Supraventricular cardiac conduction system exposure in breast cancer patients treated with radiotherapy and association with heart and cardiac chambers doses.

Purpose: To assess sinoatrial node (SAN) and atrioventricular node (AVN) doses for breast cancer (BC) patients treated with 3D-CRT and evaluate whether "large" cardiac structures (whole heart and four cardiac chambers) would be relevant surrogates. Material and methods: This single center study was based on 116 BCE patients (56 left-sided, 60 right-sided) treated with 3D-CRT without respiratory gating strategies and few IMN irradiations from 2009 to 2013. The heart, the left and right ventricles (LV, RV), the left and right atria (LA, RA) were contoured using multi-atlases for auto-segmentation. The SAN and the AVN were manually delineated using a specific atlas. Based on regression analysis, the coefficients of determination (R2) were estimated to evaluate whether "large" cardiac structures were relevant surrogates (R2 > 0.70) of SAN and AVN doses. Results: For left-sided BC, mean doses were: 3.60 ± 2.28 Gy for heart, 0.47 ± 0.24 Gy for SAN and 0.74 ± 0.29 Gy for AVN. For right-sided BC, mean heart dose was 0.60 ± 0.25 Gy, mean SAN dose was 1.57 ± 0.63 Gy (>85 % of patients with SAN doses > 1 Gy) and mean AVN dose was 0.51 ± 0.14 Gy. Among all "large" cardiac structures, RA appeared as the best surrogate for SAN doses (R2 > 0.80). Regarding AVN doses, the RA may also be an interesting surrogate for left-sided BC (R2 = 0.78), but none of "large" cardiac structures appeared as relevant surrogates among right-sided BC (all R2 < 0.70), except the LA for patients with IMN (R2 = 0.83). Conclusions: In BC patients treated 10 years ago with 3D-CRT, SAN and AVN exposure was moderate but could exceed 1 Gy to the SAN in many right-sided patients with no IMN-inclusion. The RA appeared as an interesting surrogate for SAN exposure. Specific conduction nodes delineation remains necessary by using modern radiotherapy techniques.

Risk of pacemaker implantation after radiotherapy for breast cancer: A study based on French nationwide health care database sample.

BACKGROUND: Among cardiac complications of breast cancer radiotherapy (BC RT), there are very limited data on arrhythmia and conduction disorders, in particular severe cases requiring permanent pacemaker implantation (PPMI). Therefore, this exploratory study aimed to evaluate the risk of PPMI for BC patients treated with RT, compared with the general population and with BC patients not treated with RT. METHODS: The study was performed on a 1/97 representative sample of the French health care database (EGB database). Adult women with a first BC treated with or without RT between 2008 and 2016 were included, followed until 2018, and de novo PPMI were identified. We compared the PPMI incidence in BC cohort relative to the general population with standardized incidence ratio (SIR) and evaluated the risk of PPMI in RT patients compared to patients without RT with a competing risk survival analysis. RESULTS: A total of 3853 BCE patients were included. Among BC patients treated with RT, 28 PPMI cases were observed compared with 13 expected cases, corresponding to a SIR of 2.18 [95% CI: 1.45-3.06]. For BC patients not treated with RT, the SIR was 1.01 [95% CI: 0.40-1.90]. Patients treated with RT showed a borderline significant higher risk of PPMI compared with those not treated with RT (subdistribution Hazard Ratio = 2.08, 95% CI 0.87-4.97, p = 0.09). CONCLUSIONS: Our exploratory findings indicate that, over the last decade in France, BC patients treated with RT appeared to be at higher risk of PPMI than general population. Further studies are needed to expand on this topic.

Joint Position Paper of the Working Group of Pacing and Electrophysiology of the French Society of Cardiology (SFC) and the Société française d'imagerie cardiaque et vasculaire diagnostique et interventionnelle (SFICV) on magnetic resonance imaging in patients with cardiac electronic implantable devices.

