Prevalence and long-term prognosis of patients with 'narrower than normal' QRS complexes.

Aims: Very narrow QRS have been reported in sudden death survivors but prevalence and prognosis role of narrow QRS is unknown. Methods and results: 546 healthy men between 50 and 60 years (group 1) and 373 similar patients with coronary artery disease (368 men, group 2) underwent signal averaged ECG (SA-ECG) allowing precise measurement of QRS duration. All cause-mortality was determined after 18 ± 3 years follow-up. Mean QRS duration was 97 ± 13 ms in group 1 and 103 ± 16 ms in group 2. Tenth percentile was 84 ms in group 1 and 85 ms in group 2. All cause-mortality in group 1 was 10.4% (57/546): 6/85 in case of QRS <85 ms (7%) and 2/23 (9%) in case of QRS >120 ms (ns). HR for all-cause mortality was 0.75 (95% CI 0.32-1.76, P = 0.52) for QRS <85 ms and 0.86 (95% CI 0.21-3.53, P = 0.84) for QRS >120 ms. All cause mortality in group 2 was 29% (109/373): 7/44 in case of QRS <85 ms (16%) and 22/44 (50%) in case of QRS >120 ms (P = 0.002). HR for all-cause mortality was 0.65 (95% CI 0.29-1.45, P = 0.29) for QRS <85 ms and 1.73 (95% CI 1.02-2.94, P = 0.05) for QRS >120 ms. Conclusion: QRS duration <80-85 ms can be observed in a significant proportion of middle-aged healthy males and in similar patients with ischemic heart disease. Narrow QRS were not linked to prognosis in any group.

Sudden QRS morphology change during ventricular pacing in a scar-related isthmus What is the mechanism?

We present an example of sudden modification in QRS morphology during ventricular pacing inside a scar-related isthmus. This is explained by a "concealed" sudden block in both the orthodromic and antidromic wavefront directions, allowing then the activation to proceed through a now overt antidromic conduction.

Impact of Substrate-Based Ablation of Ventricular Tachycardia on Cardiac Mortality in Patients With Implantable Cardioverter-Defibrillators.

INTRODUCTION: This study sought to determine if the acute procedural outcome of ventricular tachycardia (VT) substrate ablation is associated with a mortality benefit in patients with implantable cardioverter-defibrillators (ICD). METHODS AND RESULTS: A total of 195 ICD recipients (65 ± 11years) with ischemic or nonischemic dilated cardiomyopathy underwent substrate-based ablation targeting elimination of local abnormal ventricular activities (LAVA). Acute procedural success, which was defined as elimination of all identified LAVA in addition to the lack of VT inducibility, was achieved in 95 (49%) patients. During a median follow-up of 23 months, patients with acute procedure success had a significantly lower incidence of ICD shocks compared to those with ablation failure (8% vs. 30%, P < 0.001). In multivariate analysis, acute procedural success was associated with a lower risk of VT recurrence (hazard ratio [HR] 0.30, 95% confidence interval [CI] 0.18-0.49, P < 0.001) and all-cause mortality (HR 0.32, 95% CI 0.17-0.60, P < 0.001). While the impact of ablation success on mortality was not statistically significant in patients with LVEF > 35% (HR 0.45, 95% CI 0.15-1.34, P = 0.15) and those with NYHA class I/II (HR 0.63, 95% CI 0.29-1.40, P = 0.26), it was marked in patients with LVEF ≤ 35% (HR 0.30, 95% CI 0.14-0.62, P = 0.001) and NYHA class III/IV (HR 0.17, 95% CI 0.05-0.57, P = 0.004). CONCLUSIONS: LAVA elimination in addition to VT noninducibility as a procedural outcome for substrate-based ablation is associated with reduced mortality and better VT-free survival during follow-up. This prognostic benefit may be most pronounced in patients with severe heart failure as indicated by severely depressed LV function and NYHA class III/IV symptoms.

Management of outflow tract ventricular arrhythmias.

