ORCID Profile
0000-0002-6414-7453
Current Organisations
American College of Chest Physicians
,
American College of Cardiology
,
Cardiac Society of Australia and New Zealand
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Related Links
Publications
Aortic Root Dilatation in Marfan's Syndrome
Publisher: Elsevier BV
Date: 06-1997
Abstract: We report two cases of Marfan's syndrome with coexistent obstructive sleep apnea (OSA) in which treatment with nasal continuous positive airway pressure was associated with attenuation of aortic root dilatation, a serious complication of the syndrome. We speculate that coexistent OSA promotes progressive aortic dilatation in some patients with Marfan's syndrome.
Is obstructive sleep apnoea a rapid eye movement-predominant phenomenon?
Publisher: Elsevier BV
Date: 09-2000
DOI: 10.1093/BJA/85.3.354
Abstract: Obstructive sleep apnoea (OSA) is thought to be worse during rapid eye movement (REM) sleep. REM rebound in the late postoperative period can follow the REM suppression shown to occur after some types of surgery. This is thought to worsen nocturnal episodic hypoxaemia, leading to greater cardio-respiratory risk. We set out to determine if OSA was a REM-predominant phenomenon. We reviewed the sleep clinic records of 64 consecutive patients with a diagnosis of OSA on full overnight polysomnography and sufficient data to determine the presence of a sleep stage predominance. OSA was diagnosed if the number of apnoeas/hypopnoeas per hour of sleep, the respiratory disturbance index (RDI), was greater than 10. The variables recorded for the purposes of this study were the RDI and the minimum blood oxygen saturation using pulse oximetry (SpO2min) for both REM and non-rapid eye movement (NREM) sleep. All values are presented as mean (SD). The Wilcoxon signed rank test was used for statistical analysis. The means for NREM and REM RDI were, respectively, 36 (26) and 38 (27) per hour (P = 0.96). In 32 of the 64 patients (50%) the RDI in NREM was greater than in REM. Thirty-one (48%) had a larger number during REM. One patient had identical RDIs for both REM and NREM. Sixty-two patients had satisfactory pulse oximetry recordings for both NREM and REM, and the mean SpO2min values were, respectively, 84 (7) and 82 (13)% (P = 0.15). Twenty-nine patients (47%) had a lower SpO2min in REM (seven by more than 10% and two by more than 40%), while 24 (39%) were lower in NREM (two by more than 10%). Nine patients (14%) had identical values in REM and NREM. In contrast to suggestions that OSA is a REM-predominant phenomenon, this study suggests that respiratory disturbance is not greatly affected by sleep stage, in most patients. While a small number clearly desaturate much more during REM, the majority do not. Thus, postoperative REM rebound may worsen OSA in some patients, but in many it may do otherwise. The implications of postoperative sleep disturbance are therefore likely to be more complex than previously suggested.
Treatment of obstructive sleep apnoea leads to improved microvascular endothelial function in the systemic circulation.
Publisher: BMJ
Date: 06-2006
Obstructive sleep apnea and cardiovascular disease.
Publisher: Elsevier BV
Date: 05-2003
DOI: 10.1016/S0735-1097(03)00184-0
Abstract: Obstructive sleep apnea (OSA) is a common disorder associated with an increased risk of cardiovascular disease and stroke. As it is strongly associated with known cardiovascular risk factors, including obesity, insulin resistance, and dyslipidemia, OSA is an independent risk factor for hypertension and has also been implicated in the pathogenesis of congestive cardiac failure, pulmonary hypertension, arrhythmias, and atherosclerosis. Obesity is strongly linked to an increased risk of OSA, and weight loss can reduce the severity of OSA. The current standard treatment for OSA-nasal continuous positive airway pressure (CPAP)-eliminates apnea and the ensuing acute hemodynamic changes during sleep. Long-term CPAP treatment studies have shown a reduction in nocturnal cardiac ischemic episodes and improvements in daytime blood pressure levels and left ventricular function. Despite the availability of effective therapy, OSA remains an underdiagnosed and undertreated condition. A lack of physician awareness is one of the primary reasons for this deficit in diagnosis and treatment.
