Short- and Long-Term Effects of High-Intensity Interval Training vs. Moderate-Intensity Continuous Training on Left Ventricular Remodeling in Patients Early After ST-Segment Elevation Myocardial Infarction-The HIIT-EARLY Randomized Controlled Trial.

Aim: Due to insufficient evidence on the safety and effectiveness of high-intensity interval training (HIIT) in patients early after ST-segment elevation myocardial infarction (STEMI), we aimed to compare short- and long-term effects of randomized HIIT or moderate-intensity continuous training (MICT) on markers of left ventricular (LV) remodeling in STEMI patients receiving optimal guideline-directed medical therapy (GDMT). Materials and Methods: Patients after STEMI (<4 weeks) enrolled in a 12-week cardiac rehabilitation (CR) program were recruited for this randomized controlled trial (NCT02627586). During a 3-week run-in period with three weekly MICT sessions, GDMT was up-titrated. Then, the patients were randomized to HIIT or isocaloric MICT for 9 weeks. Echocardiography and cardiopulmonary exercise tests were performed after run-in (3 weeks), end of CR (12 weeks), and at 1-year follow-up. The primary outcome was LV end-diastolic volume index (LVEDVi) at the end of CR. Secondary outcomes were LV global longitudinal strain (GLS) and cardiopulmonary fitness. Results: Seventy-three male patients were included, with the time between STEMI and start of CR and randomization being 12.5 ± 6.3 and 45.8 ± 10.8 days, respectively. Mixed models revealed no significant group × time interaction for LVEDVi at the end of CR (p = 0.557). However, there was a significantly smaller improvement in GLS at 1-year follow-up in the HIIT compared to the MICT group (p = 0.031 for group × time interaction). Cardiorespiratory fitness improved significantly from a median value of 26.5 (1st quartile 24.4; 3rd quartile 1.1) ml/kg/min at randomization in the HIIT and 27.7 (23.9; 31.6) ml/kg/min in the MICT group to 29.6 (25.3; 32.2) and 29.9 (26.1; 34.9) ml/kg/min at the end of CR and to 29.0 (26.6; 33.3) and 30.6 (26.0; 33.8) ml/kg/min at 1 year follow-up in HIIT and MICT patients, respectively, with no significant group × time interactions (p = 0.138 and 0.317). Conclusion: In optimally treated patients early after STEMI, HIIT was not different from isocaloric MICT with regard to short-term effects on LVEDVi and cardiorespiratory fitness. The worsening in GLS at 1 year in the HIIT group deserves further investigation, as early HIIT may offset the beneficial effects of GDMT on LV remodeling in the long term.

Young endurance training starting age in non-elite athletes is associated with higher proximal aortic distensibility.

OBJECTIVE: Decreased proximal aortic distensibility (AD) is known to significantly predict all-cause mortality and cardiovascular events among individuals without overt cardiovascular disease. This cross-sectional study investigated the association of endurance training (ET) parameters, namely, ET starting age, ET years and yearly ET volume with AD in non-elite endurance athletes. METHODS: Healthy, normotensive, male Caucasian participants of a 10-mile race were assessed with a 2D echocardiogram and comprehensive interview. Ascending aortic diameters were measured simultaneously with pulse pressure. Aortic strain, AD and aortic stiffness index were calculated. Predictors of AD were investigated among training parameters by linear regression models corrected for age, resting heart rate, stroke volume index and mean blood pressure. RESULTS: Ninety-two of 121 athletes (aged 42±8 years) had sufficient echocardiogram quality and were used for analysis. ET starting age (range 6-52 years) and years of ET (range 2-46 years) were highly collinear and used in two separate models for AD. Significant factors for AD were ET starting age, 10-mile race time and resting heart rate in model I, and age, years of ET, 10-mile race time and heart rate in model II (all p<0.01). CONCLUSIONS: In our cohort of healthy, non-elite, middle-aged runners, AD was significantly higher in athletes with younger ET starting age or more years of ET (in the model adjusted for confounders). In the model with years of ET, age had a negative contribution to AD, suggesting that with older age, the benefit of more years of ET on AD decreased. Future studies assessing the effect of exercise training on arterial properties should include training starting age.

