No Influence of Heart Rate on Early Diastolic Time Intervals

Sekiya, Motohiro; Hamada, Mareomi; Mukai, Mikio; Shigematsu, Yuji; Ochi, Takaaki; Hiwada, Kunio

doi:10.1159/000470426

Cited by 4 publications

(3 citation statements)

References 13 publications

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“…8 The rationale for this sound in patients with dilated ventricles is believed to be an inability of the left ventricle to accept the increased transmitral flow during the period of rapid filling.6 In humans, the heart rate has been shown to have no influence on the early diastolic intervals. 48 If this is also valid in the dog, it may explain why no correlation was found between the heart rate and the Q-S3 interval in this study. A constant diastolic portion of the Q-S3 interval means that electromechanical systole (Q-S2 interval) is the only source of variation in the Q-S3 interval.…”

Section: Discussionmentioning

confidence: 70%

Heart Sounds and Murmurs: Changes Related to Severity of Chronic Valvular Disease in the Cavalier King Charles Spaniel

Häggström

Kvart

Hansson

1995

Veterinary Internal Medicne

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Auscultatory, phonocardiographic (PCG), radiographic, and echocardiographic evidence of chronic valvular disease (CVD) were studied in 79 Cavalier King Charles Spaniels with a mean age of 7.6 years (SD 2.6). Cardiac murmurs were present in 59 of the dogs and the intensity of the systolic cardiac murmur, assessed by auscultation (grade 1-6). was correlated (P < .001) t o the severity of CVD (heart failure class) and t o the echocardiographical dimensions of the heart (left atrial ratio, La/Ao-d, and left ventricular end diastolic diameter, LVEDD) (both P < .001).The heart sounds and duration of electromechanical systole (042) were investigated in all dogs using measurements obtained from PCG recordings. Normal regression equations describing the relation between heart rate and systolic intervals (Q-Sl, Q-S2 and Sl-S2) were established based on observations in 1 1 normal control Cavalier King Charles Spaniels. The total electromechanical systole (Q-S2). 0-S1, and S1 -S2 intervals in the 59 dogs were related to the corresponding normal regression equation. A shortening of Q-S2 and S1 -S2 intervals were found in dogs belonging t o heart failure class I (Q-S2; P < .01 and S1 -S2; P < .05), class II, and classes Ill and IV (both P < ,001). The ratio of the amplitudes of the first (SI) and second heart hronic valvular disease (CVD) is commonly ob-C served in old dogs of small to medium size breeds.'-3 Lesions associated with CVD start with a progressive thickening and contraction of the atrioventricular valves leading to insufficient coaptation of the leaflets. This causes an increasing regurgitation of blood with accompanying enlargement of the atrium and ventricle. The areas of contact along the free border of the mitral cusps and corresponding chordae tendineae are commonly a f f e~t e d ,~ but the tricuspid valves can also display pathological changes; the pulmonary and aortic valves are seldom affe~ted.~ The animal can compensate for the valvular insufficiency for a period of time, but decompensation and, usually, left-sided congestive heart failure may ultimately desounds (S2) measured on the PCG recordings was found t o be increased in dogs belonging t o class I (P < .Ol), class II, and classes 111 and IV (both P < .OOl). The relationship between cardiac dimensions (LVEDD and La/Ao-d) and Sla/ S2a ratio was described by quadratic regression and found to be significant for both parameters (LVEDD; P < .001, R2 = .54 and La/Ao-d; P < .001, R2 = .63). The presence of a third heart sound (S3) was detected, using PCG, in 21 of the 68 dogs. The proportion of dogs exhibiting S3 increased with heart failure class (and increasing cardiac dimensions) (P < ,001 ). These findings were confirmed by observations in 13Cavalier King Charles Spaniels with cardiac failure progressing from heart failure class I toclass II (Mean LVEDDfrom Ao-d from 1.09 t o 1.43). An increase in intensity of the heart murmur, assessed by auscultation, increase in the ratio of the amplitudes of S1 and S2, as well as a shortening in Q-S2 and S1 -S2 in...

