Age at onset and gender of patients with different types of supraventricular tachycardias

Cannon A wave validation as a diagnostic tool in paroxysmal supraventricular tachycardias

OBJECTIVE

The presence of cannon A waves, the so called "frog sign", has traditionally been considered diagnostic of atrioventricular nodal re-entrant tachycardia (AVNRT). Nevertheless, it has never been systematically evaluated. The aim of this study is to assess the independent diagnostic utility of cannon A waves in the differential diagnosis of supraventricular tachycardias (SVTs).

METHODS

We prospectively included 100 patients who underwent an electrophysiology (EP) study for SVT. The right jugular venous pulse was recorded during the study. In 61 patients, invasive central venous pressure (CVP) was registered as well. CVP increase is thought to be related with the timing between atria and ventricle depolarization; two groups were prespecified, the short VA interval tachycardias (including typical AVNRT and atrioventricular reciprocating tachycardia (AVRT) mediated by a septal accessory pathway) and the long VA interval tachycardias (including atypical AVNRT and AVRT mediated by a left free wall accessory pathway).

RESULTS

The relationship between cannon A waves and AVNRT did not reach the statistical significance (OR: 3.01; p = .058); On the other hand, it was clearly associated with the final diagnosis of a short VA interval tachycardia (OR: 10.21; p < .001). CVP increase showed an inversely proportional relationship with the VA interval during tachycardia (b = -.020; p < .001). CVP increase was larger in cases of AVNRT (4.0 mmHg vs. 1.2 mmHg; p < .001) and short VA interval tachycardias (3.9 mmHg vs. 1.2 mmHg; p < .001).

CONCLUSION

The presence of cannon A waves is associated with the final diagnosis of short VA interval tachycardias.

3D transvenous radiofrequency ablation of manifest epicardial posterior-septal accessory pathways in children: Can technology innovations improve the outcome?

INTRODUCTION

The aim of the study was to revise our more recent experience about epicardial posterior-septal accessory pathways radiofrequency transcatheter ablation in children and young patients using a transvenous approach through the coronary sinus, to understand if new mapping and ablation technologies can increase success rate and safety.

METHODS AND RESULTS

Twenty children (mean age 13 ± 3 years) with epicardial posterior-septal accessory pathways (14 in coronary sinus and 6 in the middle cardiac vein) underwent radiofrequency transcatheter ablation with CARTO-3® system with help of the CARTO-Univu® module. Acute success rate was 73%. No patient was lost to follow-up (mean time 11.4 ± 9 months). The recurrence rate was 19%. Two patients underwent a successful redo-procedure; the overall long-term success rate was 65%. Navistar® catheter presented the highest acute success rate in the coronary sinus. Navistar SmartTouch® was the only catheter that did not present recurrences after the acute success, and it was successfully used in two patients previously unsuccessfully treated with a Navistar ThermoCool®. Acute success rate was 79% without image integration with angio-CT, while it was 63% after the introduction of CARTO-Merge®.

CONCLUSION

Epicardial posterior-septal accessory pathways can be definitively eliminated by transvenous radiofrequency transcatheter ablation in more than half of the cases in children. Acute success rate does not seem to depend on catheters used, but contact-force catheter seems to be useful in cases with recurrences. Image integration with cardiac-CT does not increase success rate, but it is useful to detect coronary sinus alterations to better guide ablation strategy.

Arrhythmias in Female Patients: Incidence, Presentation and Management

There is a growing appreciation for differences in epidemiology, treatment, and outcomes of cardiovascular conditions by sex. Historically, cardiovascular clinical trials have under-represented females, but findings have nonetheless been applied to clinical care in a sex-agnostic manner. Thus, much of the collective knowledge about sex-specific cardiovascular outcomes result from post hoc and secondary analyses. In some cases, these investigations have revealed important sex-based differences with implications for optimizing care for female patients with arrhythmias. This review explores the available evidence related to cardiac arrhythmia care among females, with emphasis on areas in which important sex differences are known or suggested. Considerations related to improving female enrollment in clinical trials as a way to establish more robust clinical evidence for the treatment of females are discussed. Areas of remaining evidence gaps are provided, and recommendations for areas of future research and specific action items are suggested. The overarching goal is to improve appreciation for sex-based differences in cardiac arrhythmia care as 1 component of a comprehensive plan to optimize arrhythmia care for all patients.

