Permanent Cardiac Pacing After Open Heart Surgery: Congenital Heart Disease

A retrospective review of 6,004 patients who underwent open repair of congenital heart defects revealed that 132 patients (2.2%) required permanent cardiac pacing postoperatively. The indications for pacing were early atrioventricular (AV) block in 55%, late onset AV block in 31%, and sick sinus syndrome in 14%. A ventricular septal defect (VSD) was the most common congenital anomaly present alone or in association with other lesions in 67% of the patients. Atrial surgery accounted for 21% of the patients requiring pacing. Ten-year patient survival was found to be 66% (+/- 6%). Thirty-five percent of the deaths were sudden and unexpected, presumably due to an arrhythmia. Reoperation for pacing system failure has occurred too frequently (12% per year). The most common causes for reoperation were battery failure (44%) and exit block (25%).     

Phosphine gas poisoning

Phostoxin is a fumigant used in rural areas. We report a case of phostoxin ingestion which resulted in the release of lethal phosphine gas. The patient developed a profound metabolic acidosis and cardiovascular depression and died. During treatment and after death, he continued to emit the noxious gas which was dangerous to staff, and resulted in evacuation of the emergency department. Such events tend to be associated with myth and hysteria and the lack of ready access to reliable information. They represent a unique challenge to the emergency physician.     

Recipient to Donor Conduction of Atrial Tachycardia Following Orthotopic Heart Transplantation

We report a case of atrial tachycardia in a 60-year-old male 8 years postorthotopic heart transplantation. At electrophysiology study, the clinical rhythm was found to arise from the remnant of the recipient atrium and was successfully terminated by delivery of radiofrequencv energy. Surgical scars formed at the anastomosis of the recipient and donor atrium during the time of orthotopic heart transplantation are thought to electrically isolate the two areas. Although rarely recognized, dysrhythmias originating from the recipient atrial remnant may occur more often than previously thought.     

CONSTRUCTION OF A MODEL FOR COMPUTER-ASSISTED DIAGNOSIS: APPLICATION TO THE PROBLEM OF NON-TOXIC GOITRE

This study describes the construction of a model for the computer-assisteddiagnoses of non-toxic goitre. From a study of 53 patients with Hashimoto's disease, 51 withsimple goitre and 51 with thyroid cancer, information was obtainedwhich was used in the construction of a probability matrix.The diagnosis was confirmed histologically in all of these patients. The probability matrix was constructed from 30 pieces of informationrelating to the results of history taking, clinical examination,and laboratory investigations and consisted of a table of theobserved incidence of each piece of information in each of thethree diseases. This probability matrix was then fed into anElliott 803 automatic digital computer and formed the memoryof the computer for these three diseases. A fresh series of 88 patients, 43 with Hashimoto's disease,26 with simple goitre, and 19 with thyroid cancer were thenstudied. Clinical information and the results of laboratorystudies were provided as data to the computer to calculate adiagnosis for these patients. Two slightly different applications of probability theory wereused for each calculation. In one (Bayesian probability) theratio of the prior probabilities that any patient would haveHashimoto's disease, simple goitre, or thyroid cancer beforeany tests or observations had been made, were taken to be 10:89and 1 respectively on the basis of observations previously madeon a population of patients attending a thyroid clinic. In theother application of probability theory (relative likelihood)the prior probabilities of occurrence of the three diseaseswere assumed to be equal. The diagnoses given by both methods were compared with eachother and with the diagnosis of a clinician experienced in dealingwith thyroid disorders. In all patients in whom discordenceof opinion occurred a histological diagnosis was accepted asthe final diagnosis. The method using relative likelihood was considered to be superiorto the method using Bayesian probability for in no patient didrelative likelihood miss a diagnosis of thyroid cancer whenthe clinician diagnosed thyroid cancer. This was not true forBayesian probability which missed three cases of clinicallyobvious cancer. The possible reasons for this superiority ofrelative likelihood are discussed in the paper. The results given by relative likelihood agreed with the clinician'scorrect diagnosis of Hashimoto's disease in 26 of 28 patients.The calculated diagnosis was wrong in two of these patientsin whom the clinician made the correct diagnosis. In another12 patients in whom the clinician made a wrong diagnosis, thecalculations based on relative likelihood gave the correct diagnosis.In a further three patients the clinical and calculated diagnoseswere both wrong. In 24 of the 26 patients with simple goitre the clinician madethe correct diagnosis. In 21 of these patients the diagnosiscalculated by relative likelihood was correct and in three patientsit was wrong. In two patients both the calculated and clinicaldiagnoses were wrong. Of the 19 patients with thyroid cancer 16 were correctly diagnosedby relative likelihood and by clinician alike. The remainingthree patients in this group were incorrectly diagnosed by both. It is concluded that the results of this study support the contentionthat a correct diagnosis can be calculated using the theoryof conditional probability. Many difficulties remain to be overcomein what still remains a highly experimental approach to theproblem of diagnosis. ²Present address, Medical Research Council, Computer ServicesCentre, 171-4 Tottenham Court Road, London, W.1. ³Western Infirmary, Glasgow, W.1.     