PURPOSE OF REVIEW: Outflow tract ventricular arrhythmias represent an important chapter in clinical electrophysiology. Recent investigations enhance the knowledge in that field and highlight new important concepts in ventricular arrhythmogenesis. RECENT FINDINGS: Recent publications have revealed new interesting results in the field of outflow tract ventricular arrhythmias. The embryonic phenotype is maintained in the adult outflow tract, which leads to conduction slowing in some circumstances. Outflow tract ventricular arrhythmias unrelated to any detectable abnormal area may happen in structural heart disease. Promising results are expected using noninvasive high-density ECG mapping for outflow tract ventricular arrhythmia localization. In an experimental model of Brugada syndrome, late fractionated activity at the outflow tract was shown to result from repolarization heterogeneity. Malignant ventricular arrhythmias from the right ventricular outflow tract should be suspected in case of syncopal episode and when ectopies display a positive QRS complex in lead I. Ablation was shown to be superior to drug therapy for outflow tract ventricular arrhythmia in a recent prospective randomized study. Recent reports described novel previously unsuspected locations for ventricular arrhythmia, while some still poorly recognized structures are implicated in outflow tract ventricular arrhythmia. SUMMARY: Recent findings have shed new light on the basic and clinical electrophysiology of the outflow tract, which may enhance the management of patients with benign outflow tract ventricular arrhythmia and solve the complex relationships between outflow tract ventricular arrhythmia and sudden death.

Lack of Correlations between Electrophysiological and Anatomical-Mechanical Atrial Remodeling in Patients with Atrial Fibrillation.

BACKGROUND: Atrial fibrillation (AF) progressively leads to electrical remodeling (ER) and anatomical-mechanical remodeling (AR), whose relationships in humans remain poorly known. METHODS: ER and AR were compared in patients undergoing percutaneous radiofrequency (RF) ablation for AF. ER was defined by right and left appendage activation rates as a surrogate for atrial refractory periods. AR was approached by left atrial (LA) diameters and area and left atrial appendage (LAA) area and contractile function (mean emptying flow velocity) (LAAFV) before RF ablation. Mean duration between successive LAA contractions was considered as LAA mechanical rate. RESULTS: Forty-one patients (31 men, age: 64 ± 9 years) with paroxysmal (27%), persistent (61%), or long-persistent AF (12%) were prospectively included (ejection fraction: 44 ± 16%). Parameters exploring AR were highly correlated to each other: LA area (28 ± 7 cm(2) ), LAA area (5.7 ± 2.25 cm(2) ), LA transverse (49 ± 7 mm), and anteroposterior diameter (59 ± 13 mm) or LAAFV (29 ± 13 cm/s; P < 0.05 for each comparison). Parameters exploring ER were also highly correlated: right atrial appendage (RAA; 181 ± 39 ms) and LAA (176 ± 33 ms) activation rates (P < 0.0001). There was no significant correlation between any ER and AR parameter. Only LAA mechanical rate (174 ± 36 ms) was correlated to LAA or RAA activations rates (P ≤ 0.01). CONCLUSION: ER and AR are not mutually related, atrial activation rate being not correlated to LA or LAA size or function. Thus, the mechanisms leading to AF-induced atrial remodeling may differ for anatomical and electrophysiological aspects.

Radio-frequency ablation as primary management of well-tolerated sustained monomorphic ventricular tachycardia in patients with structural heart disease and left ventricular ejection fraction over 30%.

AIMS: Patients with well-tolerated sustained monomorphic ventricular tachycardia (SMVT) and left ventricular ejection fraction (LVEF) over 30% may benefit from a primary strategy of VT ablation without immediate need for a 'back-up' implantable cardioverter-defibrillator (ICD). METHODS AND RESULTS: One hundred and sixty-six patients with structural heart disease (SHD), LVEF over 30%, and well-tolerated SMVT (no syncope) underwent primary radiofrequency ablation without ICD implantation at eight European centres. There were 139 men (84%) with mean age 62 ± 15 years and mean LVEF of 50 ± 10%. Fifty-five percent had ischaemic heart disease, 19% non-ischaemic cardiomyopathy, and 12% arrhythmogenic right ventricular cardiomyopathy. Three hundred seventy-eight similar patients were implanted with an ICD during the same period and serve as a control group. All-cause mortality was 12% (20 patients) over a mean follow-up of 32 ± 27 months. Eight patients (40%) died from non-cardiovascular causes, 8 (40%) died from non-arrhythmic cardiovascular causes, and 4 (20%) died suddenly (SD) (2.4% of the population). All-cause mortality in the control group was 12%. Twenty-seven patients (16%) had a non-fatal recurrence at a median time of 5 months, while 20 patients (12%) required an ICD, of whom 4 died (20%). CONCLUSION: Patients with well-tolerated SMVT, SHD, and LVEF > 30% undergoing primary VT ablation without a back-up ICD had a very low rate of arrhythmic death and recurrences were generally non-fatal. These data would support a randomized clinical trial comparing this approach with others incorporating implantation of an ICD as a primary strategy.