Sex Differences in Incidence, Clinical Characteristics and Outcomes in Children and Young Adults Hospitalized for Clinically Suspected Myocarditis in the Last Ten Years-Data from the MYO-PL Nationwide Database

There is a widespread lack of systematic knowledge about myocarditis in children and young adults in European populations. The MYO-PL nationwide study aimed to evaluate sex differences in the incidence, clinical characteristics, management and outcomes of all young patients with a clinical diagnosis of myocarditis, hospitalized in the last ten years. The study involved data (from the only public healthcare insurer in Poland) of all (n = 3659) patients aged 0–20 years hospitalized for myocarditis in the years 2011–2019. We assessed clinical characteristics, management and five-year outcomes. Males comprised 75.4% of the study population. The standardized incidence rate of myocarditis increased over the last ten years and was, on average, 7.8 and 2.5 (in males and females, respectively). It was the highest (19.5) in males aged 16–20 years. The highest rates of hospital admissions occurred from late autumn to early spring. Most myocarditis-directed diagnostic procedures, including laboratory tests, echocardiography, coronary angiography, cardiac magnetic resonance and endomyocardial biopsy, were performed in a low number of patients, particularly in females. Most patients required rehospitalization for cardiovascular reasons. The results of this large epidemiological study showed an increasing incidence of myocarditis hospitalizations in young patients over last ten years and that it was sex-, age- and season-dependent. Survival in young patients with myocarditis was age- and sex-related and usually it was worse than in the national population. The general management of myocarditis requires significant improvement.

Epicardial Ablation of Supraventricular Tachycardias

Supraventricular arrhythmias are the most common cardiac arrhythmias encountered; however, it is uncommon that supraventricular tachycardias require percutaneous epicardial access for successful mapping and ablation. There are particular scenarios where epicardial access and ablation should be considered. Certain accessory pathways particularly in the posteroseptal region may require epicardial access for successful ablation. These pathways may also be approached from within the coronary sinus system. In addition, tachycardias near the phrenic nerve in the right atrium or left atrium may require epicardial access for successful ablation or to allow displacement of the phrenic nerve facilitating safe catheter ablation.

Gender Differences in Arrhythmias: Focused on Atrial Fibrillation

There are significant differences in clinical presentation and treatment of atrial fibrillation (AF) between women and men. The primary goal of AF management is to restore sinus rhythm and to prevent various complications, including stroke and heart failure. In many areas of AF, such as prevalence, clinical manifestations, morbidity, risk factors, pathophysiology, treatment strategies, and complications, gender-specific variability is observed and needs to be further addressed by large-scale population researches or randomized clinical trials, which help to promote the customization of AF treatment programs, hence to maximize the success rate of AF therapy in both sexes. This review highlights our current understanding of these gender differences in AF and how these differences affect treatment decisions on AF.

Review article: The utility of troponin and other investigations in patients presenting to the emergency department with supraventricular tachycardia

Patients with supraventricular tachycardia commonly present to the ED. There is a lack of consensus regarding assessment of these patients. Our aim was to determine the utility of troponin and four other investigations (full blood examination, electrolyte levels, thyroid function tests and chest X-rays) commonly requested for these patients. MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials (January 1992-March 2017) were searched for randomised controlled trials and observational studies (of sample size greater than 10). Our search strategy yielded no randomised controlled trials and seven observational studies with significant statistical heterogeneity among selected studies (I² 87.3%, P < 0.001). Included studies investigated a total of 1155 patients. All studies reported on the utility of troponin testing in this patient population. The pooled proportion of patients investigated with troponin was 0.66 (95% confidence interval 0.44-0.88). The pooled proportion of positive troponin tests was 0.32 (95% confidence interval 0.23-0.41). Only one study reported on the utility of the remaining four investigations with abnormal results as follows: thyroid stimulating hormone 14%, haemoglobin 6%, white cell count 19% and chest X-ray 22%. Investigations are commonly requested for patients presenting with supraventricular tachycardia. Troponin testing is commonly performed with a high proportion of positive findings although these results did not appear to be associated with major adverse cardiac events. Heterogeneity among studies and low levels of evidence precluded conclusions on full blood examinations, electrolyte levels, thyroid testing and utility of chest X-rays in this patient population.

