Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0037315 (sleep apnea)
 8,000 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Voluntary end-expiratory apnoea in a 23-year-old asymptomatic mild hypertensive patient consistently elicited bradyarrhythmias (complete heart block and sinus pause) and sympathetic activation to muscle blood vessels, indicating simultaneous sympathetic and parasympathetic activation during apnoea. The sympathetic bradyarrhythmic response to apnoea was potentiated by hypoxia and eliminated by atropine. Baroreflex activation also attenuated the bradycardic response to apnoea. A 43-year-old hypertensive patient with sleep apnoea also exhibited bradyarrhythmias (sinus arrest for up to 10 s) and a fall in perfusion pressure to less than 50 mmHg during episodes of sleep apnoea. These cardiovascular changes were associated with a reduction in oxygen saturation to levels as low as 35%. Neither patient was on any medication. Simultaneous sympathetic and parasympathetic activation during episodes of apnoea may predispose to cardiovascular catastrophe. These chemoreflex mediated autonomic changes are inhibited by baroreflex activation. We propose that patients with impaired baroreflexes (patients with hypertension or heart failure and premature infants) may be especially susceptible to excessive autonomic responses to chemoreflex stimulation during periods of apnoea. In these patient groups, bradyarrhythmias, hypoxia, hypoperfusion and sympathetic activation during apnoea may predispose to sudden death.
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PMID:Parasympathetic hyperresponsiveness and bradyarrhythmias during apnoea in hypertension. 149 63

Patients with mitochondrial disease may present to the Intensive Care Unit (ICU) with a variety of neurological and general medical disorders. Eleven patients were admitted to a neurological ICU between 1970 and 1992 because of respiratory insufficiency, status epilepticus and/or metabolic encephalopathy associated with mitochondrial disease. Respiratory impairment occurred in eight patients and was associated with nocturnal hypoventilation due to respiratory muscle weakness, aspiration due to bulbar weakness and abnormalities of central control leading to a reduced CO2 drive, irregular respiratory patterns and sleep apnoea. Seven patients received continuous respiratory support during the acute illness; three were subsequently weaned to domiciliary ventilation, and four died. Five patients had stroke-like episodes, which in two were recurrent. Four patients developed tonic-clonic grand mal epilepsy associated with myoclonic fits (2 patients), absences (2), focal fits (1) and status epilepticus (2). Encephalopathy was associated with recurrent lactic acidosis (2 patients), cardiac failure (2), hyponatraemia (2), renal abnormalities (3) and complete heart block (1). Although rare, mitochondrial disease should be considered in any patient with unexplained respiratory failure, intractable epilepsy, lactic acidosis or recurrent stroke.
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PMID:Management of mitochondrial disease on an intensive care unit. 776 70

Sinus arrest and atrioventricular (AV) block have been demonstrated in as much as 30% of patients with sleep apnea (SA). The reversal of heart block after tracheostomy has been shown. Nasal continuous positive airway pressure (nCPAP) now is widely used as the treatment of SA, but little data are available on the effect of nCPAP on heart block in patients with SA. During a 17-mo period 239 patients were found to have SA in an ambulatory study. Heart block was identified in 17 (16 male, one female) of these patients. Standard polysomnography and two-channel long-term ECG before and during nCPAP therapy were performed in order to assess the effect of nCPAP on SA and heart block. Mean age of the 17 patients was 50.7 yr (range, 27 to 78 yr), mean respiratory disturbance index (RDI) was 90/h (SD +/- 36.1) before nCPAP and 6/h (SD +/- 6.2) on the second treatment night. The number of episodes of heart block during sleep decreased significantly (p < 0.001) from 1,575 before therapy to 165 during nCPAP. In 12 patients (70.6%) heart block was totally prevented by nCPAP. In another three patients, there was a 71 to 97% reduction in the number of episodes of heart block on the second treatment night, and in two of them a complete reversal occurred thereafter. Two patients exhibited an increase in block frequency during nCPAP, which was reversed after 4 wk of nCPAP in one but persisted in the other.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Reversal of sinus arrest and atrioventricular conduction block in patients with sleep apnea during nasal continuous positive airway pressure. 781 57

Sleep apnea has been associated with various types of cardiac dysrhythmias; however, complete heart block has not been reported to occur in this condition. This brief report describes the case of a patient who developed episodes of prolonged complete heart block during sleep apnea. Nasal continuous positive airway pressure resulted in complete resolution of the heart block.
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PMID:Sleep apnea and complete heart block. 786 41

