Cardiac remodeling in middle-aged endurance athletes: relation between signal-averaged electrocardiogram and LV mass.

The relationship between structural and electrical remodeling in the heart, particularly after long-standing endurance training, remains unclear. Signal-averaged electrocardiogram (SAECG) may provide a more sensitive method to evaluate cardiac remodeling than a 12-lead electrocardiogram (ECG). Accurate measures of electrical function (SAECG filtered QRS duration (fQRSd) and late potentials (LP) and left-ventricular (LV) mass (cardiac magnetic resonance, CMR) can allow an assessment of structural remodeling and QRS prolongation. Endurance athletes (45-65 yr old, >10 yr of endurance sport), screened to exclude cardiac disease, had standardized 12-lead ECG, SAECG, resting echocardiogram (ECHO), and CMR performed. SAECG fQRSd was correlated with QRS duration on the 12-lead ECG, and ECHO and CMR-derived LV mass. Participants (n = 82, 67% male, mean age: 54 ± 6 yr, mean V̇o2max: 50 ± 7 mL/kg/min) had a CMR-derived LV mass of 118 ± 28 g/m2 and a fQRSd of 112 ± 8 ms (46% had abnormal fQRSd (>114 ms), and 51% met clinical threshold for abnormal SAECG). fQRSd was positively correlated with the 12-lead ECG QRS duration (r = 0.83), ECHO-derived LV mass (r = 0.60), CMR-derived LV mass (r = 0.58) and LV end-diastolic volume (r = 0.63, P < 0.001 for all). fQRSd had higher correlations with ECHO and CMR-derived LV mass than 12-lead ECG (P < 0.0008 and P < 0.0005, respectively). In conclusion, in a healthy cohort of middle-aged endurance athletes, the SAECG is often abnormal by conventional criteria, and is correlated with structural remodeling, but CMR evaluation does not indicate pathologic structural remodeling. SAECG fQRSd is superior to the 12-lead ECG for the electrocardiographic evaluation of LV mass.NEW & NOTEWORTHY Study findings indicate that a positive correlation exists between electrical (SAECG fQRSd) and structural indices (LV mass) in middle-aged endurance athletes with normal physiological LV adaptation, in the absence of known cardiac pathology. SAECG fQRSd may also provide an alternative, superior method for identifying increased LV mass compared to other 12-lead ECG criteria.

Pulmonary hemodynamic and right ventricular responses to brief and prolonged exercise in middle-aged endurance athletes.

Right ventricular (RV) function is closely coupled to pulmonary arterial (PA) hemodynamics and is believed to decline with prolonged exercise. A linear pressure-flow relationship is thought to exist between PA pressures and increasing exercise intensity in athletes, yet a paucity of directly measured pulmonary hemodynamic data exists supporting this contention. We sought to describe the PA pressure, PA wedge pressure (PAWP), and RV functional responses to brief and prolonged exercise in endurance-trained athletes. Twenty-one healthy athletes (54 ± 5 yr) underwent right heart catheterization to assess pulmonary hemodynamics during graded, submaximal exercise. Measurements were made at rest and during three stages of steady-state, semiupright cycle ergometry at heart rates of 100 beats/min (EX1), 130 beats/min (EX2), and 150 beats/min (EX3). Five athletes completed an additional 34 min at 130 beats/min for a total exercise time of 60 min [prolonged exercise (PLG)]. PA pressures and PAWP increased significantly at EX1 without a further rise at EX2, EX3, or PLG. PAWP adjusted for absolute work rate demonstrated a significant decline as exercise intensity increased from EX1 to EX2. The resistance compliance time constant decreased at EX1 without further changes at EX2, EX3, and prolonged exercise. RV function did not decline during PLG. After an initial rise in PA pressure and PAWP during early, nonsteady-state exercise, values remained constant despite increases in exercise intensity and duration. These data indicate that in healthy, middle-aged endurance-trained athletes, the PA and pulmonary venous/left atrial compartments rapidly accommodate high conduit flows produced during intensive and prolonged exercise while maintaining RV function. NEW & NOTEWORTHY The right ventricular (RV)-pulmonary arterial (PA) circulatory unit has not been well studied during prolonged exercise, and this study provides an ecological approach that reflects a typical bout of endurance training integrating a transition from rest to exercise with successive increases in intensity, progressing to steady-state, sustained exercise. We demonstrated a remarkably constant response of the PA and PA wedge pressure during incremental, steady-state exercise and that no changes occur in pulmonary pressures throughout prolonged exercise, concomitant to a preservation of RV performance.

