[Cancer and implantable cardiac defibrillator. Causality, confusion or chance?]

INTRODUCTION AND OBJECTIVES

implantable cardiac defibrillator (ICD) has been established as a therapy for malignant ventricular arrhythmias in patients at high risk of suffering them. Some studies suggest a possible relationship between the development of cancer and some prosthetic materials. Likewise, some investigations describe a higher incidence of cancer in patients with an ICD that suggest a potential relationship.

METHODS

Retrospective cohort study of patients that underwent implantation of an ICD in the Complejo Hospitalario de Navarra between 2000 and 2016. The follow-up finished in June 2018. Sociodemographic, comorbidities and oncological data was analysed. Cancer incidence rates were estimated and compared with the general population data and with data of a cohort of patients with reduced LVEF heart failure. Risk of cancer models were adjusted by competitive risk models.

RESULTS

497 patients were included, mostly male (89.1%), with a mean age of 59.98 (14.98) years and a proportion of smokers of 67.6% and of ischaemic heart disease of 51.6%. The cancer incidence rate in the sample was 1230.9 per 100.000 person-year. In our study, features associated with cancer were older age, higher tobacco use and ischaemic cardiopathy.

CONCLUSIONS

In our sample of ICD carriers the incidence of cancer is high. This finding mainly seems to be related to tobacco usage and higher age.

Validation of multiparametric approaches for the prediction of sudden cardiac death in patients with Brugada syndrome and electrophysiological study

INTRODUCTION AND OBJECTIVES

Multiparametric scores have been designed for better risk stratification in Brugada syndrome (BrS). We aimed to validate 3 multiparametric approaches (the Delise score, Sieira score and the Shanghai BrS Score) in a cohort with Brugada syndrome and electrophysiological study (EPS).

METHODS

We included patients diagnosed with BrS and previous EPS between 1998 and 2019 in 23 hospitals. C-statistic analysis and Cox proportional hazard regression models were used.

RESULTS

A total of 831 patients were included (mean age, 42.8±13.1; 623 [75%] men; 386 [46.5%] had a type 1 electrocardiogram (ECG) pattern, 677 [81.5%] were asymptomatic, and 319 [38.4%] had an implantable cardioverter-defibrillator). During a follow-up of 10.2±4.7 years, 47 (5.7%) experienced a cardiovascular event. In the global cohort, a type 1 ECG and syncope were predictive of arrhythmic events. All risk scores were significantly associated with events. The discriminatory abilities of the 3 scores were modest (particularly when these scores were evaluated in asymptomatic patients). Evaluation of the Delise and Sieira scores with different numbers of extra stimuli (1 or 2 vs 3) did not substantially improve the event prediction c-index.

CONCLUSIONS

In BrS, classic risk factors such as ECG pattern and previous syncope predict arrhythmic events. The predictive capabilities of the EPS are affected by the number of extra stimuli required to induce ventricular arrhythmias. Scores combining clinical risk factors with EPS help to identify the populations at highest risk, although their predictive abilities remain modest in the general BrS population and in asymptomatic patients.

Long-term prognosis of women with Brugada syndrome and electrophysiological study

BACKGROUND

A male predominance in Brugada syndrome (BrS) has been widely reported, but scarce information on female patients with BrS is available.

OBJECTIVE

The purpose of this study was to investigate the clinical characteristics and long-term prognosis of women with BrS.

METHODS

A multicenter retrospective study of patients diagnosed with BrS and previous electrophysiological study (EPS) was performed.