Outcomes in Patients Requiring Cardioversion Following Catheter Ablation of Atrial Fibrillation

Outcomes of Cardioversion Post AF Ablation.   Introduction: Early recurrence of atrial tachyarrhythmias is commonly noted after catheter ablation of atrial fibrillation (AF). The long-term outcomes of patients who require cardioversion for persistent AF after AF ablation is not known. This study reports the outcomes of patients who underwent cardioversion for persistent AF or atrial flutter following an AF ablation procedure.
Methods: The patient population comprised 55 patients (mean age 58 ± 10 years, 35% paroxysmal) who underwent catheter ablation of AF and subsequently required electrical cardioversion for persistent AF (45 patients) or atrial flutter (10 patients). Cardioversion was defined as early (within 90 days of the ablation procedure) or late (between 90 and 180 days following ablation).
Results: The mean follow-up duration was 15 ± 8 months. Forty-six of the 55 patients (84%) patients experienced recurrence during follow-up. The average time to recurrence after cardioversion was 37 days. Of the 55 patients, 8 (15%) patients had a complete success, 11 (20%) patients had a partial success and 36 patients (65%) had a failed outcome. Seven of the 43 patients (16%) who underwent early cardioversion had a complete success as opposed to one of 12 patients (8%) who underwent late cardioversion (P = 0.49).
Conclusions: This study shows that >80% of patients who undergo cardioversion for persistent AF or atrial flutter after AF ablation have recurrence. The timing of cardioversion did not affect the outcome. These findings allow clinicians to provide realistic expectations to patients regarding the long-term outcome and/or requirement for a second ablation procedure. (J Cardiovasc Electrophysiol, Vol. 21, pp. 27–32, January 2010)     

A Prospective Study Evaluating the Role of Obesity and Obstructive Sleep Apnea for Outcomes After Catheter Ablation of Atrial Fibrillation

Effect of Obesity and OSA on Outcomes Post AF Ablation . Background: Obesity and obstructive sleep apnea (OSA) have a strong association with atrial fibrillation (AF). The purpose of this study was to prospectively determine the effects of obesity, assessed by the body mass index (BMI) and OSA on the efficacy of catheter ablation of AF. Methods: The patient population consisted of 109 patients (mean age: 60 ± 10 years, 79% male, 67% paroxysmal, mean BMI 28 ± 5 kg/m²) who underwent catheter ablation of AF. Based on BMI, patients were classified as normal (<25 kg/m²), overweight (≥25 and <30 kg/m²), or obese (≥30 kg/m²). OSA was assessed by the Berlin questionnaire. Clinical success was defined as at least 90% reduction in AF burden after 3‐month blanking period. Mean duration of follow‐up was 11 ± 4 months. Results: Of the 75 patients with clinical success, 25 (33%) had normal BMI, 29 (39%) were overweight, and 21 (28%) were obese. Among the 34 patients with failed outcome, 5 (15%) had normal BMI, 14 (41%) were overweight, and 15 (44%) were obese (P = 0.04). Twenty‐eight of the 48 patients with OSA (58%) had clinical success as opposed to 47 of the 61 patients (77%) without OSA (P = 0.036). On multivariate analysis, only BMI emerged as an independent predictor of procedural failure ((OR 1.11, CI: 1.00–1.21, P = 0.03). Conclusions: The results of this prospective study show that obesity, a modifiable risk factor, is an independent predictor of procedural failure after catheter ablation of AF. Whether treating obesity may improve the results of catheter ablation of AF warrants further investigation. (J Cardiovasc Electrophysiol, Vol. 21, pp. 521‐525, May 2010)     

Two‐Year Clinical Registry Follow‐up of Endothelial Progenitor Cell Capture Stent Versus Sirolimus‐Eluting Bioabsorbable Polymer‐Coated Stent Versus Bare Metal Stents in Patients Undergoing Primary Percutaneous Coronary Intervention for ST Elevation Myocardial Infarction

Background: Endothelial progenitor cell (EPC) capture stent is designed to promote rapid endothelization and healing and is potentially useful in patients undergoing primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI). We studied the intermediate‐term efficacy and safety of EPC stent and compared that with sirolimus‐eluting bioabsorbable polymer stent (CURA) and bare metal stent (BMS) in AMI patients. Methodology: Patients presenting with AMI who underwent primary PCI with the respective stents between January 2004 and June 2006 were enrolled in the single‐center clinical registry. The study end‐points were major adverse cardiac events (MACE) and stent thrombosis. Results: A total of 366 patients (EPC = 95, CURA = 53, BMS 218) were enrolled. Baseline demographics including age, gender, diabetes, renal impairment, predischarge left ventricular ejection fraction, and creatinine kinase level were comparable among the groups. Procedural success rate was 99.5%. Post‐procedural thrombolysis in myocardial infarction (TIMI) 3 flow was achieved in EPC 91.6%, CURA 96.2%, and BMS 88.5% (P = 0.209). At 2 years, the MACE rate was EPC 13.7%, CURA 15.1%, and BMS 19.7% (P = 0.383). Target vessel revascularizations (TVR) were EPC 4.2%, CURA 9.4%, and BMS 6.0% (P = 0.439). Nonfatal myocardial infarctions were EPC 1.1%, CURA 3.8%, and BMS 4.1% (P = 0.364). One patient in the EPC group had acute stent thrombosis. There was no late stent thrombosis in the EPC group. Conclusion: EPC stent appeared to be safe and had comparable clinical efficacy with a BMS when used in the AMI setting. At 2‐year follow‐up, the EPC group showed favorable, single‐digit TVR rate and stent thrombosis remained a low‐event occurrence. (J Interven Cardiol 2010;23:101‐108)     

