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Biomedical subjects

Frank A Fish

Publications and source records attributed to Frank A Fish.

12 recordsLinked to original sources
PubMed2006

Andersen-Tawil syndrome.

Andersen-Tawil syndrome (ATS) is a rare condition consisting of ventricular arrhythmias, periodic paralysis, and dysmorphic features. In 2001, mutations in KCNJ2, which encodes the a subunit of the potassium channel Kir2.1, were identified in patients with ATS. To date, KCNJ2 is the only gene implicated in ATS, accounting for approximately 60% of cases. ATS is a unique channelopathy, and represents the first link between cardiac and skeletal muscle excitability. The arrhythmias observed in ATS are distinctive; patients may be asymptomatic, or minimally symptomatic despite a high arrhythmia burden with frequent ventricular ectopy and bidirectional ventricular tachycardia. However, patients remain at risk for life-threatening arrhythmias, including torsades de pointes and ventricular fibrillation, albeit less commonly than observed in other genetic arrhythmia syndromes. The characteristic heterogeneity at both the genotypic and phenotypic levels contribute to the continued difficulties with appropriate diagnosis, risk stratification, and effective therapy. The initial recognition of a syndromic association of clinically diverse symptoms, and the subsequent identification of the underlying molecular genetic basis of ATS has enhanced both clinical care, and our understanding of the critical function of Kir2.1 on skeletal muscle excitability and cardiac action potential.

Journal Article↗
PubMed2006

Sustained slow pathway conduction: superior to dual atrioventricular node physiology in young patients with atrioventricular nodal reentry tachycardia?

BACKGROUND: Young patients with atrioventricular nodal reentry tachycardia (AVNRT) frequently do not display discrete dual AV node physiology (DAVNP) as classically defined. The purpose of the study was to investigate the prevalence of sustained slow pathway conduction (SSPC; PR > RR during atrial pacing) in young patients with AVNRT and compare it to dual atrioventricular node physiology. METHODS: The presence of SSPC and DAVNP was prospectively assessed before and after radiofrequency catheter ablation in 61 young patients (age 4-23 years) with typical AVNRT. RESULTS: Prior to ablation, 32 (52%) displayed DAVNP, while 46 (75%) displayed SSPC; 7 patients (11%) had neither marker. Patients with DAVNP were older than those without (15 +/- 3 vs 13 +/- 4, P = 0.027) and the prevalence increased with age (38% <13 years, 50% 13-15, 70% >15, P = 0.041), while SSPC showed no age predilection. Patients under 13 years displayed SSPC more commonly than DAVNP (81% vs 38%, P = 0.004). DAVNP persisted after ablation in 10/32 (31%) patients, compared to 6/46 (13%) with persistent SSPC after ablation. The ability to use loss of the marker (present before, absent after ablation) as a surrogate for successful ablation was greater for SSPC than for DAVNP (66% vs 36%, P = 0.001). CONCLUSION: SSPC is more common than DAVNP in young patients with AVNRT. SSPC is eliminated more frequently than DAVNP after acutely successful ablation, and appears to be a better indicator of the substrate for AVNRT. Elimination of SSPC may serve as a useful surrogate endpoint for slow pathway ablation.

Adolescent↗
PubMed2005

Management of intra-atrial reentrant tachycardia.

PURPOSE OF REVIEW: Intraatrial reentrant tachycardia (IART), a difficult arrhythmia to manage, is likely to become more prevalent as the population of patients with congenital heart disease grows. While pharmacologic therapy alone often remains inadequate, important advances in nonpharmacologic therapy have occurred recently, enhancing the currently available therapeutic options. This review focuses on advances in electroanatomic mapping and catheter ablation, developments in arrhythmia surgery, and device therapy for IART. RECENT FINDINGS: While catheter ablation for IART has high early recurrence rates, the lack of late recurrence in long-term follow-up is encouraging. Acute success may be improved with greater appreciation for reentrant circuits with current electroanatomic mapping systems, and with larger lesions that can be achieved with the use of irrigated-tip catheters. Arrhythmia surgery at the time of Fontan revision has good short-term and medium-term results, and is being studied as a prophylactic measure at initial Fontan surgery. Device therapy for IART now includes algorithms to prevent atrial arrhythmias, as well as antitachycardia pacing, which can be used safely and has very high efficacy for certain subgroups. SUMMARY: Due to recent advances in mapping and ablation technology, coupled with developments in arrhythmia surgery and device therapy, the armamentarium of nonpharmacologic management of IART has become more potent. There are still, however, unique challenges posed by patients with congenital heart disease, and long-term follow-up in large numbers of patients with IART are required for this expanding population of patients.

