Maria Luce Caputo

An in-silico analysis of the effect of heart position and orientation on the ECG morphology and vectorcardiogram parameters in patients with heart failure and intraventricular conduction defects

AIM The aim of this study was to investigate the influence of geometrical factors on the ECG morphology and vectorcardiogram (VCG) parameters. METHODS Patient-tailored models based on five heart-failure patients with intraventricular conduction defects (IVCDs) were created. The heart was shifted up to 6 cm to the left, right, up, and down and rotated ±30° around the anteroposterior axis. Precordial electrodes were shifted 3 cm down. RESULTS Geometry modifications strongly altered ECG notching/slurring and intrinsicoid deflection time. Maximum VCG parameter changes were small for QRS duration (-6% to +10%) and QRS-T angle (-6% to +3%), but considerable for QRS amplitude (-36% to +59%), QRS area (-37% to +42%), T-wave amplitude (-41% to +36%), and T-wave area (-42% to +33%). CONCLUSION The position of the heart with respect to the electrodes is an important factor determining notching/slurring and voltage-dependent parameters and therefore must be considered for accurate diagnosis of IVCDs.

True idiopathic ventricular fibrillation in out-of-hospital cardiac arrest survivors in the Swiss Canton Ticino: prevalence, clinical features, and long-term follow-up

Aims Out‐of‐hospital cardiac arrest (OHCA) in the absence of evident structural heart disease is rare and can be due to subclinical cardiomyopathy and primary electrical disorders, including idiopathic ventricular fibrillation (IVF) with early repolarization (ER) pattern. Aim of this study was to investigate prevalence, clinical features, and long‐term prognosis of IVF in OHCA survivors with otherwise normal 12‐lead electrocardiograms (ECGs). Methods and results Patients with IVF in the absence of ER pattern or atrioventricular conduction abnormalities were considered eligible for this study. A total of 3407 OHCAs occurred in our region from 2000 to 2014. Out‐of‐hospital cardiac arrests of presumed cardiac origin were 2192; of them, 644 presented with a ventricular arrhythmia (VT/VF) as first shockable rhythm. Among them, a total of 74 implantable cardioverter‐defibrillators were implanted for secondary prevention. Ventricular arrhythmia was considered idiopathic in 11 (15%) of these patients. Over a mean follow‐up time of 85 ± 47 months (median: 42 months), ECG was found abnormal in three cases. In the remaining eight patients (6 males; median age: 45 years), no ECG or structural abnormalities were detected during the follow‐up. Prevalence of IVF in OHCA survivors with first‐shockable rhythm was 1.2%. During the long‐term follow‐up, no patient died or experienced ICD interventions. No new echocardiographic abnormal findings were revealed. Conclusions Idiopathic ventricular fibrillation is rare occurring in 1.2% of OHCA survivors presenting with a shockable rhythm. The initial diagnosis can change in up to 27% of cases. Patients with IVF and no ER pattern or AV conduction disturbances have a good prognosis during a long‐term follow‐up.

Better management of out-of-hospital cardiac arrest increases survival rate and improves neurological outcome in the Swiss Canton Ticino.

Abstract Aim To determine the incidence of out-of-hospital cardiac arrest (OHCA) fulfilling Utstein criteria in the Canton Ticino, Switzerland, the survival rate of OHCA patients and their neurological outcome. Methods and results All OHCAs treated in Canton Ticino between 1 January 2005 and 31 December 2014 were followed until either death or hospital discharge. The survival and neurological outcome of those OHCA fulfilling Utstein criteria are reported. A total of 3367 OHCAs occurred in the Canton Ticino over a 10-year period. Resuscitation was attempted in 2298 patients; of those 1492 (65%) were of presumed cardiac origin, 454 fulfilling the Utstein comparator criteria. About 69% [95% confidence interval (CI), 66.6–71.4%] of the patients had a bystander-witnessed arrest; a dispatched cardiopulmonary resuscitation (CPR) steadily and significantly increased from 2005 to 2014. Out-of-hospital cardiac arrest occurred prevalently home (67%), in men (71%) of a mean age of 71 ± 13 years. There were no statistically significant differences either in demographic characteristics of OHCA victims over these years or in presenting rhythm. There was a progressive increase in the survival at discharge from 15% in 2005 to 55% in 2014; overall 96% (95% CI, 93.3–99.9%) of the survivors had a good neurological outcome. Conclusion The significant increase in Utstein comparator survival rates and improved neurological outcome in OHCA victims in Canton Ticino are the result of an effective OHCA management programme which includes large-scale public education, a coordinated fast EMS response, high density of external defibrillators, and advances in clinical interventions for OHCAs.

