performed. RESULTS: A total of 883 patients who underwent LVAD implantation were included in our study. ES occurred in 7% (n = 61) of patients with a median of 13 days (interquartile range [IQR]: 5-297 days) following surgery. We found 57% of patients (n = 35) developed ES within 30 days, while 43% (n = 26) patients developed ES at a median of 545  (IQR 152-1032) days after surgery. Following ES, 26% of patients died within 1 year. Patients with ES had a significant association with a history of ventricular arrhythmias and implantable cardioverter defibrillator (ICD) shocks before the procedure. ES was significantly associated with reduced survival compared to patients without ES (hazards ratio [HR]: 1.92, 95% CI: 1.39-2.64, p < .001). CONCLUSION: Following LVAD implantation, the rate of ES was 7% with majority of ES occurring within 30 days of LVAD. Risk factors for ES included pre-implant history of ventricular arrhythmias and ICD shock. ES was significantly associated with reduced survival compared to patients without ES.

Impact of infective versus sterile transvenous lead removal on 30-day outcomes in cardiac implantable electronic devices.

BACKGROUND: Transvenous lead removal (TLR) is associated with increased mortality and morbidity. This study sought to evaluate the impact of TLR on in-hospital mortality and outcomes in patients with and without CIED infection. METHODS: From January 1, 2017, to December 31, 2020, we utilized the nationally representative, all-payer, Nationwide Readmissions Database to assess patients who underwent TLR. We categorized TLR as indicated for infection, if the patient had a diagnosis of bacteremia, sepsis, or endocarditis during the initial admission. Conversely, if none of these conditions were present, TLR was considered sterile. The impact of infective vs sterile indications of TLR on mortality and major adverse events was studied. RESULTS: Out of the total 25,144 patients who underwent TLR, 14,030 (55.8%) received TLR based on sterile indications, while 11,114 (44.2%) received TLR due to device infection, with 40.5% having systemic infection and 59.5% having isolated pocket infection. TLR due to infective indications was associated with a significant in-hospital mortality (5.59% vs 1.13%; OR = 5.16; 95% CI 4.33-6.16; p < 0.001). Moreover, when compared with sterile indications, TLR performed due to device infection was associated with a considerable risk of thromboembolic events including pulmonary embolism and stroke (OR = 3.80; 95% CI 3.23-4.47, p < 0.001). However, there was no significant difference in the conversion to open heart surgery (1.72% vs. 1.47%, p < 0.111), and infection was not an independent predictor of cardiac (OR = 1.12; 95% CI 0.97-1.29) or vascular complications (OR = 1.12; 95% CI 0.73-1.72) between the two groups. CONCLUSION: Higher in-hospital mortality and rates of thromboembolic events associated with TLR resulting from infective indications may warrant further pursuing this diagnosis in patients.

Effect of age on in-hospital outcomes of transvenous lead extraction for infected cardiac implantable electronic device.