[Factors Associated with Direct Oral Anticoagulants versus Vitamin K Antagonists in Patients with Non-valvular Atrial Fibrillation]. / Facteurs associés à la prescription d'anticoagulants oraux directs versus anti-vitamines K dans la fibrillation atriale non valvulaire.

OBJECTIVE: Describing the factors associated with direct oral anticoagulants (DOA) prescription in patients with atrial fibrillation (AF). METHOD: This study was performed in Toulouse on a cohort of patients received in rhythmology consultation, treated with vitamin K antagonists (VKA) or DOA for AF. A multivariate model was performed using logistic regression to describe the factors associated with DOA prescription and secondly, those associated with discontinuation of the anticoagulant. RESULTS: Among the 140 patients included, 96 (66%) were treated with VKA and 48 (34%) with DOA. Recent AF diagnosis (OR 7.52, 95% CI [2.41;23.29], p = 0.001), previous exposure to VKA (OR 17.11, 95% CI [4.48;60.91], p<0.001), and no current exposure to anti-platelet agents (APA) (OR 7.69, 95% CI [1.22; 50.00], p = 0.030) were associated to DOA prescription. Discontinuation of the anticoagulant (n=24) was associated to DOA intake (OR 2.71, 95% CI [1.21; 6.08], p = 0.016). DISCUSSION: DOA are less prescribed than VKA in patients treated with APA. DOA switch to VKA was not systematic in patients diagnosed for a long time. However, international normalized ratio (INR) values were stable in most of patients treated with VKA at the switching to DOA. A more powerful study would confirm the factors associated with DOA prescription.

Detection of T-wave beat-by-beat variations prior to ventricular arrhythmias onset in ICD-stored intracardiac electrograms: the Endocardial T-Wave Alternans Study (ETWAS).

BACKGROUND: The aim of the Endocardial T-Wave Alternans Study was to prospectively assess the presence of T-wave alternans (TWA) or beat-to-beat repolarization changes on implantable cardioverter-defibrillator (ICD)-stored electrograms (EGMs) immediately preceding the onset of spontaneous ventricular tachycardia (VT) or fibrillation (VF). METHODS: Thirty-seven VT/VF episodes were compared to 116 baseline reference EGMs from the same 57 patients. A Bayesian model was used to estimate the T-wave waveform in each cardiac beat and a set of 10 parameters was selected to segment each detected T wave. Beat-by-beat differences in each T-wave parameter were computed using the absolute value of the difference between each beat and the following one. Fisher criterion was used for determining the most discriminant T-wave parameters, then top-M ranked parameters yielding a normalized cumulative Fisher score > 95% were selected, and analysis was applied on these selected parameters. Simulated TWA EGMs were used to validate the algorithm. RESULTS: In the simulation study, TWA was detectable even in the case of the smallest simulated alternans of 25 µV. In 13 of the 37 episodes (35%) occurring in nine of 16 patients, significant larger beat-to-beat variations before arrhythmia onset were detected compared to their respective references (median one positive episode per patient). Parameters including the T-wave apex amplitude seem the more discriminant parameters. CONCLUSIONS: Detection of beat-by-beat repolarization variations in ICD-stored EGMs is feasible in a significant subset of cases and may be used for predicting the onset of ventricular arrhythmias.

Incessant atrio-ventricular node reentrant tachycardia induced by unapparent dual atrio-ventricular node conduction.