RESULTS

Among 770 patients, 177 (23%) were female. At presentation, 150 (84.7%) were asymptomatic. Females presented less frequently with a type 1 electrocardiographic pattern (30.5% vs 55.0%; P <.001), had a higher rate of family history of sudden cardiac death (49.7% vs 29.8%; P <.001), and had less sustained ventricular arrhythmias (VAs) on EPS (8.5% vs 15.1%; P = .009). Genetic testing was performed in 79 females (45% of the sample) and was positive in 34 (19%). An implantable cardioverter-defibrillator was inserted in 48 females (27.1%). During mean (± SD) follow-up of 122.17 ± 57.28 months, 5 females (2.8%) experienced a cardiovascular event compared to 42 males (7.1%; P = .04). On multivariable analysis, a positive genetic test (18.71; 95% confidence interval [CI] 1.82-192.53; P = .01) and atrial fibrillation (odds ratio 21.12; 95% CI 1.27-350.85; P = .03) were predictive of arrhythmic events, whereas VAs on EPS (neither with 1 or 2 extrastimuli nor 3 extrastimuli) were not.

CONCLUSION

Women with BrS represent a minor fraction among patients with BrS, and although their rate of events is low, they do not constitute a risk-free group. Neither clinical risk factors nor EPS predicts future arrhythmic events. Only atrial fibrillation and positive genetic test were identified as risk factors for future arrhythmic events.

The clinical impact of untreated slow ventricular tachycardia in patients carrying implantable cardiac defibrillators

INTRODUCTION

The clinical impact of slow ventricular tachycardia (VT), occurring in patients carrying implantable cardiac defibrillators (ICD), is still under debate.

METHODS AND RESULTS

From the UMBRELLA registry (multicenter, observational, and prospective study on patients with ICD), 659 episodes of slow VT were observed in 97 patients. Untreated slow VT (n = 93) had longer duration (23.7 min, CI95%: 10-39), compared with episodes treated effectively by anti-tachycardia pacing (ATP; n = 527; 0.32 min, IC95%: 0.22-0, 48) or shock (n = 39; 1 min, CI95%: 0.8-1.2). Despite of longer duration, the time to the first contact with the medical services was similar to those episodes treated by ATP (50 days [CI95%: 45-55] vs. 41 days [CI95%: 39-44]). However, both were significantly longer than the time observed in episodes treated with shock (10 days, CI95%: 6-15). This tendency was maintained with successive interrogations of the device (2nd and 3rd). There were no significant differences in mortality during follow-up (48 ± 16 months), neither other adverse outcomes, between patients who presented untreated slow TV and those who did not (log-rank p = 0.28). In a Cox regression analysis, the variable "presenting untreated episodes of slow VT" was not able to predict mortality. However, being in sinus rhythm (vs. atrial fibrillation, OR: 0.31, p = 0.009), narrower QRS (OR: 1.036, p = 0.037) and diabetes (OR 4.673, p = 0.049) appropriately predict survival.

CONCLUSIONS

Untreated slow VT does not significantly worsen patient prognosis. Our results support the limitation of therapies to ATP only, thus avoiding therapies that have been associated with increased risk of morbidity and mortality.

Antitachycardia pacing for shock prevention in patients with hypertrophic cardiomyopathy and ventricular tachycardia

BACKGROUND

Hypertrophic cardiomyopathy (HCM) carries an increased risk of sudden death due to ventricular arrhythmias (VAs). The implantable cardioverter-defibrillator (ICD) is a well-established therapy for treatment of VA. Monomorphic ventricular tachycardias (MVTs) are frequent in HCM patients and suitable for antitachycardia pacing (ATP) termination.

OBJECTIVE

The purpose of this study was to describe ventricular tachycardia (VT) characteristics in a population of HCM patients with ICD and to study the effectiveness and safety of ATP for MVT.

METHODS

Data were obtained from the multicenter prospective observational UMBRELLA trial, which included all patients with HCM and ICD followed by the CareLink Monitoring System. All episodes of VA were collected and analyzed. ATP effectiveness and safety were described, and factors related to ATP effectiveness were studied with generalized estimating equation (GEE) models.