Heart rate-dependent left ventricular diastolic function in patients with and without heart failure.

BACKGROUND: Chronic heart rate (HR) reduction in the treatment of heart failure (HF) with systolic dysfunction is beneficial, but the immediate mechanical advantages or disadvantages of altering HR are incompletely understood. We examined the effects of increasing HR on early and late diastole in humans with and without HF. METHODS AND RESULTS: We studied force-interval relationships of the left ventricle (LV) in 11 HF patients and 14 control subjects. HR was controlled by right atrial pacing, and LV pressure was recorded by a micromanometer-tipped catheter. The time constant of isovolumic relaxation (tau) was calculated, and simultaneous sonographic images were analyzed for LV volumes. The end-diastolic pressure-volume relationship (EDPVR) was analyzed with the use of a single-beat method. Tau was shortened in response to increasing HR in both groups; the slope of this relationship was steeper in HF than in control subjects. The predicted volume at a theoretic pressure of 0 mm Hg (V30) increased at higher HRs compared with baseline, shifting the predicted EDPVR compliance curve to the right in HF patients but not in control subjects. CONCLUSIONS: In HF, changes in HR affect early relaxation and diastolic compliance to a greater extent than in control subjects. Our study reinforces current recommendations for HR-lowering drug treatment in HF.

Short-term high-intensity interval and continuous moderate-intensity training improve maximal aerobic power and diastolic filling during exercise.

PURPOSE: This study examined the effects of short-term high-intensity interval training (HIT) and continuous moderate-intensity training (CMT) on cardiac function in young, healthy men. METHODS: Sixteen previously untrained men (mean age of 25.1 ± 4.1 years) were randomly assigned to HIT and CMT (n = 8 each) and assessed before and after six sessions over a 12-day training period. HIT consisted of 8-12 intervals of cycling for 60 s at 95-100% of pre-training maximal aerobic power (VO(2max)), interspersed by 75 s of cycling at 10% VO(2max). CMT involved 90-120 min of cycling at 65% pre-training VO(2max). Left ventricular (LV) function was determined at rest and during submaximal exercise (heart rate ~105 bpm) using two-dimensional and Doppler echocardiography. RESULTS: Training resulted in increased calculated plasma volume (PV) in both groups, accompanied by improved VO(2max) in HIT (HIT: from 39.5 ± 7.1 to 43.9 ± 5.5 mL kg(-1) min(-1); CMT: from 39.9 ± 5.9 to 41.7 ± 5.3 mL kg(-1) min(-1); P < 0.001). Resting LV function was not altered. However, increased exercise stroke volume (P = 0.02) and cardiac output (P = 0.02) were observed, secondary to increases in end-diastolic volume (P < 0.001). Numerous Doppler and speckle tracking indices of diastolic function were similarly enhanced during exercise in both training groups and were related to changes in PV. CONCLUSION: Short-term HIT and CMT elicit rapid improvements in VO2max and LV filling without global changes in cardiac performance at rest.

Left atrial functional changes following short-term exercise training.

BACKGROUND: Exercise-induced adaptations of the human atria remain understudied, particularly early in the training process. We examined the effects of short-term high-intensity interval training (HIT) and continuous moderate-intensity training (CMT) on left atrial (LA) systolic and diastolic function, relative to left ventricular (LV) function in young, healthy men, by speckle tracking echocardiography (STE). METHODS: Fourteen untrained men (mean age = 25 ± 4 years) were randomized to HIT or CMT, and assessed before and after six training sessions over a 12-day period. HIT included 8-12 intervals of cycling for 60 s at 95-100% of maximal aerobic power (VO2MAX), interspersed by 75 s of cycling at 10 % VO2MAX. CMT consisted of 90-120 min of cycling at 65% VO2MAX. RESULTS: VO2MAX increased following HIT and CMT by 11.5 and 5.5%, respectively (p < 0.05). Calculated plasma volume expanded 11 % following HIT and 10% following CMT (p < 0.005). Resting LV volumes and ejection fraction were unaltered following training. Peak atrial longitudinal strain increased following HIT (41.8 ± 5.2%-47.1 ± 3.7%, p < 0.01) and CMT (38.5 ± 4.6%-41.7 ± 6.0%, p < 0.01). Atrial systolic strain rate increased following HIT (1.6 ± 0.2%/s-2.0 ± 0.3%/s, p < 0.01) and CMT (1.6 ± 0.2%/s-1.9 ± 0.2%/s, p < 0.01). CONCLUSIONS: LA function assessed by STE improves rapidly during short-term intensive exercise training.