Magnetic resonance imaging (MRI) has become the reference imaging for the management of a large number of diseases. The number of MR examinations increases every year, simultaneously with the number of patients receiving a cardiac electronic implantable device (CEID). A CEID was considered an absolute contraindication for MRI for years. The progressive replacement of conventional pacemakers and defibrillators by MR-conditional CEIDs and recent data on the safety of MRI in patients with "MR-nonconditional" CEIDs have progressively increased the demand for MRI in patients with a CEID. However, some risks are associated with MRI in CEID carriers, even with "MR-conditional" devices because these devices are not "MR-safe". A specific programing of the device in "MR-mode" and monitoring patients during MRI remain mandatory for all patients with a CEID. A standardized patient workflow based on an institutional protocol should be established in each institution performing such examinations. This joint position paper of the Working Group of Pacing and Electrophysiology of the French Society of Cardiology and the Société française d'imagerie cardiaque et vasculaire diagnostique et interventionnelle (SFICV) describes the effect and risks associated with MRI in CEID carriers. We propose recommendations for patient workflow and monitoring and CEID programming in MR-conditional, "MR-conditional nonguaranteed" and MR-nonconditional devices.

Outcomes after cryoablation vs. radiofrequency in patients with paroxysmal atrial fibrillation: impact of pulmonary veins anatomy.

AIMS: Pulmonary vein isolation is the mainstay of treatment in catheter ablation of paroxysmal atrial fibrillation (AF). Cryoballoon ablation has been introduced more recently than radiofrequency ablation, the standard technique in most centres. Pulmonary veins frequently display anatomical variants, which may compromise the results of cryoballoon ablation. We aimed to evaluate the mid-term outcomes of cryoballoon ablation in an unselected population with paroxysmal AF from an anatomical viewpoint. METHODS AND RESULTS: Consecutive patients with paroxysmal AF who underwent a first procedure of cryoballoon ablation or radiofrequency were enrolled in this single-centre study. All patients underwent systematic standardized follow-up. Comparisons between radiofrequency and cryoballoon ablation (Arctic Front™ or Arctic Front Advance™) were performed regarding safety and efficacy endpoints, according to pulmonary vein (PV) anatomical variants. A total of 687 patients were enrolled (376 radiofrequency and 311 cryoballoon ablation). Baseline characteristics and distribution of PV anatomical variants were generally similar in the groups. After a mean follow-up of 14 ± 8 months, there was no difference in the incidence of relapse (17.0% cryoballoon ablation vs. 14.1% radiofrequency, P = 0.25). We observed no interaction of PV anatomical variants on mid-term procedural success. CONCLUSION: Our findings suggest that mid-term outcomes of cryoballoon ablation for paroxysmal AF ablation are similar to those of radiofrequency, regardless of PV anatomy. The presence of anatomical variants of PVs should not discourage the referral of patients with paroxysmal AF for cryoballoon ablation.

European survey on efficacy and safety of duty-cycled radiofrequency ablation for atrial fibrillation.

AIMS: Duty-cycled radiofrequency ablation (RFA) has been used for atrial fibrillation (AF) for around 5 years, but large-scale data are scarce. The purpose of this survey was to report the outcome of the technique. METHODS AND RESULTS: A survey was conducted among 20 centres from seven European countries including 2748 patients (2128 with paroxysmal and 620 with persistent AF). In paroxysmal AF an overall success rate of 82% [median 80%, interquartile range (IQR) 74-90%], a first procedure success rate of 72% [median 74% (IQR 59-83%)], and a success of antiarrhythmic medication of 59% [median 60% (IQR 39-72%)] was reported. In persistent AF, success rates were significantly lower with 70% [median 74% (IQR 60-92%)]; P = 0.05) as well as the first procedure success rate of 58% [median 55% (IQR 47-81%)]; P = 0.001). The overall success rate was similar among higher and lower volume centres and were not dependent on the duration of experience with duty-cycled RFA (r = -0.08, P = 0.72). Complications were observed in 108 (3.9%) patients, including 31 (1.1%) with symptomatic transient ischaemic attack or stroke, which had the same incidence in paroxysmal and persistent AF (1.1 vs. 1.1%) and was unrelated to the case load (r = 0.24, P = 0.15), bridging anticoagulation to low molecular heparin, routine administration of heparin over the long sheath, whether a transoesophageal echocardiogram was performed in every patient or not and average procedure times. CONCLUSION: Duty-cycled RFA has a self-reported success and complication rate similar to conventional RFA. After technical modifications a prospective registry with controlled data monitoring should be conducted to assess outcome.

