Supraventricular Arrhythmias in Patients With Pulmonary Arterial Hypertension

The onset of supraventricular arrhythmias (SVA) may be associated with clinical worsening in patients with pulmonary arterial hypertension (PAH). However, limited data have been reported, especially at long-term follow-up. Aim of this study was to investigate the incidence of SVA in our patients with PAH, the risk factors correlated to their onset and the prognostic impact. All consecutive patients with PAH without history of SVA were enrolled. Incidence of new SVA was investigated and also the risk factors for SVA. Primary end point of the study was the impact of SVA on a composite of all-cause mortality and re-hospitalization, whereas mortality was the secondary end point. Seventy-seven patients were enrolled. No significant differences in the clinical or instrumental baseline characteristics between the 2 study groups were reported. During a median follow-up of 35 months (interquartile range 21.5 to 53.5), 17 (22%) patients experienced SVA. Development of SVA was associated with worsening of prognostic parameters at the follow-up: increasing of World Health Organization (WHO) functional class (p = 0.005) and N-terminal-pro-brain natriuretic peptide (NT-proBNP) (p = 0.018) and reduction of 6-minute walking distance (p = 0.048), tricuspid annular plane systolic excursion (TAPSE) (p = 0.041), and diffusing capacity of the lung for carbon monoxide (p = 0.025). The primary end point occurred in 13 patients (76%) in the SVA group and in 22 patients (37%) in the group without SVA (p = 0.004), whereas 9 patients (53%) among those with SVA died during the follow-up compared with 8 (13%) among those without (p = 0.001). At multivariate analysis, development of SVA was independently associated with an increased risk to meet the both primary (hazard ratio 2.13; 95% confidence interval 1.07 to 4.34; p = 0.031) and secondary (hazard ratio 4.1; 95% confidence interval 1.6 to 10.6; p = 0.004) end points. In conclusion, during the 3-year follow-up period, 1/3 of patients with PAH developed SVA, which was related to worsening of hemodynamic and functional parameter and independently predicted adverse prognosis.

Treatment of supraventricular tachycardia in infants: Analysis of a large multicenter database

OBJECTIVE

Supraventricular tachycardia (SVT) is the most common arrhythmia in infants. Infants are typically treated with antiarrhythmic medications, but there is a lack of evidence guiding management, thus exposing infants to risks of both inadequate therapy and medication adverse events. We used data from a large clinical database to better understand current practices in SVT management, safety of commonly used medications, and outcomes of hospitalized infants treated for SVT.

METHODS

This retrospective data analysis included all infants discharged from Pediatrix Medical Group neonatal intensive care units between 1998 and 2012 with a diagnosis of SVT who were treated with antiarrhythmic medications. We categorized infants by the presence of congenital heart disease other than patent ductus arteriosus. Medications were categorized as abortive, acute, or secondary prevention therapies. We used descriptive statistics to describe medication use, adverse events, and outcomes including SVT recurrence and mortality.

RESULTS

A total of 2848 infants with SVT were identified, of whom 367 (13%) had congenital heart disease. Overall, SVT in-hospital recurrence was high (13%), and almost one fifth of our cohort (18%) experienced an adverse event. Mortality was 2% in the overall cohort and 6% in the congenital heart disease group (p<0.001). Adenosine was the most commonly used abortive therapy, but there was significant practice variation in therapies used for acute treatment and secondary prevention of SVT.

CONCLUSION AND PRACTICE IMPLICATION

Significant variation in SVT treatment and suboptimal outcomes warrant future clinical trials to determine best practices in treating SVT in infants.

Frequency of supraventricular arrhythmias in patients with idiopathic pulmonary arterial hypertension