Taquicardias supraventriculares. Estado del arte

<p>Las taquicardias supraventriculares son un grupo de entidades clínicas prevalentes en la población general, pero que afectan con mayor frecuencia a la población adulta; son ritmos rápidos y generalmente regulares en los cuales se encuentra implicada alguna estructura por encima de la bifurcación del haz de His para formación o perpetuación. El diagnóstico de estas entidades requiere un abordaje clínico sistemático, siendo el electrocardiograma de superficie la principal herramienta para su adecuada clasificación. El tratamiento de las taquicardias supraventriculares dependerá del estado hemodinámico del paciente, el cual definirá el requerimiento de terapia eléctrica o tratamiento médico. Se debe hacer una selección adecuada de los pacientes que requieren estudio electrofisiológico y ablación.</p>

Outcomes in Women Undergoing Electrophysiological Procedures

The number of invasive electrophysiological procedures is steadily increasing in Western countries, as the age of the population increases and technologies advance. In recent years, gender-related differences in cardiac rhythm disorders have been increasingly appreciated, which can potentially have a great impact on the outcomes of invasive electrophysiological procedures. Among supraventricular arrhythmias, women have a higher incidence of atrioventricular nodal re-entrant tachycardia and a significantly lower incidence of atrioventricular re-entrant tachycardia compared with males, and present to ablation procedures later and after having failed more antiarrhythmic drugs. The results of catheter ablation of atrial fibrillation in women have been reported worse than in men. This finding is possibly due to a later referral of females to ablation procedures, who present older and with a higher incidence of long-standing persistent atrial fibrillation. With regard to cardiac device implantation procedures, a smaller survival benefit from prophylactic implantable cardioverter defibrillator (ICD) implantation has been shown in women, essentially due to gender-specific differences in the clinical course of patients with severe left ventricular dysfunction, with women dying predominantly from non-arrhythmic causes. On the other side, the clinical outcome of cardiac resynchronisation therapy seems to be more favourable in women, who experience a greater degree of reverse left ventricular remodelling and a striking decrease of heart failure events or mortality after biventricular pacing. This review will summarise the available evidence on gender-related differences in outcomes of invasive electrophysiological procedures.

Clinical and electrophysiological characteristics of typical atrioventricular nodal reentrant tachycardia in the elderly - changing of slow pathway location with aging

BACKGROUND

The aim of this study was to retrospectively evaluate the clinical and electrophysiological characteristics of elderly patients with typical atrioventricular nodal reentrant tachycardia (AVNRT), and to assess the acute safety and efficacy of slow-pathway radiofrequency (RF) ablation in this specific group of patients.

METHODS AND RESULTS

The present study retrospectively included a total of 1,290 patients receiving successful slow-pathway RF ablation for typical slow-fast AVNRT. Patients were divided into 2 groups: group I included 1,148 patients aged <65 years and group II included 142 patients aged >65 years. The required total procedure duration and total fluoroscopy exposure time were significantly higher in group II vs. group I (P=0.005 and P=0.0001, respectively). The number of RF pulses needed for a successful procedural end-point was significantly higher in group II than in group I (4.4 vs. 7.2, P=0.005). While the ratio of the anterior location near to the His-bundle region was significantly higher in group II, the ratio of posterior and midseptal locations were significantly higher in group I (P=0.0001). The overall procedure success rates were similar. There was no significant difference between the 2 groups in respect of the complications rates.

CONCLUSIONS

This experience demonstrates that RF catheter ablation, targeting the slow pathway, could be considered as first-line therapy for typical AVNRT patients older than 65 years as well as younger patients, as it is very safe and effective in the acute period of treatment.