[Rhythm control - cardioversion]. / Contrôle du rythme sinusal - Cardioversion.

In case of persistent and symptomatic atrial fibrillation, a pharmacological cardioversion under effective anticoagulation treatment may be performed according to current guidelines. In the absence of return to sinus rhythm, a Direct-Current cardioversion can be performed. After returning to sinus rhythm will arise the question of anticoagulation and antiarrhythmic drugs treatments that will be most often long-term pursued.

[How to evaluate sudden cardiac death risk after myocardial infarction?]. / Comment évaluer le risque de mort subite dans les suites d'un infarctus du myocarde ?

Sudden cardiac death is the mode of death of more than half of coronary heart disease patients. Preventing sudden cardiac death involves prevention of ventricular arrhythmias occurrence as well as the treatment by an implantable cardioverter defibrillator. The evaluation of sudden cardiac death risk should consider the underlying cardiopathy, the associated coronary risk factors and all pharmacological treatment efficient to reduce ventricular remodeling and myocardial ischemia. Only significant low ejection fraction and positive ventricular testing in some cases are now considered are now considered by the current French recommendations for cardioverter defibrillator implantation in primary prevention. However, other noninvasive markers such as heart rate variability and T wave alternans are of interest in sudden cardiac death risk stratification after myocardial infarction.

[Risks of pulmonary vein isolation by radiofrequency for the treatment of paroxysmal atrial fibrillation: a single centre experience of the first 200 patients]. / Risques liés a l'isolement par radiofréquence des veines pulmonaires pour le traitement de la fibrillation auriculaire paroxystique: expérience monocentrique des 200 premiers patients.

The authors report the initial experience of an electrophysiological laboratory starting ablation for atrial fibrillation, a promising technique which is not yet widely practiced because of the risks related to the procedure. The incidence of severe complications (tamponade, pulmonary vein stenosis, ischaemic events) did not appear to be different in the first 100 procedures compared with the next 100 procedures: 3% in the two groups. The selection of patients, strict perioperative management and the initial support by confirmed operators seem to be the factors which minimise the complications rate of the procedure.

[Characterization of premature ventricular contraction initiating ventricular fibrillation]. / Caractéristiques morphologiques des extrasystoles ventriculaires initiatrices des fibrillations ventriculaires.

UNLABELLED: The aim of this study is to characterize the electrocardiographic features of premature ventricular contractions (PVC) from different anatomical region that trigger ventricular fibrillation (VF). METHODS AND RESULTS: 36 consecutives patients (20 males, 42+/-14 yrs) undergoing VF ablation from 7 centres were studied (22 with idiopathic VF, 4 associated with a long QT syndrome, 3 with Brugada syndrome, 4 with ischaemic cardiomyopathy and 3 associated with other substrate). Mapping of these PVC showed 2 different origins, which were then confirmed by ablation: right ventricular outflow tract (RVOT) (22%) and peripheral Purkinje network (81%). One patient had PVC from both origins (Brugada). RVOT PVC were frequent but had triggered only 5+/-5 episodes of VF for 26+/-33 months. Purkinje PVC were more likely to be present during electrical storm with 18+/-28 episodes of VF for 33+/-45 months. Right Purkinje PVC have a left bundle branch block with superior axis morphology whereas left Purkinje ones have a right bundle branch block. The axis of activation showed variation from inferior to superior depending on the area of origin from the Purkinje network and the exit site to the myocardium. However Purkinje PVC were characterized by short QRS duration (126+/-18 vs 145+/-13ms for RVOT PVC; p=0.05). In addition the coupling interval was significantly shorter compared to RVOT PVC (292+/-45 vs 358+/-37ms respectively; p=0.005). CONCLUSION: PVC initiating VF demonstrate specific electrocardiographic features that facilitate determination of their origin. Ablation of these typical PVC is feasible in order to reduce ICD shock.

