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Travers G, González-Alonso J, Riding N, Nichols D, Shaw A, Périard JD. Exercise heat acclimation has minimal effects on left ventricular volumes, function and systemic hemodynamics in euhydrated and dehydrated trained humans. Am J Physiol Heart Circ Physiol 2020; 319:H965-H979. [DOI: 10.1152/ajpheart.00466.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
This study demonstrates that 10 days of exercise heat acclimation has minimal effects on left ventricular volumes, intrinsic cardiac function, and systemic hemodynamics during prolonged, repeated semirecumbent exercise in moderate heat, where heart rate and blood volume are similar to preacclimation levels. However, progressive dehydration is consistently associated with similar degrees of hyperthermia and tachycardia and reductions in blood volume, diastolic filling of the left ventricle, stroke volume, and cardiac output, regardless of acclimation state.
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Affiliation(s)
- Gavin Travers
- Athlete Health and Performance Research Centre, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
- Centre for Human Performance, Exercise and Rehabilitation, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, United Kingdom
- Division of Sport, Health and Exercise Sciences, Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - José González-Alonso
- Centre for Human Performance, Exercise and Rehabilitation, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, United Kingdom
- Division of Sport, Health and Exercise Sciences, Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Nathan Riding
- Athlete Health and Performance Research Centre, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | - David Nichols
- Sport Development Centre, Loughborough University, Loughborough, United Kingdom
| | - Anthony Shaw
- Athlete Health and Performance Research Centre, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | - Julien D. Périard
- Athlete Health and Performance Research Centre, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
- University of Canberra Research Institute for Sport and Exercise, University of Canberra, Bruce, Australia
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The restoration of chronotropic competence in heart failure patients with normal ejection fraction (RESET) study: rationale and design. J Card Fail 2009; 16:17-24. [PMID: 20123314 DOI: 10.1016/j.cardfail.2009.08.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 08/12/2009] [Accepted: 08/17/2009] [Indexed: 01/08/2023]
Abstract
BACKGROUND Heart failure with preserved ejection fraction (HFpEF) is the predominant form of heart failure among the elderly and in women. However, there are few if any evidence-based therapeutic options for HFpEF. The chief complaint of HFpEF is reduced tolerance to physical exertion. Recent data revealed that 1 potential mechanism of exertional intolerance in HFpEF patients is inadequate chronotropic response. Although there is considerable evidence demonstrating the benefits of rate-adaptive pacing (RAP) provided from implantable cardiac devices in patients with an impaired chronotropic response, the effect of RAP in HFpEF is unknown. METHODS AND RESULTS The Restoration of Chronotropic CompEtence in Heart Failure PatientS with Normal Ejection FracTion (RESET) study is a prospective, multicenter, double-blind, randomized with stratification, study assessing the effect of RAP on peak oxygen consumption and quality of life. RAP therapy will be evaluated in a crossover paired fashion for each patient within each study stratum. Study strata are based on patient beta-blocker usage at time of enrollment. The study is powered to assess the impact of pacing independently in both strata. CONCLUSIONS The RESET study seeks to evaluate the potential benefit of RAP in patients with symptomatic mild to moderate HFpEF and chronotropic impairment. Study enrollment began in July 2008.
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Saxon LA, Stevenson WG, Middlekauff HR, Stevenson LW. Increased risk of progressive hemodynamic deterioration in advanced heart failure patients requiring permanent pacemakers. Am Heart J 1993; 125:1306-10. [PMID: 8480582 DOI: 10.1016/0002-8703(93)90999-p] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
To determine the influence of long-term permanent pacing systems on survival in patients with severe left ventricular dysfunction, data from 557 consecutive patients hospitalized with advanced heart failure for cardiac transplant evaluation and discharged on medical therapy were reviewed. Permanent pacemakers were identified in 42 (8%) patients. One-year actuarial risk of death from heart failure or urgent transplantation in paced patients was higher (49%) than that of a control group, matched for the severity of heart failure (15%, p = 0.003). Sudden death did not differ between paced patients and controls.