BACKGROUND: The real-world data on the safety profile of transvenous lead extraction (TLE) for infected cardiac implantable electronic devices (CIED) among elderly patients is not well-established. This study aimed to evaluate the hospital outcomes between patients of different age groups who underwent TLE for infected CIED. METHOD: Using the Nationwide Readmissions Database, our study included patients aged ≥18 years who underwent TLE for infected CIED between 2017 and 2020. We divided the patients into four groups: Group A. Young (<50 years), Group B. Young intermediate (50-69 years old), Group C. Older intermediate (70-79 years old), and Group D. Octogenarian (≥80 years old). We then analyzed the in-hospital outcome and 30-day readmission between these age groups. RESULTS: A total of 10,928 patients who were admitted for TLE of infected CIED were included in this study: 982 (9.0%) patients in group A, 4,234 (38.7%) patients in group B, 3,204 (29.3%) patients in group C and 2,508 (23.0%) of patients in group D. Our study demonstrated that the risk of early mortality increased with older age (Group B vs. Group A: OR: 1.92, 95% CI: 1.19-3.09, p < .01; Group C vs. Group A: OR: 2.47, 95% CI: 1.51-4.04, p < .01; Group D vs. Group A: OR: 2.82, 95% CI: 1.69-4.72, p < .01). The risk of non-home discharge also increased in elderly groups (Group B vs. Group A: OR: 1.89; 95% CI: 1.52-2.36; p < .01; Group C vs. Group A: OR: 2.82; 95% CI 2.24-3.56; p < .01; Group D vs. Group A: OR: 4.16; 95% CI: 3.28-5.28; p < .01). There was no significant difference in hospitalization length and 30-day readmission between different age groups. Apart from a higher rate of open heart surgery in group A, the procedural complications were comparable between these age groups. CONCLUSION: Elderly patients had worse in-hospital outcomes in early mortality and non-home discharge following the TLE for infected CIED. There was no significant difference between elderly and non-elderly groups in prolonged hospital stay and 30-day readmission. Elderly patients did not have a higher risk of procedural complications.

Incidentally Discovered Right Atrial Mass: A Rare and Unexpected Etiology.

Primary cardiac sarcoma is a rare type of intracardiac mass. This report describes a patient with atrial flutter who had a new right atrial mass incidentally discovered on transesophageal echocardiography. A thrombus was suspected based on radiographic appearance, but there was minimal change with anticoagulation. The mass was resected and found to be an undifferentiated pleomorphic cardiac sarcoma, an uncommon sub-type within the already rare category of primary cardiac neoplasms. This report highlights the importance of considering primary malignancy and thoroughly correlating radiographic and clinical evidence during the diagnostic workup of patients with intracardiac masses.

A real-world experience of atrioventricular synchronous pacing with leadless ventricular pacemakers.

AIMS: The MicraTM transcatheter pacing system (TPS) (Medtronic) is the only leadless pacemaker that promotes atrioventricular (AV) synchrony via accelerometer-based atrial sensing. Data regarding the real-world experience with this novel system are scarce. We sought to characterize patients undergoing MicraTM -AV implants, describe percentage AV synchrony achieved, and analyze the causes for suboptimal AV synchrony. METHODS: In this retrospective cohort study, electronic medical records from 56 consecutive patients undergoing MicraTM -AV implants at the Mayo Clinic sites in Minnesota, Florida, and Arizona with a minimum follow-up of 3 months were reviewed. Demographic data, comorbidities, echocardiographic data, and clinical outcomes were compared among patients with and without atrial synchronous ventricular pacing (AsVP) ≥ 70%. RESULTS: Sixty-five percent of patients achieved AsVP ≥ 70%. Patients with adequate AsVP had smaller body mass indices, a lower proportion of congestive heart failure, and prior cardiac surgery. Echocardiographic parameters and procedural characteristics were similar across the two groups. Active device troubleshooting was associated with higher AsVP. The likely reasons for low AsVP were small A4-wave amplitude, high ventricular pacing burden, and inadequate device reprogramming. Importantly, in patients with low AsVP, subjective clinical worsening was not noted during follow-up. CONCLUSION: With the increasing popularity of leadless pacemakers, it is paramount for device implanting teams to be familiar with common predictors of AV synchrony and troubleshooting with MicraTM -AV devices.

Optogenetic Control of Engrafted Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes in Live Mice: A Proof-of-Concept Study.