[Brugada syndrome and supraventricular arrhythmias]. / Syndrome de Brugada et arythmies supraventriculaires. A propos d'une observation clinique.

The author reports the case of a 46-year old patient diagnosed with idiopathic ventricular fibrillation (Brugada syndrome) further to induction of class Ic antiarrhythmic therapy for the management of paroxystic ventricular fibrillation. It would appear that this diagnosis is increasingly frequent in young patients with Brugada syndrome shown to be minimal or intermittent on electrocardiograms. Atrial arrhythmia was the only rhythmic pathology objectively evidenced in this patient and the author was consequently led to reconsider its prevalence in patients presenting this syndrome both in the literature and according to his personal experience.

Electrical storm in Brugada syndrome successfully treated using isoprenaline.

A case of an electrical storm occurring in a patient implanted with a cardioverter-defibrillator for Brugada syndrome is reported. Recurrent ventricular fibrillation was initiated by short-coupled isolated monomorphic ventricular premature beats probably originating from the right ventricular outflow tract, associated with a manifest electrocardiographic pattern of Brugada syndrome. Infusion of atropine accelerated the heart rate but did not prevent ventricular fibrillation, however, low doses of isoprenaline quickly obviated any recurrence of ventricular fibrillation. This was associated with the disappearance of the short-coupled premature beats together with a normalization of the electrocardiographic pattern. Possible mechanisms are discussed according to the accepted pathophysiological hypothesis.

[Holter EKG for the hypertensive heart disease]. / Intérêt du holter ECG dans la surveillance de la cardiopathie hypertensive.

During chronic mechanical overload induced by hypertension, left ventricular hypertrophy predisposes to atrial and ventricular arrhythmias. Atrial arrhythmias, mainly atrial fibrillation, decrease cardiac output and increase the risk of embolism whereas ventricular arrhythmias remain the major cause of sudden death. In hypertensive patients, Holter EKG recordings frequently detect atrial or ventricular premature beats and more rarely atrial or ventricular tachycardia. In these patients, the presence of non-sustained ventricular tachycardia is considered as an independent predictor of mortality. Moreover, this non invasive method through the assessment of heart rate variability allows the study of the autonomic control of the heart, known to modulate occurrence of arrhythmias.

[Left ventricular hypertrophy and sinus variability in arterial hypertension]. / Hypertrophie ventriculaire gauche et variabilité sinusale au cours de l'hypertension artérielle.

BACKGROUND: Previous studies of heart rate variability (HRV) in systemic hypertension have yielded conflicting results. We sought to assess the alterations of HRV in hypertensive patients with or without left ventricular hypertrophy (LVH). METHODS: 195 hypertensive patients in sinus rhythm, mean age 53 +/- 11 years, without diabetes mellitus, nor symptomatic coronary disease or systolic dysfunction, were prospectively enrolled. Echocardiographic examination allowed their subdivision in 3 groups: normal geometry (112), concentric remodeling (43) and LVH (40). Time and frequency domain measures of HRV were obtained from 24 h Holter ECG recordings in all patients as in 40 control subjects. RESULTS: In comparison with control subjects, the 3 hypertensive groups presented a significant decrease of SDNN and total frequency power both indexes of global HRV; a significant decrease of pNN50 and high frequency power, indexes of HRV reflecting parasympathetic tone, and a significant decrease of SDANN and low frequency power, indexes reflecting sympathetic modulation of HRV. Comparisons among the three hypertensive groups showed that patients with LVH had significantly (p < 0.05) lower low frequency power (5.5 +/- 1.0 Ln m2) than patients with left ventricular normal geometry (5.9 +/- 0.8 Ln m2) or concentric remodeling (5.9 +/- 0.9 Ln m2). CONCLUSION: Assessment of HRV in hypertensive patients shows a constant decrease of parasympathetic indexes and a more markedly reduction of sympathetic parameters in presence of LVH.