Supraventricular arrhythmias (SVA) may be risk factors of prognosis in patients with pulmonary arterial hypertension. SVA are increasingly reported in patients with pulmonary hypertension, but little is known about their incidence and outcomes for patients with idiopathic pulmonary arterial hypertension (IPAH) in a large cohort. In this 6-year prospective multicenter study, 280 patients with IPAH were enrolled to investigate the incidence of SVA and assess risk factors, clinical manifestation, management, and impact on survival. The cumulative 6-year incidence of SVA was 15.8%. The most common types of SVA were atrial fibrillation (n = 16) and atrial flutter (n = 13), followed by atrial tachycardia (n = 11). Most episodes of SVA were associated with significant clinical deterioration and right-sided cardiac failure. Sinus rhythm was successfully restored in most patients, resulting in clinical recovery. Increased right ventricular diameter, left atrial area, and higher right atrial pressure and pulmonary vascular resistance were associated with increased risk for experiencing SVA. SVA predicted a greater risk for mortality in a stepwise forward Cox analysis (hazard ratio 4.757, 95% confidence interval 2.695 to 8.397, p <0.001). Kaplan-Meier survival curves showed that patients with SVA, mainly permanent SVA, had a lower survival rate than those who did not develop SVA (p = 0.008). In conclusion, SVA often lead to clinical deterioration and may be associated with an increased risk for death in a large cohort of patients with IPAH. Restoration and maintenance of sinus rhythm are important treatment goals in patients with IPAH.

Association of certain chronic maternal diseases with the risk of specific congenital heart defects: a population-based study

OBJECTIVE

Previous epidemiological studies have evaluated cases with all congenital heart defects (CHDs), rather than analysing different types of CHD. The objective of this study was to evaluate the possible association of certain chronic maternal diseases with the risk of different types of CHD, because the role of possible environmental factors in the origin of CHDs is unclear in the vast majority of patients.

STUDY DESIGN

Different types of CHD, diagnosed after lethal outcome (autopsy report) or after surgical intervention (catheter or correction), were evaluated in order to estimate the possible role of chronic maternal diseases in their origin. This analysis was based on the rates of medically recorded chronic maternal diseases in 3562 live-born cases with CHDs, 38,151 population controls without any birth defects, and 16,602 malformed controls with other isolated congenital abnormalities, using the data set of the population-based Hungarian Case-Control Surveillance of Congenital Abnormalities (1980-1996).

RESULTS

Maternal epilepsy treated with carbamazepine and migraine were found to be associated with higher risk of ventricular septal defect; panic disorders were associated with higher risk of hypoplastic left heart; type I diabetes mellitus was associated with higher risk of coarctation of the aorta; chronic hypertension was associated with higher risk of ventricular septal defect, common atrioventricular canal and common truncus; and paroxysmal supraventricular tachycardia was associated with higher risk of atrial septal defect secundum, common atrioventricular canal and ventricular septal defect.

CONCLUSION

In conclusion, certain chronic maternal diseases were found to be associated with higher risk of specific CHDs. Appropriate treatment of these diseases may help to prevent these CHDs.

[Ventricular and supraventricular arrhythmias in women]

There are few gender-related differences in electrophysiology regarding occurrence, clinical symptoms and prognosis of arrhythmias. Women tend to have higher incidence of sinus tachycardia and atrio-ventricular nodal re-entry tachycardia. Atrial fibrillation is more frequent among men, but women have worse prognosis as their mortality is higher, "rhythm control" strategy is less favorable and the thromboembolic risk is greater. Ventricular arrhythmias are less common in women and their significance is smaller. As women have longer QTc interval and torsade de pointes is typical women's arrhythmia, physicians must be very careful ordering QT-elongating drugs. Coronary heart disease (CHD) is seldom background for ventricular tachycardia and women with CHD and arrhythmias have better prognosis than men. Sex hormones play important role in women's electrophysiology. Pregnancy increase risk of supraventricular tachycardia and decrease occurrence of torsade de pointes.

Recurrence rate of PSVT (paroxysmal supraventricular tachycardia) in Rajavithi emergency department

BACKGROUND

PSVT (Paroxysmal Supraventricular Tachycardia) is a common heart disease, especially in young people. Although PSVT is not a life-threatening illness, its symptoms occur in a sudden onset and with increasing frequency. Because of the severity of its symptoms, it can interfere with patients' quality of life and lead to an increase in anxiety levels. The authors found that patients with PSVT tended to have recurrence of symptoms; however, there has been no previous study in Thailand of the rate of recurrent PSVT in adults. Moreover, there has been no study of the factors which precipitate PSVT cause recurrence, and result in hospitalization.

OBJECTIVE

To study the rate of recurrence of PSVT within 90 days, the precipitating factors that cause PSVT and the relationship between the factors that affect recurrence of symptoms and result in admission to hospital.

MATERIAL AND METHOD

This was a cross-sectional study of patients who had been diagnosed with PSVT and were treated in the emergency room at Rajavithi Hospital from 1st August 2008-31st August 2011. The primary outcome was recurrence of PSVT within 90 days and its impact on hospital admission.