Testing the Effects of App-Based Motivational Messages on Physical Activity and Resting Heart Rate Through Smartphone App Compliance in Patients With Vulnerable Coronary Artery Plaques: Protocol for a
Publisher: JMIR Publications Inc.
Date: 13-03-2023
Abstract: chieving the physical activity recommendations of at least 150 to 300 minutes a week of moderate-intensity, or 75 to 150 minutes a week of vigorous-intensity aerobic exercise, is important for reducing cardiometabolic risk, but evidence shows that most people struggle to meet these goals, particularly in the mid to long-term. he Messages Improving Resting hearT Health (MIRTH) study aims to determine if: (1) sending daily motivational messages via a research app is effective in improving motivation and in promoting adherence to physical activity recommendations in men and women with coronary heart disease randomized to a 12-month intensive lifestyle intervention, and (2) the time of the day when the message is delivered impacts compliance with exercise training. single center, micro-randomized trial (MRT). Participants will be randomized daily to either receive or not receive motivational messages over two 90-day periods at the beginning (phase 1: months 4-6) and at the end (phase 2: months 10-12) of the LIfestyle VulnErable PLaqUe Study (LIVEPLUS) (ACTRN12620001151921). Wrist-worn devices (Fitbit Inspire 2) Bluetooth paired with smartphones will be used to passively collect data for proximal (i.e., physical activity duration, steps walked, heart rate within 180 minutes of receiving messages) and distal (i.e., change values for resting heart rate and total steps walked within and across both Phases 1 and 2 of the trial) outcomes. Participants will be recruited from a large academic Cardiology office practice (Central Sydney Cardiology) and Royal Prince Alfred Hospital Departments of Cardiology and Radiology. All clinical investigations will be undertaken at the Charles Perkins Centre Royal Prince Alfred clinic. In iduals aged 18 to 80 (n = 58) with stable coronary heart disease who have low attenuation plaques based on a coronary computed tomography angiography within the past 3 months and have been randomized to an intensive lifestyle intervention program will be included in MIRTH. IVEPLUS was funded in 2020 and started enrolling participants from February 2022. Recruitment for MIRTH commenced in November 2022. As of February 2023, one participant was enrolled into MIRTH and provided baseline data. his MIRTH micro-randomization trial will represent the single most detailed and integrated analysis of the effects of a comprehensive lifestyle intervention delivered via a customized mobile health (mHealth) App on smart devices, on time-based motivational messaging for patients with coronary heart disease. This study will also help inform future studies optimizing for just-in-time adaptive interventions. CTRN12622000731796 pre-results Universal Trial Number (UTN) U1111-1269-8610
The unstable ST segment early after thrombolysis for acute infarction and its usefulness as a marker of recurrent coronary occlusion
Publisher: Elsevier BV
Date: 1991
DOI: 10.1016/0002-9149(91)90430-S
Abstract: To investigate the incidence of early recurrent ST elevation after intravenous thrombolytic therapy for acute myocardial infarction, 12-lead electrocardiograms were continuously monitored for 571 +/- 326 minutes in 31 patients presenting within 4 hours of symptom onset. The study group comprised 9 women and 22 men (mean age +/- standard deviation 53 +/- 12 years), with ST elevation (anterior in 15, inferior in 16) on the initial electrocardiogram, who were given either tissue plasminogen activator (22 patients) or streptokinase (9 patients). Angiography was performed in 30 of 31 patients at 7 to 10 days. Early (less than 3 hours) resolution of ST elevation occurred in 19 patients (61%) at a median of 94 minutes (interquartile range 57 to 113) after thrombolysis, whereas 12 (39%) had no or late (greater than 6 hours) resolution. Eleven of the 19 with early resolution (58%) had either transient (5 patients) or sustained (6 patients) recurrences of ST elevation. Recurrent ST elevation was equal to or more than the initial peak elevation in 9 of 11 patients, and greater than 75% of initial peak in 2. A total of 25 episodes of recurrent ST elevation were observed in the 11 patients (19 transient and 6 sustained episodes), of which 8 (32%) were silent. The proportion of silent episodes was similar for transient (35%) and sustained (33%) recurrences. All patients with sustained recurrent ST elevation had at least 1 preceding transient recurrence. The median duration of transient recurrent ST elevation was 43 minutes (28 to 63).(ABSTRACT TRUNCATED AT 250 WORDS)
Prognosis and sleep disordered breathing in heart failure.