RESULTS

Among 251 patients followed for 47 months, 67 (26.7%) were implanted as secondary prevention. Fifty-six patients presented 326 episodes of VA (286 [87%] MVT). Mean cycle length was 312 ± 64 ms. Among 264 MVTs that received ICD therapy, 202 (76.5%) were ATP terminated. The first ATP burst was effective in 169 episodes (68.4%), and overall effectiveness of the first or second ATP burst was 73.8%. Multivariate GEE-adjusted analysis showed 2 variables related to ATP effectiveness: programming fast VT zone On vs Off (odds ratio [OR] 2.4; 95% confidence interval [CI] 1.5-5.2; P = .03) and programming ≥2 ATP bursts vs 1 burst only (OR 1.6; 95% CI 1.2-3.4; P = .04; and OR 2.9; 95% CI 1.8-6.3; P = .02; respectively).

CONCLUSION

MVT is the predominant VA in HCM patients with ICD. ATP is highly effective in terminating the majority of MVTs, and its proved effectiveness should guide device selection and programming in order to avoid unnecessary high-energy shocks.

P5425Prognostic value of NYHA functional class in heart failure patients undergoing primary prevention implantable cardioverter defibrillator therapy

Background

NYHA functional class (FC) is used for selection of heart failure (HF) patients who are candidates to primary prevention (PP) implantable cardioverter defibrillator (ICD) therapy. However, FC is subjectively estimated and concerns about its real prognostic value are still present in this setting.

Purpose

To compare whether mortality and arrhythmic risk are different, in a cohort of HF patients undergoing PP ICD-only implant, according to their FC.

Methods

All HF patients with left ventricle ejection fraction (LVEF) ≤35%, undergoing first prophylactic ICD-only implant were collected from the UMBRELLA nationwide registry (2006–2015). The sample was divided into three groups: no symptoms (NYHA I), mildly symptomatic patients (NYHA II) and severely symptomatic (NYHA III) patients. Outcomes were studied as follow: all-cause death, cardiovascular mortality and arrhythmia free survival (surrogate marker of sudden cardiac death) defined as survival free of first appropriate ICD therapy delivered in ventricular fibrillation (VF) window. Arrhythmic events were collected by remote monitoring and reviewed by a committee of experts.

Results

Six hundred and twenty one patients were identified (61.1±11.4 years, 87.3% male). Distribution of study groups was as follow: 101 patients in NYHA I; 411 in NYHA II; and 109 in NYHA III. More symptomatic patients were older and had higher prevalence of atrial fibrillation (AF) and chronic kidney disease (CKD). Higher rates of optimal medical treatment were present among study groups (beta-blockers: 92.1%; ACEI or ARB: 86.8%; aldosterone antagonists: 60.2%). After a median follow-up of 4.2 years (IQR, 2.7–5.7 years) 126 patients died (event rate: 20.3%). All-cause mortality was higher in patients with worse FC (13.9% vs. 18.3% vs. 32.9% for NYHA I, II and III respectively; p<0.001, log-rank test). Seventy-eight out of 126 deaths were related to cardiovascular causes (overall event rate: 12.6%). Cardiovascular mortality risk was also higher in more symptomatic patients (6.9% vs. 11% vs. 23.9% for NYHA I, II and III respectively; p<0.001, log-rank test). One hundred and seventeen patients received afirst appropriate ICD therapy (19.4%). Arrhythmia free survival was not different among study groups (20.8% vs. 18.7% vs. 20.8% for NYHA I, II and III, respectively; p=0.495, log-rank test). Cumulative incidence curves for the three outcomes are shown in Figure 1. After multivariate analysis, worse NYHA class independently predicted cardiovascular mortality but not all-cause death. Moreover, diabetes, AF and CKD strongly predicted both all-cause and cardiovascular mortality.

Figure 1

Conclusions

In HF patients, prophylactic ICD seems to be useful in preventing death due to life threatening arrhythmias, regardless of the baseline FC. Nevertheless, the combination of NYHA class with other comorbidities may be useful to select those ICD candidates who obtain less survival benefit.