Sleep apnea is associated with many adverse cardiovascular sequelae, including hypertension, nocturnal angina, decreased cardiac output, and bradyarrhythmias. The purpose of this study was to determine if patients referred for pacemaker therapy with asymptomatic bradyarrhythmias have underlying sleep apnea as the etiology of their bradyarrhythmias. This study included eight patients (7 males, 1 female) referred to a cardiac electrophysiology practice for pacemaker therapy. Patients included had asymptomatic bradyarrhythmias that consisted of severe sinus bradycardia, second-degree atrioventricular block, and complete heart block. In 7 of 8 patients, the bradyarrhythmias occurred at night or during the day while asleep. No patients were conditioned athletes. Symptoms often associated with bradyarrhythmias, such as lightheadedness and syncope, were not present. However, seven patients had at least one symptom suggestive of sleep apnea, such as excessive daytime fatigue, snoring, cessation of breathing during sleep (apnea), or frequent night-time awakenings. Overnight polysomnography studies were obtained on patients who had one or more symptoms suggestive of sleep apnea. In this study 7 of 8 patients (88%) referred for pacemaker therapy with asymptomatic bradyarrhythmias were documented by polysomnography to have sleep apnea. When treated with either sleep position modification, nasal continuous positive airway pressure (nasal CPAP), or tracheostomy, all seven patients had improvement in sleep apnea symptoms and remained asymptomatic from their bradyarrhythmias without pacemaker therapy over an average follow-up period of 22 months. One patient without symptoms suggestive of sleep apnea declined pacemaker therapy and remained asymptomatic. From these results, we concluded that asymptomatic transient bradyarrhythmias may suggest a diagnosis of sleep apnea. The evaluation of a patient referred for pacemaker therapy with asymptomatic bradyarrhythmias should include questions related to sleep apnea symptoms. Establishing the diagnosis of sleep apnea may reduce the need for pacemaker therapy and permit appropriate treatment of the underlying cause of these bradyarrhythmias.
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PMID:Asymptomatic bradyarrhythmias as a marker for sleep apnea: appropriate recognition and treatment may reduce the need for pacemaker therapy. 877 19

Heart block during sleep has been described in up to 10% of patients with obstructive sleep apnoea. The aim of this study was to determine the relationship between sleep stage, oxygen desaturation and apnoea-associated bradyarrhythmias as well as the effect of nasal continuous positive airway pressure (nCPAP)/nasal bi-level positive airway pressure (nBiPAP) therapy on these arrhythmias in patients without electrophysiological abnormalities. Sixteen patients (14 males and two females, mean age 49.6+/-10.4 yrs) with sleep apnoea and nocturnal heart block underwent polysomnography after exclusion of electrophysiological abnormalities of the sinus node function and atrioventricular (AV) conduction system by invasive electrophysiological evaluation. During sleep, 651 episodes of heart block were recorded, 572 (87.9%) occurred during rapid eye movement (REM) sleep and 79 (12.1%) during nonrapid eye movement (NREM) sleep stages 1 and 2. During REM sleep, the frequency of heart block was significantly higher than during NREM sleep: 0.69+/-0.99 versus 0.02+/-0.04 episodes of heart block x min(-1) of the respective sleep stage (p<0.001). During apnoeas or hypopnoeas, 609 bradyarrhythmias (93.5%) occurred with a desaturation of at least 4%. With nCPAP/ nBiPAP therapy, apnoea/hypopnoea index (AHI) decreased from 75.5+/-39.6 x h(-1) to 3.0+/-6.6 x h(-1) (p<0.01) and the number of arrhythmias from 651 to 72 (p<0.01). We conclude that: 1) 87.9% of apnoea-associated bradyarrhythmias occur during rapid eye movement sleep; 2) the vast majority of heart block episodes occur during a desaturation of at least 4% without a previously described threshold value of 72%; and 3) nasal continuous positive airway pressure or nasal bi-level positive airway pressure is the therapy of choice in patients with apnoea-associated bradyarrhythmias.
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PMID:Heart block in patients with obstructive sleep apnoea: pathogenetic factors and effects of treatment. 955 50

We report a case of an adult male in whom, one week after an anterior acute myocardial infarction, we documented nocturnal episodes of type II second degree atrio-ventricular heart block, including advanced heart block episodes (4:1). An electrophysiologic study did not show atrio-ventricular conduction abnormalities, so we suspected a possible sleep apnea syndrome, which was confirmed with a polysomnographic study. It was observed that advanced heart block episodes were preceded by significant decreases in arterial oxygen saturation. These episodes disappeared with continuous positive air pressure ventilation.
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PMID:[Advanced auriculoventricular block of atypical presentation after acute myocardial infarct in sleep apnea syndrome]. 966 4

This descriptive study describes the frequency and severity of sleep-related breathing disorders in men who are hemodynamically stable who have an acute cardiovascular illness and are hospitalized in a critical care unit. Sixty-four males, aged 55-79 years, with an acute cardiovascular illness, stable hemodynamics, and no ongoing chest pain or history of sleep apnea were studied for 1 night in the critical care unit using polysomnography. Forty-seven percent of the sample had an apnea-hypopnea index > or = 5, with events of both obstructive and central etiologies, including Cheyne-Stokes respiration. Oxygen desaturation to < or = 90% occurred in 61% of the sample. There were no episodes of chest pain, ventricular tachycardia, or heart block associated with apneic or hypopneic events; however, dysrhythmias, including sinus bradycardia, supraventricular tachycardia, and premature ventricular beats, were associated with apneic and hypopneic events.
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PMID:Sleep-related breathing disorders in patients who are critically ill. 1235 92

We report a case of a patient with an implantable cardioverter defibrillator and no prior history of heart block with managed ventricular pacing (MVP) programmed who had frequent recurrent episodes of polymorphic ventricular tachycardia. All of the episodes were initiated by transient atrioventricular block which resulted in short-long-short sequences permitted by MVP. This case illustrates that MVP should be used with caution not only in patients with complete heart block, but also in patients at risk for brief heart block due to such states as hypervagatonia due to sleep apnea.
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PMID:Frequent recurrent polymorphic ventricular tachycardia during sleep due to managed ventricular pacing. 2002 16