RESULTS

The 55 patients in the present study visited the hospital 94 times. The authors found that: 20.0% of patients had recurrence of PSVT within 90 days; 45.7% of patients had no precipitating factors; 33.0% of patients had emotional stress; and 20.0% of patients had stopped taking their medication. Patients who presented at their first visit with a heart rate of more than 200 beats per minute were more likely to have recurrence (statistically significant, HR 2.43, p = 0.017). Patients presenting with low systolic blood pressure (SBP < 90 mmHg), long duration of symptoms, structural heart disease, low serum Hematocrit concentration (Hct < 30%), serum sodium < 135 milligram, and serum potassium < 3.5 milligram were more likely to be admitted to hospital (statistically significant at p = 0.013, 0.012, 0.004, 0.001, 0.001, and 0.004 respectively).

CONCLUSION

There was a high rate of recurrence of PSVT in patients in the emergency department at Rajavithi Hospital. Significant factors affecting recurrence were patients presenting with initial heart rate of over 200 beats per minute. Low systolic blood pressure, long duration of symptoms, structural heart disease, low serum Hematocrit, low serum sodium and serum potassium were associated with hospitalization.

Incidence, characteristics, and outcome of left atrial tachycardias after circumferential antral ablation of atrial fibrillation

BACKGROUND

Antral pulmonary vein isolation (PVI) for treatment of atrial fibrillation may induce left atrial tachycardias (ATs).

OBJECTIVE

To determine the prevalence, time course of occurrence, mechanisms, and correlation with the electrocardiogram as well as the outcome of ablation of these tachycardias.

METHODS AND RESULTS

Out of the 839 patients who underwent circumferential antral radiofrequency PVI guided by a circumferential pulmonary vein catheter at our institution between February 2005 and April 2011, 35 patients (4%) developed AT during follow-up. Six patients with left AT and a previous PVI at other institutions were also included. Of these 41 patients (26 men, 63%; age 59 ± 10 years), 26 (63%) had underlying paroxysmal atrial fibrillation and 15 (37%) had persistent atrial fibrillation. AT ablation was performed 47 ± 60 weeks after initial PVI, within the first 3 months in 16 patients (39%). The tachycardia mechanism was focal in 15 patients (37%), macroreentry in 25 patients (61%), and undetermined in 1 (2%). Focal tachycardias had an isoelectric line between distinct P waves in 13 of the 15 patients (87%), while only 4 (16%) with a macroreentrant mechanism had an isoelectric line (P <.001). Although difficult to measure, a P-wave width of >140 ms had the highest sensitivity and specificity to identify macroreentrant mechanism. Ablation was acutely successful in 32 patients (78%) and not successful in 4 (10%). In 5 patients, success could not be determined as the tachycardia terminated or degenerated during mapping. During a mean follow-up of 31 ± 17 months, 11 patients (27%; n = 9 [82%] with macroreentry) underwent repeat ablation procedure for AT. Eight patients had true recurrence, for example, the same AT, and 3 patients had a second mechanism of AT.

CONCLUSIONS

With the use of an identical ablation protocol, it was found that approximately 4% of the patients developed AT after mere circumferential antral PVI. The majority of ATs developed within a few months after ablation but occurred as late as several years after the initial PVI. Macroreentry was more frequent than a focal mechanism. Broad P waves and isoelectric lines between P waves help to distinguish a focal mechanism from a macroreentrant mechanism. Ablation has a high acute success rate, and AT recurrence occurs predominantly in macroreentrant AT.

Perioperative atrial tachycardia is associated with increased mortality in infants undergoing cardiac surgery

OBJECTIVE

Few data are available on the frequency or importance of perioperative atrial tachycardia in infants. We hypothesized that atrial tachycardia in infants undergoing cardiac surgery is not rare and is associated with increased morbidity and mortality.

METHODS

From 2007 through 2010, 777 infants (median age, 1.8 months; interquartile range, 0.33-5.73) underwent cardiac surgery. Their medical records were reviewed for atrial tachycardia during the perioperative period.

