Prediction of pacemaker-induced cardiomyopathy using a convolutional neural network based on clinical findings prior to pacemaker implantation.

Risk factors for pacemaker-induced cardiomyopathy (PICM) have been previously reported, including a high burden of right ventricular pacing, lower left ventricular ejection fraction, a wide QRS duration, and left bundle branch block before pacemaker implantation (PMI). However, predicting the development of PICM remains challenging. This study aimed to use a convolutional neural network (CNN) model, based on clinical findings before PMI, to predict the development of PICM. Out of a total of 561 patients with dual-chamber PMI, 165 (mean age 71.6 years, 89 men [53.9%]) who underwent echocardiography both before and after dual-chamber PMI were enrolled. During a mean follow-up period of 1.7 years, 47 patients developed PICM. A CNN algorithm for prediction of the development of PICM was constructed based on a dataset prior to PMI that included 31 variables such as age, sex, body mass index, left ventricular ejection fraction, left ventricular end-diastolic diameter, left ventricular end-systolic diameter, left atrial diameter, severity of mitral regurgitation, severity of tricuspid regurgitation, ischemic heart disease, diabetes mellitus, hypertension, heart failure, New York Heart Association class, atrial fibrillation, the etiology of bradycardia (sick sinus syndrome or atrioventricular block) , right ventricular (RV) lead tip position (apex, septum, left bundle, His bundle, RV outflow tract), left bundle branch block, QRS duration, white blood cell count, haemoglobin, platelet count, serum total protein, albumin, aspartate transaminase, alanine transaminase, estimated glomerular filtration rate, sodium, potassium, C-reactive protein, and brain natriuretic peptide. The accuracy, sensitivity, specificity, and area under the curve of the CNN model were 75.8%, 55.6%, 83.3% and 0.78 respectively. The CNN model could accurately predict the development of PICM using clinical findings before PMI. This model could be useful for screening patients at risk of developing PICM, ensuring timely upgrades to physiological pacing to avoid missing the optimal intervention window.

The estimated glomerular filtration rate predicts pacemaker-induced cardiomyopathy.

Clinical predictors for pacemaker-induced cardiomyopathy (PICM) (e.g., a wide QRS duration and left bundle branch block at baseline) have been reported. However, factors involved in the development of PICM in patients with preserved left ventricular ejection fraction (LVEF) remain unknown. This study aimed to determine the risk factors for PICM in patients with preserved LVEF. The data of 113 patients (average age: 71.3 years; men: 54.9%) who had echocardiography before and after pacemaker implantation (PMI) among 465 patients undergoing dual-chamber PMI were retrospectively analyzed. Thirty-three patients were diagnosed with PICM (18.0/100 person-years; 95% CI 12.8-25.2). A univariate Cox regression analysis showed that an estimated glomerular filtration rate (eGFR) ≤ 30 mL/min/1.73 m2 (HR 3.47; 95% CI 1.48-8.16) and a past medical history of coronary artery disease (CAD) (HR 2.76; 95% CI 1.36-5.60) were significantly associated with the onset of PICM. After adjusting for clinical variables, an eGFR ≤ 30 mL/min/1.73 m2 (HR 2.62; 95% CI 1.09-6.29) and a medical history of CAD (HR 2.32; 95% CI 1.13-4.80) were independent risk factors for developing PICM. A medical history of CAD and low eGFR are independent risk factors for PICM in patients with preserved LVEF at baseline. These results could be helpful in predicting a decreased LVEF by ventricular pacing before PMI. Close follow-up by echocardiography is recommended to avoid a delay in upgrading to physiological pacing, such as cardiac resynchronization therapy or conduction system pacing.

Prediction of Atrial Fibrillation Being Asymptomatic at First Onset by Cardiac Pacing.

Asymptomatic or silent atrial fibrillation (AF) has long been a clinical problem due to the incidence of ischemic stroke. A method is needed to predict the development of silent AF before the occurrence of ischemic stroke. This study was focused on the symptoms of AF, especially palpitation, in pacemaker patients. We assessed the hypothesis that absence of palpitation during rapid ventricular pacing could be a predictor of future onset AF being asymptomatic.In this study, we assessed the presence of symptoms during RV pacing and AF symptoms on 145 pacemaker patients at the outpatient clinic by VVI pacing at 120 ppm. The relationship between symptoms during RV pacing and symptom during AF was assessed. The predictive value of absence of symptom during RV pacing on AF being asymptomatic was assessed.Of 145 patients, 74 had previous AF episode. Among the AF patients, absence of symptom during VVI pacing was associated with AF being asymptomatic.Of 145 patients, 71 had no previous AF events. There were 14 patients who had new-onset AF or atrial flutter (AFL) after the device implantation. Four of the 14 patients (28.6%) were symptomatic during first AF/AFL episode, and 10 (71.4%) were asymptomatic during first-onset AF. All ten patients who were asymptomatic during cardiac pacing test were asymptomatic during their initial episodes of AF as well.This study showed that absence of symptoms during rapid ventricular pacing was associated with first-onset AF being asymptomatic.

Pseudo-elevation of conduction system pacing threshold through parallel connection of an intracardiac electrogram recording system.