Publisher: BMJ
Date: 10-1998
Risk of adverse outcome in patients admitted to the coronary care unit with suspected unstable angina pectoris
Publisher: Elsevier BV
Date: 10-1989
DOI: 10.1016/0002-9149(89)90829-1
Abstract: One hundred ninety-six consecutive patients admitted to the coronary care unit with suspected unstable angina were classified clinically as having either definite (113 patients) or suspected unstable angina (83 patients) within 24 hours of admission. Patients were followed prospectively to determine their outcome in the hospital and in the first 4 months after discharge. Three patients had a non-fatal myocardial infarction in the hospital and 2 died (1 fatal myocardial infarction, 1 death immediately after coronary bypass surgery). During follow-up (mean 4.2 +/- 2.3 months), 6 additional patients had a nonfatal myocardial infarction, 4 died and 22 were readmitted with definite unstable angina. The incidence of nonfatal infarction or death was significantly lower in patients with suspected unstable angina during both the primary hospital admission (0 of 83 vs 5 of 113, p less than 0.05) and after discharge from the hospital (1 of 83 vs 9 of 113, p less than 0.05), and fewer patients with suspected unstable angina were readmitted with a recurrence of definite unstable angina (1 of 83 vs 21 of 113, p less than 0.001). Thus, a simple clinical classification into definite or suspected unstable angina performed within 24 hours of admission to the coronary care unit identified a substantial group with a low short-term risk of adverse events.
Prognostic significance of a predischarge exercise test in risk stratification after unstable angina pectoris
Publisher: Elsevier BV
Date: 09-1991
DOI: 10.1016/0735-1097(91)90789-C
Abstract: The prognostic significance of exercise testing was compared with clinical and electrocardiographic (ECG) variables in a prospective study of 107 patients with unstable angina discharged from the hospital on medical therapy. During a follow-up period of 12.8 +/- 1.4 months, 10 patients (9%) had a nonfatal myocardial infarction (n = 8) or died (n = 2) and 22 (20%) were readmitted with recurrent unstable angina. The relation between 20 clinical, ECG and exercise test variables and the risk of adverse outcome (death, nonfatal myocardial infarction or recurrent unstable angina) was analyzed using both univariate and multivariate (logistic regression) analysis. Univariate predictors of adverse outcome included diabetes mellitus, evolutionary T wave changes, T wave changes on the preexercise ECG and low maximal rate-pressure product during exercise. Independent predictors of adverse outcome in multivariate analysis included diabetes mellitus, evolutionary T wave changes after admission, rest pain during hospitalization, ST depression during exercise and low maximal rate-pressure product. A predictive model constructed using the regression equation and all independent predictors stratified patients into high and low risk groups (41% and 5% risk of adverse outcome, respectively). The result of a predischarge exercise test adds independent prognostic information to clinical and ECG data in medically treated patients with unstable angina and could be used in combination with clinical and ECG data to identify patients at risk of adverse events.
