Opportunities and drawbacks of the subcutaneous defibrillator across different clinical settings.

INTRODUCTION: The subcutaneous implantable cardioverter-defibrillator (S-ICD) is an established therapy for the prevention of sudden cardiac death (SCD) and an alternative to a transvenous implantable cardioverter-defibrillator system in selected patients. Beyond randomized clinical trials, many observational studies have described the clinical performance of S-ICD across different subgroups of patients. AREAS COVERED: Our review aimed to describe the opportunities and drawbacks of the S-ICD, focusing on their use in special populations and across different clinical settings. EXPERT OPINION: The choice to implant S-ICD should be based on the patient's tailored approach, which takes into account the adequate S-ICD screening at rest or during stress, the infective risk, the ventricular arrhythmia susceptibility, the progressive nature of the underlying disease, the work or sports activity, and the risk of lead-related complications.

Cardiac electrophysiology and pacing educational and training needs among early-career cardiologists: a national survey of the Young Committee of the Italian Association of Arrhythmology and Cardiac Pacing.

BACKGROUND: Over the past three decades, cardiac electrophysiology and pacing, including device therapy and catheter ablation of arrhythmias, has rapidly developed as a subspecialty in cardiology. Currently, there is no clear perception about the needs in cardiac electrophysiology and pacing among early-career cardiologists. METHODS: To address these concerns, the Young Committee of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC) carried out a survey among those under the age of 40 years to obtain detailed information on practical activities and formal lessons during the fellowship in cardiology and their satisfaction and proficiency level at the end of the fellowship. RESULTS: We obtained 334 answers to the survey. In invasive cardiac electrophysiology and pacing, the percentage of participants attending the activity for a longer time (3-6 months) is lower compared with those in noninvasive subspecialties. About 40% of participants did not receive lessons on interventional cardiology, cardiac electrophysiology and pacing. On the contrary, 71% of participants received an adequate number of lessons on clinical arrhythmology. The vast majority of the participants expressed satisfaction for the education received in the echocardiographic, cardiac interventional laboratories and clinical arrhythmology, but about half of the participants were unsatisfied with the education received in cardiac electrophysiology and pacing. In interventional arrhythmology, the majority of the participants declare their lack of proficiency with two peaks for more complex procedures, namely interventional electrophysiology procedures (82%) and cardiac resynchronization therapy (CRT) procedures (76%). CONCLUSION: The present survey among Italian early-career cardiologists suggests that the majority of participants consider themselves not confident in performing cardiac electrophysiology and pacing procedures. Due to the complexity of the treatment for heart rhythm disorders and the long learning curve, structured additional training in cardiac electrophysiology and pacing procedures is required after cardiology fellowship.

Factors affecting signal quality in implantable cardiac monitors with long sensing vector.

PURPOSE: Electrical artefacts are frequent in implantable cardiac monitors (ICMs). We analyzed the subcutaneous electrogram (sECG) provided by an ICM with a long sensing vector and factors potentially affecting its quality. METHODS: Consecutive ICM recipients underwent a follow-up where demographics, body mass index (BMI), implant location, and surface ECG were collected. The sECG was then analyzed in terms of R-wave amplitude and P-wave visibility. RESULTS: A total of 84 patients (43% female, median age 68 [58-76] years) were enrolled at 3 sites. ICMs were positioned with intermediate inclination (n = 44, 52%), parallel (n = 35, 43%), or perpendicular (n = 5, 6%) to the sternum. The median R-wave amplitude was 1.10 (0.72-1.48) mV with P waves readily visible in 69.2% (95% confidence interval, CI: 57.8%-79.2%), partially visible in 23.1% [95% CI: 14.3%-34.0%], and never visible in 7.7% [95% CI: 2.9%-16.0%] of patients. Men had higher R-wave amplitudes compared to women (1.40 [0.96-1.80] mV vs 1.00 [0.60-1.20] mV, P = .001), while obese people tended to have lower values (0.80 [0.62-1.28] mV vs 1.10 [0.90-1.50] mV, P = .074). The P-wave visibility reached 86.2% [95% CI: 68.3%-96.1%] in patients with high-voltage P waves (≥0.2 mV) at surface ECG. The sECG quality was not affected by implant site. CONCLUSION: In ordinary clinical practice, ICMs with long sensing vector provided median R-wave amplitude above 1 mV and reliable P-wave visibility of nearly 70%, regardless of the position of the device. Women and obese patients showed lower but still very good signal quality.

Prevalence and predictors of atrial fibrillation in patients with embolic stroke of undetermined source: a real-life single-center retrospective study.