Long-term prognosis of patients with life-threatening ventricular arrhythmias induced by coronary artery spasm

Aims

Coronary artery spasm (CAS) is associated with ventricular arrhythmias (VA). Much controversy remains regarding the best therapeutic interventions for this specific patient subset. We aimed to evaluate the clinical outcomes of patients with a history of life-threatening VA due to CAS with various medical interventions, as well as the need for ICD placement in the setting of optimal medical therapy.

Methods and results

A multicentre European retrospective survey of patients with VA in the setting of CAS was aggregated and relevant clinical and demographic data was analysed. Forty-nine appropriate patients were identified: 43 (87.8%) presented with VF and 6 (12.2%) with rapid VT. ICD implantation was performed in 44 (89.8%). During follow-up [59 (17-117) months], appropriate ICD shocks were documented in 12. In 8/12 (66.6%) no more ICD therapies were recorded after optimizing calcium channel blocker (CCB) therapy. SCD occurred in one patient without ICD. Treatment with beta-blockers was predictive of appropriate device discharge. Conversely, non-dihydropyridine CCB therapy was significantly protective against VAs.

Conclusion

Patients with life-threatening VAs secondary to CAS are at particularly high-risk for recurrence, especially when insufficient medical therapy is administered. Non-dihydropyridine CCBs are capable of suppressing episodes, whereas beta-blocker treatment is predictive of VAs. Ultimately, in spite of medical intervention, some patients exhibited arrhythmogenic events in the long-term, suggesting that ICD implantation may still be indicated for all.

Survival and arrhythmic risk among ischemic and non-ischemic heart failure patients with prophylactic implantable cardioverter defibrillator only therapy: A propensity score-matched analysis

BACKGROUND

Concerns about the efficacy of prophylactic ICD in non-ischemic cardiomyopathy (NICM) heart failure (HF) patients are still present. We aimed to assess whether survival and arrhythmic risk were different among ischemic cardiomyopathy (ICM) and NICM ICD-only patients, along with specific predictors for mortality.

METHODS

HF patients undergoing ICD-only implant were extracted from the nationwide multicenter UMBRELLA registry. Arrhythmic events were collected by remote monitoring and reviewed by a committee of experts.

RESULTS

782 patients (556 ICM; 226 NICM) were recruited: mean ejection fraction of 26.6%; 83.4% in NYHA class II-III; mean QRS duration of 108.9 ms (only 14.9% with QRS > 130 ms). After 4.35 years of mean follow-up, all-cause mortality rate was 4.2%/year. In propensity-score (PS) analysis no survival differences between ICM and NICM subgroups appeared (mortality rates: 19.4% vs. 20%, p = 0.375). Age (hazard ratio [HR] = 1.02, p = 0.009), diabetes (HR = 2.61, p ≤ 0.001), chronic obstructive pulmonary disease (HR = 2.13, p = 0.002), and previous HF (HR = 2.28, p = 0.027) correlated with increased mortality for the entire population, however atrial fibrillation (AF) (HR = 2.68, p = 0.002) and chronic kidney disease (HR = 3.74, p ≤ 0.001) emerged as specific predictors in NICM patients. At follow-up, 134 patients (17.1%) were delivered a first appropriate ICD therapy (5.1%/year) without significant differences between ICM and NICM patients in the PS analysis (17.6% vs. 15.8%, p = 0.968). ICD shocks were associated with a higher mortality (HR = 2.88, p < 0.001) but longer detection windows (HR = 0.57, p = 0.042) correlated with fewer appropriate therapies.

CONCLUSIONS

Mortality and arrhythmia free survival is similar among ICM and NICM HF patients undergoing ICD-only implant for primary prevention strategy.

Association of cardiac resynchronization therapy with the incidence of appropriate implantable cardiac defibrillator therapies in ischaemic and non-ischaemic cardiomyopathy

Aims

Cardiac resynchronization therapy (CRT) reduces the incidence of sudden cardiac death and the use of appropriate implantable cardioverter-defibrillator (ICD) therapies (AICDTs); however, this antiarrhythmic effect is only observed in certain groups of patients. To gain insight into the effects of CRT on ventricular arrhythmia (VA) burden, we compared the incidence of AICDT use in four groups of patients: patients with ischaemic cardiomyopathy vs. non-ischaemic dilated cardiomyopathy (NIDC) and patients implanted with an ICD vs. CRT-ICD.