Sex- and gender-specific research priorities for the emergency management of heart failure and acute arrhythmia: proceedings from the 2014 Academic Emergency Medicine Consensus Conference Cardiovascular Research Workgroup

The emergency department (ED) is the point of first contact for patients with acute heart failure and arrhythmias, with 1 million annual ED visits in the United States. Although the total numbers of men and women living with heart failure are similar, female patients are underrepresented in clinical studies, with current knowledge predominantly based on data from male patients. This has led to an underappreciation of the sex-specific differences in clinical characteristics and pathophysiology-based management of heart failure. Similar disparities have been found in management of acute arrhythmias, especially atrial arrhythmias that lead to an increased risk of stroke in women. Additionally, peripartum and postpartum cardiomyopathy represent a diagnostic and treatment dilemma. This article is the result of a breakout session in the cardiovascular and resuscitation work group of the 2014 Academic Emergency Medicine consensus conference "Gender-Specific Research in Emergency Medicine: Investigate, Understand, and Translate How Gender Affects Patient Outcomes." A nominal group technique was used to identify and prioritize themes and research questions using electronic mail, monthly conference calls, in-person meetings, and Web-based surveys between June 2013 and May 2014. Consensus was achieved through three rounds of nomination followed by the meeting on May 13, 2014, and resulted in seven priority themes that are essential to the common complex clinical syndrome of heart failure for both men and women and include the areas of pathophysiology; presentation and symptomatology; and diagnostic strategies using biomarkers, treatment, and mortality, with special consideration to arrhythmia management and pregnancy.

Use of adenosine in the treatment of supraventricular tachycardia in a pediatric emergency department

OBJECTIVE

Supraventricular tachycardia (SVT) is the most frequent arrhythmia requiring treatment in childhood, with an estimated incidence of 1/100 to 1/250 children. The treatment of choice of the acute event is intravenous adenosine. This study aimed to determine if doses of adenosine higher than previously described are needed to successfully revert SVT in children.

METHODS

This is a retrospective study of SVT cases in a tertiary hospital from January 2007 to December 2011.

RESULTS

A total of 44 episodes of SVT were recorded in 26 patients. Mean age was 3.1 years. In 39 patients (89%), adenosine was administered, reverting to stable sinus rhythm in 29 episodes, which represents an effectiveness of 75%. In relation to the number of doses administered, 12 patients (30%) received a single dose, with a mean (SD) response dose of 112 (35) µg/kg; 16 (41%) received 2 doses, with a mean (SD) response dose of 188 (55) µg/kg; and 9 (24%) received 3 doses, with a mean (SD) response dose of 249 (108) µg/kg. Finally, in 2 patients (4%), 4 doses of adenosine were administered, with only 1 of them responding to a dose of 300 µg/kg. The mean (SD) dose that reverted the SVT to normal sinus rhythm was 173 (84) µg/kg, and the mean (SD) number of doses administered was 1.7 (0.8) (range, 1-4). Sixty-six percent were discharged home, without the need to be transferred to pediatric intensive care unit or pediatric ward.

CONCLUSIONS

Most of the patients with SVT episodes require treatment with more than 1 dose of adenosine. Doses higher than the usually described in the guidelines are necessary to revert SVT. Most patients can be discharged home from the emergency department, without the need of hospital admission.

Atrial tachycardia mimicking atrioventricular nodal reentry tachycardia

BACKGROUND

The term supraventricular tachycardia (SVT) is used to describe tachydysrhythmias that require atrial or atrioventricular nodal tissue for their initiation and maintenance. SVT can be used to describe atrioventricular nodal reentry tachycardia, atrioventricular reentry tachycardia, and atrial tachycardia (AT). AT is the least common of these SVT subtypes, accounting for only 10% of cases. Although the suggested initial management of each SVT subtype is different, they all can present with similar symptoms and electrocardiographic findings.

OBJECTIVE

Discuss the pathophysiology, diagnosis, and treatment of AT as compared with other types of SVT.

CASE REPORT

We report a 56-year-old woman with symptoms and electrocardiographic findings consistent with SVT. Although standard treatment with intravenous adenosine failed to convert the SVT, it revealed AT as the cause of the tachydysrhythmia. The AT was successfully terminated with beta-blockade and the patient eventually underwent successful radioablation of three separate AT foci.

CONCLUSIONS

AT frequently mimics other more common forms of SVT. AT might be recognized only when standard treatment of SVT has failed. Identification of AT in this setting is crucial to allow for more definitive therapy.