INTRODUCTION: Up to one-third of ischemic strokes remained cryptogenic despite extensive investigations. Atrial fibrillation may be detected in a significant proportion of patients with embolic stroke of undetermined source, particularly after the introduction of implantable loop recorder in clinical practice. METHODS: We retrospectively included all the consecutive patients with embolic stroke of undetermined source referred to our units in the period November 2013 to December 2018 and in which an implantable loop recorder was positioned within 6 months from stroke event. Prevalence and predictors of atrial fibrillation were investigated. RESULTS: One hundred thirty-eight patients with embolic stroke of undetermined source fulfilling inclusion criteria were identified. The crude prevalence of atrial fibrillation at the end of observation period was of 45.7%. Incidence rates at 6, 12, 18, 24, and 36 months resulted, respectively, 31.8% (95% CI, 30.4-46.7), 38.0% (95% CI, 30.4-46.9), 42.6% (95% CI, 34.5-51.6), 46.6% (95% CI, 38.2-55.8), and 50.4% (95% CI, 41.6-59.9). On multivariate analysis, only excessive supraventricular electric activity and left atrial enlargement resulted to be significant predictors of atrial fibrillation (p = 0.037 and p < 0.0001, respectively). CONCLUSIONS: Atrial fibrillation may be detected in a relevant proportion (up to 50%) of patients with embolic stroke of undetermined source if a careful and extensive diagnostic work-up is employed. Excessive supraventricular electric activity and left atrial enlargement are significant predictors of the occurrence of atrial fibrillation in these patients.

[Infero-postero-lateral acute myocardial infarction caused by left ventricular myxoma embolism]. / Infarto miocardico infero-postero-laterale secondario ad embolizzazione di mixoma ventricolare sinistro.

The majority of myxomas are located in the left atrium (75%) followed by the right atrium (20%). In rare cases, myxomas can be found in the ventricles, with 2.5% reported for myxomas in the left ventricle. Systemic emboli, mostly cerebral, occur in two thirds of such patients, while coronary emboli are rare. Here we report a case of left ventricular myxoma causing infero-postero-lateral myocardial infarction, successfully treated by intracoronary thromboaspiration of myxoma embolus.

Eligibility of cardiac resynchronization therapy patients for subcutaneous implantable cardioverter defibrillators.

BACKGROUND: Before subcutaneous implantable cardioverter defibrillator (S-ICD) implantation, the adequacy of sensing is required to be verified through surface ECG screening. Our objective was to determine whether S-ICD can be considered as a supplementary therapy in patients who are receiving biventricular (BIV) pacing. METHODS: We evaluated 48 patients with BIV devices to determine S-ICD candidacy during BIV, left ventricular (LV), right ventricular (RV) pacing, and intrinsic conduction (left bundle branch block-LBBB) by using an automated screening tool. Eligibility was defined by the presence of at least one appropriate vector in the supine and standing positions. RESULTS: Eligibility was verified during BIV pacing in 34 (71%) patients. In patients screened-out, QRS duration was longer (p = 0.035) and ischemic cardiomyopathy was more frequent (p = 0.027). LV-only pacing was associated with a lower passing rate (46%) (p < 0.001 versus BIV). The LBBB QRS morphology during inhibited ventricular pacing was acceptable in 51% of patients. The QRS generated by RV pacing was acceptable in 25% of patients. In patients who passed the screening test during BIV, the QRS was not acceptable in 76% during RV pacing (i.e., accidental loss of LV capture). The concomitant adequacy during inhibited ventricular pacing (i.e., possible intrinsic conduction) was not assessed in 40% of patients. CONCLUSIONS: S-ICD may be a supplemental therapy in the majority of CRT patients. Standard BIV pacing should be preferred to the LV-only pacing mode, as it is more frequently associated with adequacy of S-ICD sensing. Spontaneous LBBB and RV-paced QRS morphologies are frequently inadequate. Therefore, in patients selected for concomitant S-ICD and CRT implantation, accidental loss of LV capture or possible intrinsic conduction must be prevented.

Atrial fibrillation termination as a procedural endpoint during ablation in long-standing persistent atrial fibrillation.

