Adrenergic control of the force-frequency and relaxation-frequency relations in patients with hypertrophic cardiomyopathy

Hideo Izawa, Mitsuhiro Yokota, Yasushi Takeichi, Masafumi Inagaki, Kohzo Nagata, Mitsunori Iwase, Toshikazu Sobue

Research output: Contribution to journalArticle

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Abstract

Background: Exercise-induced enhancement of the force-frequency and relaxation-frequency relations has been studied in conscious animals but not in intact diseased human hearts. Methods and Results: We evaluated left ventricular (LV) isovolumic contraction (dP/dt(max)) and relaxation (τ) during atrial pacing and dynamic exercise in 13 patients with nonobstructive hypertrophic cardiomyopathy (HCM) and 7 control subjects to investigate the influence of exercise on the force-frequency and relaxation-frequency relations. Group A consisted of 6 patients in whom the heart rate (HR)- dP/d(max) relation was markedly enhanced during exercise (88±30%) compared with during pacing (34±15%). Group B consisted of 7 patients in whom the HR- dP/dt(max) relation showed similar enhancement during exercise (28±7%) and atrial pacing (28±11%). There was no difference in the HR-τ (derivative method [TD] and pressure half-time method [T( 1/4 )) relation between pacing and exercise in groups A and B. Both the mean maximal wall thickness and the hypertrophy score in group B were greater than in group A (27±5 versus 19±2 mm and 7±1 versus 5±1 points, respectively; both P<.01). There was no difference in the LV peak systolic pressure, end-diastolic pressure, or the plasma level of catecholamines at baseline, at 50 W of exercise, and at peak pacing between groups A and B. The HR-dP/dt(max) relation in the control group was markedly enhanced during exercise (80±27%) compared with during pacing (32±14%). The HR-τ relation in the control group was enhanced during exercise (TD, 35±9%; T( 1/4 ), 34±8%) compared with during pacing (TD, 12±7%; T( 1/4 ), 14±7%). Conclusions: Exercise-induced enhancement of the relaxation- frequency relation was inhibited in all HCM patients, regardless of the degree of LV hypertrophy. The patients without exercise-induced enhancement of the force-frequency relation had more severe LV hypertrophy than the patients with the enhancement, indicating that the adrenergic control of the force-frequency relation may, at least in part, depend on the severity of LV hypertrophy or the stage of HCM.

Original languageEnglish
Pages (from-to)2959-2968
Number of pages10
JournalCirculation
Volume96
Issue number9
DOIs
Publication statusPublished - 04-11-1997
Externally publishedYes

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Hypertrophic Cardiomyopathy
Adrenergic Agents
Exercise
Heart Rate
Left Ventricular Hypertrophy
Blood Pressure
Control Groups
Hypertrophy
Catecholamines
Heart Diseases
Pressure

All Science Journal Classification (ASJC) codes

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

Cite this

Izawa, Hideo ; Yokota, Mitsuhiro ; Takeichi, Yasushi ; Inagaki, Masafumi ; Nagata, Kohzo ; Iwase, Mitsunori ; Sobue, Toshikazu. / Adrenergic control of the force-frequency and relaxation-frequency relations in patients with hypertrophic cardiomyopathy. In: Circulation. 1997 ; Vol. 96, No. 9. pp. 2959-2968.
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title = "Adrenergic control of the force-frequency and relaxation-frequency relations in patients with hypertrophic cardiomyopathy",
abstract = "Background: Exercise-induced enhancement of the force-frequency and relaxation-frequency relations has been studied in conscious animals but not in intact diseased human hearts. Methods and Results: We evaluated left ventricular (LV) isovolumic contraction (dP/dt(max)) and relaxation (τ) during atrial pacing and dynamic exercise in 13 patients with nonobstructive hypertrophic cardiomyopathy (HCM) and 7 control subjects to investigate the influence of exercise on the force-frequency and relaxation-frequency relations. Group A consisted of 6 patients in whom the heart rate (HR)- dP/d(max) relation was markedly enhanced during exercise (88±30{\%}) compared with during pacing (34±15{\%}). Group B consisted of 7 patients in whom the HR- dP/dt(max) relation showed similar enhancement during exercise (28±7{\%}) and atrial pacing (28±11{\%}). There was no difference in the HR-τ (derivative method [TD] and pressure half-time method [T( 1/4 )) relation between pacing and exercise in groups A and B. Both the mean maximal wall thickness and the hypertrophy score in group B were greater than in group A (27±5 versus 19±2 mm and 7±1 versus 5±1 points, respectively; both P<.01). There was no difference in the LV peak systolic pressure, end-diastolic pressure, or the plasma level of catecholamines at baseline, at 50 W of exercise, and at peak pacing between groups A and B. The HR-dP/dt(max) relation in the control group was markedly enhanced during exercise (80±27{\%}) compared with during pacing (32±14{\%}). The HR-τ relation in the control group was enhanced during exercise (TD, 35±9{\%}; T( 1/4 ), 34±8{\%}) compared with during pacing (TD, 12±7{\%}; T( 1/4 ), 14±7{\%}). Conclusions: Exercise-induced enhancement of the relaxation- frequency relation was inhibited in all HCM patients, regardless of the degree of LV hypertrophy. The patients without exercise-induced enhancement of the force-frequency relation had more severe LV hypertrophy than the patients with the enhancement, indicating that the adrenergic control of the force-frequency relation may, at least in part, depend on the severity of LV hypertrophy or the stage of HCM.",
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Adrenergic control of the force-frequency and relaxation-frequency relations in patients with hypertrophic cardiomyopathy. / Izawa, Hideo; Yokota, Mitsuhiro; Takeichi, Yasushi; Inagaki, Masafumi; Nagata, Kohzo; Iwase, Mitsunori; Sobue, Toshikazu.