Left atrial reservoir pressure-volume relations during exercise in healthy older adults.

The left atrium (LA) mediates cardiopulmonary interactions. During ventricular systole, the LA functions as a compliant reservoir that is coupled to the left ventricle (LV) and offloads volume from the pulmonary vasculature. We aimed to describe LA reservoir function using phasic relationships between pulmonary artery wedge pressure (PAWP) and LA volume events. We included healthy adults (7 M/6 F, 56 ± 8 yr) who were studied at rest and during semirecumbent cycle ergometry at a target of 100 beats/min heart rate. Right heart catheterization was performed to record the PAWP and two-dimensional (2-D) echocardiography was used to measure LA and LV volumes. We manually measured A-wave, x-trough, V-wave, and y-trough PAWP beat-by-beat, as well as minimal, maximal, and precontraction biplane LA volumes. Heart rate increased by 40 ± 7 beats/min with exercise; stroke volume and cardiac output also rose. Although all phasic PAWP measurements increased with exercise, the x-V pressure pulse during LA filling doubled from 4 ± 2 to 8 ± 4 mmHg (P = 0.001). LA minimal volume was unchanged but maximal volume increased from 39 ± 9 to 48 ± 9 mL (P < 0.001) with exercise, and so reservoir volume increased from 24 ± 5 to 32 ± 8 mL (P < 0.001). As such, calculated LA compliance decreased from 6.8 ± 3.4 to 4.8 ± 2.6 mL/mmHg (P = 0.029). The product of V-wave PAWP and LA maximal volume, a surrogate for LA wall stress, increased from 486 ± 193 to 953 ± 457 mmHg·mL (P < 0.001). In healthy older adults during submaximal exercise, the PAWP waveform shifts upward and its amplitude widens, LA filling increases, LA compliance decreases modestly, and LA wall stress may augment substantially.NEW & NOTEWORTHY We combined invasive estimates of left atrial pressure with noninvasive left atrial volume measurements made at rest and during exercise in healthy humans. Left atrial pressure and volume both increased with exercise, though the pressure increase was relatively greater, and calculated compliance decreased modestly while estimated peak wall stress nearly doubled. Our results demonstrate left atrial loading during exercise in healthy older adults and provide insight into how the left atrium mediates cardiopulmonary interactions.

Variations and inequities in access to cardiac diagnostic services in Ontario Canada.

OBJECTIVES: Echocardiography is an essential diagnostic modality known to have wide regional utilization variations. This study's objectives were to quantify regional variations and to examine the extent to which they are explained by differences in population age, sex, cardiac disease prevalence (CDP), and social determinants of health (SDH) risk. METHODS: This is an observational study of all echocardiography exams performed in Ontario in 2019/20 (n = 695,622). We measured regional variations in echocardiography crude rates and progressively standardized rates for population age, sex, CDP, and SDH risk. RESULTS: After controlling for differences in population age, sex, and CDP, Ontario's highest rate regions had echocardiography rates 57% higher than its lowest rate regions. Forty eight percent of total variation was not explained by differences in age, sex, and CDP. CDP increased with SDH risk. Access to most cardiac diagnostics was negatively correlated with SDH risk, while cardiac catheterization rates were positively correlated with SDH risk. CONCLUSION: Variations analysis that adjusts for age and sex only without including clinical measures of need are likely to overestimate the unwarranted portion of total variation. Substantial variations persisted despite a mandatory provider accreditation policy aimed at curtailing them. The associations between variations and SDH risks imply a need to redress access and outcome inequities.

Atrial fibrillation in middle-aged athletes: Impact on left atrial, ventricular and exercise performance.