Effect of self-tailored high-intensity interval training versus moderate-intensity continuous exercise on cardiorespiratory fitness after myocardial infarction: A randomised controlled trial.

BACKGROUND: Whether high-intensity interval training (HIIT) is more efficient than moderate-intensity continuous exercise (MICE) to increase cardiorespiratory fitness in patients with acute coronary syndrome at moderate-to-high cardiovascular risk is controversial. The best approach to guide training intensity remains to be determined. OBJECTIVE: We aimed to assess intensities achieved with self-tailored HIIT and MICE according to perceived exertion and to compare the effect on cardiorespiratory fitness in patients early after ST-elevation myocardial infarction (STEMI). METHODS: We included 69 males starting cardiac rehabilitation within 4 weeks after STEMI. After a 3-week run-in phase with MICE, 35 patients were randomised to 9 weeks of HIIT (2×HIIT and 1×MICE per week) and 34 patients to MICE (3×MICE). Training workload for MICE was initially set at the patients' first ventilatory threshold (VT). HIIT consisted of 4×4-min intervals with a workload above the second VT in high intervals. Training intensity was adjusted weekly to maintain the perceived exertion (Borg score 13-14 for MICE, ≥15 for HIIT). Session duration was 38min in both groups. Peak oxygen consumption (VO2) was measured by cardiopulmonary exercise testing pre- and post-intervention. RESULTS: Both groups improved peak VO2 (ml/kg/min) (HIIT +1.9, P<0.001; MICE +3.2, P<0.001, Cohen's d -0.4), but changes in VO2 were not significantly different between groups (P=0.104). Exercise regimes did not differ between groups in terms of energy expenditure or training time, but perceived exertion was higher with HIIT. CONCLUSIONS: Self-tailored HIIT was feasible in patients early after STEMI. It was more strenuous but not superior nor more time-efficient than MICE in improving peak VO2. The trial was registered at ClinicalTrial.gov (NCT02627586).

Impact of aerobic training periodisation on global and regional right ventricular strain in coronary heart disease.

Linear aerobic training periodisation (LP) is recommended for patients with coronary heart disease (CHD). However, the effects of training periodisation on the right heart mechanics in patients with CHD have never been examined. This study aimed to explore the effects of LP and non-linear periodisation (NLP) on right heart mechanics. We prospectively randomised CHD patients to 12 weeks of aerobic training with LP or NLP. While there was a weekly increase in energy expenditure with LP, there was a steeper increase during the first 3 weeks, followed by a decrease in the fourth week with NLP. Echocardiography was performed at baseline and after the training period to assess the right ventricular free wall (RVFW) and right atrial strain. Thirty patients with CHD were included (NLP, n = 16; LP, n = 14). The traditional right and left heart parameters showed no significant time effects. There was a decrease of RVFW strain with time in both groups (+1.3 ± 0.9% with NLP, and +1.5 ± 0.8% with LP; p = 0.033). Mid-ventricular RVFW strain changed significantly with time (+2.0 ± 1.3% with NLP, and from +2.3 ± 1.2% with LP; p = 0.025). There was no time effect on the right atrial strain. In stable CHD patients, LP and NLP resulted in right ventricular strain decrements with a segment-specific pattern. This study was registered at ClinicalTrials.gov (identifier number: NCT03414996). Novelty: In stable coronary heart disease patients, both linear and non-linear aerobic training periodisation programs result in right ventricular strain decrements with time, particularly in the mid-ventricular segment. Traditional right and left heart parameters and right atrial strain showed no significant time effect in both 12 weeks aerobic training periodisation programs.

Heart rate kinetics during standard cardiopulmonary exercise testing in heart transplant recipients: a longitudinal study.

