Suleyman Metin

Atrial fibrillation presented with syncope in a jet pilot during daily briefing on squadron.

INTRODUCTION Syncope may be the initial clinical presentation of atrial fibrillation (AF) and has a great potential for incapacitation during flight. Herein is presented the case of a jet pilot who had paroxysmal palpitations accompanied with presyncope which progressed to syncope and was found to be associated with AF. CASE REPORT A 23-yr-old male jet pilot had a sudden syncope at the fifth minute of his presentation during the daily flight briefing. After he regained consciousness, he was transferred to the intensive care unit of the military hospital. His medical history revealed two episodes of syncope which resulted in spontaneous recovery and were not reported to the flight surgeon. He had no abnormal findings on his physical examination except heart rate, which was irregular and 110 bpm with a rapid ventricular response. His diagnosis was AF. Laboratory tests, including thyroid hormones, CBC, transthoracic echocardiography, ultrasonography of the abdomen, chest X-rays, and also a tilt table test, were normal. He had completely normal findings on 24-h ECG Holter monitoring except rare ventricular extrasystoles and had a negative treadmill stress test. AF spontaneously converted to sinus rhythm during the follow-up in the intensive care unit. He was temporarily grounded and returned to flying duties after a 3-mo follow-up period without any recurrent arrhythmia. DISCUSSION Syncope has various mechanisms and etiologies, and also a benign prognosis on the ground. However, not only vasovagal syncope, but also AF may be among the frequent causes of syncope in aviators and pilots, as was the case in the current study.

Neuropsychological evaluation of children and adolescents with acute carbon monoxide poisoning

Objectives Carbon monoxide (CO) poisoning is a worldwide health problem. We have limited information regarding psychological adversities of CO poisoning in children and adolescents. The aim of this study was (1) to investigate the effects of severe CO poisoning on cognitive functions, mood, and behaviors in children and adolescents and (2) to identify factors related to occurrence of neuropsychological symptoms. Methods This study included pediatric patients, who were evaluated after CO poisoning at the Department of Child and Adolescent Psychiatry between January 2012 and April 2013. The patients were evaluated at 2 time points. The first evaluation was done when they were discharged from emergency department, and the second evaluation was done 1 month after CO poisoning. Turkish versions of internationally recognized tests were used to evaluate anxiety, depressive symptoms, attention, visual-spatial skills, memory, and behaviors of patients. Results Twenty-seven patients were analyzed. The mean age of the patients was 11.8 ± 2.7 years (range, 6–18 years). The mean carboxyhemoglobin level was 31.5% ± 7.8% (range, 19%–51%) dir. Delayed neurological sequel was observed in only 1 patient, who had headache and tinnitus. We found that carboxyhemoglobin level was not correlated with later neuropsychiatric test scores. However, we found a correlation between history of loss of consciousness and anxiety symptom level, hyperbaric oxygen (HBO) therapy session and behavioral problems, and time to HBO therapy and attention problems. Conclusions We suggest that CO exposure duration, history of loss of consciousness, time to HBO therapy, and the number of HBO therapy session affect neuropsychological symptom levels and occurrence of attention and behavioral problems.

Military jet pilots have higher p-wave dispersions compared to the transport aircraft aircrew.