RESULTS

Of the 777 patients, 64 (8.2%) developed atrial tachycardia. The independent risk factors for developing atrial tachycardia included surgical age 6 months or younger (odds ratio, 4.4; 95% confidence interval, 1.1-19.15), use of 3 or more inotropes (odds ratio, 2.9; 95% confidence interval, 1.4-6.2), and heterotaxy syndrome (odds ratio, 2.9; 95% confidence interval, 1.1-7.4). All-cause mortality in the atrial tachycardia group was increased (21.9% vs 7.2%, P<.001) during a median follow-up period of 14.6 months (interquartile range, 6.8-24.6), and atrial tachycardia was independently associated with decreased survival (hazard ratio, 1.9; 95% confidence interval, 1.1-3.8). Infants with perioperative atrial tachycardia had a longer hospital length of stay (32 vs 17 days, P<.001) and duration of inotrope use (10.5 vs 3.0 days, P<.001). A total of 57 patients received antiarrhythmic therapy, with propranolol the most common (n=31). Among the survivors, 48 patients received outpatient antiarrhythmic therapy, which was successfully discontinued in 23 patients at a median duration of 14 months (interquartile range, 5.7-18.6) without recurrence.

CONCLUSIONS

Atrial tachycardia is common in infants undergoing cardiac surgery and is independently associated with decreased survival. Among survivors, antiarrhythmic agents successfully controlled atrial tachycardia in most patients with a low recurrence risk after discontinuation.

Usefulness of radiofrequency ablation of supraventricular tachycardia to decrease inappropriate shocks from implantable cardioverter-defibrillators

Inappropriate implantable cardioverter-defibrillator (ICD) therapies can lead to significant adverse events and increased mortality. These therapies are often the result of supraventricular tachycardias (SVTs). The objective of this study was to evaluate the incidence of SVT leading to inappropriate shocks in a large cohort of patients with ICDs and assess the efficacy of radiofrequency ablation (RFA) in decreasing these therapies. Patients with ICDs and recurrent SVTs were identified. A cohort of patients with ICD therapies subsequently underwent electrophysiologic study and RFA. Eighty-four patients (13%) were found to have SVT leading to 122 inappropriate ICD shocks and 130 episodes of antitachycardia pacing therapies. Median time to SVT onset after ICD implantation was 269 days. Electrophysiologic studies were performed in 30 patients. Successful RFA was performed for atrial tachycardia, atrial flutter, or atrioventricular nodal reentrant tachycardia in 22 patients. Ninety-five percent of patients who underwent successful SVT ablation had no further inappropriate ICD therapies compared to 63% of patients in whom ablation was not performed during a mean follow-up of 20.7 ± 11.9 months. In conclusion, SVT is responsible for a significant number of inappropriate ICD therapies. RFA is an effective strategy to substantially decrease subsequent inappropriate ICD therapies.

[Metabolic syndrome impact on arrhythmias genesis in elderly women]

The article discusses the data of a study aimed at the impact of the metabolic syndrome on arrhythmias in elderly women. Analysis of the data showed that supraventricular arrhythmias were detected in most part of elderly women, ventricular arrhythmias a few less. The share of prognostically unfavorable arrhythmias is small, but they develop linked to the metabolic changes, and dangerous ventricular arrhythmias and atrial fibrillation develop more often in patients with metabolic syndrome.

Common types of supraventricular tachycardia: diagnosis and management

The most common types of supraventricular tachycardia are caused by a reentry phenomenon producing accelerated heart rates. Symptoms may include palpitations (pulsation in the neck), chest pain, lightheadedness or dizziness, and dyspnea. It is unusual for supraventricular tachycardia to be caused by structurally abnormal hearts. Diagnosis is often delayed because of the misdiagnosis of anxiety or panic disorder. Patient history is important in uncovering the diagnosis, whereas the physical examination may or may not be helpful, and usually necessitates use of a Holter monitor or an event recorder to capture the arrhythmia and confirm a diagnosis. Treatment consists of short-term or as needed pharmacotherapy using calcium channel or beta blockers when vagal maneuvers fail to halt or slow the rhythm. In those who require long-term pharmacotherapy, atrioventricular nodal blocking agents or class IC or III antiarrhythmics can be used; however, these agents should generally be managed by a cardiologist. Catheter ablation is an option in patients with persistent or recurrent supraventricular tachycardia who are unable to tolerate long-term pharmacologic management. If Wolff-Parkinson-White syndrome is present, expedient referral to a cardiologist is warranted because ablation is a potentially curative option.