High volume endurance training may increase the risk of paroxysmal atrial fibrillation (AF) in middle-aged athletes. Limited data are available describing the cardiovascular phenotype of middle-aged endurance athletes, or the impact of AF on atrial function and exercise performance performed in sinus rhythm. The purpose of this study was to characterize LA phasic function at rest and during exercise in athletes with paroxysmal AF, and to determine its impact on exercise performance. Fifteen endurance trained males (EA) (56 ± 5 years) without AF and 14 endurance trained males with paroxysmal AF (EA-AF) (55 ± 8 years) underwent echocardiography during cycle-ergometry at light and moderate intensities. Resting LA maximal volumes were similar between EA and EA-AF (30 ± 4 vs. 29 ± 8 ml/m2, p = 0.50), and there were no differences in atrial electromechanical delay (AEMD). During moderate intensity exercise, EA-AF had reduced LA conduit (30 ± 6 vs. 40 ± 5 ml/m2, p = 0.002) LA booster volumes (17 ± 5 vs. 21 ± 4 ml/m2, p = 0.021), and reduced LV stroke volumes (100 ± 12 vs. 117 ± 16 ml, p = 0.007). These results demonstrate that exercise testing in athletes with AF unmasks evidence of adverse functional cardiac remodelling that may contribute to impaired exercise performance. It is unclear whether these functional alterations are the consequence of AF. Reductions in LA conduit volume, LA booster volume, and LV stroke volume during exercise may be helpful in clinical management and distinguishing pathologic from physiologic remodelling.

Frequency-dependent left ventricular performance in women and men.

We aimed to determine whether sex differences in humans extend to the dynamic response of the left ventricular (LV) chamber to changes in heart rate (HR). Several observations suggest sex influences LV structure and function in health; moreover, this physiology is also affected in a sex-specific manner by aging. Eight postmenopausal women and eight similarly aged men underwent a cardiac catheterization-based study for force-interval relationships of the LV. HR was controlled by right atrial (RA) pacing, and LV +dP/dt(max) and volume were assessed by micromanometer-tipped catheter and Doppler echocardiography, respectively. Analysis of approximated LV pressure-volume relationships was performed using a time-varying model of elastance. External stroke work was also calculated. The relationship between HR and LV +dP/dt(max) was expressed as LV +dP/dt(max) = b + mHR. The slope (m) of the relationship was steeper in women compared with men (11.8 ± 4.0 vs. 6.1 ± 4.1 mmHg·s(-1)·beats(-1)·min(-1), P = 0.01). The greater increase in contractility in women was reproducibly observed after normalizing LV +dP/dt(max) to LV end-diastolic volume (LVVed) or by measuring end-systolic elastance. LVVed and stroke volume decreased more in women. Thus, despite greater increases in contractility, HR was associated with a lesser rise in cardiac output and a steeper fall in external stroke work in women. Compared with men, women exhibit greater inotropic responses to incremental RA pacing, which occurs at the same time as a steeper decline in external stroke work. In older adults, we observed sexual dimorphism in determinants of LV mechanical performance.

The effect of endogenous estrogen on Doppler-estimated right ventricular systolic pressure during exercise.

We evaluated the effect of endogenous estrogen levels on exercise-related changes in right ventricular systolic pressure (RVSP) of healthy, eumenorrheic, sedentary women. Volunteers were studied at two separates phases of the menstrual cycle (LO and HI estrogen phases), exercised on a semi-supine ergometer with escalating workload and monitored continuously by 12-lead ECG and automated blood pressure cuff. At each exercise stage, Doppler echocardiography measurements were obtained and analyzed to determine RVSP. Fourteen subjects (age 24 ± 5) were studied. Exercise duration was significantly higher on the HI estrogen day, but no significant differences in hemodynamic response to exercise were found between the two study days. There were also no significant differences with respect to heart rate (HR) acceleration during early exercise, as well as resting and peak RVSP, HR, blood pressure, and rate pressure product. Doppler-estimated RVSP demonstrated a linear relationship to HR at a ratio of 1 mm Hg (1 mm Hg = 133.3224 Pa) for every 5 bpm (beats per minute) increase in HR. There were no differences in the slope of this relationship between HI and LO estrogen phases of the menstrual cycle. Our findings did not demonstrate any effect of endogenous estrogen levels on the modulation of the pulmonary vascular response to exercise in healthy women.

Impact of a Mandated Accreditation Process on 1,045 Registered Echocardiographic Service Providers in a Previously Unregulated, Publicly Funded Environment.