Sex and gender aspects in antiarrhythmic therapy

Although cardiac arrhythmia had long been considered a predominantly male syndrome, it is now clear that arrhythmia is also a primary cause of mortality in women. Notably, the manifestation of specific arrhythmia syndromes appears to be gender specific. In particular, female sex is an independent risk factor for development of torsade de pointes (TdP) arrhythmias not only in congenital long QT syndromes but also in acquired long QT syndromes which occur as adverse effects of existing drugs. Males, on the other hand, are more likely to develop Brugada syndrome. Recent clinical and experimental studies suggest that these differences may stem from intrinsic sex differences in cardiac tissue. These include fundamental electrical differences resulting from variable ion channel expression and diverse sex hormonal regulation via long-term genomic and acute nongenomic pathways, and sex differences in drug responses and metabolisms. Undoubtedly, determining the effect of gender on cardiac function will be difficult and require sophisticated methodologies. However, gender differences underlying predilection to distinct arrhythmia syndromes must be revealed so that new therapeutic strategies that take gender into account can be applied to at-risk patients.

Rationale and design of the NO-PARTY trial: near-zero fluoroscopic exposure during catheter ablation of supraventricular arrhythmias in young patients

INTRODUCTION

Radiofrequency catheter ablation is the mainstay of therapy for supraventricular tachyarrhythmias. Conventional radiofrequency catheter ablation requires the use of fluoroscopy, thus exposing patients to ionising radiation. The feasibility and safety of non-fluoroscopic radiofrequency catheter ablation has been recently reported in a wide range of supraventricular tachyarrhythmias using the EnSite NavX™ mapping system. The NO-PARTY is a multi-centre, randomised controlled trial designed to test the hypothesis that catheter ablation of supraventricular tachyarrhythmias guided by the EnSite NavX™ mapping system results in a clinically significant reduction in exposure to ionising radiation compared with conventional catheter ablation.

METHODS

The study will randomise 210 patients undergoing catheter ablation of supraventricular tachyarrhythmias to either a conventional ablation technique or one guided by the EnSite NavX™ mapping system. The primary end-point is the reduction of the radiation dose to the patient. Secondary end-points include procedural success, reduction of the radiation dose to the operator, and a cost-effectiveness analysis. In a subgroup of patients, we will also evaluate the radiobiological effectiveness of dose reduction by assessing acute chromosomal DNA damage in peripheral blood lymphocytes.

CONCLUSIONS

NO-PARTY will determine whether radiofrequency catheter ablation of supraventricular tachyarrhythmias guided by the EnSite NavX™ mapping system is a suitable and cost-effective approach to achieve a clinically significant reduction in ionising radiation exposure for both patient and operator.

Arrhythmias in women

There are important gender differences in cardiac electrophysiology that affect the epidemiology, presentation, and prognosis of various arrhythmias. Women have been noted to have higher resting heart rates compared to men. They also have a longer QT interval, which puts them at an increased risk for drug-induced torsades de pointes. Women with atrial fibrillation are at a higher risk of stroke, and they are less likely to receive anticoagulation and ablation procedures compared to men. Women have a lower risk of sudden cardiac death and are less likely to have known coronary artery disease at the time of an event compared to men. Both men and women have been shown to derive an equal survival benefit from implantable cardioverter defibrillators and cardiac resynchronization therapy, although these devices are significantly underutilized in women. Women also appear to have a better response to cardiac resynchronization therapy in terms of reduced numbers of hospitalizations and more robust reverse ventricular remodeling. Further studies are required to elucidate the underlying pathophysiology of these sex differences in cardiac arrhythmias.

Paroxysmal regular supraventricular tachycardia: the diagnostic accuracy of the transesophageal ventriculo-atrial interval

OBJECTIVE

To establish the diagnostic accuracy of the transesophageal ventriculo-atrial (VA) interval in patients with paroxysmal supraventricular tachycardia (PSVT) and normal baseline electrocardiogram (ECG).