Long-term neurodevelopmental outcome after fetal arrhythmia

OBJECTIVE

The purpose of this study was to determine the long-term neurodevelopmental outcome in fetuses with severe tachy- or bradyarrhythmia.

STUDY DESIGN

This was a follow-up study to assess the neurologic, mental, and psychomotor development in cases with fetal cardiac arrhythmia.

RESULTS

A total of 44 fetuses were diagnosed with fetal tachy- or bradyarrhythmia: 28 fetuses had supraventricular tachycardia (SVT); 7 fetuses had atrial flutter (AF), and 9 fetuses had atrioventricular block (AVB). The mortality rate was low (6%; 2/35 fetuses) in the SVT and AF groups and high in the AVB group (78%; 7/9 fetuses). Six patients were lost to follow-up evaluation (14%). Neurodevelopmental outcome was normal in all survivors in the SVT and AF groups, except for 1 patient who experienced plexus brachialis injury because of shoulder dystocia. Two of the 3 survivors in the AVB group had severe developmental delay.

CONCLUSION

The mortality rate and neurodevelopmental impairment in infants with SVT and AF are low, but the mortality rate in infants with AVB is elevated.

Long-term low-dose amiodarone therapy in the management of ventricular and supraventricular tachyarrhythmias: efficacy and safety

BACKGROUND

Amiodarone hydrochloride has been in use for two decades for the control of ventricular and supraventricular arrhythmias. Established and emerging evidence indicates that amiodarone has an antiarrhythmic efficacy superior to that of most other drugs.

HYPOTHESIS

The study was undertaken to evaluate the efficacy and acceptability of low-dose amiodarone therapy in the long-term management of supraventricular and ventricular tachyarrhythmias.

METHODS

A total of 124 patients with symptomatic drug-refractory or life-threatening arrhythmias managed with low-dose oral amiodarone therapy over a 10-year period was analyzed retrospectively. Of these, 45 patients (36%) had ventricular arrhythmias, 52 (42%) had atrial arrhythmias, and 27 (22%) had atrioventricular reentry tachycardia. Loading doses of amiodarone 600 mg daily for 1 week were administered for supraventricular arrhythmias and 600-1200 mg daily for 2 weeks for ventricular arrhythmias. Maintenance daily doses were 194 +/- 48 and 206 +/- 55 mg, respectively. Mean treatment duration was 32 +/- 28 months, with 326.3 patient years of therapy.

RESULTS

Of 39 patients with sustained ventricular tachyarrhythmias, the actuarial incidence of satisfactory arrhythmia control (absence of sudden cardiac death or nonfatal arrhythmia recurrence) was 78% at 1 year and 71% at 2 years. Satisfactory control of supraventricular arrhythmias (mean ventricular rate < 100/min with significant symptomatic improvement for sustained atrial arrhythmias and < 1 attack per year for paroxysmal atrial or atrioventricular arrhythmias) was achieved in 73, 65, and 62% of patients at 1, 2, and 3 years, respectively. The cumulative incidence of amiodarone-related adverse effects was 5.8 per 100 patient years, with drug withdrawal required in 12 patients (9.7%). Fifteen patients had thyroid dysfunction, 2 had hepatic toxicity, and 1 developed nonfatal pulmonary fibrosis. Overall, the incidence of successful use of amiodarone (satisfactory arrhythmia control and freedom from side effects) was 67, 59, and 53% at 1, 2, and 3 years, respectively.

CONCLUSIONS

The results of this study suggest that the efficacy of low-dose amiodarone therapy in the management of serious ventricular and supraventricular arrhythmias would be similar to those achieved with higher doses, but with a much more acceptable side effect profile.

Supraventricular arrhythmias in noncompaction of left ventricle: Is this a frequent complication?

BACKGROUND

Isolated left ventricular noncompaction is the result of incomplete myocardial morphogenesis, leading to persistence of the embryonic myocardium. The condition is recognised by an excessively prominent trabecular meshwork and deep intertrabecular recesses of the left ventricle. Whether these intertrabecular recesses are a favorable substrate for supraventricular arrhythmias is unclear, even if the incidence of chronic heart failure seems to be high.

RESULTS

We evaluated a continuous series of 238 patients affected by noncompaction. In 4 cases the patients reported palpitations and in 4 an episode of syncope. Periodic holter monitoring was performed every 6 months for 4 years. Only 9 patients had documented atrial fibrillation. In no cases we observed supraventricular tachycardia.

