Obstructive Sleep Apnea, Obesity, and the Risk of Incident Atrial Fibrillation Apoor S. Gami, Dave O. Hodge, Regina M. Herges, Eric J. Olson, Jiri Nykodym, Tomas Kara, Virend K. Somers Obesity is a ...risk factor for atrial fibrillation/flutter (AF), and obstructive sleep apnea (OSA) is associated with both obesity and AF. It is unknown whether OSA predicts new-onset AF independently of obesity. We assessed the incidence of AF during an average of 4.7 years follow-up in a cohort of 3,542 Olmsted County adults without a history of AF who underwent polysomnography from 1987 to 2003. In subjects <65 years of age, independent predictors of incident AF were age, male gender, coronary artery disease, body mass index, and the decrease in nocturnal oxygen saturation, which is an important pathophysiological consequence of OSA.
Objectives The authors sought to characterize the left atrial (LA) and pulmonary vein (PV) electrophysiological and hemodynamic features in obese patients with atrial fibrillation (AF). Background ...Obesity is associated with increased risk for AF. Methods A total of 63 consecutive patients with AF who had normal left ventricular (LV) ejection fraction and who underwent catheter ablation were studied. Atrial and PV electrophysiological studies were performed at the time of ablation with hemodynamic assessment by cardiac catheterization, and LA/LV structure and function by echocardiography. Patients were compared on the basis of body mass index (BMI): <25 kg/m2 (n = 19) and BMI ≥30 kg/m2 (n = 44). Results At a 600-ms pacing cycle length, obese patients had shorter effective refractory period (ERP) in the left atrium (251 ± 25 ms vs. 233 ± 32 ms, p = 0.04), and in the proximal (207 ± 33 ms vs. 248 ± 34 ms, p < 0.001) and distal (193 ± 33 ms vs. 248 ± 44 ms, p < 0.001) PV than normal BMI patients. Obese patients had higher mean LA pressure (15 ± 5 mm Hg vs. 10 ± 5 mm Hg, p < 0.001) and LA volume index (28 ± 12 ml/m2 vs. 21 ± 14 ml/m2 , p = 0.006), and lower LA strain (5.5 ± 3.1% vs. 8.8 ± 2.8%; p < 0.001) than normal BMI patients. Conclusions Increased LA pressure and volume, and shortened ERP in the left atrium and PV are potential factors facilitating and perpetuating AF in obese patients with AF.
Two-dimensional and Doppler-derived echocardiographic data on normal St. Jude Medical mechanical mitral valve prosthesis function have been reported but remain limited.
Comprehensive retrospective ...two-dimensional and Doppler echocardiographic assessment of 368 normal St. Jude Medical mechanical mitral valve prostheses was performed early after implantation. The early postimplantation hemodynamic profiles of 98 patients were compared with profiles obtained by follow-up transthoracic echocardiography performed <13 months after implantation.
Using mean ± 2 SDs to define the normal distribution of values for Doppler-derived hemodynamic variables, the calculated normal ranges of values were as follows: mean gradient, 2 to 7 mm Hg; peak early mitral diastolic velocity (E velocity), 1.1 to 2.4 m/sec; time-velocity integral of the mitral valve prosthesis (TVIMVP) 20 to 50 cm; ratio of the TVIMVP to the time-velocity integral of the left ventricular outflow tract (TVILVOT), 0.9 to 2.5; pressure half-time, 35 to 99 msec; and effective orifice area, 1.12 to 3.24 cm(2). Patients with severe prosthesis-patient mismatch (ie, indexed effective orifice area ≤ 0.9 cm(2)/m(2)) had significantly higher mean gradients, E velocity, TVIMVP, and TVIMVP/TVILVOT. There was a trend for longer pressure half-times for patients with severe prosthesis-patient mismatch than for patients without severe prosthesis-patient mismatch, but none of these patients had pressure half-times > 130 msec. Among the 98 patients with follow-up transthoracic echocardiography <1 year after implantation, no significant differences were observed between early postimplantation findings and follow-up hemodynamic profiles.
This study establishes parameters (mean ± 2 SDs) defining the distribution of values for Doppler-derived hemodynamic data with normal St. Jude Medical mechanical mitral valve prostheses. Prostheses with hemodynamic values outside these parameters are likely dysfunctional; however, prosthesis dysfunction may be present even when hemodynamic values are within these ranges.
Doppler-derived hemodynamic data for normal tricuspid valve bioprostheses are limited.
A comprehensive retrospective Doppler echocardiographic assessment of 285 normal Carpentier-Edwards Duraflex, ...Medtronic Mosaic, St. Jude Medical Biocor, Carpentier-Edwards Perimount, and Medtronic Hancock II tricuspid valve bioprostheses was performed early after implantation. All the important Doppler-derived hemodynamic variables reported to date for mitral valve prostheses were used. Mean values for hemodynamic variables were obtained by averaging measurements of five and nine consecutive cardiac cycles.