OBJECTIVES For the purpose of flight safety military aircrew must be healthy. P-wave dispersion (PWD) is the p-wave length difference in an electrocardiographic (ECG) examination and represents the risk of developing atrial fibrillation. In the study we aimed at investigating PWD in healthy military aircrew who reported for periodical examinations. MATERIAL AND METHODS Seventy-five asymptomatic military aircrew were enrolled in the study. All the subjects underwent physical, radiologic and biochemical examinations, and a 12-lead electrocardiography. P-wave dispersions were calculated. RESULTS The mean age of the study participants was 36.15±8.97 years and the mean p-wave duration was 100.8±12 ms in the whole group. Forty-seven subjects were non-pilot aircrew, and 28 were pilots. Thirteen study subjects were serving in jets, 49 in helicopters, and 13 were transport aircraft pilots. Thirty-six of the helicopter and 11 of the transport aircraft aircrew were non-pilot aircrew. P-wave dispersion was the lowest in the transport aircraft aircrew, and the highest in jet pilots. P-wave dispersions were similar in the pilots and non-pilot aircrew. Twenty-three study subjects were overweight, 19 had thyroiditis, 26 had hepatosteatosis, 4 had hyperbilirubinemia, 2 had hypertension, and 5 had hyperlipidemia. The PWD was significantly associated with thyroid-stimulating hormone (TSH) levels. Serum uric acid levels were associated with p-wave durations. Serum TSH levels were the most important predictor of PWD. CONCLUSIONS When TSH levels were associated with PWD, uric acid levels were associated with p-wave duration in the military aircrew. The jet pilots had higher PWDs. These findings reveal that military jet pilots may have a higher risk of developing atrial fibrillation, and PWD should be recorded during periodical examinations.

Age and Aortic Diameters in Pilots

BACKGROUND Pilots are exposed to various physical and hemodynamic stresses during flight. Aortic dilatation may be one of the important consequences of flight-related stress. In this study, we evaluated whether or not variation in aortic diameter was associated with the type of aircraft and the age of pilots. MATERIALS AND METHODS Medical records of 87 jet aircraft pilots (JP) (mean age = 30.0 ± 7.0 years) and 65 non-jet aircraft pilots (NJP) (mean age = 32.63 ± 5.7) were reviewed. Echocardiographic diameters of the aortic sinus (AoS) and ascending aorta (AoAsc) were measured using standard echo probe positions. RESULTS Aortic diameters were not statistically different between JP and NJP. Regression analysis revealed that the diameters of the AoS (R = 0.484, R(2) = 0.234, p < 0.001) and AoAsc (R = 0.514, R(2) = 0.264, p < 0.001) were significantly associated with age in the JP group. Whereas, there was not any relationship found between age and the diameters of the AoS and AoAsc in the NJP group. CONCLUSION Jet pilots had aortic enlargement as they became older in contrast to the NJP group. Although the aortic diameters were not within the critical ranges in the JP group, these results could suggest that flight-related stresses might result in acute aortic syndromes in the long term.

The Use of Hyperbaric Oxygen Therapy in Dentistry.

Dear Editor, We appreciate the article “Hyperbaric Oxygen Therapy(HBOT) - Can It Be the New Era in Dentistry?” written by Devaraj et al., [1]. In present review, the authors have mentioned the history, mode of action, indications, contraindications, complications and the applications of hyperbaric oxygen therapy in dentistry. Thanks to the authors for their contribution on the literature. HBOT is increasingly used to treat the many conditons. In the present review, HBOT is defined as administration of 100% oxygen to a patient with a pressure greater than one atmosphere at sea level. According to the Undersea and Hyperbaric Medical Society (UHMS) committee report 2003 and most hyperbaric medicine specialists, the oxygen pressure should be applied 1.4 atmospheres absolute (ATA) as the minimum therapeutic dosage to gain benefit from hyperbaric oxygen therapy. Besides the mentioned 13 approved indications of hyperbaric oxygen therapy, sudden hearing loss is also approved by UHMS Board of Directors since October 8, 2011 [2]. The authors stated “Asymptomatic pulmonary lesions which are seen on chest. X- ray” as one of the contraindications of hyperbaric oxygen therapy. We agree with the authors. Air cysts or blebs in the lungs may predispose pulmonary barotrauma (PBT) by causing air trapping. Interestingly, Toklu et al., surveyed 98 European HBO centres for their attitude to patients with bleb and bullae. They found that a significant portion of the HBO centers accept patients with pulmonary bleb or bullae, X-ray is the mostly used screening tool for patients with a history of pulmonary disease and the prevalence of pulmonary barotrauma in these centers was found only 0.00045%, surprisingly [3]. These study results make us to question the outcome of asymptomatic pulmonary lesions. Furthermore X-Ray screening tool has a low sensitivity for this kind of lesions. The authors mentioned about the pressure equalization problems which predominantly affect the middle ear and the nasal sinus. We think that additionally to these concerns, barotraumatic lesions can occur in any trapped air e.g. dental abscess after failed filling or in periodontitis and subgingival anaerobes which may cause gaseous lesions. These lesions can cause a very strong sharp pain particularly in the ascent phase of the hyperbaric oxygen therapy when the pressure decreases and volume begins to re-expanse. As a conclusion, hyperbaric oxygen therapy provides the most benefit in tissues with vessels which have good blood flow, the anatomical structure of the mouth with its rich vascular beds is an advantage to benefit from this treatment. So we support the idea of using this treatment modality in dentistry.