AIMS: Heart transplantation (HTx) results in complete autonomic denervation of the donor heart, causing resting tachycardia and abnormal heart rate (HR) responses to exercise. We determined the time course of suggestive cardiac reinnervation post HTx and investigated its clinical significance. METHODS AND RESULTS: Heart rate kinetics during standard cardiopulmonary exercise testing at 2.5-5 years after HTx was assessed in 58 patients. According to their HR increase 30 s after exercise onset, HTx recipients were classified as denervated (slow responders: <5 beats per minute [b.p.m.]) or potentially reinnervated (fast responders: ≥5 b.p.m.). Additionally, in 30 patients, longitudinal changes of maximal oxygen consumption and HR kinetics were assessed during the first 15 post-operative years. At 2.5-5 years post HTx, 38% of our study population was potentially reinnervated. Fast responders were significantly younger (41 ± 15 years) than slow responders (53 ± 13 years, P = 0.003) but did not differ with regard to donor age, immunosuppressive regime, cardiovascular risk factors, endomyocardial biopsy, or vasculopathy parameters. While HR reserve (56 ± 20 vs. 39 ± 15 b.p.m., P = 0.002) and HR recovery after 60 s (15 ± 11 vs. 5 ± 6 b.p.m., P < 0.001) were greater in fast responders, resting HR, peak HR of predicted, and peak oxygen consumption of predicted were comparable. CONCLUSIONS: Signs of reinnervation occurred mainly in younger patients. Maximal oxygen consumption was independent of HR kinetics.

Impact of 2 different aerobic periodization training protocols on left ventricular function in patients with stable coronary artery disease: an exploratory study.

We compared the impacts of linear (LP) and nonlinear (NLP) aerobic training periodizations on left ventricular (LV) function and geometry in coronary artery disease (CAD) patients. Thirty-nine CAD patients were randomized to either a 3-month isoenergetic supervised LP or NLP. All underwent standard echocardiography with assessment of 3D LV ejection fraction (LVEF), diastolic function, strain (global longitudinal, radial, and circumferential), and strain rate at baseline and study end. Training was performed 3 times/week and included high-intensity interval and moderate-intensity continuous training sessions. Training load was progressively increased in the LP group, while it was deeply increased and intercepted with a recovery week each fourth week in the NLP group. For the 34 analyzed patients, we found similar improvements for 3D LVEF (effect size (ES): LP, 0.29; NLP, 0.77), radial strain (ES: LP, 0.58; NLP, 0.48), and radial strain rate (ES: LP, 0.87; NLP, 0.17) in both groups (time for all: p ≤ 0.01). All other parameters of cardiac function remained similar. In conclusion, NLP and LP led to similar improvements in 3D LVEF and radial strain, suggesting a favourable positive cardiac remodelling through myofibers reorganization. These findings must be investigated in patients with more severe cardiac dysfunction. The study was registered on ClinicalTrials.gov (NCT03443193). Novelty: Linear and nonlinear periodization programs improved radial strain, accompanied by improvement of ejection fraction. Both aerobic periodization programs did not negatively impact cardiac function in coronary artery disease patients.

Cardiac function during heat stress: impact of short-term passive heat acclimation.

A lower heart rate (HR) during heat exposure is a classic marker of heat acclimation (HA), although it remains unclear whether this adaptation occurs secondary to reduced thermal strain and/or improvements in cardiac function. We evaluated the hypothesis that short-term passive HA reduces HR and improves cardiac function during passive heating. Echocardiography was performed under thermoneutral and hyperthermic conditions in 10 healthy adults (9 men/1 woman, 29 ± 6 yr old), pre and post 7 days of controlled hyperthermia. HR (P = 0.61), stroke volume (P = 0.99), and cardiac output (P = 0.99), were similar on days 1 and 7 of HA. Core (pre: 38.17 ± 0.42, post: 38.15 ± 0.27°C, P = 0.95) and mean skin (pre: 38.24 ± 0.41, post: 38.51 ± 0.29°C, P = 0.17) temperatures were similar during hyperthermic echocardiographic assessments. Cardiac systolic function was unaffected by HA (P ≥ 0.10). HA attenuated the decrease in end-diastolic volume (pre: -18 ± 18, post: -12 ± 19 mL, P = 0.05), accentuated the greater atrial contribution to diastolic filling (pre: +11 ± 5, post: +14 ± 5%, P = 0.02), and attenuated the increase in left atrial reservoir strain rate (pre: +1.5 ± 1.2, post: +0.8 ± 0.8 1/s, P = 0.02) during heating. Nonetheless, there were no differences in HR (pre: 106 ± 12, post: 104 ± 12 beats/min, P = 0.50), stroke volume (pre: 65 ± 15, post: 68 ± 13 mL, P = 0.55), or cardiac output (pre: 6.9 ± 2.0, post: 7.1 ± 1.7 L/min, P = 0.70) during passive heating. Short-term controlled hyperthermia HA results in limited adaptations of cardiac function during passive heating.NEW & NOTEWORTHY A lower heart rate during heat exposure is a classic marker of heat acclimation (HA). It remains unknown if improved cardiac function contributes to this response. A 7-day passive HA protocol did not alter cardiac systolic function during passive heating, whereas it improved some indexes of diastolic function in young adults. Nonetheless, heart rate during heating was unaffected by HA. These results suggest that passive HA induces limited adaptations in cardiac function during passive heating.