Background: Cellular transplantation has emerged as promising approach for treating cardiac diseases. However, a poor engraftment rate limits our understanding on how transplanted cardiomyocytes contribute to cardiac function in the recipient's heart. Methods: The CRISPR/Cas9 technique was employed for stable and constitutive gene expression in human-induced pluripotent stem-cell-derived cardiomyocytes (hiPSC-CMs). Myocardial infarction was induced in adult immunodeficient mice, followed by intramyocardial injection of hiPSC-CMs expressing either CCND2/channelrhodopsin 2 (hiPSC-CCND2OE/ChR2OECMs) or CCND2/luciferase (hiPSC-CCND2OE/LuciOECMs). Six months later, hemodynamics and intramural electrocardiogram were recorded upon blue light illuminations in anesthetized, open-chest mice. Results: Blue light resets automaticity of spontaneously beating hiPSC-CCND2OE/ChR2OECMs in culture, but not that of hiPSC-CCND2OE/LuciOECMs. Response to blue light was also observed in mice carrying large (>106 cells) intracardiac grafts of hiPSC-CCND2OE/ChR2OECM but not in mice carrying hiPSC-CCND2OE/LuciOECMs. The former exhibited single premature ventricular contractions upon light illumination or ventricular quadrigeminy upon second-long illuminations. At the onset of premature ventricular contractions, maximal systolic ventricular pressure decreased while ventricular volume rose concomitantly. Light-induced changes reversed upon resumption of sinus rhythm. Conclusions: We established an in vivo model for optogenetic-based modulation of the excitability of donor cardiomyocytes in a functional, reversible, and localized manner. This approach holds unique value for studying electromechanical coupling and molecular interactions between donor cardiomyocytes and recipient hearts in live animals.

Single-site ventricular pacing via the coronary sinus in patients with tricuspid valve disease.

Aims: To evaluate coronary sinus single-site (CSSS) left ventricular pacing in adult patients with normal left ventricular ejection fraction (LVEF) when traditional right ventricular lead implantation is not feasible or is contraindicated. Methods and results: We performed a retrospective analysis of 23 patients with tricuspid valve surgery/disease who received a CSSS ventricular pacing lead to avoid crossing the tricuspid valve. Two matched control populations were obtained from patients receiving (i) conventional right ventricular single-site (RVSS) leads and (ii) coronary sinus leads for cardiac resynchronization therapy (CSCRT). Main outcomes of interest were lead stability, electrical lead parameters and change in LVEF during long-term follow-up. Successful CSSS pacing was accomplished in all 23 patients without any procedural complications. During the 5.3 ± 2.8-year follow-up 22/23 (95.7%) leads were functional with stable pacing and sensing parameters, and 1/23 (4.3%) was extracted for unrelated reasons. Compared to CSSS leads, the lead revision/abandonment was similar with RVSS leads (Hazard ratio (HR) 0.87, 95% confidence interval (CI) 0.03, 22.0), but was higher with CSCRT leads (HR 7.41, 95% CI 1.30, 139.0). There was no difference in change in LVEF between CSSS and RVSS groups (-2.4 ± 11.0 vs. 1.5 ± 12.8, P = 0.76), but LVEF improved in CSCRT group (11.2 ± 16.5%, P = 0.002). Fluoroscopy times were longer during implantation of CSSS compared to RVSS leads (25.6 ± 24.6 min vs. 12.3 ± 18.6 min, P = 0.049). Conclusion: In patients with normal LVEF, single-site ventricular pacing via the coronary sinus is a feasible, safe and reliable alternative to right ventricular pacing.

Molecular cloning and in silico characterization of knottin peptide, U2-SCRTX-Lit2, from brown spider (Loxosceles intermedia) venom glands.