METHODS

The transesophageal VA interval during tachycardia was recorded in 318 patients (age 45 ± 17 years, 58% female) with PSVT and a normal surface ECG between attacks. Subsequently, all patients underwent an ablation procedure establishing the correct tachycardia diagnosis.

RESULTS

AV nodal reentrant tachycardia (AVNRT), AV reentrant tachycardia through a concealed accessory pathway (AVRT), and ectopic atrial tachycardia (EAT) were found in 213, 95, and 10 cases, respectively. Receiver operating characteristic curve analysis identified an optimal cutoff for a binary categorization of AVNRT versus AVRT/EAT at ≤80 ms (area under the curve 0.891). Owing to a biphasic distribution, AVNRT was very likely at VA intervals ≤90 ms with a sensitivity, specificity, and positive predictive value (PPV) of 87%, 91%, and 95%. In the range 91-160 ms the corresponding values for AVRT were 88%, 95%, and 88% (90%, 99%, and 98% in male patients). In the small group with VA intervals >160 ms (n = 29), the diagnosis was less clear (PPV of 67% for AVNRT).

CONCLUSIONS

In patients with sudden onset regular tachycardia and a normal ECG during sinus rhythm, a transesophageal VA interval of ≤80 ms has the highest diagnostic accuracy to diagnose AVNRT versus AVRT/EAT. Overall, the biphasic distribution of VA intervals suggests considering AVNRT at 90 ms and below and AVRT between 91 and 160 ms (in particular in male patients) while the diagnosis is vague at VA intervals above 160 ms.

Wolff-Parkinson-White syndrome in young people, from childhood to young adulthood: relationships between age and clinical and electrophysiological findings

Purpose

The aim of the present study was to evaluate the characteristics of electrophysiologic studies (EPS) and radiofrequency ablation (RFA) performed in subjects aged less than 30 years with Wolff-Parkinson-White (WPW) syndrome, particularly pediatric patients under 18 years of age, based on our experience.

Methods

Two hundred and one consecutive patients with WPW syndrome were recruited and divided to 3 groups according to age: group 1, 6 to 17 years; group 2, 18 to 29 years; and group 3, 30 to 60 years. The clinical, electrophysiological, and therapeutic data for these patients were evaluated by a retrospective medical record review.

Results

A total of 73 (36%) of these patients were <30 years of age. Although there were more males than females in group 2 (male:female, 31:11), there was no sex difference in group 1 (male:female, 16:15). Left accessory pathway was detected less frequently in group 1 (32%, 10/31) than in group 2 (57%, 24/42) and group 3 (63%, 81/128) (P=0.023 and P=0.002, respectively).

Conclusion

The present study describes several different electrophysiological characteristics in children and adolescents with WPW syndrome. Therefore, when EPS and RFA are performed in children and adolescence with WPW syndrome, we recommend that these characteristics be considered.

Sex differences in linear and nonlinear heart rate variability during early recovery from supramaximal exercise

Women demonstrate greater RR interval variability than men of similar age. Enhanced parasympathetic input into cardiac regulation appears to be not only greater in women, but also protective during periods of cardiac stress. Even though women may have a more favorable autonomic profile after exercise, little research has been conducted on this issue. This study was designed to examine the cardiac autonomic response, in both male and female participants, during the early recovery from supramaximal exercise. Twenty-five individuals, aged 20 to 33 years (13 males and 12 females), performed a 30-s Wingate test. Beat-to-beat RR series were recorded before and 5 min after exercise, with the participants in the supine position and under paced breathing. Linear (spectral analysis) and nonlinear analyses (detrended fluctuation analysis (DFA)) were performed on the same RR series. At rest, women presented lower raw low frequency (LF) power and higher normalized high frequency (HF) power. Under these conditions, the LF/HF ratio of women was also lower than that of men (p<0.05), but there were no differences in the short-term scaling exponent (α1). Even though both sexes showed a significant modification in linear and nonlinear measures of heart rate variability (HRV) (p<0.05), women had a greater change in LF/HF ratio and α1 than men from rest to recovery. This study demonstrates that the cardiac autonomic function of women is more affected by supramaximal exercise than that of men. Additionally, DFA did not provide additional information about sexual dimorphisms, compared with conventional spectral HRV techniques.