We present the case of a patient with incessant slow-fast atrio-ventricular (AV) node reentrant tachycardia induced by dual AV node conduction with aborted conduction to the ventricles. The unapparent conduction over the slow pathway was suspected here because of spontaneous nodal echoes without QRS complexes occurring during sinus rhythm, manifested as isolated premature atrial beats and which repetitively induced the tachycardia.

Transseptal implantation of a left ventricular pacing lead for an ectopic location of the coronary sinus ostium in the left atrium.

Congenital abnormalities of the coronary sinus (CS) are rare but can be responsible for unsuccessful implantation of a cardiac resynchronization therapy device. We report the case of an ectopic drainage of the CS in the left atrium. A left ventricular lead was implanted by the transseptal route.

Atrial oversensing by an LV lead during typical flutter: the interest of electronic repositioning.

Occurrence of supraventricular tachycardia is a common cause of clinical impairment for patients implanted with CRT devices. We report the case of atrial activity oversensing by the left ventricular (LV) lead during typical flutter, which led to LV pacing inhibition. Temporary reprogramming of the LV detection from standard bipolar to extended bipolar and cavotricuspid isthmus ablation solved this problem.

Ventricular fibrillation in loop recorder memories in a patient with early repolarization syndrome.

We report the first documentation of spontaneous ventricular fibrillation by a loop recorder in a patient with an ECG pattern of early repolarization (ER) in the inferior leads and presenting with syncope.

Microvolt T-wave alternans in short QT syndrome.

BACKGROUND: T-wave alternans (TWA) is an accepted marker of risk for malignant ventricular arrhythmias, for which prognosis value has been established in different populations. Short QT syndrome (SQTS) is a very rare primary electrical disease carrying the risk of ventricular fibrillation. TWA in SQTS has not been evaluated yet. METHODS: Thirteen patients with SQTS (QT = 308 ± 16 ms, QTc = 329 ± 10 ms, heart rate = 69 ± 8 beats/min) underwent microvolt TWA measurement using spectral analysis. TWA testing was performed using Heartwave II (Cambridge Heart™, Inc., Bedford, MA, USA) during bicycle exercice and classified as negative, positive, or indeterminate according to the published standards for clinical interpretation. RESULTS: Twelve patients were male (mean age 23 ± 5 years). Five were asymptomatic, three presented with aborted sudden cardiac death, and five with unexplained syncope. Six patients belonged to two unrelated families, while familial cases of SQTS were present for two other patients. A familial history of sudden death (SD) was present for seven patients. Ventricular fibrillation was inducible in three patients. Four patients were implanted with an implantable cardioverter-defibrillator and one presented with polymorphic ventricular tachycardia during follow-up. TWA was negative in each but one patient (indeterminate). Maximal negative heart rate was 118 ± 12 beats/min. Patients with previous SD displayed significant shorter QT and higher resting heart rate compared to the remaining cases. CONCLUSIONS: TWA testing is negative in 12 of 13 SQTS patients, even in the symptomatic or inducible ones. Measurement of TWA using conventional protocol and criteria for risk stratification in SQTS seems therefore useless.

Cardiac screening before returning to elite sport after SARS-CoV-2 infection.

BACKGROUND: SARS-CoV-2 infection can induce cardiac damage. Therefore, in the absence of clear data, a cardiac evaluation was recommended for athletes before returning to play after recent SARS-CoV-2 infection. AIM: To assess the proportion of anomalies detected by this cardiac screening. METHODS: We reviewed the medical files of elite athletes referred for cardiac evaluation before returning to play after a non-hospitalized SARS-CoV-2 infection (based on a positive polymerase chain reaction or antigen test) from March 2020 to July 2021 in 12 French centres. RESULTS: A total of 554 elite athletes (professional or national level) were included (median age 22 years, 72.0% male). An electrocardiogram (ECG), echocardiogram and exercise test were performed in 551 (99.5%), 497 (89.7%) and 293 (52.9%) athletes, respectively. We found anomalies with a potential link with SARS-CoV-2 infection in four ECGs (0.7%), three echocardiograms (0.6%) and three exercise tests (1.0%). Cardiac magnetic resonance imaging was performed in 34 athletes (6.1%), mostly due to abnormal first-line examinations, and was abnormal in one (2.9%). The rates of those abnormalities were not higher among athletes with cardiac symptoms or more severe forms of non-hospitalized SARS-CoV-2 infection. Only one athlete had a possible SARS-CoV-2 myocarditis and sport was temporally contraindicated. None had a major cardiac event declared during the follow-up. CONCLUSION: The proportion of cardiac involvement after non-hospitalized forms of SARS-CoV-2 infection in athletes are very low. Systematic cardiac screening before returning to play seems to be unnecessary.