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Section: Discussionmentioning

confidence: 70%

Heart Sounds and Murmurs: Changes Related to Severity of Chronic Valvular Disease in the Cavalier King Charles Spaniel

Häggström

Kvart

Hansson

1995

Veterinary Internal Medicne

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“…A similar change in arteriolar muscle was also suggested by the increased TPR. The large increase in IRT is not explained by the small fall in heart rate (Sekiya et al 1991).…”

Section: Discussionmentioning

confidence: 71%

Subpressor Calcium Infusion Increases Isovolumic Left Ventricular Relaxation Time and Atrial Natriuretic Peptide in Humans

Finn

Gordon

Seneviratne

et al. 1992

Clin Exp Pharma Physio

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1. Subpressor calcium infusion for 1 h, which raised calcium levels to the upper limit of normal in normal subjects, increased plasma and urinary levels of atrial natriuretic peptide (ANP). 2. Heart rate fell, presumably due to carotid baroreflex stimulation (supported by the fall in noradrenaline) and the resultant fall in cardiac output prevented the expected rise in blood pressure due to the rise in total peripheral resistance (TPR). Thus the increase in ANP was not explained by an increase in blood pressure or noradrenaline. 3. There was no evidence for increased atrial stretch (no increase in atrial area or early velocity of left ventricular filling) as a mechanism for increased ANP. 4. Isovolumic left ventricular relaxation time increased, early velocity of ventricular filling decreased and TPR increased, consistent with increased tone in left ventricular and arteriolar muscle. 5. This suggests a direct effect of calcium on the atrial myocyte, stimulating ANP either through contractile or secretory mechanisms.

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“…With regard to the left ventricular diastolic functions, the isovolumic relaxation time (IRT) is one of the most popular and reliable indices and has been used to assess the cardiac functions in various cardiac diseases [5][6][7][8], It is well known that no significant influence of the heart rate on IRT is observed over a wide range of R-R intervals [9,10]; therefore, it is advantageous to use IRT in assess ing the changes of left ventricular function in various heart diseases.…”

Section: Introductionmentioning

confidence: 99%

Does Isovolumic Relaxation Time Reflect the Severity of Left Ventricular Hypertrophy in Patients with Essential Hypertension?

Hamada¹,

Shigematsu²,

Abe³

et al. 1992

Am J Noninvas Cardiol

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To elucidate whether the isovolumic relaxation time (IRT) reflects the severity of left ventricular hypertrophy, IRT and left ventricular mass index (LVMI) were measured in 43 patients with essential hypertension and in 17 normotensive controls. The hypertensive patients were subdivided into three groups based on interventricular septal thickness (IVST) and left ventricular posterior wall thickness (PWT), determined echocardiographically, and clinical symptoms. IVST and PWT in group 1 patients (n = 10) were less than 10 mm, IVST and/or PWT in group 2 (n = 23) were 10 mm or greater, and the hypertensive patients in group 3 (n = 10) were in class III of the New York Heart Association Classification of hypertension. The IRT was prolonged in accordance with the increase in LVMI in groups 1 and 2. Though the LVMI showed no significant difference between normotensive controls and group 1, the IRT was significantly longer in group 1 patients (p < 0.05). The LVMI was markedly greater in group 3 than in group 2 (p < 0.01), but the IRT showed no significant difference. This finding indicates that there might be a limit of IRT prolongation associated with myocardial hypertrophy due to essential hypertension. In conclusion, IRT reflects the severity of left ventricular hypertrophy in patients with mild to moderate essential hypertension, but does not in advanced stages of hypertension.

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No Influence of Heart Rate on Early Diastolic Time Intervals

Cited by 4 publications

References 13 publications

Heart Sounds and Murmurs: Changes Related to Severity of Chronic Valvular Disease in the Cavalier King Charles Spaniel

Heart Sounds and Murmurs: Changes Related to Severity of Chronic Valvular Disease in the Cavalier King Charles Spaniel

Subpressor Calcium Infusion Increases Isovolumic Left Ventricular Relaxation Time and Atrial Natriuretic Peptide in Humans

Does Isovolumic Relaxation Time Reflect the Severity of Left Ventricular Hypertrophy in Patients with Essential Hypertension?

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