Parallel connection of an electrophysiology recording system (EP system) to equipment for conduction system pacing (CSP) has been widely used for fine monitoring of intracardiac electrograms and pacing evaluation. We experienced a case showing unexpected pacing threshold exacerbation under specific conditions when the EP system was connected in parallel. We evaluated the underlying mechanism using an ex vivo model. An ex vivo pacing and intracardiac electrogram monitoring model was generated using an oscilloscope, pacing system analyzer (PSA), EP system, and simulated heart. The discrepancy between expected output at the PSA and the actual measured output value at the simulated heart was measured under various conditions and using various combinations of pacing equipment. Parallel connection of the EP system was associated with reduced electrical output from the PSA as recorded at the simulated heart. The unexpected adverse effects were particularly noticeable when using an RMC-5000 EP system with the pacing function on. The trouble is completely resolved by simply turning off the pacing function of the system. There is a possibility that the EP system might increase the pacing threshold in CSP when the PSA and EP system is are deployed in parallel. The issue may provoke pseudo failure of CSP due to the high pacing threshold. When the RMC-5000 is used for conduction system pacing in parallel with a PSA for the pacing test, the pacing function of RMC-5000 should be turned off.

Fluoroless and contrast-free catheter ablation without a lead apron in routine clinical practice.

The technique of catheter ablation has been improved within the past few decades, especially by three-dimensional (3D) mapping system. 3D mapping system has reduced radiation exposure but ablation procedures still require fluoroscopy. Our previous study showed the safety and efficacy of catheter ablation based on intracardiac echogram combined with CARTOSOUND/CARTO3 system, however fluoroscopy use for an average of 16 min is required for this procedure. The present study was aimed to reduce radiation exposure to zero and establish a radiation free catheter ablation method with the goal of utilizing it in routine clinical practice. We conducted single center, retrospective study during 2019 April to 2020 February. Consecutive 76 patients were enrolled. In the first 18 cases, the previously reported procedure (CARTOSOUND/CARTO3 method) was used. The remaining 58 cases were transitioned to fluoroless catheter ablation. The procedure time, success rates and complication rates were analyzed. Not only AF patients but atrial flutter (AFL), paroxysmal supraventricular tachycardia (PSVT) and ventricular arrhythmia patients were included. Catheter positioning, catheter visualization and collecting the geometry of each camber of the heart were conducted by using contact force and ICE based geometry on CARTO system without either prior computed tomography (CT) or magnetic resonance image (MRI). In fluoroless group, all catheter ablations were successfully performed without lead aprons. No complications occurred in either group. There were no significant differences in procedure time in any type of procedure (Total procedure time Fluoro-group; 149 ± 51 min vs. Fluoroless-group; 162 ± 43 min, N.S.), (PSVT 170 ± 53 min vs. 162 ± 29 min, N.S.), (AFL 110 ± 70 min vs. 123 ± 43 min, N.S.), (AF 162 ± 43 min vs. 163 ± 32 min, N.S.). The total radiation time was reduced to zero in fluoroless group. Catheter ablation with ICE and 3D mapping system guide without fluoroscopy could be safely performed with a high success rate, without any prior CT/MRI 3D images. Radiation was reduced completely for patients and staff, negating the need for protective wear for operators.

Direct left atrial ICE imaging guided ablation for atrial fibrillation without employing contrast medium.

BACKGROUND: Preoperative and intraoperative use of a contrast medium is unavoidable in catheter ablation for atrial fibrillation, which can become a particularly significant issue for patients suffering from renal impairment. OBJECTIVE: The purpose of this study is to investigate the feasibility and safety of a technique for atrial fibrillation ablation without a contrast medium via intra-cardiac ultrasound imaging only. METHODS: We prepared the geometry of the pulmonary vein and left atrium via a SOUNDSTAR catheter from inside the left atrium, without preoperative and intraoperative investigations using contrast mediums, for computed tomography or magnetic resonance imaging and pulmonary venography. This was followed by retrospective investigation of the success rate and complications observed in 200 successive paroxysmal and persistent atrial fibrillation cases that underwent catheter ablation from January 2011 to November 2012. The outcomes were assessed after the one-year follow-up. RESULTS: Inserting a SOUNDSTAR catheter into the left atrium was successful in all cases, wherein rendering of all pulmonary veins and the left atrium was possible, and extensive encircling pulmonary vein isolation was successful in all cases. The sinus rhythm maintenance rate one year after the procedure was 90.4% for paroxysmal atrial fibrillation and 76.0% for persistent atrial fibrillation. The major complication rate was 0.5% (cardiac tamponade), with no cases presenting aggravation of renal function. CONCLUSION: Atrial fibrillation ablation using an intra-cardiac ultrasound from the left atrium without employing a contrast medium was safe, with no adverse effects on renal function.

Progressive coronary artery-pulmonary artery fistula after size-mismatch cardiac transplantation.

Patients who have undergone cardiac transplantation are occasionally complicated by the development of a coronary artery fistula. It has been reported that a majority of coronary artery fistulas in a post-heart transplant setting communicate with the right ventricle. Moreover, most had a favorable prognosis and were rarely associated with hemodynamic disorder. In contrast, the present report describes a case with a progressive coronary artery fistula that drained into the pulmonary artery in a Japanese male who underwent size-mismatch orthotopic cardiac transplantation from a white male donor. The fistula gradually enlarged and a left-to-right shunt deteriorated over a 5-year period after transplantation. In this case, because the coronary fistula drained into the pulmonary artery, endomyocardial biopsy was not considered as a possible cause of the fistula. It is conceivable that size-mismatch heart transplantation may be associated with the development of fistula.