Relationship between Chemosensitivity, Obesity and Blood Pressure in Obstructive Sleep Apnoea
Publisher: Informa UK Limited
Date: 1994
DOI: 10.3109/08037059409101521
Abstract: It has previously been documented that patients with obstructive sleep apnoea (OSA) have an abnormal blood pressure (pressor) response to acute hypoxia when awake. The relationship between hypoxic chemosensitivity and 24 h blood pressure in OSA is not known. Twenty-four hour ambulatory BP (ABP) was measured at 15 min intervals for 24 h using a non-invasive device (Oxford Medilog ABP or Spacelabs 90207 recorder) in 49 men (mean age 51 +/- 9 years), with OSA. The BP response to acute hypoxia was measured either directly (radial arterial line) or indirectly (Finapress) during wakefulness. The pressor response to hypoxia (expressed as the slope of the regression line of mean BP on % fall in arterial oxygen saturation) was compared with the results of the ABP recording, sleep study data and clinical variables. A pressor response to acute hypoxia was present in all patients (mean 1.4 +/- 1.1 mmHg/% delta SaO2, range 0.1-4.5). There was a relationship between the magnitude of the pressor response to hypoxia, severity of sleep apnoea (RDI and minimum SaO2) and central obesity (waist measurement). In contrast, there was no relationship between BP response to hypoxia during wakefulness and 24-h BP. However, increasing obesity and severity of OSA were associated with loss of the normal fall in BP at night. We conclude that enhanced chemosensitivity is common in OSA but there is no demonstrable link between chemosensitivity and mean daytime or night-time ABP.
Obstructive sleep apnea a respiratory syndrome with protean cardiovascular manifestations.
Publisher: Elsevier BV
Date: 11-2009
Diagnosis and treatment of obstructive sleep apnea is key to achieving optimal results after catheter ablation of atrial fibrillation.
Publisher: Elsevier BV
Date: 02-2014
Repetitive hypoxia increases lipid loading in human macrophages-a potentially atherogenic effect.
Publisher: Elsevier BV
Date: 04-2005
DOI: 10.1016/J.ATHEROSCLEROSIS.2004.11.010
Abstract: Obstructive sleep apnea (OSA) is characterized by repetitive episodes of hypoxia and is associated with an increase in cardiovascular disease. We, therefore, investigated the effect of repetitive hypoxia on two key early events in atherogenesis lipid loading in foam cells and monocyte adhesion to endothelial cells. Human macrophages were loaded with acetylated low-density lipoproteins. During lipid loading, the cells were exposed to 30 min cycles of 2%/21% oxygen or control (room air, 5% CO(2) incubator). Human umbilical vein endothelial cells (HUVECs) were also exposed to 30 min cycles of repetitive hypoxia or control conditions and monocyte adhesion measured. Cell adhesion molecules E-selectin, ICAM-1 and VCAM-1 were measured by ELISA. Repetitive hypoxia increased cholesteryl ester uptake by macrophages (127+/-5% compared to controls p=0.003). By contrast, monocyte adhesion to HUVECs and cell adhesion molecule expression were unchanged by exposure to repetitive hypoxia, compared to controls (p >0.1). Repetitive hypoxia, at levels relevant to tissues such as the arterial wall, enhances lipid uptake into human macrophages. This may contribute to accelerated atherosclerosis in OSA patients.
Abnormal breathing during sleep and increased central chemoreflex sensitivity in congestive heart failure.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 12-09-2000
Ventilatory control in patients with sleep apnoea and left ventricular dysfunction: comparison of obstructive and central sleep apnoea
Publisher: European Respiratory Society (ERS)
Date: 1998
DOI: 10.1183/09031936.98.11010007
Abstract: Sleep apnoea is common in patients with heart failure. While most patients have central sleep apnoea (CSA), a minority have obstructive sleep apnoea (OSA). The pathophysiology of CSA is not well understood. We hypothesized that central chemosensitivity would be an important pathophysiological factor in patients with CSA, and not in OSA. The aim of this study was to compare ventilatory responses between patients with CSA and those with OSA. Acute ventilatory responses to eucapnic hypoxia and hyperoxic hypercapnia were measured during wakefulness in 34 patients (33 males and one female, aged 59±8 yrs (mean± sd )), with stable medically-treated left ventricular dysfunction (LVD) and sleep apnoea (18 OSA and 16 CSA). Patients with CSA had a decreased awake end-tidal carbon dioxide tension (4.1± 0.5 kPa), increased ventilatory response to carbon dioxide (0.65±0.43 L·min -1 ·kPa P CO 2 -1 ), and eucapnic hypoxic responses in the normal range (0.6±0.4 L·min -1 /% fall in arterial oxygen saturation ( S a,O 2 )). In contrast, patients with OSA had normal endtidal carbon dioxide tension (4.9±0.5 kPa), and normal ventilatory responses to hypercapnia (0.29±0.16 L·min -1 ·kPa P CO 2 -1 ) and hypoxia (0.5±0.5 L·min -1 /% fall in S a,O 2 ). These findings suggest that augmented chemosensitivity to hypercapnia may be an important factor in the pathophysiology of central sleep apnoea in patients with heart failure.