Methods and results

We analysed 689 consecutive patients (mean follow-up 37 ± 16 months) included in the Umbrella registry, a multicentre prospective registry including patients implanted with ICD or CRT-ICD devices with remote monitoring capabilities in 48 Spanish Hospitals. The primary outcome was the time to first AICDT. Despite a worse clinical risk profile, NIDC patients receiving a CRT-ICD had a lower cumulative probability of first AICDT use at 2 years compared with patients implanted with an ICD [24.7 vs. 41.6%, hazard ratio (HR): 0.49, P = 0.003]; on the other hand, there were no significant differences in the incidence of first AICDT use at 2 years in ischaemic patients (22.6 vs. 21.9%, P = NS). Multivariate analysis confirmed the association of CRT with lower AICDT rates amongst NIDC patients (Adjusted HR: 0.55, CI 95% 0.35-0.87).

Conclusions

These data suggest that CRT is associated with significantly lower rates of first AICDT use in NIDC patients, but not in ischaemic patients. This study suggests that ICD patients with NIDC and left bundle branch block experiencing VAs may benefit from an upgrade to CRT-ICD despite being in a good functional class.

Shock Reduction With Antitachycardia Pacing Before and During Charging for Fast Ventricular Tachycardias in Patients With Implantable Defibrillators

INTRODUCTION AND OBJECTIVES

Fast ventricular tachycardias in the ventricular fibrillation zone in patients with an implantable cardioverter-defibrillator are susceptible to antitachycardia pacing (ATP) termination. Some manufacturers allow programming 2 ATP bursts: before charging (BC) and during (DC) charging. The aim of this study was to describe the safety and effectiveness of ATP BC and DC for fast ventricular tachycardias in the ventricular fibrillation zone in patients with an implantable cardioverter-defibrillator in daily clinical practice.

METHODS

Data proceeded from the multicenter UMBRELLA trial, including implantable cardioverter-defibrillator patients followed up by the CareLink monitoring system. Fast ventricular tachycardias in the ventricular fibrillation zone until a cycle length of 200ms with ATP BC and/or ATP DC were included.

RESULTS

We reviewed 542 episodes in 240 patients. Two ATP bursts (BC/DC) were programmed in 291 episodes (53.7%, 87 patients), while 251 episodes (46.3%, 153 patients) had 1 ATP burst only DC. The number of episodes terminated by 1 ATP DC was 139, representing 55.4% effectiveness (generalized estimating equation-adjusted 60.4%). There were 256 episodes terminated by 1 or 2 ATP (BC/DC), representing 88% effectiveness (generalized estimating equation-adjusted 79.3%); the OR for ATP effectiveness BC/DC vs DC was 2.5, 95%CI, 1.5-4.1; P <.001. Shocked episodes were 112 (45%) for ATP DC vs 35 (12%) for ATP BC/DC, representing an absolute reduction of 73%. The mean shocked episode duration was 16seconds for ATP DC vs 19seconds for ATP BC/DC (P=.07).

CONCLUSIONS

The ATP DC in the ventricular fibrillation zone for fast ventricular tachycardia is moderately effective. Adding an ATP burst BC increases the overall effectiveness, reduces the need for shocks, and does not prolong episode duration.

[Persistent left superior vena cava. Implications in central venous catheterisation]

The placement of central catheters through the subclavian and jugular venous path can be complicated by the cannulation of an artery or an aberrant venous path. The most frequent anomaly of the embryological development of the caval vein is the persistence of the left superior vena cava (LSVC). The implantation of catheters in the LSVC can be suspected by its anomalous route in thorax radiography. Gasometry and the pressure curve of the vessel make it possible to rule out an arterial catheterisation. Diagnostic confirmation is obtained through angiography, echocardiography, computerised tomography or cardiac resonance. The doctor who regularly implants central venous catheters must be familiar with the anatomy of the venous system and its variants and anomalies, since their presence might influence the handling of the patient.

