Triggered intracellular calcium waves in dog and human left atrial myocytes from normal and failing hearts.

AIMS: Abnormal intracellular Ca2+ cycling contributes to triggered activity and arrhythmias in the heart. We investigated the properties and underlying mechanisms for systolic triggered Ca2+ waves in left atria from normal and failing dog hearts. METHODS AND RESULTS: Intracellular Ca2+ cycling was studied using confocal microscopy during rapid pacing of atrial myocytes (36 °C) isolated from normal and failing canine hearts (ventricular tachypacing model). In normal atrial myocytes (NAMs), Ca2+ waves developed during rapid pacing at rates ≥ 3.3 Hz and immediately disappeared upon cessation of pacing despite high sarcoplasmic reticulum (SR) load. In heart failure atrial myocytes (HFAMs), triggered Ca2+ waves (TCWs) developed at a higher incidence at slower rates. Because of their timing, TCW development relies upon action potential (AP)-evoked Ca2+ entry. The distribution of Ca2+ wave latencies indicated two populations of waves, with early events representing TCWs and late events representing conventional spontaneous Ca2+ waves. Latency analysis also demonstrated that TCWs arise after junctional Ca2+ release has occurred and spread to non-junctional (cell core) SR. TCWs also occurred in intact dog atrium and in myocytes from humans and pigs. ß-adrenergic stimulation increased Ca2+ release and abolished TCWs in NAMs but was ineffective in HFAMs making this a potentially effective adaptive mechanism in normals but potentially arrhythmogenic in HF. Block of Ca-calmodulin kinase II also abolished TCWs, suggesting a role in TCW formation. Pharmacological manoeuvres that increased Ca2+ release suppressed TCWs as did interventions that decreased Ca2+ release but these also severely reduced excitation-contraction coupling. CONCLUSION: TCWs develop during the atrial AP and thus could affect AP duration, producing repolarization gradients and creating a substrate for reentry, particularly in HF where they develop at slower rates and a higher incidence. TCWs may represent a mechanism for the initiation of atrial fibrillation particularly in HF.

Perceived compliance and barriers to care in sublingual immunotherapy.

BACKGROUND: For allergy immunotherapy to be effective, patient compliance is critical. However, aqueous sublingual immunotherapy (SLIT) may be considered demanding for patients, requiring strict daily dosing and refilling of medication at regular intervals. In this study we sought to determine how patients perceive their own compliance with SLIT and identify barriers that may hinder compliance. METHODS: Using a retrospective review, 46 patients currently undergoing aqueous SLIT were identified to have less-than-excellent compliance based on frequency of clinic visits for SLIT refills. Twenty-eight of these patients completed a phone survey regarding symptom improvement, compliance, and barriers to care. In addition, 56 patients who withdrew from therapy before completion were polled about barriers to adherence. RESULTS: Of the 28 patients participating in the initial phone survey, 24 (86%) reported subjective improvement in symptoms on SLIT, despite less-than-excellent compliance. Nineteen (68%) of these patients perceived their own compliance to be excellent. Eighteen patients (65%) reported the inconvenience of scheduling and attending clinic appointments to be the main reason for noncompliance. The most common reasons for withdrawal from therapy were cost (27%), lack of effectiveness (25%), and difficulty with compliance (14%). CONCLUSION: The majority of aqueous SLIT patients perceived their compliance to be excellent, although, based on a previous study, these patients did not reach excellent compliance benchmarks. Inconvenience of clinic visits and cost of therapy were found to be the most common barriers to care. Despite what providers perceived as less-than-excellent compliance, 82% of patients reported symptom improvement with SLIT.

Speech outcomes in children with 22q11.2 deletion syndrome following surgery for velopharyngeal insufficiency.

OBJECTIVE: The purpose of this study was to identify prognostic factors associated with improved speech outcomes following surgical correction for velopharyngeal insufficiency (VPI) in pediatric patients with 22q11.2 deletion syndrome (22q11DS). METHODS: Eighteen patients were identified via retrospective chart review of patients with 22q11DS between 2005 and 2014. Patient characteristics, medical histories, associated comorbidities, surgical procedures, and pre- and postoperative perceptual hypernasality (subjectively rated 1-5 with 5 being the most severe) were gathered for each patient. RESULTS: 12 patients (67%) experienced improvement in hypernasality following corrective surgery for VPI. Higher severity of hypernasality preoperatively was found to be indicative of a lower chance of improvement with VPI surgery. Of 8 patients with a preoperative hypernasality score of 5, 3 (38%) showed improvement in hypernasality postoperatively, while 9 out of 10 (90%) of patients with a preoperative hypernasality score less than 5 showed postoperative improvement. Females were also found to have worse speech outcomes compared to males. CONCLUSION: 22q11DS patients presenting with severely hypernasal speech preoperatively are less likely to show improvement in hypernasality following corrective surgery for VPI. Those patients with moderate hypernasality are most likely to benefit from surgery.

Otopolyposis With Middle Ear Allergic Mucin in a Patient With Allergic Fungal Rhinosinusitis.