Central sleep apnea and heart failure.
Publisher: Massachusetts Medical Society
Date: 27-01-2000
Electroencephalographic arousals during sleep do not alter the pressor response to Cheyne-Stokes respiration in subjects with chronic heart failure.
Publisher: Wiley
Date: 21-11-2007
DOI: 10.1111/J.1365-2869.2007.00616.X
Abstract: This study examined the influence of electroencephalographic (EEG) arousal on the magnitude and morphology of the pressor response to Cheyne-Stokes respiration (CSR) in subjects with congestive heart failure (CHF). Thirteen subjects with stable CHF (left ventricular ejection fraction, 26 +/- 7%) and CSR (apnea-hypopnea index 52 +/- 15 h(-1)) underwent overnight polysomnography with beat-to-beat measurement of systemic arterial blood pressure (BP). CSR events were ided into those with or without an EEG arousal defined according to the criteria of the American Sleep Disorders Association. The pressor response was quantified in terms of the delta BP change (difference between the minimum BP during apnea and maximum BP during hyperpnea). Changes in the morphology of the pressor response were assessed by sub iding in idual respiratory events into six periods (three during apnea: A1, A2, A3 and three during hyperpnea: H1, H2, H3). Considerable fluctuations in BP and heart rate (HR) were observed across the CSR cycle (delta mean BP 20.2 +/- 6.5 mmHg). The presence of an EEG arousal did not alter the litude of fluctuations in BP. Mean blood pressure (MBP) increased 21.0 +/- 7.5 mmHg with arousal versus 19.3 +/- 5.8 mmHg without arousal (NS). A repeated measures ANOVA showed no significant interaction between the presence of arousal and the proportional change in mean BP across the six periods, indicating that an EEG arousal had no effect on the morphology of MBP change during CSR [F(5,60) = 1.44, P = 0.22]. This study showed that EEG-defined arousal does not lify the pressor response to CSR in CHF.
Treatment of obstructive sleep apnoea leads to enhanced pulmonary vascular nitric oxide release.
Publisher: Elsevier BV
Date: 05-2008
DOI: 10.1016/J.IJCARD.2007.04.001
Abstract: Obstructive sleep apnoea (OSA) is associated with pulmonary hypertension, however neither the pathogenesis of pulmonary vascular disease nor the effect of successful treatment of OSA on pulmonary vascular physiology has been characterised. Seven subjects aged 52 (range 36-63) years with moderate to severe obstructive sleep apnoea (apnoea-hypopnoea index>15/h) had detailed pulmonary vascular reactivity studies, before and after 3 months of successful treatment with nasal continuous positive airways pressure (CPAP). On both occasions, we measured pulmonary pressure, flow velocity, flow and resistance, at baseline and in response to acetylcholine (an endothelium-dependent dilator), sodium nitroprusside (an endothelium-independent dilator), l-NMMA (an antagonist of nitric oxide synthesis) and l-Arginine (the substrate of nitric oxide). At baseline, pulmonary flow increased in response to acetylcholine and nitroprusside and fell in response to l-NMMA. Following CPAP treatment, the decrease in flow to l-NMMA was significantly greater (to 62+/-6% of control value vs 85+/-6% of pre-treatment p=0.01), consistent with enhanced basal release of nitric oxide. The acetylcholine response tended to be greater after treatment (174+/-26% of control vs 147+/-12% of pre-CPAP, p=0.22), however the nitroprusside response was unchanged. Successful treatment of obstructive sleep apnoeic episodes in sleep results in enhanced nitric oxide release by the pulmonary microvascular circulation.