Acceleration forces can effect cardiovascular structure

Dear Editor, We read the article ‘‘Effect of high sustained ?Gz stress on myocardial mitochondrial ultrastructure, respiratory function, and antioxidant capacity in rats’’ written by Chen et al. [1] with great interest. They concluded that high sustained positive acceleration had damaged cellular level of mitochondrial ultrastructure, respiratory function, and antioxidant capacity in rats. These results are very important in researching the effects of acceleration forces on organisms, especially aviators. Thanks to the authors for their contribution. Otherwise, the results of studies about the effects of acceleration forces on cardiovascular system in organisms and aviators might be controversial. There are a few data on the subject. Burns et al. [2] have recently demonstrated that repeated exposure to acceleration forces may lead to the formation of myocardial scar tissue in swine. On the other hand, a review of the subject by Laughlin concluded that this effect does not occur in humans [3]. In a previous study, Grossman et al. [4] investigated the effect of acceleration forces on cardiac morphologic changes in jet fighter pilots. They also assessed the exposure to acceleration forces in jet fighter pilots compared to low-performance aircraft pilots. They did find significant effects on cardiac and aortic indexes. Furthermore, we have previously investigated the negative or positive cardiac responses to this occupational high ?Gz exposure. We concluded that long-term ?Gz exposure has no effects on aortic and cardiac morphologic and systolic functions, but has effects on right ventricular diastolic functions in aviators [5]. In another study, Carter et al. [6] showed that exposure to G-force and anti-G maneuvers does not appear to worsen cardiac and valve function in aviators with a bicuspid aortic valve. The effects of acceleration (?Gz) forces on the cardiovascular system has been the subject of extensive research [7, 8]. As noted in this study, the results are very exciting and promising that the ?G stress negatively affects the cellular components at the level of mitochondria in rats. Similar to that, there are some studies about the effects of acceleration on the cellular level [9–12]. This study showed the acute effects of ?G stress on the cardiac structure, but cumulative and chronic exposure of the G stress should be investigated for daily practice. We want to learn what the authors think about the effects of acceleration on aortic and cardiac structures. In conclusion, the subject is very timely and we need further studies to better understand and investigate more potentially harmful effects of high ?Gz stress on the human heart, and, subsequently, help to prevent heart injury.

Bicuspid aortic valve may affect aortic dimensions in aviators: response.