No clinically significant difference was found in the mean values obtained for the Doppler parameters when measurements were averaged from five or nine consecutive cardiac cycles. The mean value for the mean gradient was 5.2 mm Hg. Regardless of valve type and body surface area, pressure half-time was <200 msec for all 76 patients in whom it could be measured. Mean gradient <9 mm Hg, E velocity <2.1 m/sec, time-velocity integral of the tricuspid valve prosthesis <66 cm, and ratio of the time-velocity integral of the tricuspid valve prosthesis to the time-velocity integral of the left ventricular outflow tract <3.3 were recorded in 254 of the 285 patients (89%).
This study establishes parameters for Doppler-derived hemodynamic data for various types of normal tricuspid valve bioprostheses. These threshold values (mean + 2 standard deviations) are specific, but not sensitive, for identifying tricuspid valve bioprosthesis dysfunction. Prostheses with hemodynamic values that are higher than these threshold values are likely dysfunctional, but in select cases, tricuspid valve bioprosthesis dysfunction may be present even when hemodynamic values are lower than these thresholds.
Objectives This study sought to identify the risk of sudden cardiac death (SCD) associated with obstructive sleep apnea (OSA). Background Risk stratification for SCD, a major cause of mortality, is ...difficult. OSA is linked to cardiovascular disease and arrhythmias and has been shown to increase the risk of nocturnal SCD. It is unknown if OSA independently increases the risk of SCD. Methods We included 10,701 consecutive adults undergoing their first diagnostic polysomnogram between July 1987 and July 2003. During follow-up up to 15 years, we assessed incident resuscitated or fatal SCD in relation to the presence of OSA, physiological data including the apnea-hypopnea index (AHI), and nocturnal oxygen saturation (O2 sat) parameters, and relevant comorbidities. Results During an average follow-up of 5.3 years, 142 patients had resuscitated or fatal SCD (annual rate 0.27%). In multivariate analysis, independent risk factors for SCD were age, hypertension, coronary artery disease, cardiomyopathy or heart failure, ventricular ectopy or nonsustained ventricular tachycardia, and lowest nocturnal O2 sat (per 10% decrease, hazard ratio HR: 1.14; p = 0.029). SCD was best predicted by age >60 years (HR: 5.53), apnea-hypopnea index >20 (HR: 1.60), mean nocturnal O2 sat <93% (HR: 2.93), and lowest nocturnal O2 sat <78% (HR: 2.60; all p < 0.0001). Conclusions In a population of 10,701 adults referred for polysomnography, OSA predicted incident SCD, and the magnitude of risk was predicted by multiple parameters characterizing OSA severity. Nocturnal hypoxemia, an important pathophysiological feature of OSA, strongly predicted SCD independently of well-established risk factors. These findings implicate OSA, a prevalent condition, as a novel risk factor for SCD.
Background Peripheral arterial disease (PAD) is associated with an excessive risk for cardiovascular events and mortality. To determine measures prognostic of adverse events, ankle-brachial index ...(ABI) was compared with dobutamine stress echocardiography (DSE) in patients referred to our vascular center for the evaluation of PAD. Methods The medical records of consecutive patients referred for the concurrent evaluation of PAD and coronary artery disease (CAD) between 1992 and 1995 were reviewed for subsequent cardiovascular events and death. Results Among 395 patients (mean age, 69.7 ± 9.6 years; 40% women), 341 had abnormal ABI and 268 had abnormal DSE (95 fixed and 173 stress-induced wall motion abnormalities). During a mean follow-up of 4.7 years, 27.3% of patients experienced a cardiovascular event, and 39.4% died. By multivariate analysis, ABI provided the strongest prediction of all-cause mortality (hazard ratio HR, 2.34; 95% confidence interval CI, 1.36 to 4.05; P = .002). Conversely, DSE with inducible or fixed wall motion abnormalities showed no association with cardiovascular events or increased mortality in multivariate analysis. The only DSE variable independently predictive of mortality was decreased left ventricular ejection fraction (<50%) at peak stress (HR, 1.70; 95% CI, 1.22 to 2.36; P = .002). Statin and aspirin therapy, but not β-blockers, were protective. There was no relation between ABI and wall motion index score at rest or after stress. Conclusions In high-risk patients referred to our vascular center for the evaluation of PAD, the assessment of ABI provided a strong independent prediction of all-cause mortality. Therefore, proper interpretation of this simple, affordable, and reproducible measure extends beyond the assessment of PAD severity. Although a poor left ventricular response to dobutamine was also predictive, other echo variables were not.
Normal Doppler-derived hemodynamic data for mitral valve bioprostheses are limited.
To establish parameters for identifying normal function for each of the 3 types of bioprostheses examined, we ...conducted a comprehensive, retrospective, two-dimensional, and Doppler echocardiographic assessment of 179 patients who underwent implantation of the Medtronic Hancock II or the Medtronic Mosaic (Medtronic, Inc, Minneapolis, MN) porcine mitral valve bioprosthesis or the Carpentier-Edwards Perimount (Edwards Lifesciences LLC, Irvine, CA) bovine pericardial mitral valve bioprosthesis.
