[Cardiac damage due to scorpion envenomation: case involving atrial flutter]

The purpose of this report is to describe a case of scorpion envenomation observed in northern Chad in a 24-year-old-man with no medical history. The victim rapidly developed supraventricular arrhythmia due to catecholaminergic storm induced by the neurotoxic activity of the venom. Cardiomyopathy that can lead to fatal acute heart failure is a risk after scorpion envenomation. Heart damage is observed in 1% of scorpion envenomation cases and can result from several mechanisms, i.e., adrenergic myocarditis (as in the patient herein), toxic myocarditis or myocardial ischemia. Few articles describing supraventricular arrhythmia following scorpion envenomation have been published. It is paroxystic and regresses spontaneously in case of transient catecholaminergic storm. Occurrence of atrial flutter, even if not associated with heart failure, is an indication of severe scorpion envenomation and requires close patient monitoring and symptomatic treatment using betablocking drugs. The efficacy of specific treatment for scorpion envenomation, i.e., immunotherapy, remains controversial.

Toxicité myocardique des catécholamines: à propos de deux observations

INTRODUCTION

The role of catecholamines in the cardiac expression of pheochromocytoma is well-known. The physiopathology of the syndrome of Tako-tsubo remains more unclear.

EXEGESIS

We describe 2 clinical cases of acute coronary syndrome with left ventricular dysfunction and no coronary artery stenosis. The first, a syndrome of Tako-tsubo, also known as transient left ventricular apical ballooning syndrome, is characterized by transient wall-motion in the absence of obstructive epicardial coronary disease. The second is a pheochromocytoma with myocardial suffering during hypertension crisis. Through the similarities of these 2 observations, we discuss the physiopathological assumptions to explain the syndrome of Tako-tsubo by underlining the essential place of the catecholamine hypersecretion.

CONCLUSION

Syndrome of Tako-tsubo and pheochromocytoma are 2 distinct clinical entities. The link between these 2 affections is probably the pathogenic role in cardiac toxicity with the catecholamines.

[Right bundle branch block: electrocardiographic and prognostic features]

The electrocardiographic appearances and the significance of right bundle branch block were described at the beginning of the 20th century. Typical appearances include prolongation > 0.12 s of the QRS complex, RR' or rR' or Rr' appearances in V1 and widened S waves in the leads exploring the left ventricle (SI, aVL, V5 and V6). A delay in the appearance of the intrinsic deflection > 0.08 s may also be observed in the right precordial leads and negative T waves with ST depression may be seen in V1 and sometimes in V2. Left axis deviation of the QRS complex greater than - 45 degrees suggests associated left anterior hemiblock. Right axis deviation beyond + 120 degrees is equivocal. The principal differential ECG diagnosis is the Brugada syndrome, a familial arrhythmogenic autosomal dominant cardiomyopathy of variable penetration. This diagnosis is suggested when ECG abnormalities are observed in patients with a personal or family history of sudden death. Right bundle branch block only seems to have haemodynamic consequences in cardiac failure with associated asynchrony of the left ventricle or in certain cases of right ventricular dilatation encountered in congenital heart disease. The prognosis of right bundle branch block in the absence of underlying cardiac disease is good but it may be poor in other cases, particularly coronary artery disease. Moreover, the prognosis of right bundle branch block to complete atrioventricular block is rare in the absence of associated cardiac disease.

[Multislice computed tomography to detect coronary stenosis among asymptomatic patients with cardiovascular risk factors and equivocal prior stress test: preliminary study]

Multislice computed tomography (MSCT) is a non-invasive and validated technique to detect coronary stenoses. Some questions remain about its accuracy to detect coronary stenoses (CS), especially for asymptomatic patients (P) when a prior stress test isn't conclusive.

METHODS

MSCT was performed among 45 asymptomatic men (mean age: 58,3 +/- 16), with a high ten year risk of fatal cardiovascular disease (SCORE 2003 data for low-risk regions of Europe), without any previous coronary history and with previous non conclusive exercise testing. When significant (> 50%) CS was suspected at MSCT, an angiocoronarography (AC) was done.