Effects of interval training on risk markers for arrhythmic death: a randomized controlled trial.

OBJECTIVE: To compare the effects of high-intensity interval training versus moderate-intensity continuous training on risk markers of arrhythmic death in patients who recently suffered from an acute coronary syndrome. DESIGN: Double-blind (patient and evaluator) randomized controlled trial. SETTING: Cardiovascular Prevention and Rehabilitation Centre (EPIC Centre) of the Montreal Heart Institute, Montreal, Canada. SUBJECTS: A total of 43 patients were randomized following an acute coronary syndrome. INTERVENTIONS: Patients were assigned to either high-intensity interval training (n = 18) or isocaloric moderate-intensity continuous training (n = 19), three times a week for a total of 36 sessions. MAIN MEASURES: Heart rate recovery for 5 minutes, heart rate variability for 24 hours, occurrence of ventricular arrhythmias, and QT dispersion were measured before and after the 36 sessions of training. RESULTS: Among the 43 patients randomized, 6 participants in the high-intensity interval training group stopped training for reasons unrelated to exercise training and were excluded from the analyses. Heart rate recovery improved solely in the high-intensity interval training group, particularly at the end of recovery period (p < 0.05). There were no differences in heart rate variability, occurrence of ventricular arrhythmias, or QT dispersion parameters between the groups at study end. CONCLUSION: Despite the lack of power to detect any large difference between the two interventions with respect to risk markers of arrhythmic death, high-intensity interval training appears safe and may be more effective at improving heart rate recovery relative to moderate-intensity continuous training in our patients following acute coronary syndrome.

Age at start of endurance training is associated with patterns of left ventricular hypertrophy in middle-aged runners.

BACKGROUND: Left ventricular hypertrophy (LVH) is a physiological adaptation to long-term endurance training. We investigated the impact of age at start of endurance training on LV geometry in a cohort of male, middle-aged, non-elite endurance athletes. METHODS: A total of 121 healthy, normotensive, Caucasian participants of a 10-mile race were recruited and assessed with an echocardiogram and a comprehensive interview. Athletes were classified based on patterns of LVH. RESULTS: Thirty-five athletes (31%) had LVH. Athletes with eccentric LVH (16%) were significantly younger at start of endurance training compared to athletes with concentric LVH (15%, 14 ±â€¯5 years vs. 31 ±â€¯8 years; P < 0.001). Although the yearly volume of endurance training was comparable between athletes with eccentric and concentric LVH, athletes with eccentric LVH had shorter race times. All athletes with an increased LV end diastolic volume index (LVEDVI; ≥74 ml/m2) started endurance training before or at age 25. CONCLUSIONS: In our cohort of non-elite middle-aged runners, eccentric LVH was found only in athletes with an early start of endurance training. In case of a mature starting age, endurance training may, contrary to what is commonly assumed, also lead to concentric LVH. The consideration of endurance training starting age may lead to a better understanding of morphological adaptations of the heart.

