Safety of dobutamine stress echocardiography. A 24 h Holter monitoring study.

BACKGROUND: Dobutamine-atropine stress echocardiography is an efficient method in the evaluation of patients with coronary artery disease. However, because high-dose dobutamine is potentially arrhythmogenic, the safety of this stress modality has been questioned. METHODS: We performed a 24 h Holter monitoring, before and immediately after this test, in 73 consecutive patients (60 men and 13 women), mean age 60 +/- 12 years. Twenty-eight patients had had a recent myocardial infarction, 25 had stable chronic angina, 10 chronic ischaemic cardiomyopathy and 10 idiopathic dilated cardiomyopathy. Dobutamine was progressively increased (5-40 micrograms.kg-1.min-1) and atropine was injected in 30 patients. Arrhythmias and ST-segment deviation before and after the stress test were evaluated. RESULTS: The mean peak dobutamine dose was 32 +/- 11 micrograms.kg-1.min-1. The heart rate at rest and at peak dose was, respectively, 69 +/- 16 and 110 +/- 28 beats.min-1. Side effects during the injection of dobutamine were mainly ventricular (n = 14) or atrial (n = 4) premature contractions. Three patients had non-sustained ventricular tachycardia and five had hypotension during the test. No sustained episode of supraventricular or ventricular tachycardia was observed during the study. Non-sustained supraventricular and ventricular tachycardias were detected in 8 and 21 patients before and in 11 and 16 patients after dobutamine stress echocardiography (P = ns). Asymptomatic ST-segment deviation was observed in two patients before and four after dobutamine stress echocardiography. An increase in total ischaemic time (20 vs 102 mn) was observed after the test, but only five patients had ST modifications. A separate analysis of patients with and without beta-blocker did not alter these results. In addition, when the occurrence of significant arrhythmias was stratified according to a left ventricular ejection fraction threshold of 45%, we observed no difference in frequency and severity of cardiac arrhythmias. CONCLUSION: This study demonstrates that dobutamine stress echocardiography does not significantly increase arrhythmia during the following 24 h. Further studies are required to evaluate the influence of the test on ST-segment modification during the same period.

[Morphological study by transesophageal echocardiography and clinical aspects of ruptured chordae tendineae in the elderly]. / Etude morphologique par échocardiographie transoesophagienne et aspects cliniques de la rupture de cordages mitral chez le sujet âgé.

Ruptured mitral chordae tendinae is a classical complication of myxomatous mitral valves or Barlow's syndrome. This complication is controversial in non-myxomatous mitral valve. Of 91 consecutive patients with mitral valve prolapse examined over an 18 months period by transthoracic and transesophageal echocardiography, 42 (18 women and 24 men) with an average age of 76 +/- 8 years (60-93 years) had ruptured mitral chordae tendinae. The thickness of the anterior mitral leaflet measured at the distal third of the valve by transesophageal echocardiography enabled the identification of two groups of patients; group I: > 3 mm (24 patients), average 4.8 +/- 0.8 mm and group II: < or = 3 mm (18 patients), average 2.6 +/- 0.3 mm. The diameter of the mitral ring and left atrium, the length of the anterior mitral leaflet, the left ventricular end diastolic dimensions and fractional shortening, were measured by transthoracic 2D echocardiography (mitral ring) and M mode (other parameters). Ruptured chordae were detected in only 13 cases (31%) by transthoracic echocardiography; 38% were asymptomatic and a chance finding at transesophageal echocardiography. No significant difference was observed between the two groups with respect to age, gender presence of hypertension, dimensions of the cardiac chambers, fractional shortening or localisation of the prolapse related to the ruptured chordae. Fifty-eight per cent of patients in group I were in NYHA functional classes 3-4 as compared to 16% in group II (p < 0.02). The size of the left atrium was significantly greater in group I, 51 +/- 8 mm vs 38 +/- 7 mm (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

[Physiological limits of variations in heart rate measured by the Holter method in 134 normal subjects]. / Etude des limites physiologiques des variations de la fréquence cardiaque par la méthode de Holter chez 134 sujets normaux.

Ambulatory 24 hour electrocardiography by the Holter method was carried out in 134 normal subjects (59 men, 75 women, mean age: 42.5 +/- 14 years). The average heart rate over 24 hours was 75 +/- 9 bpm, 82 +/- 10 bpm during the daytime and 64 +/- 8 bpm at night. Maximal and minimal momentary variations (over 5 minutes) were small during the night (+23% and -7%) and greater during the daytime (+47% and -16%). The heart rate slowed progressively over a two hour period before going to bed an increased progressively over a three hour period, reaching a peak and then slightly falling before getting up. The average heart rates of women were faster than in men (+5 bpm). The average heart rate fell with age from 30 years onwards (-0.4 bpm per year). Tobacco consumption did not seem to affect the heart rate. Supraventricular extrasystoles were observed in 68% of subjects during the day, and in 50% during the night; ventricular extrasystoles occurred in 42% of subjects by day and in 23% by night. Only 22% of subjects had no extrasystolic activity. Tobacco consumption and sex were unrelated to the incidence and frequency of extrasystoles. On the other hand, the incidence and frequency of extrasystoles were very significantly related to age.