[Atrial flutter: a possible early sign of acute rejection in heart transplantation. A case report]. / Le flutter atrial: un témoin précoce possible du rejet aigu chez le transplanté cardiaque. A propos d'une observation.

The authors report the case of a cardiac transplant patient with a recurrence of atrial flutter two months after electrical cardioversion and despite long-term preventive treatment with amiodarone. Early investigation for signs of rejection with 4 endomyocardial biopsies was negative. Aggravation of the haemodynamic status due to flutter with a rapid ventricular response led to an attempted radio-frequency ablation. Endocavitary mapping confirmed persistence of sinus activity in the native atrium and the presence of a circuit of type I isthmic flutter (anticlockwise circuit) in the donor atrium. Ablation by radio-frequency in the same procedure was successful. A fifth myocardial biopsy the same day finally confirmed stage 3A acute rejection. No signs of recurrent rejection or arrhythmia have been observed after 24 months' follow-up in this patient. This preliminary experience confirms the need to look for graft rejection by repeated myocardial biopsies in cardiac transplant, patients with atrial flutter and the efficacy of radio-frequency ablation in cases of resistance to conventional therapy.

Prognostic value of heart rate variability in time domain analysis in congestive heart failure.

AIMS: Analysis of heart rate variability is a noninvasive tool that allows to study autonomic control of the heart. Several studies have shown disturbed heart rate variability in patients with chronic heart failure (CHF). We sought to assess the prognostic value of time domain measures of heart rate variability in CHF. METHODS AND RESULTS: We prospectively enrolled 190 patients with CHF in sinus rhythm, mean age 61+/-12 years, 109 (57.4 %) in NYHA class II and 81 (42.6 %) in class III or IV, mean cardiothoracic ratio 57.6+/-6.4 % and mean left ventricular ejection fraction 28.2+/-8.8 %, 85 (45 %) with ischemic and 105 (55 %) with idiopathic dilated cardiomyopathy. Time domain measures of heart rate variability were obtained from 24 h Holter ECG recordings. During follow-up (22+/-18 months), 55 patients died. In multivariate analysis, independent predictors for all-cause mortality were: ischemic heart disease, cardiothoracic ratio > or =60 % and standard deviation of all normal RR intervals <67 ms (RR=2.5, 95 % CI 1.5--4.2). CONCLUSIONS: Depressed heart rate variability has independent prognostic value in patients with CHF.

[Prophylactic value of automatic implantable defibrillators: a case report of a patient with asymptomatic Brugada syndrome]. / Intérêt prophylactique du défibrillateur automatique implantable: à propos d'une observation de patient ayant un syndrome de Brugada asymptomatique.

The authors report the case of an asymptomatic 32 year old man with no family history of sudden death but with ECG changes suggesting Brugada's syndrome. He underwent implantation of an automatic defibrillator after inducible syncope ventricular fibrillation had been demonstrated during electrophysiological investigation. The later occurrence of three episodes of ventricular fibrillation treated by the defibrillator confirmed a posteriori the logic of this therapeutic approach.

[Ventricular tachycardia by branch to branch re-entry. Familial case with Steinert's disease]. / Tachycardie ventriculaire par réentrée de branche à branche. Cas familial avec maladie de Steinert.