Exercise-induced cardiac remodeling in non-elite endurance athletes: Comparison of 2-tiered and 4-tiered classification of left ventricular hypertrophy.

BACKGROUND: Long-term endurance sport practice leads to eccentric left ventricular hypertrophy (LVH). We aimed to compare the new 4-tiered classification (4TC) for LVH with the established 2-tiered classification (2TC) in a cohort of normotensive non-elite endurance athletes. METHODS: Male participants of a 10-mile race were recruited and included when blood pressure (BP) was normal (<140/90 mmHg). Phenotypic characterization of LVH was based on relative wall thickness (2TC), and on LV concentricity2/3 (LV mass/end-diastolic volume [LVM/EDV]2/3) plus LVEDV index (4TC). Parameters of LV geometry, BP, cumulative training hours, and race time were compared between 2TC and 4TC by analysis of variance, and post-hoc analysis. RESULTS: Of 198 athletes recruited, 174 were included. Mean age was 41.6±7.5 years. Forty-two (24%) athletes had LVH. Allocation in the 2TC was: 32 (76%) eccentric LVH and 10 (24%) concentric LVH. Using the 4TC 12 were reclassified to concentric LVH, and 2 to eccentric LVH, resulting in 22 (52%) eccentric LVH (7 non-dilated, 15 dilated), and 20 (48%) concentric LVH (all non-dilated). Based on the 2TC, markers of endurance training did not differ between eccentric and concentric LVH. Based on the 4TC, athletes with eccentric LVH had more cumulative training hours and faster race times, with highest values thereof in athletes with eccentric dilated LVH. CONCLUSIONS: In our cohort of normotensive endurance athletes, the new 4TC demonstrated a superior discrimination of exercise-induced LVH patterns, compared to the established 2TC, most likely because it takes three-dimensional information of the ventricular geometry into account.

Sports engagement and age at first myocardial infarction in men under 55 years of age.

OBJECTIVE: Low levels of physical activity in childhood are associated with clustering of cardiovascular risk factors (CVRF) as predisposition for atherosclerosis. We assessed the association between sports engagement and age at first myocardial infarction (MI) in a cohort of men under 55 years of age. METHODS: The Bern percutaneous coronary intervention Registry (NCT 02241291) was analyzed from March 2009 until January 2012. Male patients with first MI, age 18 to 54 years and body mass index ≤25kg/m2 were included. Patients were stratified into two groups based on their starting age with organized sports ≥1 h/week outside school (EARLY: <18, CONTROL: ≥18 years or never). We assessed age at time of first MI, CVRF, and volume of sports training. RESULTS: Of 4,394 consecutive patients, 123 fulfilled the inclusion criteria (EARLY n = 81, CONTROL n = 42). Age at the time of first MI was 3 years younger in the EARLY compared to the CONTROL group (46.8±6.0 vs. 49.8±4.6 years, p = 0.006). Total lifetime training hours, and average yearly training hours, both, before and after age 18, were significantly greater in the EARLY group. Years of training <18 years were weakly inversely correlated with age at first MI (r2 = 0.075, p = 0.002). The proportion of sports-related MI was not different between EARLY and CONTROL (13.6% vs. 11.9%). Patients in the EARLY group had fewer CVRF (2 vs. 3; p = 0.001). Prevalence of smoking was equally high in both groups (63.0% and 64.3%). CONCLUSIONS: In our patients aged 54 and younger, the first MI occurred 3 years earlier in those who started regular sports activity before age 18, despite a more active lifestyle and favorable CVRF profile.

Sports-related sudden cardiac deaths in the young population of Switzerland.