In: Circulation, Vol. 96, No. 9, 04.11.1997, p. 2959-2968.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Adrenergic control of the force-frequency and relaxation-frequency relations in patients with hypertrophic cardiomyopathy

AU - Izawa, Hideo

AU - Yokota, Mitsuhiro

AU - Takeichi, Yasushi

AU - Inagaki, Masafumi

AU - Nagata, Kohzo

AU - Iwase, Mitsunori

AU - Sobue, Toshikazu

PY - 1997/11/4

Y1 - 1997/11/4

N2 - Background: Exercise-induced enhancement of the force-frequency and relaxation-frequency relations has been studied in conscious animals but not in intact diseased human hearts. Methods and Results: We evaluated left ventricular (LV) isovolumic contraction (dP/dt(max)) and relaxation (τ) during atrial pacing and dynamic exercise in 13 patients with nonobstructive hypertrophic cardiomyopathy (HCM) and 7 control subjects to investigate the influence of exercise on the force-frequency and relaxation-frequency relations. Group A consisted of 6 patients in whom the heart rate (HR)- dP/d(max) relation was markedly enhanced during exercise (88±30%) compared with during pacing (34±15%). Group B consisted of 7 patients in whom the HR- dP/dt(max) relation showed similar enhancement during exercise (28±7%) and atrial pacing (28±11%). There was no difference in the HR-τ (derivative method [TD] and pressure half-time method [T( 1/4 )) relation between pacing and exercise in groups A and B. Both the mean maximal wall thickness and the hypertrophy score in group B were greater than in group A (27±5 versus 19±2 mm and 7±1 versus 5±1 points, respectively; both P<.01). There was no difference in the LV peak systolic pressure, end-diastolic pressure, or the plasma level of catecholamines at baseline, at 50 W of exercise, and at peak pacing between groups A and B. The HR-dP/dt(max) relation in the control group was markedly enhanced during exercise (80±27%) compared with during pacing (32±14%). The HR-τ relation in the control group was enhanced during exercise (TD, 35±9%; T( 1/4 ), 34±8%) compared with during pacing (TD, 12±7%; T( 1/4 ), 14±7%). Conclusions: Exercise-induced enhancement of the relaxation- frequency relation was inhibited in all HCM patients, regardless of the degree of LV hypertrophy. The patients without exercise-induced enhancement of the force-frequency relation had more severe LV hypertrophy than the patients with the enhancement, indicating that the adrenergic control of the force-frequency relation may, at least in part, depend on the severity of LV hypertrophy or the stage of HCM.

AB - Background: Exercise-induced enhancement of the force-frequency and relaxation-frequency relations has been studied in conscious animals but not in intact diseased human hearts. Methods and Results: We evaluated left ventricular (LV) isovolumic contraction (dP/dt(max)) and relaxation (τ) during atrial pacing and dynamic exercise in 13 patients with nonobstructive hypertrophic cardiomyopathy (HCM) and 7 control subjects to investigate the influence of exercise on the force-frequency and relaxation-frequency relations. Group A consisted of 6 patients in whom the heart rate (HR)- dP/d(max) relation was markedly enhanced during exercise (88±30%) compared with during pacing (34±15%). Group B consisted of 7 patients in whom the HR- dP/dt(max) relation showed similar enhancement during exercise (28±7%) and atrial pacing (28±11%). There was no difference in the HR-τ (derivative method [TD] and pressure half-time method [T( 1/4 )) relation between pacing and exercise in groups A and B. Both the mean maximal wall thickness and the hypertrophy score in group B were greater than in group A (27±5 versus 19±2 mm and 7±1 versus 5±1 points, respectively; both P<.01). There was no difference in the LV peak systolic pressure, end-diastolic pressure, or the plasma level of catecholamines at baseline, at 50 W of exercise, and at peak pacing between groups A and B. The HR-dP/dt(max) relation in the control group was markedly enhanced during exercise (80±27%) compared with during pacing (32±14%). The HR-τ relation in the control group was enhanced during exercise (TD, 35±9%; T( 1/4 ), 34±8%) compared with during pacing (TD, 12±7%; T( 1/4 ), 14±7%). Conclusions: Exercise-induced enhancement of the relaxation- frequency relation was inhibited in all HCM patients, regardless of the degree of LV hypertrophy. The patients without exercise-induced enhancement of the force-frequency relation had more severe LV hypertrophy than the patients with the enhancement, indicating that the adrenergic control of the force-frequency relation may, at least in part, depend on the severity of LV hypertrophy or the stage of HCM.

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JF - Circulation

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