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Affiliation(s)
- L A Saxon
- Medical Center, University of California, Los Angeles
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McGuire MA, Lau KC, Davis LM, Knight P, Uther JB, Ross DL. Permanent junctional reciprocating tachycardia misdiagnosed as 'cardiomyopathy'. AUSTRALIAN AND NEW ZEALAND JOURNAL OF MEDICINE 1991; 21:239-41. [PMID: 1872752 DOI: 10.1111/j.1445-5994.1991.tb00450.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In a nine-year-old female, cardiac failure was erroneously attributed to idiopathic cardiomyopathy and cardiac transplantation was planned. The actual cause of cardiac failure was permanent junctional reciprocating tachycardia (PJRT), a rare form of supraventricular tachycardia. The diagnostic error was discovered before transplantation was performed and the arrhythmia was treated surgically. This resulted in return of near normal cardiac function.
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Affiliation(s)
- M A McGuire
- Cardiology Unit, Westmead Hospital, Sydney, NSW, Australia
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Brown JM, Grosso MA, Reiter MJ, Mann DE, Whitman GJ, Harken AH. Chronic supraventricular tachycardia can cause severe ventricular dysfunction, which can be surgically repaired. J Thorac Cardiovasc Surg 1988. [DOI: 10.1016/s0022-5223(19)35190-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Damiano RJ, Tripp HF, Asano T, Small KW, Jones RH, Lowe JE. Left ventricular dysfunction and dilatation resulting from chronic supraventricular tachycardia. J Thorac Cardiovasc Surg 1987. [DOI: 10.1016/s0022-5223(19)36329-9] [Citation(s) in RCA: 71] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Nesto RW, Kowalchuk GJ. The ischemic cascade: temporal sequence of hemodynamic, electrocardiographic and symptomatic expressions of ischemia. Am J Cardiol 1987; 59:23C-30C. [PMID: 2950748 DOI: 10.1016/0002-9149(87)90192-5] [Citation(s) in RCA: 343] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The development of an ischemic event, whether silent or painful, represents the cumulative impact of a sequence of pathophysiologic events. Each ischemic episode is initiated by an imbalance between myocardial oxygen supply and demand that may ultimately be manifested as angina pectoris. This sequence of events can be termed the ischemic cascade. The significance of this concept resides in the fact that it redirects the focus from the end result--angina--to the more fundamental, underlying pathophysiologic factors that precede it. Specifically, these events include diminished left ventricular compliance, decreased myocardial contractility, increased left ventricular end-diastolic pressure, ST-segment changes and, occasionally, angina pectoris.
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Packer DL, Bardy GH, Worley SJ, Smith MS, Cobb FR, Coleman RE, Gallagher JJ, German LD. Tachycardia-induced cardiomyopathy: a reversible form of left ventricular dysfunction. Am J Cardiol 1986; 57:563-70. [PMID: 3953440 DOI: 10.1016/0002-9149(86)90836-2] [Citation(s) in RCA: 404] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Eight patients, aged 5 to 57 years, with uncontrolled symptomatic tachycardia for 2.5 to 41 years (mean 15) and significant left ventricular (LV) dysfunction in the absence of any other apparent underlying cardiac disease underwent evaluation. Incessant tachycardia was present for 0.5 to 6.0 years (mean 2.1) in 7 patients. One patient had an ectopic atrial tachycardia and 7 patients had an accessory atrioventricular pathway that participated in reciprocating tachycardia. Six patients underwent surgery; the ectopic focus was ablated in 1 patient and an accessory pathway was divided in 5 patients. One patient underwent open ablation of the His bundle and 1 patient underwent closed-chest ablation of the atrioventricular conduction system. Myocardial biopsy specimens were obtained from 5 patients, none of which yielded a specific diagnosis. Pretreatment radionuclide angiography demonstrated a mean ejection fraction (EF) of 19 +/- 9% (range 10 to 35%). Following tachycardia control a marked improvement in LV function was noted in 6 of 8 patients at rest and in 1 additional patient during exercise. The EF increased to 33 +/- 17% (range 16 to 56%) an average of 8 days after treatment and to 45 +/- 15% (range 22 to 67%) at late follow-up 3.5 +/- 40 months (mean 17) later (p less than 0.005). Seven patients remain asymptomatic 11 to 40 months (mean 22) after the corrective procedure and have resumed normal activities. These findings suggest that chronic uncontrolled tachycardia may result in significant LV dysfunction, which is reversible in some cases after control of the arrhythmia.
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