BACKGROUND: This review was undertaken to examine the impact of a standards-based, mandated accreditation process on several aspects of echocardiographic service delivery in a single-payer, previously unregulated environment. METHODS: In the province of Ontario, virtually all echocardiographic services are funded by the Ministry of Health and Long Term Care. The Echocardiography Quality Improvement (EQI) process was introduced in 2012 and subsequently linked formally to reimbursement in 2016. Previously, payment for echocardiographic services in Ontario was unregulated. The impact of EQI on the number of facilities, echocardiographic volumes, costs, quality standards, and physician service provision were compared before and after implementation. RESULTS: Of the initial 1,045 registrants, 604 (57.8%) have been accredited or accreditation is expected having successfully resolved identified deficiencies. The remaining registrants were either never functionally operating (323 [30.9%]) or have withdrawn services (118 [11.3%]) since mandatory registration became a requirement for reimbursement. A number of factors identified facilities that were able to most promptly meet EQI standards, including hospital-based, academic, and multiple-physician facilities. The average annual increase in the utilization of echocardiographic services before EQI was 6.7%, decreasing to 2.7% since. The proportion of repeat examinations decreased in community-based facilities. Since 2013, costs for echocardiographic services have totaled about $92.3 million less than predicted by pre-2012 trends. To address standards, some small, more isolated facilities sought out alliances with larger facilities, particularly those affiliated with academic hospitals. CONCLUSIONS: EQI is demonstrably a means for improving quality while reducing the rate of growth and repeat examinations.

Left ventricular contractile function is preserved during prolonged exercise in middle-aged men.

We examined left ventricular (LV) performance before, during, and following prolonged exercise (EX) in 12 healthy middle-aged men [means +/- SE: age = 43.5 +/- 1.9 yr; maximal O(2) uptake (Vo(2max)) = 51.7 +/- 1.5 ml.kg(-1).min(-1)]. Subjects cycled for 120 min at 65% Vo(2max) (75% of maximal heart rate). Two-dimensional echocardiography (ECHO) to determine tissue-Doppler longitudinal myocardial strain and strain rate, LV ejection fraction (EF), end-diastolic (EDV), end-systolic (ESV), and stroke volume (SV) at baseline and after 5, 30, and 120 min of EX and following 30 min of recovery. In addition, hematocrit and plasma norepinephrine (NE) were measured. From baseline to 5 min of EX, there were significant increases in LV longitudinal strain (-23.20 +/- 0.87 to -27.63 +/- 1.07%; P < 0.01), strain rate (-1.50 +/- 0.15 to -2.08 +/- 0.14 s(-1); P < 0.01), and EF (56.3 +/- 2.2 to 77.1 +/- 1.0%; P < 0.05) with continued increases by both at 30 min of exercise vs. SV, EDV, and ESV, which remained constant. After 120 min of EX, HR and NE increased further with reductions in SV, cardiac output, and systolic blood pressure without changes in strain or strain rate. EDV decreased after 120 min of EX (-9.2- vs. 30-min value; P = 0.05) along with a hemoconcentration (baseline = 41.3 +/- 1.0 vs. EX = 45.1 +/- 1.2%; P < 0001) and significant reduction in body mass despite a mean fluid consumption of 1.8 +/- 0.2 liters throughout EX. After 30 min of recovery, LV longitudinal strain was depressed relative to baseline (-23.20 +/- 0.87 to -19.57 +/- 1.21%; P < 0.01). The reduction in LV SV during prolonged EX occurred without changes in the LV contractile state and is likely secondary to reduced LV preload. A reduction in LV contractility despite a reduced afterload following exercise may be due to factors unique to the recovery period and do not appear to contribute to a reduction in SV during prolonged exercise.

Takotsubo in Acute and Chronic Coronary Artery Disease.

Cardiomyopathy of Takotsubo syndrome (TS) is typically triggered by an emotional stress in postmenopausal women. Coexistent coronary artery disease presents diagnostic dilemmas in patients with TS, as seen in the 2 cases presented. In the first case, acute coronary syndrome acts as a physical trigger for TS when a middle-aged man presents with an inferior myocardial infarct, and in the second case, coronary artery disease is a bystander when an elderly woman develops TS after a fall and facial trauma. The novel teaching point is that acute non-left anterior descending acute coronary syndrome could trigger TS.

La cardiomyopathie du syndrome de Takotsubo (ST) est généralement déclenchée par un stress émotionnel chez les femmes en postménopause. Comme nous l'avons observé dans les 2 cas présentés, la coronaropathie coexistante pose des dilemmes en matière de diagnostic chez les patients atteints du ST. Dans le premier cas, le syndrome coronarien aigu agit comme un déclencheur physique du ST lorsqu'un homme d'un certain âge subit un infarctus de la région inférieure du myocarde, et dans le second cas, la coronaropathie constitue un « spectateur ¼ lorsqu'une femme âgée subit un ST après une chute et un traumatisme facial. La nouvelle leçon à retenir est que le syndrome coronarien aigu qui ne provient pas de l'artère interventriculaire antérieure pourrait déclencher le ST.