BACKGROUND: Ablation of long-standing persistent atrial fibrillation (AF) remains challenging, with a lower success rate than paroxysmal AF. A reliable ablation endpoint has not been demonstrated yet, although AF termination during ablation may be associated with higher long-term maintenance of sinus rhythm (SR). OBJECTIVE: The purpose of this study was to determine whether the method of AF termination during ablation predicts mode of recurrence or long-term outcome. METHODS: Three hundred six patients with long-standing persistent AF, free of antiarrhythmic drugs (AADs), undergoing a first radiofrequency ablation (pulmonary vein [PV] antrum isolation and complex fractionated atrial electrograms) were prospectively included. Organized atrial tachyarrhythmias (AT) that occurred during AF ablation were targeted. AF termination mode during ablation was studied in relation to other variables (characteristics of arrhythmia recurrence, redo procedures, the use of adenosine/isoproterenol for redo, and comparison of focal versus macroreentrant ATs). Long-term maintenance of SR was assessed during the follow-up. RESULTS: During AF ablation, six of 306 patients converted directly to SR, 172 patients organized into AT (with 38 of them converting in SR with further ablation), and 128 did not organize or terminate and were cardioverted. Two hundred eleven of 306 patients (69%) maintained in long-term SR without AADs after a mean follow-up of 25 +/- 6.9 months, with no statistical difference between the various AF termination modes during ablation. Presence or absence of organization during ablation clearly predicted the predominant mode of recurrence, respectively, AT or AF (P = .022). Among the 74 redo ablation patients, 24 patients (32%) had extra PV triggers revealed by adenosine/isoproterenol. Termination of focal ATs was correlated with higher long-term success rate (24/29, 83%) than termination of macroreentrant ATs (20/35, 57%; P = .026). CONCLUSION: AF termination during ablation (conversion to AT or SR) could predict the mode of arrhythmia recurrence (AT vs. AF) but did not impact the long-term SR maintenance after one or two procedures. AT termination with further ablation did not correlate with better long-term outcome, except with focal ATs, for which termination seems critical.

Appraising the pathophysiologic impact of coronary collaterals as measured by fractional flow reserve on symptoms and signs of myocardial ischemia.

BACKGROUND: The purpose of coronary revascularization in stable patients is anginal relief, yet there is no linear relationship between stenosis severity and clinical significance. A major factor in this complex lesion-myocardium interaction is collateral flow. We aimed to define which collateral flow cut-offs separate asymptomatic from symptomatic patients during coronary occlusion. METHODS: Patients undergoing percutaneous transluminal coronary angioplasty for a single stenotic lesion were selected, collaterals were appraised angiographically, and fractional flow reserve was used during prolonged balloon occlusion to measure collateral flow index (FFRcoll). Changes in anginal symptoms, ST-T segment, and left ventricular wall motion were appraised before and during/shortly after balloon dilation. Receiver-operating-characteristic curves and area under the curve were computed to identify the most appropriate FFRcoll cut-offs. RESULTS: Twenty consecutive patients were enrolled. At baseline, 10 patients had angiographic evidence of collaterals, whereas 10 had no angiographic evidence of collateral flow distal to the target lesion. FFRcoll had an excellent discriminatory performance for the presence of angiographic collaterals (area under the curve = 0.90, P = 0.003), a good discriminatory performance for the occurrence of angina (area under the curve = 0.80, P = 0.025), and a trend toward a good discriminatory performance for the occurrence of asynergy (area under the curve = 0.81, P = 0.06). On the basis of receiver-operating-characteristic curves, an FFRcoll cut-off greater than 0.26 could reliably distinguish patients with adequate collaterals (sensitivity = 0.90, specificity = 0.80), whereas a greater than 0.41 cut-off distinguished patients having angina or wall motion abnormalities from those remaining asymptomatic. CONCLUSION: This study shows that distal collateral pressure greater than 41% of proximal perfusion pressure protects from anginal symptoms or regional systolic dysfunction during coronary occlusion, whereas a greater than 26% cut-off is more appropriate to identify angiographically evident collaterals ensuring distal myocardial viability.

Idiopathic thrombocytopenic purpura and percutaneous coronary stenting: a dangerous duo?

Dual antiplatelet therapy is a mainstay in the management of patients undergoing coronary stenting. Whether this is also appropriate in patients with a diagnosis of idiopathic thrombocytopenic purpura (ITP) is unclear. We report the case of a 66-year-old man with ITP admitted for an acute coronary syndrome. On admission platelets were 110 x 10(9)/L without petechiae or purpura, and coronary angiography revealed multivessel disease with significant left main involvement. Given the unfeasibility of surgical revascularization with cardiopulmonary bypass because of ITP, a staged percutaneous revascularization strategy was chosen. Both left circumflex and right coronary arteries were treated with bare-metal stenting during the index admission. After 4 weeks of strict clinical monitoring and evidence of a stable total platelet count on oral prednisone, percutaneous coronary intervention with drug-eluting stenting was performed in the left main and left anterior descending arteries. He was then discharged on lifelong aspirin and a 6-month clopidogrel regimen without thrombotic or bleeding complications. Given the paucity of data on ITP and stenting, no strict recommendations can be proposed and treatment should be individualized to minimize both bleeding and thrombosis risks. Nonetheless, this case suggests the feasibility of percutaneous revascularization in selected patients with multivessel coronary disease and ITP.