Inhibitor cystine knots (ICKs) are a family of structural peptides with a large number of cysteine residues that form intramolecular disulfide bonds, resulting in a knot. These peptides are involved in a variety of biological functions including predation and defense, and are found in various species, such as spiders, scorpions, sea anemones, and plants. The Loxosceles intermedia venom gland transcriptome identified five groups of ICK peptides that represent more than 50 % of toxin-coding transcripts. Here, we describe the molecular cloning of U2-Sicaritoxin-Lit2 (U2-SCRTX-Lit2), bioinformatic characterization, structure prediction, and molecular dynamic analysis. The sequence of U2-SCRTX-Lit2 obtained from the transcriptome is similar to that of µ-Hexatoxin-Mg2, a peptide that inhibits the insect Nav channel. Bioinformatic analysis of sequences classified as ICK family members also showed a conservation of cysteine residues among ICKs from different spiders, with the three dimensional molecular model of U2-SCRTX-Lit2 similar in structure to the hexatoxin from µ-hexatoxin-Mg2a. Molecular docking experiments showed the interaction of U2-SCRTX-Lit2 to its predictable target-the Spodoptera litura voltage-gated sodium channel (SlNaVSC). After 200 ns of molecular dynamic simulation, the final structure of the complex showed stability in agreement with the experimental data. The above analysis corroborates the existence of a peptide toxin with insecticidal activity from a novel ICK family in L. intermedia venom and demonstrates that this peptide targets Nav channels.

Binding of phenothiazines into allosteric hydrophobic pocket of human thioredoxin 1.

Thioredoxins are multifunctional oxidoreductase proteins implicated in the antioxidant cellular apparatus and oxidative stress. They are involved in several pathologies and are promising anticancer targets. Identification of noncatalytic binding sites is of great interest for designing new allosteric inhibitors of thioredoxin. In a recent work, we predicted normal mode motions of human thioredoxin 1 and identified two major putative hydrophobic binding sites. In this work we investigated noncovalent interactions of human thioredoxin 1 with three phenotiazinic drugs acting as prooxidant compounds by using molecular docking and circular dichroism spectrometry to probe ligand binding into the previously predicted allosteric hydrophobic pockets. Our in silico and CD spectrometry experiments suggested one preferred allosteric binding site involving helix 3 and adopting the best druggable conformation identified by NMA. The CD spectra showed binding of thioridazine into thioredoxin 1 and suggested partial helix unfolding, which most probably concerns helix 3. Taken together, these data support the strategy to design thioredoxin inhibitors targeting a druggable allosteric binding site.

Binding sites and hydrophobic pockets in Human Thioredoxin 1 determined by normal mode analysis.

The Thioredoxin (Trx) system plays important roles in several diseases (e.g. cancer, viral infections, cardiovascular and neurodegenerative diseases). Therefore, there is a therapeutic interest in the design of modulators of this system. In this work, we used normal mode analysis to identify putative binding site regions for Human Trx1 that arise from global motions. We identified three possible inhibitor's binding regions that corroborate previous experimental findings. We show that intrinsic motions of the protein are related to the exposure of hydrophobic regions and non-active site cysteines that could constitute new binding sites for inhibitors.

Effect of head-up tilt-table testing on left ventricular longitudinal strain in patients with neurocardiogenic syncope.

Recent studies have shown conflicting data regarding left ventricular (LV) function in patients with neurocardiogenic syncope, with some investigators reporting a marked decrease in LV end-systolic wall stress and stress-corrected fractional shortening. We sought to determine the characteristics of resting LV deformation in patients with neurocardiogenic syncope by selective motion tracking of subendocardial and subepicardial regions using speckle tracking echocardiography. We assessed resting LV function in 82 patients undergoing head-up tilt-table (HUTT) testing. Patients were divided into 3 groups based on a positive HUTT test with associated co-morbid conditions (n = 30), no associated co-morbid conditions (n = 30), or negative HUTT results (n = 22). LV longitudinal, circumferential, and radial strains were obtained by speckle tracking echocardiography of subendocardial and subepicardial regions in each group and compared with resting LV deformation in 20 healthy control subjects. Compared with endocardial longitudinal strain in control subjects, that in patients with positive HUTT results was attenuated, irrespective of co-morbid conditions (p <0.05). Circumferential and radial strains did not differ among groups. On multivariate logistic regression analysis, endocardial longitudinal strain was an independent predictor (odds ratio, 1.16; p = 0.01) of positive HUTT test results. In conclusion, resting LV longitudinal strain is attenuated in patients with positive HUTT test results. Overall, these results may suggest that an increase in resting LV contractility is not a prerequisite for development of neurocardiogenic syncope.

