Visualization of left atrial appendage and assessment of its function by transthoracic second harmonic imaging and contrast-enhanced pulsed Doppler.

BACKGROUND: Low flow velocity within the left atrial appendage, as assessed by transoesophageal echocardiography, is a predictor of thromboembolism and of a low success rate of cardioversion of atrial fibrillation. However, the semi-invasive nature does limit its serial application as a screening technique. METHODS AND RESULTS: We investigated the value of transthoracic second harmonic echocardiography and pulsed Doppler at baseline and after intravenous contrast injection to visualize the left atrial appendage and assess blood flow velocities within its cavity. We studied 51 consecutive patients undergoing transoesophageal echocardiography. After transoesophageal echocardiography, transthoracic second harmonic imaging was performed and the left atrial appendage was visualized in 46 patients. Interpretable pulsed Doppler tracings of left atrial appendage flow were obtained at baseline in 39 patients and in 45 patients during Levovist administration. The correlations between peak emptying velocity of left atrial appendage as measured by transoesophageal echocardiography and by transthoracic standard and contrast-enhanced Doppler were 0.81 and 0.91, respectively. The agreement between transoesophageal echocardiography and transthoracic contrast-enhanced pulsed Doppler echocardiography in classifying left atrial appendage flow velocity patterns was 93%. Left atrial appendage thrombus was detected by transthoracic second harmonic imaging in only one of the eight patients shown by transoesophageal echocardiography to have a thrombus. However, all but one of the patients with left atrial appendage thrombus and/or spontaneous echocardiographic contrast at transoesophageal echocardiography had <30cm/s left atrial appendage flow velocity by transthoracic Doppler. CONCLUSIONS: This study shows that left atrial appendage can be visualized by transthoracic second harmonic imaging and that the flow velocity within its cavity is reliably measured by pulsed Doppler in a substantial fraction of patients. Contrast enhancement improves the feasibility and the accuracy of transthoracic evaluation of left atrial appendage flow velocity. The practical value of these results in predicting thromboembolic risk and success of cardioversion of atrial fibrillation needs to be proved by prospective studies.

Complete atrioventricular block with unwidened QRS complex during hyperkalemia.

Purkinje and ventricular myocardial fibers are thought to be more sensitive to hyperkalemia than sinoatrial and atrioventricular (AV) nodes, although complete AV block due to hyperkalemia can occur. We describe a case in which hyperkalemia in a patient affected by renal failure is responsible for complete AV block without QRS complex prolongation. Temporary endoventricular pacing was essential in restoration of adequate renal blood flow and excretion of exceeding serum potassium with subsequent normalization of AV conduction.

Systemic thrombolysis for acute myocardial infarction in a renal transplant recipient.

This study describes the successful management of an acute myocardial infarction occurring in a renal transplant recipient with thrombolytic therapy. Although primary coronary angioplasty has been addressed as an alternative therapeutic approach, this approach raises concern for angiography-related contrast media renal toxicity. However, pharmacological therapy with thrombolytics is effective and relatively safe and should be considered as the first-choice treatment in today's clinical setting.

[Isolated cardiac amyloidosis. Presentation of a clinical case]. / Amiloidosi cardiaca isolata.

A 48-year old patient affected by congestive heart failure came to our observation for cardiac arrest due to ventricular fibrillation. After cardiopulmonary resuscitation and defibrillation he underwent complete evaluation. Echo Doppler findings were consistent with restrictive cardiomyopathy. Laboratory findings revealed monoclonal gammopathy and plasma cells dyscrasia. Diagnosis of amyloidosis was then suspected and biopsies of different organs and tissues were performed. Presence of amyloid deposits was found only in myocardial specimens from the right ventricle. Medical treatment with drugs of various classes, administered during hemodynamic invasive monitoring, was uneffective in improving the hemodynamic and clinical status of the patient and he entered in a heart transplantation list. He died six months later, while awaiting for transplantation. Although isolated cardiac amyloidosis is quite rare, we believe that this condition has ever to be kept in mind during differential diagnosis of restrictive cardiomyopathies and we remark that endomyocardial biopsy was mandatory and necessary for certain diagnosis in this case; in addition, the unefficacy of drugs nowadays available for treatment of congestive heart failure in amyloid cardiomyopathy is confirmed.