CONCLUSIONS

Noncompaction alone does not seem to be a risk factor for supraventricular arrhythmias.

[Supraventricular tachycardia in infants and children]

INTRODUCTION

Supraventricular tachycardia (SVT) is the second most frequent form of arrhythmia in pediatrics after extrasystole.

OBJECTIVES

1. To determine the clinical characteristics and treatment of SVT in infants and children. 2. To determine treatment response and the drugs used.

METHOD

A retrospective review of 61 cases of SVT requiring PICU admission (1999-2004) was performed. PICU admission was due to persistent SVT after vagal maneuvers.

RESULTS

There were 61 patients and 39 were boys (63.9%). The mean age was 2.1 years (SD +/- 3.1). Twelve patients had congenital heart disease (19.7%); three (4.9%) were admitted after heart surgery, and the remaining patients had no antecedents (60.7%). The mean cardiac frequency was 238 beats/min (SD +/- 42.86). Heart failure (HF) was observed in 14 patients (23%). Statistically significant differences were found between the presence of HF and time since onset (p < 0.01) and younger age (p < 0.01). The most frequent diagnosis was SVT due to re-entry in 28 patients (45.9%). Medical treatment was required in 46 patients (75.4%) and response was achieved in 35 (57.4%). At crisis the first drug used was adenosine triphosphate (ATP) in 35 patients (61.4%) with good response in 21 (36.8%). As maintenance therapy digoxin was used in 29 patients (50.9%) without relapses in 22 (78.6%). Radiofrequency ablation was required in 17 patients (27.9%), and there were three relapses (17.6%). The ages of patients who underwent ablation ranged from 3.5 days to 13 years.

CONCLUSIONS

1. HF was observed mainly in infants. 2. Most of the patients had good response to ATP therapy. 3. Radiofrequency ablation was mainly required in patients aged more than 1 year.

U.S. emergency department visits for supraventricular tachycardia, 1993-2003

BACKGROUND

Supraventricular tachycardia (SVT) is often described as a recurrent condition that leads to emergency department (ED) visits. However, the epidemiology of ED visits for SVT is unknown.

OBJECTIVES

To define the frequency of SVT in U.S. EDs and to analyze patient characteristics, ED management, and disposition for such visits.

METHODS

The authors analyzed data from the National Hospital Ambulatory Medical Care Survey, 1993-2003. SVT cases were identified by using the International Classification of Diseases, Ninth Revision, Clinical Modification codes 426.7 or 427.0 in any of the three diagnostic fields.

RESULTS

Of the 1.1 billion ED visits over the 11-year study period, an estimated 555,000 (0.05%; 95% confidence interval [CI] = 0.04% to 0.06%) were related to SVT. The annual frequency and population rate appear stable between 1993 and 2003 (p for trend = 0.35). Compared with non-SVT visits, those with SVT were more likely to be older than 65 years of age (26% vs. 15%, p < 0.01) and female (70% vs. 53%, p < 0.01). Electrocardiograms were documented for most visits (91%; 95% CI = 85% to 96%). Approximately half of the patients (51%; 95% CI = 40% to 61%) received an atrioventricular nodal blocking medication, most frequently adenosine (26%; 95% CI = 17% to 36%). SVT visits ended in hospital admission for 24% (95% CI = 15% to 34%). At the other extreme, 44% (95% CI = 32% to 56%) were discharged without planned follow-up.

CONCLUSIONS

Supraventricular tachycardia accounts for approximately 50,000 ED visits each year. Higher visit rates in older adults and female patients are consistent with prior studies of SVT in the general population. This study provides an epidemiologic foundation that will enable future research to assess and improve clinical management strategies of SVT in the ED.

[Supraventricular paroxysmal tachycardias during pregnancy: the therapeutic tactics and prognosis]

The paper contains recommendations on treatment of supraventricular paroxysmal tachycardias (SVPT) during pregnancy. The recommendations are based on contemporary literature data and authors" own data. SVPT in postural syndrome are shown to be benign and to demand no continuous antiarrhythmic therapy, while tachycardiac attacks are terminated by vagal tests and adenosine application. Relapsing and steady forms of SVPT with a high heart rate are accompanied by subjective symptoms and require preventive antiarrhythmic therapy, which should be conducted considering risk/benefit ratio. According to the authors, sotalol is the most effective and safe pharmaceutical.