Sports participation and myocarditis: Influence of sport types on disease severity.

OBJECTIVE: To study, in the context of acute myocarditis (AM) in sportsmen, the association between the category of sport practiced and the severity of AM. DESIGN: Retrospective study. SETTING: Single tertiary center. PATIENTS: 82 sportspeople (≥2.5 h of sport per week) who presented an AM. ASSESSMENT OF RISK FACTORS: The type of sport activity before AM were collected. MAIN OUTCOME MEASURES: Complicated AM was defined by a left ventricular ejection fraction <50% or the use of inotropic drugs or ventricular assist device. RESULTS: Mean age was 29 ± 9 year-old, 77 (94%) were men. Sixteen (20%) had a complicated AM. Practicing sport over 6 h a week or a Mitchell's Class IIIA sport were associated with complicated AM (44 vs. 17%, p = 0.019 and 38 vs. 11%, p = 0.008, respectively). Practicing a Mitchell's Class IC sport was associated with uncomplicated AM (6 vs. 38%, p = 0.008). CONCLUSION: In sportspeople's AM, the pattern of sport activity (static or dynamic component, practice intensity) is associated with the disease's severity.

Concealed left superior accessory pathway. Distinctive features of retrograde atrial activation and successful ablation using transseptal approach.

Concealed left superior accessory pathways are very infrequent and can be difficult to diagnose and ablate. We describe here the case of a patient presenting with reciprocating tachycardia involving superior and inferior left accessory pathways. Left superior accessory pathway was suspected because of the simultaneous retrograde atrial activation at the distal coronary sinus (CS) and His bundle lead and could be successfully ablated using transseptal catheterization.

A cardio-neurological form of laminopathy: dilated cardiomyopathy with permanent partial atrial standstill and axonal neuropathy.

We present the first form of laminopathy connected with a new mutation of the lamin A/C gene expressed by dilated cardiomyopathy and partial atrial standstill associated with Charcot-Marie-Tooth type 2 axonal neuropathy. The rapid development of the cardiac disease was controlled by medical treatment and resynchronization therapy associated with a defibrillator.

Surgical catheter ablation of ventricular tachycardia using left thoracotomy in a patient with hindered access to the left ventricle.

We report the case of a patient presenting with incessant monomorphic ventricular tachycardia resistant to antiarrhythmic drugs, and in whom usual percutaneous vascular or pericardial access to the left ventricle was hindered by mechanical aortic and mitral prosthetic valves. Because an epicardial location was suspected by electrocardiogram features and because access to the target area through the coronary sinus was not possible, we decided to perform a surgically based radiofrequency (RF) ablation. Catheter mapping of the epicardial surface through surgical left lateral thoracotomy in the operating room confirmed the epicardial location of the arrhythmogenic substrate and allowed successful RF ablation of the clinically incessant tachycardia. Combined surgical and electrophysiological approach should therefore be performed when RF ablation is needed in case of unadvisable, difficult, or failed nonsurgical percutaneous access.

Reverse left septal activation during intermittent left bundle-branch block: indirect proof for concealed retrograde left bundle-branch activation.

Concealed retrograde activation of bundle branch has been often proposed for explaining the persistence of functional rate-dependent bundle-branch block, but direct proof of such a mechanism in man has rarely been demonstrated. We report intracardiac recordings compatible with a reversal of activation of the left basal interventricular septum during intermittent left bundle-branch block. In our case, however, retrograde activation into the left bundle-branch cannot be recordable, probably due to the concealment within the muscular septal activation, even if this may explain the perpetuation of bundle-branch block according to the linking phenomenon.