BACKGROUND: In Switzerland, ECG screening was first recommended for national squad athletes in 1998. Since 2001 it has become mandatory in selected high-risk professional sports. Its impact on the rates of sports-related sudden cardiac death (SCD) is unknown. OBJECTIVE: We aimed to study the incidence, causes and time trends of sports-related SCD in comparison to SCD unrelated to exercise in Switzerland. METHODS: We reviewed all forensic reports of SCDs of the German-speaking region of Switzerland in the age group of 10 to 39 years, occurring between 1999 and 2010. Cases were classified into three categories based on whether or not deaths were associated with sports: no sports (NONE), recreational sports (REC), and competitive sports (COMP). RESULTS: Over the 12-year study period, 349 SCD cases were recorded (mean age 30±7 years, 76.5% male); 297 cases were categorized as NONE, 31 as REC, and 21 as COMP. Incidences of SCD per 100,000 person-years [mean (95% CI)] were the lowest in REC [0.43 (0.35-0.56)], followed by COMP [1.19 (0.89-1.60)] and NONE [2.46 (2.27-2.66)]. In all three categories, coronary artery disease (CAD) with or without acute myocardial infarction (MI) was the most common cause of SCD. Three professional athletes were identified in COMP category which all had SCD due to acute MI. There were no time trends, neither in overall, nor in cause-specific incidences of SCD. CONCLUSIONS: The incidence of SCD in young individuals in Switzerland is low, both related and unrelated to sports. In regions, like Switzerland, where CAD is the leading cause of SCD associated with competitions, screening for cardiovascular risk factors in addition to the current PPS recommendations might be indicated to improve detection of silent CAD and further decrease the incidence of SCD.

Cardiopulmonary adaptation to short-term high altitude exposure in adult Fontan patients.

OBJECTIVE: High altitude-related hypoxia induces pulmonary vasoconstriction. In Fontan patients without a contractile subpulmonary ventricle, an increase in pulmonary artery pressure is expected to decrease circulatory output and reduce exercise capacity. This study investigates the direct effects of short-term high altitude exposure on pulmonary blood flow (PBF) and exercise capacity in Fontan patients. METHODS: 16 adult Fontan patients (mean age 28±7 years, 56% female) and 14 matched controls underwent cardiopulmonary exercise testing with measurement of PBF with a gas rebreathing system at 540 m (low altitude) and at 3454 m (high altitude) within 12 weeks. RESULTS: PBF at rest and at exercise was higher in controls than in Fontan patients, both at low and high altitude. PBF increased twofold in Fontan patients and 2.8-fold in the control group during submaximal exercise, with no significant difference between low and high altitude (p=0.290). A reduction in peak oxygen uptake at high compared with low altitude was observed in Fontan patients (22.8±5.1 and 20.5±3.8 mL/min/kg, p<0.001) and the control group (35.0±7.4 and 29.1±6.5 mL/min/kg, p<0.001). The reduction in exercise capacity was less pronounced in Fontan patients compared with controls (9±12% vs 17±8%, p=0.005). No major adverse clinical event was observed. CONCLUSIONS: Short-term high altitude exposure has no negative impact on PBF and exercise capacity in Fontan patients when compared with controls, and was clinically well tolerated. TRIAL REGISTRATION NUMBER: NCT02237274: Results.

Sports-related sudden cardiac death in Switzerland classified by static and dynamic components of exercise.

BACKGROUND: Sports-related sudden cardiac deaths (SrSCDs) occur most frequently in highly dynamic and/or static sports. We aimed to assess the incidence and characteristics of SrSCDs in Switzerland and to compare SrSCD occurrence according to sports categories with the sports participation behaviour in the general population. METHODS: Between 1999 and 2010, forensic reports of SrSCDs in young individuals (10-39 years of age) were retrospectively reviewed and categorised based on peak static (increasing from I to III) and dynamic sports components (increasing from A to C). Data were compared to the sports participation behaviour of the Swiss population. RESULTS: Sixty-nine SrSCDs were identified. Forty-eight (69.6%) occurred during recreational sports (REC) and 21 (30.4%) during competitive sports (COMP). Incidences (per 100,000 athlete person-years) for COMP and REC were 0.90 and 0.52, respectively (p = 0.001). Most SrSCDs occurred in IC (23 cases, 33.3%), followed by IIC (13, 18.9%), IIIA and IIIC (11 each, 15.9%), IIIB (6, 8.7%), IIA (4, 5.8%) and IB sports categories (1, 1.5%). No SrSCDs were found in IA and IIB sports categories. Incidences between sports categories (IIIA 0.25, IB 0.25, IC 0.18, IIC 0.33 and IIIC 0.25) were not significantly different except to IIA (0.94, p < 0.001), due to the fact that few people were involved in this sports category. Coronary artery disease (CAD) was the most common underlying pathology of SrSCD. CONCLUSIONS: In this Swiss cohort, incidence of SrSCD was very low and similar in all sports categories classified by their static and dynamic components. However, the incidence was higher in COMP compared to REC, and CAD proved to be the most common underlying cause of SrSCD.