Incidence and clinical relevance of supraventricular tachyarrhythmias in pulmonary hypertension

BACKGROUND

In patients with severe pulmonary hypertension (PH), right ventricular function is a main determinant of clinical stability and outcome. Supraventricular tachyarrhythmias (SVTs) may compromise cardiac function and threaten prognosis in patients with PH, but the incidence and clinical relevance of SVTs in PH and chronic right ventricular failure have not been evaluated.

METHODS

In a 6-year retrospective single-center analysis, 231 consecutive patients followed for pulmonary arterial hypertension, or inoperable chronic thromboembolic PH were studied for SVTs. Analysis included incidence, clinical consequences, treatment, and outcome.

RESULTS

Thirty-one episodes of SVT were observed in 27 of 231 patients (cumulative incidence 11.7%, annual risk 2.8% per patient), including atrial flutter (n = 15), atrial fibrillation (n = 13), and AV nodal reentry tachycardia (n = 3). Supraventricular tachyarrhythmia onset was almost invariably associated with marked clinical deterioration and right ventricular failure (84% of SVT episodes). Outcome was strongly associated with the type of SVT and restoration of sinus rhythm. During follow-up, cumulative mortality was low (6.3%, follow-up 26 +/- 23 months) when sinus rhythm was restored (all cases of AV nodal reentry tachycardia and atrial flutter). In contrast, 9 of 11 patients with sustained atrial fibrillation died from right ventricular failure (cumulative mortality 82%, follow-up 11 +/- 8 months).

CONCLUSIONS

In patients with PH, SVTs constitute a relevant problem, often resulting in clinical deterioration. Sustained atrial fibrillation may be associated with a high risk of death from right ventricular failure.

Radiofrequency catheter ablation of an orthodromic tachycardia in a patient with single ventricle

Radiofrequency catheter ablation of a recurrent orthodromic tachycardia was performed in a 10-year-old child with single ventricle and bidirectional Glenn procedure before a Fontan operation. Identification of a His bundle electrogram was achieved at the postero-inferior atrioventricular (AV) groove by the inferior vena cava route, and electrophysiological demonstration of a concealed accessory pathway-mediated tachycardia was possible when a ventricular extrastimuli given during the His bundle refractoriness showed advancement of the atrium. A single energy application during tachycardia in the right antero-superior region of the AV groove resulted in the definitive interruption of the accessory pathway.

Incidence of Atrial Fibrillation in Heart Transplant Patients: Long-Term Follow-Up

BACKGROUND

The incidence of atrial fibrillation (AF) in heart transplant patients has not been well documented.

METHODS

To determine the incidence of AF in a cohort of patients undergoing cardiac transplantation, clinical data were obtained from a prospectively collected database for all consecutive orthotopic heart transplantation (OHT) patients and for all consecutive coronary artery bypass graft (CABG) surgery patients between January 1984 and March 2004 at our institution. A cohort of 1,714 OHT patients and low-risk CABG (normal ejection fraction [EF] and no left ventricular hypertrophy [LVH]) patients were age- and sex-matched.

RESULTS

The average age in the two groups was 56 +/- 7 years with 87% male and 81% white race and body mass index (BMI) of 26 +/- 4. There were 3 cases of AF (0.3%) in the OHT group and 757 cases of AF (21%) in the low-risk CABG group. The strongest independent predictor of freedom from postoperative AF was having had a transplant (odds ratio [OR] 96, 95% confidence interval [CI] 13-720). The incidence of AF, atrial flutter (AFL), and supraventricular tachycardia (SVT) in OHT was 0.33, 2.8%, and 1.3%, respectively. Given that incidence of AF, AFL, and SVT in historical post-CABG population is 25%, 17%, and 4.3%, transplanted patients appear to have lower incidence of AF, AFL, and SVT than the reference population. Consistent with this, transplanted patients underwent few ablation procedures for atrial arrhythmias. Additionally, the three patients with AF had bicaval anastomoses suggesting the possibility of PACs originating in the donor superior vena cava (SVC) or IVC (inferior vena cava) initiating AF in these patients.

CONCLUSIONS

In a cohort study of transplant and low-risk CABG patients, the strongest independent predictor of freedom from AF is having undergone transplant surgery. One potential explanation for the markedly lower incidence of AF may be effective isolation of thoracic veins with documented cases retaining the native SVC.