High rate of subcutaneous implantable cardioverter-defibrillator sensing screening failure in patients with Brugada syndrome: a comparison with other inherited primary arrhythmia syndromes

Aims Subcutaneous implantable cardioverter-defibrillator (S-ICD) can avoid important complications associated with transvenous leads in patients with inherited primary arrhythmia syndromes, who do not need pacing therapy. Few data are available on the percentage of patients with inherited arrhythmia syndromes eligible for S-ICD implantation. Aim of this study was to analyse the eligibility for S-ICD in a series of patients with Brugada syndrome (BrS), and to compare it with patients with other channelopathies. Methods and results Patients presenting with BrS, long-QT syndrome (LQTS), early repolarization syndrome (ERS), and idiopathic ventricular fibrillation (IVF) were considered eligible for this study. ECG screening was performed by analysis of QRS complex and T wave morphology recorded in standing and supine position. Eligibility was defined when ≥1 sense vector was acceptable in both supine and standing position. A total of 100 patients (72 males; mean age: 46 ± 17 years) underwent S-ICD sensing screening. Sixty-one patients presented with BrS, 21 with LQTS, 14 with IVF, and 4 with ERS. Thirty-four patients with BrS (56%) presented with spontaneous type 1 ECG. In the other 27 patients (44%), type 1 ECG was unmasked by ajmaline. Overall, rate of screening failure was 13%. Patients with BrS had a higher rate of inappropriate morphology analysis as compared with other channelopathies (18% vs. 5%, P = 0.07) and had a lower number of suitable sensing vectors (49.6% vs. 84.7% vs. P < 0.001). Ajmaline challenge unmasked sensing failure in 14.8% of drug-induced BrS patients previously considered eligible. In all patients, the reason for sensing inappropriateness was due to the presence of high T wave voltages. Conclusion S-ICD screening failure occurs in up to 13% of patients with inherited primary arrhythmia syndromes. Patients with BrS present a higher rate of screening failure as compared with other cardiac channelopathies.

Clinical utility of routine use of continuous transesophageal echocardiography monitoring during transvenous lead extraction procedure

BACKGROUND Data on the use of transesophageal echocardiography (TEE) during transvenous lead extraction (TLE) procedures are scarce. OBJECTIVE The purpose of this study was to assess the routine use of TEE during transvenous lead extraction. METHODS From January 2009 to January 2014, TLE of 241 leads in 168 patients (mean age 70 ± 13 years, 129 male, left ventricular ejection fraction 37% ± 13%) was performed. Indication for TLE was lead dysfunction (56.5%), upgrade (27.0%), infection (13%), or other (3.1%). TLE techniques combined a mechanical approach amended by laser technique if required. Extraction procedures were performed with patients under general anesthesia with continuous invasive arterial blood pressure and TEE monitoring. RESULTS TEE was possible in all except 1 patient. TEE images in different projections were acquired and stored before and immediately after extraction of each lead. TLE was complete for 236 of 241 leads (97.9%); 4 distal lead tips (1.7%) remained in situ, and 1 dual-coil implantable cardioverter-defibrillator electrode (0.4%) could not be removed. New TEE findings after TLE were observed in 7 of 161 cases (4.3%): pericardial effusion (mild in 4 [2.5%] and severe in 1 [0.6%]) and worsening of tricuspid valve insufficiency (2 patients [1.2%]). The only case of severe pericardial effusion occurred after laceration of the superior vena cava, which required immediate rescue surgery (0.6%, confidence interval 0.01-3.3). In all other cases, TEE findings did not entail immediate diagnostic or therapeutic measures. CONCLUSION New TEE findings produced during TLE necessitating immediate therapeutic measures occurred in only 0.6% of cases, suggesting the limited utility of routine continuous TEE monitoring during TLE.

High recurrence of device-related adverse events following transvenous lead extraction procedure in patients with cardiac resynchronization devices.

Little is known about the clinical outcome and recurring system‐related adverse events (SAE) in cardiac resynchronization therapy (CRT) patients after transvenous lead extraction (TLE).

Temporal trends and long term follow-up of implantable cardioverter defibrillator therapy for secondary prevention: A 15-year single-centre experience☆

BACKGROUND The aim of this study was to determine overall and aetiology-related incidence of secondary prevention ICD implantation over the last 15years in Canton Ticino and to assess clinical outcome according to time period of implantation. METHODS AND RESULTS Consecutive patients treated by implantation of an ICD for secondary prevention from 2000 to 2015 were included in the current study and compared between 5-year cohorts (2000/2004; 2005/2009; 2010/2015). Yearly implantation rate, changing in clinical presentation over years and events during follow-up were evaluated. One-hundred fifty six patients were included. ICD implantation rate increased from 2.1 in 2000-2005 to 5.1 in 2010-2015, respectively (p 0.001). There was an increase in the proportion of non-ischaemic patients and of ventricular tachycardia (VT) as presenting rhythm. No differences in appropriate ICD interventions were observed according to aetiology, presenting arrhythmia or type of device. Reverse remodelling was observed more often in non-ischaemic patients, without any influence on the occurrence of appropriate interventions. Previous myocardial infarction (MI), atrial fibrillation (AF), NYHA class 2-3 and left ventricular ejection fraction (LVEF)<35% were predictors of appropriate therapies during follow-up. CONCLUSIONS Rate of implants for secondary prevention indication has almost doubled during the last 15years. Importantly, there has been a progressive increase of non-ischaemic patients receiving an ICD, and of VT as presenting rhythm. Patients had an overall good survival and a relatively low incidence of appropriate therapies. Improvement of ejection fraction did not correlate with risk reduction of ventricular arrhythmias.