Noninvasive pressure preset ventilation for the treatment of Cheyne-Stokes respiration during sleep.
Publisher: European Respiratory Society (ERS)
Date: 06-2001
DOI: 10.1183/09031936.01.99086101
Abstract: Cheyne-Stokes respiration (CSR) during sleep is common in patients with congestive heart failure (CHF). This pattern of breathing fragments sleep, leading to daytime symptoms of sleepiness and fatigue. It was hypothesized that by controlling CSR with noninvasive pressure preset ventilation (NPPV), there would be a decrease in sleep fragmentation and an improvement in sleep quality. Nine patients (eight males, one female mean±sd 65±11 yrs) with symptomatic CSR diagnosed on overnight polysomnography (apnoea/hypopnoea index (AHI) 49±10·h −1 , minimum arterial oxygen saturation ( S a,O 2 , 77±7%) and CHF (left ventricular ejection fraction 25±8%) were studied. After a period of acclimatization to NPPV (variable positive airway pressure (VPAP) II ST TM , Sydney, NSW, Australia and bilevel positive airway pressure (BiPAP) TM , Murraysville, PA, USA), sleep studies were repeated on therapy. NPPV almost completely abolished CSR in all patients with a reduction in AHI from 49±10 to 6±5·h −1 (p .001). Residual respiratory events were primarily due to upper airway obstruction at sleep on-set. Arousal index was markedly decreased from 42±6 to 17±7·h −1 (p .001). Sleep architecture showed a trend toward improvement with a reduction in stage 1 and 2 (79±7% during the diagnostic night versus 72±10% during NPPV, (p=0.057)), whilst sleep efficiency, slow-wave sleep (SWS), and rapid eye movement (REM) were not altered. Controlling Cheyne-Stokes respiration with noninvasive pressure preset ventilation resulted in reduced arousal and improved sleep quality in the patients with congestive heart failure. Noninvasive pressure preset ventilation should be considered a potential therapy for Cheyne-Stokes respiration in congestive heart failure in those patients who do not respond or fail to tolerate nasal continuous positive airway pressure therapy.
Measurement of crackles during sleep may have a role to play in titration of positive airway pressure (PAP) modalities in heart failure
Publisher: Elsevier BV
Date: 12-2021
Haemodynamic responses to obstructive sleep apnoeas in premenopausal women.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-1999
DOI: 10.1097/00004872-199917050-00003
Abstract: Obstructive apnoeas during sleep are associated with marked cyclical blood pressure fluctuations in men with obstructive sleep apnoea (OSA). Haemodynamic responses to OSA in women are largely unknown. We aimed to investigate haemodynamics during apnoeic events in women with OSA and to assess the influence of the menstrual cycle on these responses. Full overnight polysomnography and continuous non-invasive blood pressure monitoring was performed in 13 women with OSA during follicular and luteal phases of the menstrual cycle. Change in blood pressure (deltaBP) from pre- to post-apnoea termination was measured for each apnoeic cycle. Only 10 of 13 subjects ovulated. In women who ovulated, pressor responses to apnoea termination occurred in both non-rapid eye movement (NREM) and rapid eye movement (REM) sleep, but substantially increased during the luteal phase of ovulatory cycles [NREM change in mean arterial pressure (deltaMAP) 12 +/- 3 mmHg during the follicular phase and 20 +/- 3 mmHg during the luteal phase, P < 0.001 REM deltaMAP 11 +/- 3 mmHg during the follicular phase and 23 +/- 3 mmHg during the luteal phase, P < 0.001]. Sleep apnoea severity did not change during the cycle in NREM sleep, but was reduced in REM during the luteal phase. Changes in pressor responses were absent in non-ovulating subjects. Obstructive apnoeas in women were associated with marked blood pressure changes, similar to those previously reported in men. While respiratory events improved slightly in the luteal phase, blood pressure responses to these events increased by approximately 100%. Thus, the menstrual cycle has discordant effects on the respiratory and cardiovascular effects of OSA in women.