Outcome of invasive electrophysiological procedures and gender: are males and females the same?

The aim of this review is to summarize the available evidence on gender-related differences in outcome of invasive electrophysiological procedures. Gender exerts significant influences on the epidemiology, pathophysiology, and clinical presentation of many cardiac rhythm disorders. Women with supraventricular arrhythmias have a higher incidence of atrioventricular nodal reentrant tachycardia, a lower prevalence of atrioventricular accessory pathways, and increased arrhythmia inducibility during luteal phases of the menstrual cycle. Catheter ablation of supraventricular arrhythmias appears equally effective in the 2 genders, although women present to catheter ablation later, with more symptoms, and after having failed more antiarrhythmic drugs. The outcome of catheter ablation of atrial fibrillation in women has been reported worse than in men, which may be explained by a later referral. Accordingly, women present to catheter ablation with a higher incidence of long-standing persistent atrial fibrillation. Of note, the outcome of catheter ablation of atrial flutter does not seem to differ between genders. To date, with regard to ventricular arrhythmias, no gender-related differences in outcome of catheter ablation procedures have been reported. However, pathophysiology and risk factors underlying ventricular arrhythmias appear different in the two genders. Severe left ventricular dysfunction does not perform equally as a predictor for sudden cardiac death in women as compared to men, and the survival benefit of prophylactic implantable cardioverter-defibrillator (ICD) implantation in women is inconclusive. On the other hand, the clinical outcome after cardiac resynchronization therapy seems to be more favorable in women, who experience a greater degree of reverse left ventricular remodeling.

Gender-specific aspects in the clinical presentation of cardiovascular disease

More than a quarter of a million women die each year in the industrialized countries from cardiovascular diseases (CVD), and current projections indicate that this number will continue to rise with our ageing population. Important sex-related differences in the prevalence, presentation, management and outcomes of different CVD have discovered in the last two decades of cardiovascular research. Nevertheless, much evidence supporting contemporary recommendations for testing, prevention and treatment of CVD in women is still extrapolated from studies conducted predominantly in men. The compendium of CVD indicates that current research and strategy development must focus on gender-specific issues to address the societal burden and costs related to these incremental shifts in female gender involvement. Indeed, this significant burden of CVD in women places unique diagnostic, treatment and financial encumbrances on our society that are only further intensified by a lack of public awareness about the disease on the part of patients and clinicians alike. This societal burden of the disease is, in part, related to our poor understanding of gender-specific pathophysiologic differences in the presentation and prognosis of CVD and the paucity of diagnostic and treatment guidelines tailored to phenotypic differences in women. In this, scenario is of outmost importance to know these differences to provide the best care for female patients, because under-recognition of CVD in women may contribute to a worse clinical outcome. This review will provide a synopsis of available evidence on gender-based differences in the initial presentation, pathophysiology and clinical outcomes of women affected by CVD.

A multicenter, long-term study on arrhythmias in children with Ebstein anomaly

To assess the prevalence, history, and treatment of arrhythmias, in particular preexcitation and Wolff-Parkinson-White (WPW) syndrome, in patients with Ebstein anomaly (EA) during childhood and adolescence, we performed a multicenter retrospective study of all consecutive live-born patients with EA, diagnosed, and followed by pediatric cardiologists between 1980 and 2005 in The Netherlands. During a follow-up after EA diagnosis of 13 years 3 months (range: 6 days to 28 years 2 months), 16 (17%) of the 93 pediatric EA patients exhibited rhythm disturbances. Nine patients showed arrhythmic events starting as of the neonatal period. Supraventricular tachycardia was noted in 11 patients. One patient died in the neonatal period due to intractable supraventricular tachycardia resulting in heart failure and one patient died at 5 weeks of age most probably due to an arrhythmic event. The 14 surviving patients all show preexcitation, albeit 4 of them intermittently, and all have a right-sided accessory pathway location. Nine patients underwent catheter ablation of an accessory pathway. Only four patients are currently on antiarrhythmic drugs. The 17% prevalence of rhythm disturbances in pediatric EA patients, most commonly supraventricular arrhythmias, is significantly lower than in adult EA patients. Life-threatening rhythm disturbances are not frequent early in life. Symptomatic patients are well treated with radiofrequency catheter ablation.