Value of high-resolution mapping in optimizing cryoballoon ablation of atrial fibrillation

BACKGROUND Unrecognized incomplete pulmonary vein isolation (PVI), as opposed to post-PVI pulmonary vein reconnection, may be responsible for clinical recurrences of atrial fibrillation (AF). To date, no data are available on the use of high-resolution mapping (HRM) during cryoballoon (CB) ablation for AF as the index procedure. The aims of this study were: - to assess the value of using a HRM system during CB ablation procedures in terms of ability in acutely detecting incomplete CB lesions; - to compare the 8-pole circular mapping catheter (CMC, Achieve) and the 64-pole mini-basket catheter (Orion) with respect to pulmonary vein (PV) signals detection at baseline and after CB ablation; - to characterize the extension of the lesion produced by CB ablation by means of high-density voltage mapping. METHODS Consecutive patients with drug-resistant paroxysmal or early-persistent AF undergoing CB ablation as the index procedure, assisted by a HRM system, were retrospectively included in this study. RESULTS A total of 33 patients (25 males; mean age: 59 ± 18 years, 28 paroxysmal AF) were included. At baseline, CMC catheter revealed PV activity in 102 PVs (77%), while the Orion documented PV signals in all veins (100%). Failure of complete CB-PVI was more frequently revealed by atrial re-mapping with the Orion as compared to the Achieve catheter (24% vs 0%, p < 0.05). A repeat ablation was performed in 8 patients (24%). In 9% of cases, the Orion catheter detected far-field signals originating from the right atrium. Quantitative assessment of the created lesion revealed a significant reduction of the left atrial area having voltage >0.5 mV. A total of 29 patients (88%) remained free of symptomatic AF during a mean follow-up of 13.2 ± 3.7 months. CONCLUSION Atrial re-mapping after CB ablation by means of a HRM system improves the detection of areas of incomplete ablation, characterizes the extension of the cryo-ablated tissue and can identify abolishment of potential non-PVI related sources of AF.

The relation between local repolarization and T-wave morphology in heart failure patients

BACKGROUND Both duration and morphology of the T-wave are regarded important parameters describing repolarization of the ventricles. Conventionally, T-wave concordance is explained by an inverse relation between the time of depolarization (TD) and repolarization (TR). Little is known about T-wave morphology and TD-TR relations in patients with heart failure. METHODS Electro-anatomic maps were obtained in the left (LV) and right ventricle (RV) and in the coronary sinus (CS) in patients with heart failure with narrow (nQRS, n=8) and wide QRS complex with (LBBB, n=15) and without left bundle branch block (non-LBBB, n=7). TD and TR were determined from the thus acquired electrograms. RESULTS In nQRS and non-LBBB patients, TD-TR relations had a slope between 0 and +1, indicating that repolarization followed the sequence of depolarization. In LBBB patients, repolarization occurred significantly earlier in the RV than in the LV, fitting with the idea that the discordant T-waves in LBBB are secondary to the abnormal depolarization sequence. However, the slopes of the TD-TR relations in the LV and CS were not significantly different from zero, indicating no major spatial gradient in LV repolarization, despite a considerable gradient in depolarization. Remarkable was also the large (~100ms) transseptal gradient in repolarization. Values of the slopes of the TD-TR relation overlapped between the three patient groups, despite a difference in T-wave morphology between LBBB (all discordant) and nQRS patients (all flat/biphasic). CONCLUSIONS Discordant T-waves in LBBB patients are explained by interventricular dispersion in repolarization. T-wave morphology is determined by more factors than the TD-TR relation alone.

Changes in P-wave morphology after pulmonary vein isolation: insights from computer simulations

AIMS Apparently conflicting clinical measurements of P-wave duration (PWD) pre- vs. post-ablation have been reported. To assist the interpretation of these clinical data, we used a computer model of the atria and torso to simulate P waves before and after pulmonary vein (PV) isolation. METHODS AND RESULTS Twenty ablation patterns were designed (segmental or ipsilateral ablation; five distances to PV sleeves; addition of a roof line or not). Possible PV reconnections were introduced as gaps in the ablation lines. PWD and area were measured during sinus rhythm in vectorcardiogram (VCG) magnitude signals and on the 16-lead ECG before and after ablation, and after PV reconnection. After PV isolation, biatrial activation time was prolonged by 0-5 ms without and by 48±5 ms with roof line. Yet PWD was shortened in lead V3 and V4 by up to 15 ms. The effect of ablation on P-wave morphology was stronger when larger PV areas were isolated. Segmental and ipsilateral PV isolation led to concordant results. P-wave area increased in V1 and decreased in V6. Changes in PWD and area on the VCG were sensitive to the threshold used for detecting the end of the P wave. The occurrence of PV reconnection was best identified on leads V3, V4, and V9. CONCLUSION PV isolation and reconnection induced measurable changes on the 16-lead ECG that might be used to improve patient follow-up after ablation.