All bioprostheses were normal by clinical examination, intraoperative transesophageal echocardiography, and postoperative transthoracic echocardiography. Regardless of valve type and body surface area, the pressure half-time was < 124 ms in all patients. Mean gradient < 9.5 mm Hg, mitral E velocity < 2.6 m/s, mitral valve prosthesis time-velocity integral < 69 cm, and ratio of the mitral valve prosthesis time-velocity integral to the left ventricular outflow tract time-velocity integral < 3.4 were recorded in nearly all patients.
These cutoff values (mean + 2 standard deviation) are specific, but not sensitive, for identifying mitral valve prosthesis dysfunction. Prostheses with hemodynamic values that are higher than these cutoff values are likely dysfunctional, but in select cases, mitral valve prosthesis dysfunction may be present even when hemodynamic values are lower than these thresholds.
We aimed to determine whether smoking status affects the recurrence of atrial fibrillation or atrial flutter in patients after cardioversion. The clinical data of patients undergoing cardioversion ...for atrial flutter from January 1, 2000 to December 31, 2005 were prospectively collected. Arrhythmia recurrences were detected by retrospective review of comprehensive medical records and were determined using electrocardiography. The smoking history was prospectively collected through a standardized clinical form and subsequently categorized as lifetime nonsmoker, exsmoker, or current smoker. Univariate and multivariate associations with end points for clinical and lifestyle variables were assessed with Cox proportional hazards models. Women who were current smokers at cardioversion had a greater risk of atrial arrhythmia recurrence than did nonsmokers (hazard ratio 1.71, 95% confidence interval 1.10 to 2.67, p = 0.02). The increased risk of arrhythmia recurrence in female smokers was not seen in male smokers. Compared to lifetime nonsmokers, the mortality hazard ratio among men was 1.18 (95% confidence interval 0.88 to 1.58; p = 0.28) in exsmokers and 1.93 (95% confidence interval 1.20 to 3.11; p = 0.007) in current smokers. The risk of death after cardioversion was not increased in women. In conclusion, smoking is an independent predictor of atrial arrhythmia recurrence after cardioversion in women; however, an increased mortality risk, but not arrhythmia recurrence risk, was seen in men.
Doppler-derived hemodynamic data for normal tricuspid mechanical valve prostheses are limited.
A comprehensive retrospective Doppler echocardiographic assessment of 78 normal St. Jude Medical ...Standard (St. Jude Medical, Inc., St. Paul, MN), CarboMedics Standard (CarboMedics, Inc., Sorin Group, Burnaby, British Columbia, Canada), and Starr-Edwards (Edwards Lifesciences, LLC, Irvine, CA) mechanical tricuspid valve prostheses was performed early after implantation. We used all the important Doppler-derived hemodynamic variables reported to date, including peak early diastolic velocity (E velocity), mean gradient, pressure half-time, time velocity integral of the tricuspid valve prosthesis (TVI(TVP)), and ratio of the time velocity integral of the tricuspid valve prosthesis to the time velocity integral of the left ventricular outflow tract (TVI(TVP)/TVI(LVOT)).
The mean values obtained for the Doppler parameters did not differ significantly when the measurements from five or nine consecutive cardiac cycles were averaged. Pressure half-time was <130 msec in all 43 patients with St. Jude Medical Standard and CardioMedics Standard prostheses in whom it could be measured. Mean gradient <6 mm Hg, E velocity <1.9 m/s, TVI(TVP) <46 cm, and TVI(TVP)/TVI(LVOT) <2.1 were recorded in 59 (87%) of the 68 patients with either of these prostheses. Hemodynamic variables were considerably less favorable in patients with Starr-Edwards prostheses.
These calculated threshold values (mean + 2 SD) are useful for identifying normal tricuspid mechanical valve function. Prostheses with values for hemodynamic variables that are outside the mean + 2 SD parameters that we have calculated are most likely to be dysfunctional. However, in rare cases, mechanical tricuspid valve prostheses may be dysfunctional even when their hemodynamic parameters are within these specified ranges because of small body surface area or other factors.
Normal Doppler-derived echocardiographic data for Carpentier-Edwards Duraflex (Edwards Lifesciences, Irvine, CA) porcine bioprosthesis function in the mitral position are limited to 2 small series ...that did not include all Doppler-derived variables. The purpose of this study was to provide a comprehensive Doppler echocardiographic assessment of normal Carpentier-Edwards Duraflex mitral bioprosthesis function in a large number of patients assessed in the early postoperative phase. All of the important Doppler-derived hemodynamic variables reported to date were used. All patients had either a mitral valve prosthesis time velocity integral to left ventricular outflow tract time velocity integral ratio < 3.9 or an E velocity < 2.8. The pressure half-time was < 130 msec in all patients. Nearly all patients (97%) had an E velocity < 2.8 msec and a mitral valve prosthesis time velocity integral to left ventricular outflow tract time velocity integral ratio < 3.9 regardless of bioprosthesis size, left ventricular function, heart rate, hemoglobin, or hematocrit. With increasing bioprosthesis size, effective orifice area significantly increased, whereas the prosthesis performance index significantly decreased.
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