OBJECTIVE: The purpose of this study is to report a case of otopolyposis and middle ear allergic mucin in a patient with allergic fungal rhinosinusitis (AFRS) and no history of middle ear disease and introduce these as possible otologic manifestations of the AFRS. METHODS: A case of a 31-year-old female with the aforementioned findings is reported. A review of the pertinent literature was performed. RESULTS: We report a case of a 31-year-old female with a history of AFRS but no history of middle ear disease or hearing loss who presented to our institution complaining of aural fullness. Physical exam was significant for middle ear masses of unknown etiology. Surgical exploration revealed the presence of allergic mucin and middle ear polyposis histologically identical to tissue sampled during prior sinonasal surgeries at the same institution. Aspiration of the middle ear space did not resolve the otologic symptoms. CONCLUSION: Otopolyposis and middle ear allergic mucin are extremely rare but possible otologic manifestations of AFRS. We encourage otolaryngologists to consider this in the clinical differential diagnosis of patients with a history of AFRS with new onset otologic symptoms.

Prevalence of hearing loss in children with 22q11.2 deletion syndrome.

OBJECTIVE: The purpose of this study was to determine the prevalence and characterize the types of hearing loss in pediatric patients with 22q11.2 deletion syndrome (22q11DS). METHODS: Fifty-eight patients were identified via retrospective chart review performed of patients with 22q11DS between 1996 and 2014. Patient demographics, pertinent family history, associated comorbidities, and degree and type of hearing loss were gathered for each patient. A literature review of the National Library of Medicine's database with a focus on hearing loss and 22q11DS was performed. RESULTS: 22 patients (38%) were found to have hearing impairment: 68% with conductive hearing loss, 14% with sensorineural hearing loss, and 18% with mixed hearing loss. Patients with hearing loss regardless of type had a higher prevalence of developmental delay (55%), cleft palate (23%), articulation disorders (77%), and a greater need for tympanostomy tubes (73%) compared to patients with normal hearing. Temporal bone computed tomography scans of 5 patients revealed a variety of abnormalities in the middle and/or inner ears. CONCLUSION: Hearing impairment occurs in up to 38% of 22q11DS patients of both conductive and sensorineural types, with the conductive type being the most common. These patients have a greater need for tympanostomy tubes and a higher prevalence of developmental delay and speech articulation disorders. Early hearing screening and treatment is warranted in this population.

Ultrastructural and cellular basis for the development of abnormal myocardial mechanics during the transition from hypertension to heart failure.

Although the development of abnormal myocardial mechanics represents a key step during the transition from hypertension to overt heart failure (HF), the underlying ultrastructural and cellular basis of abnormal myocardial mechanics remains unclear. We therefore investigated how changes in transverse (T)-tubule organization and the resulting altered intracellular Ca(2+) cycling in large cell populations underlie the development of abnormal myocardial mechanics in a model of chronic hypertension. Hearts from spontaneously hypertensive rats (SHRs; n = 72) were studied at different ages and stages of hypertensive heart disease and early HF and were compared with age-matched control (Wistar-Kyoto) rats (n = 34). Echocardiography, including tissue Doppler and speckle-tracking analysis, was performed just before euthanization, after which T-tubule organization and Ca(2+) transients were studied using confocal microscopy. In SHRs, abnormalities in myocardial mechanics occurred early in response to hypertension, before the development of overt systolic dysfunction and HF. Reduced longitudinal, circumferential, and radial strain as well as reduced tissue Doppler early diastolic tissue velocities occurred in concert with T-tubule disorganization and impaired Ca(2+) cycling, all of which preceded the development of cardiac fibrosis. The time to peak of intracellular Ca(2+) transients was slowed due to T-tubule disruption, providing a link between declining cell ultrastructure and abnormal myocardial mechanics. In conclusion, subclinical abnormalities in myocardial mechanics occur early in response to hypertension and coincide with the development of T-tubule disorganization and impaired intracellular Ca(2+) cycling. These changes occur before the development of significant cardiac fibrosis and precede the development of overt cardiac dysfunction and HF.

Can triggered arrhythmias arise from propagation of calcium waves between cardiac myocytes?

Intracellular Ca2+ overload can induce regenerative Ca2+ waves that activate inward current in cardiac myocytes, allowing the cell membrane to achieve threshold. The result is a triggered extrasystole that can, under the right conditions, lead to sustained triggered arrhythmias. In this review, we consider the issue of whether or not Ca2+ waves can travel between neighboring myocytes and if this intercellular Ca2+ diffusion can involve enough cells over a short enough period of time to actually induce triggered activity in the heart. This review is not intended to serve as an exhaustive review of the literature summarizing Ca2+ flux through cardiac gap junctions or of how Ca2+ waves move from cell to cell. Rather, it summarizes many of the pertinent experimental studies and considers their results in the theoretical context of whether or not the intercellular propagation of Ca2+ overload can contribute to triggered beats and arrhythmias in the intact heart.