Acute effects of Finnish sauna and cold-water immersion on haemodynamic variables and autonomic nervous system activity in patients with heart failure.

BACKGROUND: The haemodynamic response to Finnish sauna and subsequent cold-water immersion in heart failure patients is unknown. METHODS: Haemodynamic response to two consecutive Finnish sauna (80℃) exposures, followed by a final head-out cold-water immersion (12℃) was measured in 37 male participants: chronic heart failure (n = 12, 61.8 ± 9.2 years), coronary artery disease (n = 13, 61.2 ± 10.6 years) and control subjects (n = 12, 60.9 ± 8.9 years). Cardiac output was measured non-invasively with an inert gas rebreathing method prior to and immediately after the first sauna exposure and after cold-water immersion, respectively. Blood pressure was measured before, twice during and after sauna. The autonomic nervous system was assessed by power spectral analysis of heart rate variability. Total power, low-frequency and high-frequency components were evaluated. The low frequency/high frequency ratio was used as a marker of sympathovagal balance. Sauna and cold-water immersion were well tolerated by all subjects. RESULTS: Cardiac output and heart rate significantly increased in all groups after sauna and cold-water immersion (p < 0.05), except for coronary artery disease patients after sauna exposure. Systolic blood pressure during sauna decreased significantly in all groups with a nadir after 6 min (all p < 0.05). Cold-water immersion significantly increased systolic blood pressure in all groups (p < 0.05). No change in the low/high frequency ratio was found in chronic heart failure patients. In coronary artery disease patients and controls a prolonged increase in low frequency/high frequency ratio was observed after the first sauna exposure. CONCLUSIONS: Acute exposure to Finnish sauna and cold-water immersion causes haemodynamic alterations in chronic heart failure patients similarly to control subjects and in particular did not provoke an excessive increase in adrenergic activity or complex arrhythmias.

Masked hypertension and cardiac remodeling in middle-aged endurance athletes.

OBJECTIVES: Extensive endurance training and arterial hypertension are established risk factors for atrial fibrillation. We aimed to assess the proportion of masked hypertension in endurance athletes and the impact on cardiac remodeling, mechanics, and supraventricular tachycardias (SVT). METHODS: Male participants of a 10-mile race were recruited and included if office blood pressure was normal (<140/90 mmHg). Athletes were stratified into a masked hypertension and normotension group by ambulatory blood pressure. Primary endpoint was diastolic function, expressed as peak early diastolic mitral annulus velocity (E'). Left ventricular global strain, left ventricular mass/volume ratio, left atrial volume index, signal-averaged P-wave duration (SAPWD), and SVT during 24-h Holter monitoring were recorded. RESULTS: From 108 runners recruited, 87 were included in the final analysis. Thirty-three (38%) had masked hypertension. The mean age was 42 ±â€Š8 years. Groups did not differ with respect to age, body composition, cumulative training hours, and 10-mile race time. Athletes with masked hypertension had a lower E' and a higher left ventricular mass/volume ratio. Left ventricular global strain, left atrial volume index, SAPWD, and SVT showed no significant differences between the groups. In multiple linear regression analysis, masked hypertension was independently associated with E' (beta = -0.270, P = 0.004) and left ventricular mass/volume ratio (beta = 0.206, P = 0.049). Cumulative training hours was the only independent predictor for left atrial volume index (beta = 0.474, P < 0.001) and SAPWD (beta = 0.481, P < 0.001). CONCLUSION: In our study, a relevant proportion of middle-aged athletes had masked hypertension, associated with a lower diastolic function and a higher left ventricular mass/volume ratio, but unrelated to left ventricular systolic function, atrial remodeling, or SVT.

