Roberto Di Paola | PubMed Health

PubMed2004

Left ventricular function in acute hypothyroidism: a Doppler echocardiography study.

BACKGROUND: Acute changes in cardiac parameters may occur after L-thyroxine withdrawal in patients totally thyroidectomized for thyroid cancer. The literature data regarding cardiac function in acute hypothyroidism are limited and discordant. METHODS: In order to evaluate the effects of acute hypothyroidism on cardiac function, 20 athyreotic patients (3 males, 17 females, mean age 46.4 +/- 8.6 years, range 18-58 years) underwent Doppler echocardiography during L-thyroxine therapy (euthyroid phase) and 5 weeks after hormone therapy withdrawal (hypothyroid phase). RESULTS: Significant changes in the left ventricular mass (83 +/- 12 vs 93 +/- 17 g/m2, p = 0.004) and end-diastolic volume (56 +/- 9 vs 50 +/- 9 ml/m2, p = 0.01) were found. Among systolic function parameters, the pre-ejection period/left ventricular ejection time (PEP/LVET) ratio (0.33 +/- 0.07 vs 0.40 +/- 0.08, p = 0.0002), aortic peak flow velocity corrected for heart rate (3.9 +/- 0.7 vs 3.5 +/- 0.5 cm/s, p = 0.02) and mean aortic acceleration corrected for heart rate (45 +/- 15 vs 38 +/- 9 cm/s2, p = 0.007) showed significant variations, whereas the left ventricular fractional shortening (39 +/- 5 vs 40 +/- 6%, p = NS) and ejection fraction (69 +/- 6 vs 68 +/- 7%, p = NS) did not change. Among diastolic function parameters, only the E-wave velocity decreased (73 +/- 17 vs 65 +/- 12 cm/s, p = 0.01); no significant modification was found in the A-wave velocity (62 +/- 19 vs 58 +/- 14 cm/s, p = NS), E/A ratio (1.2 +/- 0.5 vs 1.1 +/- 0.3, p = NS), isovolumic relaxation time (93 +/- 16 vs 95 +/- 37 ms, p = NS) and E-wave deceleration time (233 +/- 48 vs 235 +/- 45 ms, p = NS). The pattern of left ventricular filling remained unchanged, except in 2 patients. The Suga-Sagawa's index, a known parameter of myocardial contractility, was unchanged (5.6 +/- 2 vs 6.1 +/- 2 mmHg/ml, p = NS). The systemic vascular resistance increased (1511 +/- 599 vs 2216 +/- 408 dynes-s-cm(-5), p = 0.002), while the stroke index (39 +/- 8 vs 33 +/- 7 ml/m2, p = 0.001) and cardiac index (2.74 +/- 0.6 vs 2.07 +/- 0.5 l/min/m2, p = 0.0001) significantly decreased. CONCLUSIONS: Acute hypothyroidism was associated with left ventricular systolic dysfunction, probably due to pre- and afterload alterations rather than to an impaired myocardial contractility. The diastolic function was not significantly modified. An increase in cardiac mass was also found, possibly a consequence of early interstitial myxedema. Unlike the PEP/LVET ratio, both the fractional shortening and ejection fraction may be unreliable indicators of left ventricular systolic dysfunction in patients with acute hypothyroidism.

Acute Disease↗

PubMed2003

Preclinical thalassemic cardiopathy: a study by acoustic densitometry.

BACKGROUND: The cardiac function in thalassemia major has never been studied at ultrasonic backscatter techniques. We assessed the utility of acoustic densitometry in thalassemic patients without clinical or echocardiographic signs of heart failure. METHODS: Three groups of subjects with comparable age, sex and body surface area were analyzed: 25 with beta-thalassemia major (group A), 14 with thalassemia intermedia (group B) and 10 healthy subjects (group C). All patients were asymptomatic and without conventional echocardiographic signs of systo-diastolic dysfunction. The left ventricular mass and volumes were echocardiographically evaluated. The ultrasonic myocardial integrated backscatter signal (IBS) was recorded and analyzed by means of acoustic densitometry in the parasternal long-axis view at the septum and posterior wall, both at the basal and intermediate levels. Both the average image intensity and the systo-diastolic variations of the IBS (cyclic variation index-CVIibs and peak-to-peak intensity-PPI), respectively related to the structure and contractility of the myocardium, were calculated. The serum ferritin and liver iron concentrations were also measured, as markers of tissue iron storage. RESULTS: The CVIibs was significantly lower in groups A and B than in group C at basal (22.7 +/- 8.4 vs 22.1 +/- 7.8 vs 31.8 +/- 10.2%; p = 0.001) and intermediate septum (24.4 +/- 7.6 vs 25.3 +/- 8.1 vs 30 +/- 9.8%; p = 0.03) and at basal (25.9 +/- 7.6 vs 24.5 +/- 6.1 vs 31.1 +/- 10.6%; p = 0.02) and intermediate posterior wall (25.1 +/- 5.1 vs 24.3 +/- 6.2 vs 30.2 +/- 6.6%; p = 0.02). The PPI was also significantly lower in groups A and B than in group C. Both CVIibs and PPI were comparable in groups A and B. The average image intensity and left ventricular mass and volumes were not significantly different in the three groups. No correlation was found between the densitometric findings and markers of tissue iron storage. CONCLUSIONS: In asymptomatic patients with thalassemia major with normal conventional indexes of systo-diastolic cardiac function, acoustic densitometry may show a reduced cyclic variation of the IBS as a possible marker of initial myocardial contractile deficiency. On the contrary, neither structural alterations nor the extent of myocardial iron stores are detectable by this technique in this type of patients.

Acoustics↗