DDI pacing in the bradycardia-tachycardia syndrome.

The bradycardia-tachycardia syndrome is a subgroup within the larger category of sinus node dysfunction. Pacing is often required to treat either the protracted asystolic spells following the spontaneous termination of a paroxysmal supraventricular tachyarrhythmia or to protect the patient from pharmacologically exacerbated bradycardias. While the optimal pacing mode for this subset of patients remains debatable, recent reports have favored the use of atrial ventricular sequential pacing with intact atrial sensing (DDI). This paper reports our experience with a series of 30 consecutive patients in whom the DDI mode was utilized as part of the management of this syndrome. DDI pacing has been demonstrated to be safe, extremely effective, and easy to use in this group of patients.

Echocardiographic evaluation of right heart responses to sublingual nifedipine in dilated cardiomyopathy.

Twelve patients with dilated cardiomyopathy were studied in order to evaluate whether the favourable effect of Nifedipine on the right heart is due to a direct action of the drug on pulmonary resistances or is related to an improvement of left ventricular function. Echocardiographic examination of left and right heart was performed at basic conditions, after Nifedipine treatment--20 mg sublingually--and after 20 minutes of oxygen breathing (FiO2 75%). This was done in order to verify if oxygen vasodilating action could potentiate the Nifedipine effect. Echocardiographic date were obtained in basic conditions, 10, 20 and 30 minutes after Nifedipine and immediately after oxygen breathing. Ten normal subjects were used for comparison for basic data. Peak Nifedipine activity was observed 10 minutes after administration. At this time inferior vena cava emptying index and systolic pulsation were significantly increased, whereas left and right ventricle isometric contraction time, left and right ventricle ejection time, left and right ventricle isovolumetric relaxation time, end-diastolic left ventricular diameter, inferior vena cava diameters and systolic blood pressure had decreased, thus showing the favourable effect of Nifedipine of both heart sides. Heart rate did not significantly change. Oxygen inhalation induced a significant decrease of right ventricular isovolumetric relaxation and an increase of the inferior vena cava indexes, suggesting an improvement in right heart function, without any change in other parameters. No significant difference was found between data after-oxygen and data obtained 10' after Nifedipine, showing that the Nifedipine effect was not potentiated by oxygen.(ABSTRACT TRUNCATED AT 250 WORDS)

An unusual case of congenital double coronary arteriovenous fistula.

A double coronary arteriovenous fistula (CAVF) was observed in a ten-year-old girl. A large, tortuous, and elongated right coronary artery, communicating with the right ventricle, was detected by two-dimensional echocardiography and confirmed at angiography. To our knowledge, no echocardiographic recognition of the origin and termination of a CAVF has been reported previously. Moreover, another fistula, connecting the left anterior descending coronary artery with the main pulmonary artery was also detected by selective left coronary arteriography. The anatomy of double CAVF was confirmed on surgery. A right CAVF draining into the right ventricle and a left CAVF draining into the main pulmonary artery seemed to be a very unusual combination.

Effects of creatinol O-phosphate on serum enzymes in acute myocardial infarction.

Two groups of 23 patients, each with acute myocardial infarction, were treated. The first group (control) received glucose-insuline-K+ (GIK) over a 3-day period, and the second GIK and N-methyl-N-(beta-hydroxyethyl) guanidine O-phosphate (creatinol O-phosphate, COP) (3.06 g i.v./24 h), again for a 3-day period. The six enzymes investigated, i. e. GOT, GPT, LDH, HBDH, CK and MBCK, all decreased between 33 and 49% in the COP group as compared with the control group, reaching a degree of statistical significance of less than 0.01. The decrease in these enzymes was attributed to the protective action of COP on the cell membrane permeability, in agreement with a series of previous papers.

[Observations on the sequence of endocardial activation in the left ventricle of the normal subject]. / Osservazioni sulla sequenza d'attivazione endocardica nel ventricolo sinistro del soggetto normale.