Ventricular tachycardia by branch to branch reentry is a rare arrhythmia. It occurs in cardiomyopathies associated with conduction defects. During tachycardia a His potential precedes each QRS complex which usually has a left bundle branch block appearance. The authors report two familial cases of ventricular branch to branch tachycardia (son and mother) without cardiomyopathy. The diagnosis of Steinert's disease was made post-mortem in these two patients. In cases of branch to branch ventricular tachycardia, the diagnosis of myotonic dystrophy should be excluded. Conversely, endocavitary electrophysiological investigation with ventricular stimulation should be proposed for symptomatic patients (dizzy spells, syncope) to diagnose branch to branch ventricular tachycardia, even in cases with conduction defects which could also explain the symptoms.

Depressed low frequency power of heart rate variability as an independent predictor of sudden death in chronic heart failure.

AIMS: Identification of patients with chronic heart failure at risk for sudden death remains difficult. We sought to assess the prognostic value for all-cause and sudden death of time and frequency domain measures of heart rate variability in chronic heart failure. METHODS AND RESULTS: We prospectively enrolled 190 patients with chronic heart failure in sinus rhythm, mean age 61+/-12 years, 109 (57.4%) in NYHA class II and 81 (42.6%) in classes III or IV, mean cardiothoracic ratio 57.6+/-6.4% and mean left ventricular ejection fraction 28.2+/-8.8%, 85 (45%) with ischaemic and 105 (55%) with idiopathic dilated cardiomyopathy. Time and frequency domain measures of heart rate variability were obtained from 24 h Holter ECG recordings, spectral measures were averaged for calculation of daytime (1000h-1900h) and night-time (2300h-0600h) values. During follow-up (22+/-18 months), 55 patients died, 21 of them suddenly and two presented with a syncopal spontaneous sustained ventricular tachycardia. In multivariate analysis, independent predictors for all-cause mortality were: ischaemic heart disease, cardiothoracic ratio > or =60% and standard deviation of all normal RR intervals <67 ms (RR = 2.5, 95% CI 1.5-4.2). Independent predictors of sudden death were: ischaemic heart disease and daytime low frequency power <3.3 ln (ms(2)) (RR = 2.8, 95% CI 1.2-8.6). CONCLUSION: Depressed heart rate variability has independent prognostic value in patients with chronic heart failure; spectral analysis identifies an increased risk for sudden death in these patients.

[Utilization of heart rate at the ventilatory threshold for the prescription of intensity of exercise training in cardiac failure]. / Utilisation de la fréquence cardiaque au seuil ventilatoire dans la prescription des intensités d'entraînement à l'effort chez l'insuffisant cardiaque.

Physical exercise is a treatment for cardiac failure but a large range of intensities of exercise is proposed. The aims of this study were to determine the range of intensities of effort used and to individualize the intensities used. Thirty patients with stable cardiac failure (NYHA Classes II-III, age: 53 +/- 2.1 years, ejection fraction: 31 +/- 1.4%) underwent a cardiorespiratory exercise stress test before and after individualized training at the ventilatory threshold. However, before and after the training period, standard methods of calculation of the intensities at the ventilatory threshold showed individual differences greater than +/- 2 standard deviations, indicating different metabolic stimulations. After the individualized training programme, peak oxygen consumption on exercise (1679 +/- 100 vs 1487 +/- 89 ml.min-1, p = 0.0001) and at ventilatory threshold increased (1365 +/- 85 vs 1133 +/- 65 ml.min-1, p = 0.0001), the ventilatory threshold/peak exercise ratio increased (81.2 +/- 1.3 vs 76.7 +/- 1.4%, p = 0.0008), and there was a decrease in heart and ventilatory rates at submaximal metabolic levels (p = 0.0001). The authors conclude that protocols using intensity of effort at the ventilatory threshold give similar results with respect to improvement of aerobic capacity as other methods of indirect calculation, based on maximal heart rate of oxygen consumption. The value of this particular method lies in the adequation between aerobic capacity of the patient and the intensity of training. The results obtained attain the physiopathological aims of rehabilitation.