[Sudden death in a normal heart. Idiopathic ventricular fibrillation. Review of the literature concerning one case]

Idiopathic ventricular fibrillation is that which is produced in the absence of structural cardiac disease and of other identifiable causes of ventricular fibrillation such as cardiotoxicity, electrolytical alterations or hereditary predisposition. The case of a healthy male, aged 37, who was asymptomatic until the day he was admitted to hospital where he showed numerous episodes of ventricular fibrillation without any previous triggering, is discussed. In the examination no cause was found to explain this, and an automatic defibrillator was implanted. The requirements for its diagnosis, risk stratification and the usefulness of the tests employed, as well as the treatments proposed are discussed.

Mechanisms of sustained ventricular tachycardia in myotonic dystrophy: implications for catheter ablation

BACKGROUND

Ventricular arrhythmias have been documented and linked to the high incidence of sudden death seen in patients with myotonic dystrophy. However, their precise mechanism is unknown, and their definitive therapy remains to be established.

METHODS AND RESULTS

We studied 6 consecutive patients with myotonic dystrophy and sustained ventricular tachycardia by means of cardiac electrophysiological testing. Particular attention was paid to establish whether bundle-branch reentry was the tachycardia mechanism, and when such was the case, radiofrequency catheter ablation of either the right or left bundle branch was performed. Clinical tachycardia was inducible in all patients and had a bundle-branch reentrant mechanism. In 1 patient, 2 other morphologies of sustained tachycardia were also inducible, neither of which had ever been clinically documented, and both had a bundle-branch reentrant mechanism. Ventricular tachycardia was no longer inducible after bundle-branch ablation, except for a nonclinically documented and nonsustained ventricular tachycardia in the only patient who had apparent structural heart disease.

CONCLUSIONS

A high clinical suspicion of bundle-branch reentrant tachycardia is justified in patients with myotonic dystrophy who exhibit wide QRS complex tachycardia or tachycardia-related symptoms. Because catheter ablation will easily and effectively abolish bundle-branch reentrant tachycardia, myotonic dystrophy should always be considered in patients with sustained ventricular tachycardia. This is especially true if no apparent heart disease is found.

[Retrospective analysis of a large number of patients over 70 years old, subject to percutaneous coronary angioplasty or to surgery]

INTRODUCTION

The number of patients of advanced age with symptomatic coronary illness that need surgical or percutaneous revascularisation is increasing. The aim of the present paper is to gain knowledge of the evolution of patients over 70 years of age subjected to myocardial revascularisation.

MATERIAL AND METHODS

We compare two groups of patients, in a non-aleatory manner, subjected to angioplasty (N=65) and to surgery (N=75). The average age was 74.12 +/- 3.5 (70-85) and 71.97 +/- 1.9 (70-79) years respectively. The number of unhealthy vessels was greater in the surgical group (1.84 +/- 0.8 vs 2.65 +/- 0.8).

RESULTS

The number revascularised vessels is greater and revascularisation more complete in the surgical group (1.14 +/- 0.4 vs 2.59 +/- 0.9) and (76% vs 49%). There is no difference in mortality in both groups. The functional degree during the evolution is worse for the angioplasty group and besides more antianginous medicines are used in treatment (1.92 +/- 1.2 vs 1.26 +/- 0.8) and they are subjected more frequently to a new revascularisation.

CONCLUSIONS

Both the sick rate and the mortality of the procedure was similar in both groups. Both procedures are valid therapeutic alternatives and are acceptably safe with these patients. Surgery is more complete and is carried out on a group of patients with greater coronary distress. There are no differences in life expectancy amongst the patients treated with either of the techniques. During the follow-up period the functional degree of the surgical group is better and there are more patients treated with monotherapy.