Incidence and time frame of life-threatening arrhythmias in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention.

BACKGROUND: Life-threatening arrhythmias may complicate the hospital course of patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). The optimal duration of electrocardiographic monitoring in such patients is not well established. We aimed to determine the incidence and the time of occurrence of life-threatening arrhythmias in STEMI patients undergoing PPCI. METHODS: Data of 382 consecutive patients with STEMI undergoing PPCI were analysed regarding the occurrence of ventricular fibrillation (VF), sustained ventricular tachycardia (sVT) or bradycardia necessitating temporary or permanent pacing. RESULTS: Of these patients, 55% had inferior STEMI, 41% anterior and 4% lateral STEMI. The infarct-related arteries were the right in 41%, the left anterior descending in 41%, the left circumflex in 16%, the left main stem in 1% and a vein graft in <1%. During hospitalisation, 27 (7.0%) patients developed 29 life-threatening arrhythmias (incidence 7.6%): 19 episodes occurred during PPCI (VF n = 11, bradycardia n = 8), 9 episodes during the first 24 hours after PPCI (VF n = 7, sVT n = 2), and 1 sVT episode in a hypokalemic patient on the 4th post-procedural day. A total of 17 patients (4.5%) died within the first 30 days, and 3 of these died during the PPCI procedure. CONCLUSIONS: Life-threatening arrhythmias occur in a considerable proportion of STEMI patients undergoing PPCI during hospitalisation. Most of these arrhythmias occur during the PPCI procedure. Post-procedural life-threatening arrhythmias are virtually limited to the first 24 hours after PPCI. Thus, routine electrocardiographic monitoring beyond the first 24 hours after PPCI might not be required in most patients with uncomplicated STEMI.

Incidence of acute myocardial infarction after implementation of a public smoking ban in Graubünden, Switzerland: two year follow-up.

QUESTION UNDER STUDY: In the first year after implementation of a public smoking ban a significant decrease in the incidence of acute myocardial infarction (AMI) was observed in Graubünden. In the present study we analyzed the incidence of AMI in the second year of the ban. In addition, we investigated the contribution of smoking ban-unrelated factors to the reduced incidence of AMI incidence observed after enactment of the ban. METHODS: Data of all AMI patients who underwent coronary angiography at the Kantonsspital Graubünden, the only tertiary care hospital with a cardiac catheterization laboratory in Graubünden, between March 1st, 2009 and February 28th, 2010 were collected prospectively. Data were compared with those of the three preceding 12-month periods. We also estimated AMI incidence during the corresponding time period in Lucerne, a region with no smoke-free legislation, using data of the AMIS Plus registry. The influence of outdoor air pollution was analyzed with the help of official measurements of PM(10)- and NO(2)-concentrations in Graubünden. The prescription of lipid-lowering drugs was estimated by using sales figures in Graubünden and Lucerne. RESULTS: In Graubünden, the number of patients with AMI in the second year after adoption of the smoking ban was similar to that in the first year of the ban (188 vs. 183; P = ns) and significantly lower than in each of the two years preceding the ban (229 and 242, respectively; P <0.05 vs. each of the 12-month periods after the ban). Overall, the number of AMI patients in the two post-ban years was 21% lower than in the two pre-ban years. The reduction in the number of patients with AMI was most pronounced in non-smokers and individuals with known coronary artery disease. During the corresponding time period, no similar decrease in the incidence of AMI was observed in Lucerne. No association was found between the magnitude of outdoor air pollution and the incidence of AMI. During the observation period, the use of lipid-lowering drugs increased similarly in Graubünden and Lucerne. CONCLUSIONS: Compared with the two years preceding the implementation of a smoking ban, the incidence of AMI remained significantly reduced in the second year of the ban in Graubünden, whereas no similar reduction was seen in a comparable area without smoke-free legislation. Changes in outdoor air pollution or the use of lipid-lowering drugs did not substantially contribute to the decrease in the incidence of AMI that occurred after adoption of the ban in Graubünden.