Comparison of exercise stress testing with ambulatory electrocardiographic monitoring in the detection of myocardial ischemia after unstable angina pectoris
Publisher: Elsevier BV
Date: 1991
Sleep apnea and heart disease.
Publisher: Massachusetts Medical Society
Date: 09-03-2006
DOI: 10.1056/NEJMC053389
Testing the Effects of App-Based Motivational Messages on Physical Activity and Resting Heart Rate Through Smartphone App Compliance in Patients With Vulnerable Coronary Artery Plaques: Protocol for a
Publisher: JMIR Publications Inc.
Date: 02-10-2023
DOI: 10.2196/46082
Circadian Rhythm of Blood Pressure in Patients with Obstructive Sleep Apnea
Publisher: Informa UK Limited
Date: 1992
DOI: 10.3109/08037059209077666
Abstract: The aims of this study were to examine the circadian variation in blood pressure (BP) in obstructive sleep apnea (OSA) and to compare this between normotensive and hypertensive subjects. We measured 24-hour ambulatory BP (ABP) in 72 men (mean age 51 +/- 8 years), with OSA diagnosed on overnight sleep study. Measurements of BP were made at 15 min intervals for 24 h using either an Oxford Medilog ABP or Spacelabs 90207 recorder. All recordings were performed after > or = 3 week washout of anti-hypertensive drugs. The day-time monitoring period was defined as 07:00 hrs to 22:00 and night-time 22:00 to 07:00. The ratio of night:day systolic and diastolic BP was calculated. The patients were obese (mean body mass index 33 +/- 5 kg/m2) with a central pattern of obesity (waist:hip ratio 0.99 +/- 0.14, normal < 0.94). The mean 24-h ABP (systolic/diastolic) was 138 +/- 18/88 +/- 12 mmHg. The mean daytime ABP was 143 +/- 18/93 +/- 12 and night-time ABP 128 +/- 20/80 +/- 12 Hg. The night:day BP ratio was 0.90 +/- 0.07 (systolic) and 0.87 +/- 0.09 (diastolic) indicating that average BP was lower during the night. This pattern was similar in normotensive and hypertensive subjects. In contrast there was a significant relationship between increasing BMI and night:day blood pressure ratio (r = 0.56, p < 0.001) independent of the effects of OSA. In contrast to previous studies, men with OSA have a normal diurnal pattern of blood pressure levels. These findings suggest that any influence of OSA on BP is manifested throughout the 24-h period.
Basal stress cardiomyopathy induced by exogenous catecholamines in younger adults.
Publisher: Elsevier BV
Date: 10-2013
6 Sleep-disordered breathing and obesity
Publisher: Elsevier BV
Date: 07-1994
DOI: 10.1016/S0950-351X(05)80288-5
Abstract: Recent epidemiological data indicate that obstructive sleep apnoea (OSA) and related conditions are extremely common in the middle-aged population. Obesity is an important aetiological factor in sleep-disordered breathing with a multifactorial role in the pathogenesis of upper airway occlusion. One extreme of the spectrum of sleep-disordered breathing is obesity-hypoventilation syndrome (one type of OSA with awake respiratory failure). Sleep-disordered breathing has a number of clinical consequences, including excess cardiovascular morbidity. Obesity is an important confounder of this association. Treatment of these disorders has been revolutionized by the use of nasal continuous positive airway pressure (CPAP). Weight reduction reduces apnoea severity but is not curative in most obese patients with sleep apnoea.