Vascular-ventricular coupling during exercise is not affected by exaggerated blood pressures in endurance-trained athletes.

This study sought to examine whether cardiovascular performance during exercise, assessed using the vascular-ventricular coupling index (VVC), was affected by exaggerated blood pressure (EBP) responses in endurance-trained athletes. Subjects were middle-aged endurance-trained men and women. Blood pressure measurements and left ventricular echocardiography were performed in a semiupright position at rest and during steady-state cycling at workloads that elicited 100-110 beats/min (stage 1) and 130-140 beats/min (stage 2). These data were used to calculate effective arterial elastance index (EaI), left ventricular end-systolic elastance index (ELVI), and their ratio (VVC). Additional measurements of left ventricular volumes and function (i.e., stroke volume, cardiac output, and longitudinal strain) and indirect assessments of peripheral vascular function (i.e., total arterial compliance and peripheral vascular resistance) were examined. Fourteen subjects with EBP (EBP+, 50% men) and 14 sex-matched subjects without EBP (EBP-) participated, with results presented as EBP+ versus EBP-. EaI and ELVI increased from rest to exercise while VVC decreased, but only ELVI was different between groups at stage 1 [7.6 (1.8) vs. 6.4 (1.0) mmHg·ml-1·m-2, P = 0.045] and stage 2 [10.3 (1.6) vs. 8.0 (1.7) mmHg·ml-1·m-2, P < 0.001]. Additional comparisons revealed no group difference in the contribution of the Frank-Starling mechanism or left ventricular and peripheral vascular function during exercise. The cardiovascular adjustment to exercise in athletes with EBP is achieved through a matched increase in both EaI and ELVI, and the absence of between-group differences in left ventricular or peripheral vascular function suggests that other factors may contribute to the EBP response.NEW & NOTEWORTHY Cardiovascular performance during submaximal exercise, assessed using vascular-ventricular coupling, is unaffected by exaggerated blood pressure (EBP) responses in endurance-trained athletes. The underlying mechanisms of EBP in athletes remain unknown as changes in left ventricular and peripheral vascular function during exercise were similar in athletes with and without EBP.

Pulmonary Artery Wedge Pressure Relative to Exercise Work Rate in Older Men and Women.

PURPOSE: An augmented pulmonary artery wedge pressure (PAWP) response may explain exercise intolerance in some humans. However, routine use of exercise hemodynamic testing is limited by a lack of data from normal older men and women. Our objective was to evaluate the exercise PAWP response and the potential for sexual dimorphism in healthy, nondyspneic older adults. METHODS: Thirty-six healthy volunteers (18 men [54 ± 7 yr] and 18 women [58 ± 6 yr]) were studied at rest (control) and during two stages of semi-upright cycle ergometry, at heart rates of 100 bpm (light exercise) and 120 bpm (moderate exercise). Right heart catheterization was performed to measure pulmonary pressures. The PAWP response to exercise was assessed in context of exercise work rate and body size. RESULTS: At control, PAWP was similar between men and women. Work rates were significantly smaller in women at comparable HR (P < 0.001). PAWP increased similarly at light exercise, with no further increase at moderate exercise. When indexed to work rate alone or work rate adjusted to body weight and height, the PAWP response at light and moderate exercise was significantly elevated in women compared with men (P < 0.05 condition-sex interaction). The change in PAWP relative to the increase in cardiac output did not exceed 2 mm Hg·L·min in any volunteer at moderate exercise. CONCLUSIONS: The similar rise in the PAWP response to submaximal exercise occurs despite lower work rate in healthy older women compared with men, even when adjusted for smaller body size. It is important to consider sex in the development of normal reference ranges for exercise hemodynamic testing.

The pulmonary artery wedge pressure response to sustained exercise is time-variant in healthy adults.