To obtain information on normal left ventricular activation, endocardial recordings with an electrode catheter were made a seven left ventricular sites in ten patients undergoing diagnostic heart catheterization. All the patients had: 1) sinus rhythm; 2) normal duration and shape of the QRS complex of left chest leads; 3) normal left ventriculography, i.e. normal volume and contractility of the left ventricle. The earliest left ventricular endocardial activation was recorded at septal and/or posterior level, i.e. at the septum (6 to 16 msec, average 9.7 msec, after the onset of intracardiac QRS complex) in seven patients; at the posterior wall (0 to 4 msec, average 2.6 msec, after the onset of intracardiac QRS complex) in three patients (in one of these, the earliest activation occurred at the posterior wall and apex simulaneously). If the earliest activation occurred at the left interventricular septum, the next excited point was found on the posterior wall or at the apex, and vice versa. The latest part to be activated was on the lateral free wall in seven patients; on the posterior wall in two patients; at the apex in the last one.

[Swallowing-induced supraventricular tachycardias in an asymptomatic young man (author's transl)]. / Tachicardie sopraventricolari da deglutizione in un giovane asintomatico.

Three patterns of swallowing-induced supraventricular tachycardia in an asymptomatic young man are described. The patient had no esophageal disease. The electrophysiologic mechanism of arrhythmias remains speculative. Vagal stimulation produced by swallowing appears to cause tachcardias because atropine (1,5 mg iv) prevents their occurrrence.

[Electrophysiological evaluation of ventricular tachycardia by right and left ventricle endocardial mapping (author's transl)]. / Rilievi elettrofisiologici nelle tachicardie ventricolari con il mappaggio endoventricolare destro e sinistro.

Eight patients with ventricular tachycardia (VT) have been studied by unipolar recordings of 7 endocardial points of the left ventricle (LV) and 6 endocardial points of the right ventricle (RV) in order to record if possible: 1) where the VT arose; 2) a continuous electrical activity during the sistodiastolic phase of the intracardiac ECG [late potentials (LP)], suggesting the reciprocating mechanism of VT. All the patients underwent cardiac catheterization with left and/or right ventriculography. A coronary arteriography was performed in four cases. Four patients had no evidence of heart disease; one patient had aortic stenosis; one patient had two vessels coronary disease and extensive ipo-akinesis of the LV; two patients had dyskinetic areas of the RV. In all the cases it was possible to identify where the VT arose by means of recordings during spontaneous VT episodes (the sites of origin of the VTs were stated in the points where the intracardiac QRS began with an intrinsic deflection), or by means of asyncronous ventricular stimulation (the sites of origin of the VTs were stated in the points where the ventricular stimulation reproduced a surface ECG similar to the one recorded during spontaneous VT). The fact that the site of origin of the VT is never in the same point of the earliest endocardial activation during sinus rhythm and the fact that this site is located in a zone with rich terminations of the conduction system, suggest the reciprocating VT may develop in a circuit, with both conduction and myocardial tissue.

[The endocardial ventricular activation map in a case of intermittent BBS in phase III (author's transl)]. / Mappa dell'attivazione ventricolare endocardica in un caso di blocco di branca sinistra (BBS) intermittente (BBS in fase 3).

To obtain information on endocardial activation-sequence, unipolar recordings at seven left ventricular and six right ventricular points were performed in a 37-year-old man suffering from cardiomyopathy and tachycardia-dependent left bundle branch block (LBBB). Results were as follows: 1) the recovery time was longer in anterior than in posterior portion of left bundle branch fibers; 2) an high posterior left ventricular point was directly activated via posterior left bundle branch fibers; 3) the directly activated left ventricular zone was too small and relatively too late excited in respect of the right interventricular septum, from which the stimulus reached the left septum, to mask the LBBB electrocardiographic pattern; 4) in the presence of tachycardia-dependent LBBB the duration of left ventricular endocardial activation was about twice (62 msec) that found in the absence of tachycardia-dependent LBBB (28 msec).