Dear Editor: We read the article “ Cardiac indexes in young subjects with and without bicuspid aortic valve, ” written by Grossman et al., with great interest ( 1 ). They aimed to evaluate the effects of bicuspid aortic valve (BAV) on aortic and cardiac parameters in young healthy subjects with and without aortic regurgitation (AR). According to their study, although cardiac dimensions may be slightly increased in pilot applicants with BAV, the presence of AR of a mild-moderate degree does not infl uence aortic or cardiac indexes. They found a slight increase in systolic blood pressure in applicants with BAV and they also found an increase in aortic root diameter, left atrial diameter, left ventricular end systolic volume, interventricular septal thickness, and posterior wall thickness in those with BAV compared with those without BAV ( 1 ). These results are very important in researching the effects of BAV on cardiac structure in aviators during our daily practice. Thanks go to the authors for their contribution. But there are still few data about this subject. Carter et al. found no relationship between the aviation environment and aortic root diameter change ( 2 ). Although there were few pilots with BAV in their study, they found no signifi cant changes in the intraventricular septum width, left ventricular posterior wall width, or left ventricular performance. They found no incidents of sudden incapacitation or other medical event that jeopardized fl ight safety. We need a larger study concerning the effects of the aviation environment like exposure to G force on BAV and cardiac structure. In a recent study, Chen et al. concluded that high sustained positive acceleration had damaged mitochondrial ultrastructure, respiratory function, and antioxidant capacity at the cellular level in rats ( 3 ). In another study, Aparci et al. concluded that aortic dilation might be an occupational disease due to the nature of some professions (e.g., the military, security, weight lifters, athletes, heavy workers, etc.) and they emphasized earlier detection of aortic root dilatation and limitation of such strenuous activities in these individuals might be important for the prevention of future cases of aortic aneurysm and dissection ( 4 ). In a previous study, Grossman et al. (5) investigated the effect of acceleration forces on cardiac morphologic changes in jet fi ghter pilots. They concluded that exposure to acceleration forces in jet fi ghter pilots compared to low-performance aircraft pilots has not been found to signifi cantly affect cardiac and aortic indexes ( 5 ). In addition to these studies, we previously investigated longterm Valsalva and anti-G maneuvers and found they have no effects on aortic and cardiac morphologic and systolic functions, but do have effects on right ventricular diastolic function in aviators ( 6 , 7 ). In the present study (1), the authors concluded that similar preparticipation criteria for pilot applicants should be applied to subjects with BAV, regardless of the presence of mild-moderate AR. But we have some questions about this research. Was there any aortic coarctation or mild aortic stenosis in subjects with bicuspid aortic valve in this study? We know that aortic diameter may be increased in patients with bicuspid aortic valve with or without aortic insuffi ciency. Aortic velocity values would be useful to clarify this issue. Is there any relationship between aortic velocities and aortic dimensions? A comparison would be helpful according to the different periods, such as at the beginning of participation, after a certain number of fl ight hours, type of aircraft performance, and long-term exposure in pilots. We think that it is important due to long-term exposure to acceleration forces in pilot candidates with bicuspid aortic valve. Aortic stenosis, aortic dilatation, and ruptures are more likely with bicuspid aortic LETTER TO THE EDITOR

Radiofrequency catheter ablation of ventricular tachycardia in a military parachuter.

BACKGROUND Premature ventricular contractions (PVCs) presenting as isolated complexes are insignificant, but if they present as salvos they are considered indicators of high risk for potentially fatal arrhythmias. CASE REPORT We present the case of a 39-yr-old male military parachuter with PVCs and ventricular tachycardia that were incidentally detected on ECG and treated with radiofrequency catheter ablation (RFCA). He had no significant past medical history. Physical examination and biochemical tests were normal. Transthoracic echocardiography showed no structural heart disease. Due to frequent ventricular extrasystoles (VES) detected on his ECG, 24-h Holter monitoring was conducted and revealed VES, including 13,351 isolated PVCs, 1427 episodes of bigeminy, 397 of trigeminy, 30 couplets, and 4 salvo periods. After beta-blocker and calcium channel blocker treatment for 1 mo, his repeat 24-h Holter monitoring showed 18,414 isolated PVCs, 819 episodes of bigeminy, 181 of trigeminy, and 6 couplet VES, but no episodes of salvos. Electrophysiological studies (EPS) were performed and the baseline measurements were: basic cycle length: 890 ms; atrium His interval: 78 ms; and ventricular His interval: 54 ms. VES were found to orginate from the right ventricular outflow tract and were terminated by RFCA. Medical treatment was stopped. Repeat Holter showed no VES. The parachuter was qualified for full duties. DISCUSSION As the patient is an aircrew member and further usage of antiarrhythmic agents will interfere with his flying status, instead of initiating a drug therapy again, we performed EPS and RFCA as an effective and dependable method in order to treat and to determine his fitness.