OBJECTIVES: The clinical and prognostic significance of 'exaggerated' elevations in pulmonary artery wedge pressure (PAWP) during symptom-limited exercise testing is increasingly recognised. However, the paucity of normative data makes the identification of abnormal responses challenging. Our objectives was to describe haemodynamic responses that reflect normal adaptation to submaximal exercise in a group of community-dwelling, older, non-dyspnoeic adults. METHODS: Twenty-eight healthy volunteers (16 men/12 women; 55±6 years) were studied during rest and two consecutive stages of cycle ergometry, at targeted heart rates of 100 bpm (light exercise) and 120 bpm (moderate exercise). Right-heart catheterisation was performed to measure pulmonary artery pressures, both early (2 min) and after sustained (7 min) exercise at each intensity. RESULTS: End-expiratory PAWP at baseline was 11±3 mm Hg and increased to 22±5 mm Hg at early-light exercise (p<0.01). At sustained-light exercise, PAWP declined to 17±5 mm Hg, remaining elevated versus baseline (p<0.01). PAWP increased again at early-moderate exercise to 20±6 mm Hg but did not exceed the values observed at early-light exercise, and declined further to 15±5 mm Hg at sustained-moderate exercise (p<0.01 vs baseline). When analysed at 30 s intervals, mean and diastolic pulmonary artery pressures peaked at 180 (IQR=30) s and 130 (IQR=90) s, respectively, and both declined significantly by 420 (IQR=30) s (both p<0.01) of light exercise. Similar temporal patterns were observed at moderate exercise. CONCLUSIONS: The range of PAWP responses to submaximal exercise is broad in health, but also time-variant. PAWP may routinely exceed 20 mm Hg early in exercise. Initial increases in PAWP and mean pulmonary artery pressures do not necessarily reflect abnormal cardiopulmonary physiology, as pressures may normalise within a period of minutes.

Guidelines for the provision of echocardiography in Canada: recommendations of a joint Canadian Cardiovascular Society/Canadian Society of Echocardiography Consensus Panel.

Recognizing the central role of echocardiographic examinations in the assessment of most cardiac disorders and the need to ensure the provision of these services in a highly reliable, timely, economical and safe manner, the Canadian Cardiovascular Society and Canadian Society of Echocardiography undertook a comprehensive review of all aspects influencing the provision of echocardiographic services in Canada. Five regional panels were established to develop preliminary recommendations in the five component areas, which included the echocardiographic examination, the echocardiographic laboratory and report, the physician, the sonographer and indications for examinations. Membership in the panels was structured to recognize the regional professional diversity of individuals involved in the provision of echocardiography. In addition, a focus group of cardiac sonograhers was recruited to review aspects of the document impacting on sonographer responsibilities and qualification. The document is intended to be used as a comprehensive and practical reference for all of those involved in the provision of echocardiography in Canada.

Left atrial phasic function interacts to support left ventricular filling during exercise in healthy athletes.

We studied the contribution of phasic left atrial (LA) function to left ventricular (LV) filling during exercise. We hypothesized that reduced LV filling time at moderate-intensity exercise limits LA passive emptying and increases LA active emptying. Twenty endurance-trained males (55 ± 6 yr) were studied at rest and during light- (∼100 beats/min) and moderate-intensity (∼130 beats/min) exercise. Two-dimensional and Doppler echocardiography were used to assess phasic volumes and diastolic function. LV end-diastolic volume increased from rest to light exercise (54 ± 6 to 58 ± 5 ml/m(2), P < 0.01) and from light to moderate exercise (58 ± 5 to 62 ± 6 ml/m(2), P < 0.01). LA maximal volume increased from rest to light exercise (26 ± 4 to 30 ± 5 ml/m(2), P < 0.01) related to atrioventricular plane displacement (r = 0.55, P < 0.005), without further change at moderate exercise. LA passive emptying increased at light exercise (9 ± 2 to 13 ± 3 ml/m(2), P < 0.01) and then returned to baseline at moderate exercise, whereas LA active emptying increased appreciably only at moderate exercise (6 ± 2 to 14 ± 3 ml/m(2), P < 0.01). Thus, the total atrial emptying volume did not increase beyond light exercise, and the increase in LV filling at moderate exercise could be attributed primarily to an increase in the conduit flow volume (19 ± 3 to 25 ± 5 ml/m(2), P < 0.01). LA filling increases during exercise in relation to augmented LV longitudinal contraction. Conduit flow increases progressively with exercise in athletes, although this is driven by LV properties rather than intrinsic LA function. The pump function of the LA augments only at moderate exercise due to a reduced diastolic filling time and the Frank-Starling mechanism.