Pediatric airway foreign body retrieval: surgical and anesthetic perspectives

Airway foreign body aspiration most commonly occurs in young children and is associated with a high rate of airway distress, morbidity, and mortality. The presenting symptoms of foreign body aspiration range from none to severe airway obstruction, and may often be innocuous and nonspecific. In the absence of a choking or aspiration event, the diagnosis may be delayed for weeks to months and contribute to worsening lung disease. Radiography and high resolution CT scan may contribute to the eventual diagnosis. Bronchoscopy is used to confirm the diagnosis and retrieve the object. The safest method of removing an airway foreign body is by utilizing general anesthesia. Communication between anesthesiologist and surgeon is essential for optimal outcome. The choice between maintenance of spontaneous and controlled ventilation is often based on personal preference and does not appear to affect the outcome of the procedure. Complications are related to the actual obstruction and to the retrieval of the impacted object. The localized inflammation and irritation that result from the impacted object can lead to bronchitis, tracheitis, atelectasis, and pneumonia.     

Arousal in obstructive sleep apnoea patients is associated with ECG RR and QT interval shortening and PR interval lengthening

Sudden cardiac death appears to be more prevalent during the normal sleeping hours in obstructive sleep apnoea (OSA) patients compared with the general population as well as to cardiovascular disease patients. The reasons for this remain unclear, but there are three likely main contributors to nocturnal death in OSA patients; cardiac arrhythmias, stroke/ruptured cerebral aneurism and myocardial infarction. Particularly marked cardiovascular system activation with arousal may play a role in initiating sudden adverse cardiovascular events in OSA. The purpose of this study was to investigate cardiac RR, QT and PR interval changes in the electrocardiogram (ECG) associated with spontaneous and respiratory-related arousals in OSA patients. A detailed observational study of ECG records obtained during conventional diagnostic sleep study with no further interventions was carried out in 20 patients (12 males, age 42.8 ± 2.1 years, body mass index 35.1 ± 1.9 kg m⁻², and respiratory disturbance index 51.8 ± 6.4 events/hour). RR and QT intervals showed significant shortening during arousals. RR interval shortening was found to be greater during respiratory arousals when compared to spontaneous arousals. PR interval showed a trend toward a greater prolongation during respiratory arousal. QT interval shortening was weakly correlated with arterial oxygen saturation levels preceding arousal. In conclusion, these data suggest that despite greater cardiac acceleration following respiratory versus spontaneous arousals from sleep, QT shortening and PR prolongation responses are similar independent of arousal type. These data support that arousals produce quite marked and differential cardiac conduction system activation in OSA and that the degree and pattern of activation may be partly influenced by the presence and severity of preceding respiratory events.     

Development of a parent-report computer-adaptive test to assess physical functioning in children with cerebral palsy I: lower-extremity and mobility skills

The objective of this project was to develop computer-adaptive tests (CATs) using parent reports of physical function in children and adolescents with cerebral palsy (CP). The specific aims of this study were to (1) examine the psychometric properties of an item bank of lower-extremity and mobility skills for children with CP; (2) evaluate a CAT using this item bank; (3) examine the concurrent validity of the CAT with the Pediatric Outcomes Data Collection Instrument (PODCI) and the Functional Assessment Questionnaire (FAQ); and (4) establish the discriminant validity of simulated CATs with Gross Motor Function Classification System (GMFCS) levels and CP type (diplegia, hemiplegia, or quadriplegia). Parents ( n =190) of children and adolescents with spastic diplegic (48%), hemiplegic (22%), or quadriplegic (30%) CP consisting of 108 males and 82 females with a mean age of 10 years 7 months (SD 4y 1mo, range 2–21y) and in GMFCS levels I to V participated in item pool calibration and completed the PODCI and FAQ. Confirmatory factor analyses supported a unidimensional model for the 45 basic lower-extremity and mobility items. Simulated CATs of 5, 10, and 15 items demonstrated excellent accuracy (intraclass correlation coefficients [ICCs] >0.91) with the full item bank and had high correlations with PODCI transfers and mobility (ICC = 0.86) and FAQ scores (ICC = 0.77). All CATs discriminated among GMFCS levels and CP type. The lower-extremity and mobility skills item bank and simulated CATs demonstrated excellent performance over a wide span of ages and severity levels.