Outcomes After Late Reoperation in Patients With Repaired Tetralogy of Fallot: The Impact of Arrhythmia and Arrhythmia Surgery

BACKGROUND

We evaluated outcomes in patients requiring late reoperation after tetralogy of Fallot (ToF) repair to identify risk factors for arrhythmia and determine whether arrhythmia surgery decreased the risk of subsequent death or recurrent arrhythmia.

METHODS

Review was performed of all ToF patients from 1969 to 2005 undergoing reoperation late (> 1 year) after repair. Patients with associated lesions, except pulmonary atresia, were included. A total of 249 patients had 278 reoperations. Procedures at initial reoperation included pulmonary valve replacement (PVR) in 217, ablation in 63, and tricuspid valve repair/replacement in 46. Pre-reoperative arrhythmias were present in 75, including supraventricular tachycardia (SVT) in 31, ventricular tachycardia (VT) in 34, and SVT+VT in 10 patients.

RESULTS

Median age at reoperation was 23 years (range, 1 to 63). Ten-year survival after reoperation was 93%, and was independent of arrhythmia status (p = 0.86). Arrhythmia patients were characterized by older age at initial repair and at late reoperation, tricuspid and pulmonary regurgitation, and longer QRS duration (p < 0.001 for all). Risk factors for post-reoperative recurrent arrhythmia were longer QRS duration and not having PVR. Longer QRS duration, with a cut-point of more than 160 msec, was associated with recurrent SVT (p = 0.004). Supraventricular tachycardia ablation improved arrhythmia-free survival (75% versus 33%, p < 0.001) but VT ablation did not (96% versus 95%, p = 0.50). However, recurrent VT occurred in only 3 patients (10%).

CONCLUSIONS

Late mortality in patients undergoing reoperation after ToF repair is not impacted by pre-reoperative arrhythmia. Prolongation of QRS identifies patients at risk for recurrent VT and SVT, but recurrent VT is uncommon. Early PVR, and surgical ablation in patients with SVT, decreases arrhythmic risk.

Prevalence of inducible paroxysmal supraventricular tachycardia during esophageal electrophysiologic study in patients with unexplained stroke

BACKGROUND

The relationships between stroke and atrial tachycardia or atrial fibrillation were previously reported. Electrophysiological study is one of the means, used to detect and evaluate these atrial tachyarrhythmias. But, some other arrhythmias as paroxysmal supraventricular tachycardia, can be induced during electrophysiologic study and their significance in stroke is unknown. The aim of the study was to assess the significance of inducible paroxysmal supraventricular tachycardia (PSVT) in stroke.

METHODS

One hundred thirty seven patients, aged 61+/-12 years had unexplained stroke (group I) and were compared to 60 subjects aged 45+/-18.5 years without stroke and history of tachycardia (group II); Holter monitoring (HM), echocardiogram and esophageal electrophysiologic study (EPS) in basal state and after isoproterenol were performed.

RESULTS

Heart disease was noted in 19 group I patients (14%) and 10 group II patients (17%). In group I, atrial fibrillation or tachycardia (AF-AT) was induced in 20 patients (15%) and PSVT was induced in 19 patients (14%) aged 66+/-12 years. In group II, AF/AT was induced in 3 patients (5%); no group II patient had induced PSVT. After 3+/-1 years, in group I, one of 98 patients without induced arrhythmias had new strokes and 2 had AF; 5 patients with induced AT/AF developed AF; 5 patients with induced PSVT had PSVT's, requiring ablation in 4 of them; 1 died from a new stroke; one had a second non-fatal stroke and 3 patients developed AF (16%). In group II, there were no events.

CONCLUSION

In 14% of patients with unexplained stroke, PSVT was inducible during esophageal electrophysiologic study. Further studies are warranted to assess the significance of this finding in patients with unexplained stroke.

[Perioperative management of cardiac arrhythmia: part II]

Cardiac arrhythmias are an important cause of complications throughout the perioperative period. Although our understanding of arrhythmias has increased considerably in recent years, they remain a source of concern for anesthesiologists. Our objective was to review steps to take when diagnosing arrhythmia. Although treatment is still largely influenced by therapies used in nonsurgical patients, we will review the approaches that are most applicable to practice situations in which anesthesiologists must manage patients with arrhythmias or at high risk of developing them.