Focal mechanism of ventricular tachycardia in coronary artery disease.

BACKGROUND: Re-entry is the most common mechanism of sustained monomorphic ventricular tachycardia (VT) in patients with coronary artery disease and prior myocardial infarction (MI). OBJECTIVE: This study sought to report the electrophysiological properties of a series of patients with prior MI who underwent radiofrequency ablation (RFA) for VT originating instead from a focal source. METHODS: The electrophysiological properties of 46 patients with prior MI (male 89%, age 64.8 +/- 10.2 years) who underwent RFA for sustained VT were studied. A total of 101 VTs were induced (92 [91%] macro-re-entrant VT and 9 [9%] focal VT). RESULTS: One patient had adenosine-sensitive idiopathic focal VT. The focal VT group had a significantly shorter pre-systolic interval (electrogram to QRS) during VT compared with the macro-re-entrant VT group (36 +/- 17 ms vs. 117 +/- 67 ms, P = .001). The successful ablation sites in the focal VT group also had a significantly lower ratio (in percentage) of electrogram-QRS interval to diastolic interval (VT cycle length - QRS duration) during VT (14 +/- 8%) as compared with macro-re-entrant VTs (48 +/- 30%, P <.001). Focal VTs demonstrated an apparent point source of endocardial activation and could not be entrained, whereas 77% of macro-re-entrant VTs were entrained. Successful ablation sites for focal VT (success rate 100%) were predominantly in the basal half of the left ventricle (75%), whereas only 60% of macro-re-entrant VTs (success rate 90.7%) were basal (P = .01). However, the procedure time, VT cycle length, number of RFA applications required for success, and acute success results were not significantly different in these 2 groups. CONCLUSION: A focal mechanism is present in up to 9% of VTs in patients with CAD and prior MI that are induced during electrophysiology study for RF ablation. Mechanistic distinction from more typical macro-re-entrant VT in this population is important because ablation site characteristics are very different.

Reducing Ionizing Radiation Associated with Atrial Fibrillation Ablation: An Ultrasound-Guided Approach.

Radiation exposure with cardiac interventional procedures is an emerging concern. Patients receiving radiofrequency ablation for atrial fibrillation (AF) still routinely undergo pre-ablation computed tomography (CT) scans for definition of left atrial and pulmonary vein anatomy, as well as creation of a surrogate geometry. In an effort to decrease ionizing radiation associated with AF ablation, an ultrasound-guided surrogate geometry approach is proposed as an alternative to routine CT imaging. Ten patients underwent AF ablation using intracardiac ultrasound for the creation of a surrogate left atrial geometry (CartoSound, Biosense Webster, CA); and ten control-cases who had conventional CT-guided imaging (CartoMerge, Biosense Webster, CA) were matched for age, gender, and type of catheter ablation. Sources of radiation included 1) intraprocedural fluoroscopy (CartoSound: 151 ± 43 mGray*cm^2, CartoMerge: 174 ± 130 mGray*cm^2; p=0.6) and 2) CT ionizing radiation (CartoSound: 0 mSv, CartoMerge 9.4 ± 2.3 mSv/CT scan.) When comparing clinical success rates after a trial of previously ineffective anti-arrhythmic drugs, ultrasound-guided AF ablation was non-inferior to a CT-guided approach. This potentially obviates the need for CT-guided imaging, therefore reducing doses of ionizing radiation by nearly 10 mSv per AF catheter ablation.

Nontraditional surgical approaches for implantation of pacemaker and cardioverter defibrillator systems in patients with limited venous access.