Clinical significance of silent ischemia in unstable angina pectoris
Publisher: Elsevier BV
Date: 06-1990
DOI: 10.1016/0002-9149(90)91319-2
Abstract: In a prospective study the significance of silent ischemia was evaluated in 66 patients with a clinical diagnosis of unstable angina (no requirement for reversible ST-T changes during pain on 12-lead electrocardiograms before entry), and the results of continuous 2-channel electrocardiographic (ECG) recordings, begun within 24 hours of admission, were compared with other clinical and ECG predictors of adverse outcome. Ischemic changes were detected in 7 patients (11%) during a mean of 41 hours of recording. There were 37 episodes of transient ST-segment change (16 ST elevation, 21 ST depression) of which 11 (30%) were symptomatic and 26 (70%) were silent. All 7 patients had at least 1 silent episode and 5 also had symptomatic episodes during the recording but only 2 patients had exclusively silent episodes. During a mean follow-up of 13.3 months, 3 patients died, 5 had a nonfatal myocardial infarction and 32 required revascularization. Although transient myocardial ischemia during the continuous ECG recording, whether silent or symptomatic, was a specific predictor of subsequent nonfatal myocardial infarction or death (specificity 92%), its sensitivity for these events was low (25%). In contrast, recurrent rest pain (greater than or equal to 1 episode) occurred in all patients with these serious adverse events (sensitivity 100%, specificity 49%). Transient ischemia occurs infrequently during continuous ECG recordings in patients with unstable angina not selected by reversible ST-T changes on a 12-lead electrocardiogram at entry. Recurrent rest pain after hospital admission is a more sensitive predictor of serious events in this group.
Treatment of central sleep apnoea in congestive heart failure with nasal ventilation.
Publisher: BMJ
Date: 10-1998
Treatment of snoring and obstructive sleep apnoea by rapid maxillary expansion
Publisher: Wiley
Date: 06-1996
A case of ST elevation myocardial infarction secondary to heparin-induced thrombocytopaenia with thrombosis.
Publisher: Elsevier BV
Date: 12-2012
DOI: 10.1016/J.HLC.2012.04.023
Abstract: A 54 year-old woman with Noonan Syndrome presented with an acute anterolateral ST elevation myocardial infarction two weeks post septal myectomy and heparin exposure, on the background of known normal coronary arteries. Coronary angiography revealed acute thrombosis of the left main, left anterior descending and left circumflex arteries, which was successfully treated by percutaneous coronary intervention with overlapping bare metal stents. A positive heparin induced platelet antibody test and dramatic fall in platelet count confirmed the diagnosis of heparin induced thrombocytopaenia with thrombosis (HITTS) as the underlying diagnosis. This represents the first documented case of HITTS induced left main coronary artery thrombosis and occlusion.
Obstructive sleep apnea: novel trigger and potential therapeutic target for cardiac arrhythmias.
Publisher: Informa UK Limited
Date: 07-2010
DOI: 10.1586/ERC.10.80
Abstract: Obstructive sleep apnea (OSA), the most common form of sleep-disordered breathing, is prevalent and frequently underdiagnosed in our community. Although presenting with predominantly respiratory symptoms, the most serious complications from OSA are cardiovascular, including arrhythmias, disease of the sinus node and conducting system, and sudden cardiac death. The acute and chronic effects of OSA on the cardiovascular system, which include major effects on autonomic function during sleep and wakefulness, are potent contributors to the development and persistence of cardiac arrhythmias. Although large randomized studies are currently lacking, treatment of OSA may be an important primary or additional therapy to supplement the use of drugs or devices in the treatment of cardiac arrhythmias.
Hypoxia and inflammation.
Publisher: Massachusetts Medical Society
Date: 19-05-2011
DOI: 10.1056/NEJMC1103019
Related Organisations
American College Of Chest Physicians
Location: United States of America
Newcastle University
Location: United Kingdom of Great Britain and Northern Ireland
Cardiac Society Of Australia And New Zealand
Location: No location found
Related Funding Activities
No related grants have been discovered for Ian Wilcox.