Catheter Ablation↗
PubMed2004

Ventricular fibrillation: basic concepts.

This brief overview serves as an introduction to the vast array of basic and clinical concepts that are pertinent to the basic understanding of ventricular fibrillation, its genesis, and its clinical management.

Anti-Arrhythmia Agents↗
PubMed2004

Feasibility of the inframammary location for insertable loop recorders in young women and girls.

The parasternal location for the insertable loop recorder (ILR) has potential for erosion in small patients, and can be aesthetically unappealing, especially for young women. We assessed the feasibility of the inframammary location in nine patients, utilizing a 2 cm transverse incision at the inferior and medial border of the left or right breast. Signal quality was adequate with clearly discernable atrial and ventricular electrograms. No complications involving the surgical site were observed. Cosmetically, placement of the scar in the natural breast crease has been favorably accepted. Inframammary implantation of the ILR is feasible, and is the preferred method in young women and girls at our center.

Adolescent↗
PubMed2003

Frequency of late recurrence of intra-atrial reentry tachycardia after radiofrequency catheter ablation in patients with congenital heart disease.

Forty-seven catheter ablation procedures for intra-atrial reentry tachycardia were performed in 40 patients with palliated congenital heart disease. The acute success rate was 87% and the recurrence rate was 34% during an average follow-up of 36 months. Of those patients who had recurrence, 88% did so within 1 year of ablation. Of the 23 patients who were free of recurrence 1 year after ablation, 21 (91%) remain free from recurrence at an average of 45 months (median 39; range 15 to 88) after ablation.

Adolescent↗
PubMed2003

Inducible atrioventricular nodal reentry tachycardia in infants with a history of neonatal orthodromic reciprocating tachycardia.

Atrioventricular nodal reentry tachycardia (AVNRT) is an uncommon mechanism of supraventricular tachycardia in neonates in whom orthodromic reciprocating tachycardia (ORT) predominates. We report three patients with structurally normal hearts who presented with neonatal ORT, documented by transesophageal electrophysiology studies at 2 to 3 weeks of age. At follow-up study at 8-12 months of age, no infant had inducible ORT, suggesting spontaneous regression of congenital accessory pathways; however, each had inducible tachycardia consistent with the typical form of AVNRT. The clinical significance of this finding is unknown and warrants further study.

Anti-Arrhythmia Agents↗
PubMed2003

Congenital sick sinus syndrome caused by recessive mutations in the cardiac sodium channel gene (SCN5A).

Sick sinus syndrome (SSS) describes an arrhythmia phenotype attributed to sinus node dysfunction and diagnosed by electrocardiographic demonstration of sinus bradycardia or sinus arrest. Although frequently associated with underlying heart disease and seen most often in the elderly, SSS may occur in the fetus, infant, and child without apparent cause. In this setting, SSS is presumed to be congenital. Based on prior associations with disorders of cardiac rhythm and conduction, we screened the alpha subunit of the cardiac sodium channel (SCN5A) as a candidate gene in ten pediatric patients from seven families who were diagnosed with congenital SSS during the first decade of life. Probands from three kindreds exhibited compound heterozygosity for six distinct SCN5A alleles, including two mutations previously associated with dominant disorders of cardiac excitability. Biophysical characterization of the mutants using heterologously expressed recombinant human heart sodium channels demonstrate loss of function or significant impairments in channel gating (inactivation) that predict reduced myocardial excitability. Our findings reveal a molecular basis for some forms of congenital SSS and define a recessive disorder of a human heart voltage-gated sodium channel.

Electrocardiography↗