BACKGROUND: Indications for placement of implantable cardioverter-defibrillators (ICD) and pacemakers have expanded, and traditional transvenous implantation may not be feasible in patients with aberrant anatomy or venous obstruction. In these settings, successful lead placement has required innovative surgical approaches. A case series of successful placement of these systems in challenging patients is presented. METHODS: A 2-year retrospective study of patients undergoing placement of minimally invasive epicardial pacing leads or ICD coils was performed. RESULTS: Eleven patients underwent minimally invasive surgical placement of leads or coils. None were converted to open sternotomy. One required extension to minianterior thoracotomy. Causes of intravenous placement failure included aberrant anatomy with failure to access coronary sinus in 9 and venous occlusion in 2. Four patients had previous operations through a median sternotomy. Procedures included left video-assisted thoracoscopic (VATS) placement of a left ventricular epicardial lead in 8, left VATS conversion to minianterior thoracotomy left ventricular epicardial lead placement in 1, left VATS placement of ICD coil in 1, subxiphoid placement of a right ventricular epicardial lead in 1, subxiphoid ICD coil in 2, and subcutaneous ICD coil placement in 3. Mean hospitalization was 4.6 days. Postoperative hypotension and pulmonary edema occurred in 27% of patients. No patients died. CONCLUSIONS: Conventional transvenous lead implantation may be difficult or impossible in some patients with aberrant or occluded venous access. Novel surgical approaches with the use of minimally invasive procedures can establish optimally functional pacing and ICD systems without sternotomy and low associated morbidity.

Radiotherapy-induced pacemaker and implantable cardioverter defibrillator malfunction.

It is well known that ionizing radiation can interfere with circuits in permanent pacemakers and implantable cardioverter defibrillators. Contemporary implantable cardiac devices use complementary metal-oxide silicon in combination with other very sensitive transistors. These sensitive components are especially susceptible to electromagnetic and ionizing radiation, which can potentially cause permanent damage. Electromagnetic interference is, in general, a transient phenomenon. Radiologic imaging tests have been implicated in rare cases of implantable device dysfunction and these events have been mostly transient. The American Association of Physicists in Medicine last published recommendations regarding irradiation of pacemakers in 1994. This publication is outdated and may not be pertinent for the current technology used both in the field of artificial cardiac pacing and defibrillation and in the field of radiation oncology. Updated guidelines are definitely needed.

Value of multislice computed tomography angiography of the thorax in preparation for catheter ablation for the treatment of atrial fibrillation: the impact of unexpected cardiac and extracardiac findings on patient care.

OBJECTIVE: In patients referred for catheter ablation for the treatment of atrial fibrillation, multislice computed tomography angiography of the thorax is routinely performed to assess pulmonary vein anatomy. We sought to investigate the incidence of unexpected cardiac and extracardiac findings in this select patient population and to establish how these findings influence subsequent patient care. METHODS: Ninety-five patients (mean age 62+/-10 years, 35% female) referred to our institution for ablation therapy for atrial fibrillation between July 2003 and October 2007 underwent multislice computed tomography angiography of the thorax. Radiologists interpreted all images. Need for additional testing, consultation and eventual diagnosis were assessed by electronic record review. RESULTS: A total of 83 (5 cardiac, 78 extracardiac) unexpected findings were observed in 50/95 (53%) of patients. The findings prompted 23 additional tests (5 cardiac, 18 noncardiac) in 15/95 (16%) of patients and 8 subsequent referrals in 7/95 (7%) patients. In 6 patients the findings significantly altered future patient care and resulted in postponement of ablation therapy in 4 patients. In 2 patients, extracardiac findings (pulmonary emboli and adenocarcinoma of the lung) were of potentially life-saving consequence. CONCLUSIONS: In patients undergoing multislice computed tomography angiography of the thorax in anticipation of planned catheter ablation therapy for the treatment of atrial fibrillation, unexpected findings are common and of potentially significant value. In comparison, there is a higher prevalence of unexpected extracardiac, rather than cardiac findings. Further investigation of these findings may lead to postponement of ablation therapy, but may also be of potentially lifesaving consequence.