RESULTS

Eighteen MSCT were normal, unsignificant CS (< 50%) were detected on 14 MSCT and significant coronary stenoses (SCS) for 13 P. Among this 13 P, 19 SCS were identified: 2 SCS of left main coronary artery (CA), 9 of the left descending CA, 6 of the right CA and 2 of the left circumflex CA. 13 CS were confirmed at AC. Finally, because of critical angiographic lesions +/- ischemia at nuclear tomoscintigraphy (NT), 9 P had coronary revascularization (7 catheter based, 2 surgical bypass), 4 P had medical treatment.

DISCUSSION

Benefits of this preliminary study are obvious: 9 coronary revascularization/45 P. However, the place of MSCT for the screening of CS is uncertain, but may be usefull as a complement for the screening of coronary arterial disease.

[Automobile driving and implantable defibrillators]

The consequences of implanting an automatic cardioverter defibrillator (ICD) on vehicle driving in France are poorly known. This retrospective study examined the behaviour at the wheel of ICD recipients who were recommended to abstain from driving for 3 to 6 months after device implantation. The study population included 98 patients (mean age = 59.5 +/- 14.8 years) followed for a mean of 24. +/- 23.9 months, who underwent ICD implant for ventricular tachycardia (65% of patients ventricular fibrillation (15%), syncope (8%), as part of a research protocol of myocardial cell transplantation 6%, or for primary prevention (5%). The underlying heart disease was ischemic in 59% of patients dilated cardiomyopathy in 11%,hypertrophic cardiomyopathy in 8%, valvular in 6%. Brugada syndrome in 4%, right ventricular arrhythmogenic cardiomyopathy in 2%, and miscellaneous disorders in 9% of patients. Five patients died without post mortem interrogation of the ICD. Only 28% of drivers remembered, and 13% observed, the recommended driving limitations. However, 45% (the oldest) claimed to drive prudently. During follow-up, 47% of patients received an ICD shock. Their mean it ventricular ejection fraction was 34 +/- 14%, versus 43 +/- 18% in patients who received no ICD therapy (p = 0.015). Syncope occurred in 16% who received ICD shocks. Shocks were delivered during driving in 6 patients, without consequent accident. Despite their non-observance of recommended driving limitations. ICD recipients suffered few traffic accidents. Legislation in France should reproduce the guidelines issued by European professional societies and enacted by the British laws.

[The heart and aerobatics]

Aerobatics is an aerial sport which has many physiological constraints, principally cardiovascular, with a risk if not adapted of sudden mid-air incapacity which could jeopardise aviation safety, and thus justifies the selection and surveillance of pilots. The aeronautical constraints during flight are multiple, related to the environment traversed, how the aircraft functions and its movements. Those which cause accelerations (+G in particular) pose the problem of haemodynamic tolerance because they can induce loss of consciousness due to cerebral hypoxia. Tolerance of acceleration varies among individuals; it can be improved with training, certain protective manoeuvres, and is reduced by hypoxia, certain medications, dehydration and heat. Moreover, in aerobatics certain tricks require manoeuvres which reduce this tolerance to +G accelerations. This is the "push-pull" effect (_G acceleration immediately followed by +G acceleration). This leads to a risk of sudden loss of consciousness with a load factor much lower than that which the pilot knows he is capable of tolerating. Besides the haemodynamic effects, the existence of an actual acceleration cardiomyopathy has been suggested but has not been proven in man. Finally, while changes in cardiac rhythm during accelerations are usual and relate to changes in vaso-sympathetic balance, ventricular and supra-ventricular rhythm disturbances are rare and are related to the intensity and duration of the acceleration.

[Severe pneumococcal meningitis and ceftriaxone allergy]

We report the case of a 51-year-old man with an allergy to amoxicillin/acid clavulanique who presented with Streptococcus pneumoniae meningitis. Initial treatment consisted of an association of antibiotics including ceftriaxone. Six days after treatment was initiated the patient developed skin reaction and the diagnosis of allergy to ceftriaxone was established by the dosage of specific IgE. Typically Streptococcus pneumoniae meningitis is treated with vancomycin and a third-generation cephalosporin. This association had to be modified because cross allergy to cephalosporins could have developed in this patient who had previously reacted to penicillins.