Sex-dependent gene regulatory networks of the heart rhythm

Expression level, control, and intercoordination of 66 selected heart rhythm determinant (HRD) genes were compared in atria and ventricles of four male and four female adult mice. We found that genes encoding various adrenergic receptors, ankyrins, ion channels and transporters, connexins, cadherins, plakophilins, and other components of the intercalated discs form a complex network that is chamber dependent and differs between the two sexes. In addition, most HRD genes in atria had higher expression in males than in females, while in ventricles, expression levels were mostly higher in females than in males. Moreover, significant chamber differences were observed between the sexes, with higher expression in atria than ventricles for males and higher expression in ventricles than atria for females. We have ranked the selected genes according to their prominence (new concept) within the HRD gene web defined as extent of expression coordination with the other web genes and stability of expression. Interestingly, the prominence hierarchy was substantially different between the two sexes. Taken together, these findings indicate that the organizational principles of the heart rhythm transcriptome are sex dependent, with the newly introduced prominence analysis allowing identification of genes that are pivotal for the sexual dichotomy.

More reasons why men and women are not the same (gender differences in electrophysiology and arrhythmias)

It has become increasingly apparent in recent years that there are important differences in the presentation and clinical course of many cardiovascular disorders in men and women. These gender differences extend to clinical cardiac electrophysiology, with respect to basic electrophysiology as well as the presentation and clinical courses of many arrhythmias. Women have been noted to have higher heart rates at rest and longer corrected QT intervals compared with men. Differences in gender hormones may explain some of these findings, but precisely how is still not well understood. Differences have also been documented in the incidence and prevalence of specific arrhythmias, including atrial fibrillation, other supraventricular tachycardias, and sudden cardiac death. Variations in arrhythmia frequency with respect to the menstrual cycle have been observed. In addition, an increase in arrhythmia frequency or the new onset of arrhythmias has been noted during pregnancy. With the increasing use of implantable cardioverter defibrillators and cardiac resynchronization therapy, it has been shown that men and women derive equal survival and symptom reduction benefit. However, it has been found that the use of these devices in women is much lower than would be expected from the prevalence of disease in the population. The reasons for this lower utilization rate are not well understood and remain to be explored. In conclusion, the goal of this review is to summarize the currently available published reports regarding gender differences in cardiac electrophysiology and arrhythmias and to provide an update from recent studies.

Long-term outcome of patients with atrioventricular node reentrant tachycardia

BACKGROUND

Little information is available on the natural history of patients with AVNRT. The purpose of this study was to compare the outcome of patients with Atrioventricular node reentrant tachycardia (AVNRT) who underwent ablation with those on antiarrhythmic therapy and those not receiving drugs.

METHODS

93 consecutive patients (mean age=33.5+/-18.1 years) with AVNRT referred to our institution from 1988 to 1993 were prospectively followed-up for a mean of 13.2+/-2.0 years (range=11.4-16.1 years).

RESULTS

18 patients underwent ablation (group 1), 24 received antiarrhythmic therapy (group 2), 38 received no drugs or remained on drug therapy for only few months (group 3), 3 died and 10 were lost to follow-up. The frequency of symptoms at the baseline was higher in group 1 than in groups 2 and 3 (7.8+/-3.7, 3.5+/-2.3, 2.3+/-1.9 episodes/month, respectively; p<0.02 in group 1 vs. group 3). At the end of the follow-up 18/18 (100%) of group 1, 14/23 (61%) of group 2 and 17/38 of group 3 (44.7%) reported being asymptomatic for the previous 3 years. Group 3 patients who became asymptomatic had a shorter duration of symptoms before enrolment (3.7+/-1.5 vs. 7.1+/-3.6 years, p<0.05) and a shorter mean length of the tachycardia episodes (3.8+/-2.4 vs. 42.6+/-17.8 min, p<0.02) than patients from the same group who remained symptomatic.

CONCLUSIONS

The main result of this study is that during a long-term follow-up a considerable number of untreated patients with AVNRT become asymptomatic. This finding should be considered for choosing treatment modality and for calculating healthcare costs of ablation vs. medical therapy.