A hand-carried cardiac ultrasound device in the outpatient cardiology clinic reduces the need for standard echocardiography.

OBJECTIVE: To assess the potential value and cost-effectiveness of a hand-carried ultrasound (HCU) device in an outpatient cardiology clinic. METHODS: 222 consecutive patients were prospectively enrolled in the study. When standard echocardiography (SE) was specifically indicated on the basis of clinical history, electrocardiogram and physical examination, the same cardiologist (level-2 or level-3 trained) immediately performed an HCU examination. The cardiologist then reassessed the clinical situation to confirm or cancel the SE request according to the information provided by HCU. The SE examination was performed by a sonographer and examined in a blinded fashion by a cardiologist expert in echocardiography. Findings from the two examinations were compared. RESULTS: HCU was performed in 108/222 patients, and a definite diagnosis was established in 34 of them (31%), making SE examination potentially avoidable. In the 74 patients with inconclusive HCU results and for whom SE was still indicated, the decision was mainly dictated by the lack of spectral Doppler modality in the HCU system. The overall agreement between HCU and SE for diagnosis of normal/abnormal echocardiograms was 73% (kappa = 0.4). On the basis of the potentially avoided SE examinations and the obviated need for a second cardiac consultation, a total cost saving of euro2142 per 100 patients referred for echocardiography was estimated. CONCLUSIONS: The use of a simple HCU device in the outpatient cardiology clinic allowed reliable diagnosis in one third of the patients referred for echocardiography, which translates into cost and time saving benefits.

[Role of echocardiography in the treatment of heart failure with permanent electric stimulation]. / Ruolo dell'ecocardiografia nel trattamento dello scompenso cardiaco con elettrostimolazione permanente.

Permanent cardiac pacing has been proposed for the treatment of atrioventricular and intraventricular conduction defects and related hemodynamic alterations which may worsen the performance of the failing heart. The initial positive results of right sided atrioventricular synchronous pacing have not been confirmed in later studies involving a larger number of patients with different clinical characteristics. The reason of these conflicting results may be related to the poor understanding of the complex interaction between the adopted pacing mode and the different type, grade and hemodynamic significance of conduction defects. The negative hemodynamic effects of the altered sequence and synchrony of ventricular activation during right sided pacing may outweigh the benefits of an optimal atrioventricular synchrony. Biventricular stimulation has been proposed to improve the electromechanical activation of the left ventricle in patients with left bundle branch block. Ongoing prospective studies are evaluating the potential benefits of biventricular stimulation versus alternative treatments. Although there are no standard indications to cardiac pacing in heart failure it seems that this therapeutic tool may be of value in selected patients with conduction defects which unfavorably affect the cardiac function and that are amenable to be corrected by an appropriate pacing modality. Doppler echocardiography, in its different applications, emerges has a key technique for the selection of patients who may benefit from permanent pacing and for the selection of the best pacing modality. Doppler echocardiography criteria may also be useful in the selection of homogeneous groups of patients to be enrolled in prospective studies aimed at assessing the potential benefits of permanent pacing versus alternative treatments.

Effect of electrode configuration and capacitor size on internal atrial defibrillation threshold using leads currently used for ventricular defibrillation.

BACKGROUND: Previous studies have shown that endocardial atrial defibrillation, using lead configurations specifically designed for ventricular defibrillation, is feasible but the substantial patient discomfort might prevent the widespread use of the technique unless significant improvements in shock tolerability are achieved. It has been suggested that the peak voltage or the peak current but not the total energy delivered determines the patient pain perception and therefore, lower defibrillating voltage and current achieved with modifications in lead and waveforms may increase shock tolerability. This study was undertaken to evaluate the effect, on the atrial defibrillation threshold (ADFT), of the addition of a patch electrode (mimicking the can electrode) to the right ventricle (RV)-superior vena cava (SVC) lead configuration. The influence of capacitor size on ADFT using the RV-SVC+skin patch configuration was also assessed. METHODS: In 10 patients (pts) (Group 1) cardioversion thresholds were evaluated using biphasic shocks in two different configurations: 1) right ventricle (RV) to superior vena cava (SVC); 2) RV to SVC+skin patch. In a second group of twelve patients (Group 2) atrial defibrillation thresholds of biphasic waveforms that differed with the total capacitance (90 or 170 microF) were assessed using the RV to SVC+skin patch configuration. RESULTS: In Group 1 AF was terminated in 10/10 pts (100 %) with both configurations. There was no significant difference in delivered energy at the defibrillation threshold between the two configurations (7.1 +/- 5.1 J vs 7.1 +/- 2.6 J; p < 0.05). In group 2 AF was terminated in 12/12 pts (100%) with both waveforms. The 170 microF waveform provided a significantly lower defibrillating voltage (323.7 +/- 74.6 V vs 380 +/- 70.2 V; p < 0.03) and current (8.1 +/- 2.7 A vs 10.0 +/- 2.3 A; p < 0.04) than the 90 microF waveform. All pts, in both groups, perceived the shock of the lowest energy tested (180 V) as painful or uncomfortable. CONCLUSIONS: The addition of a patch electrode to the RV-SVC lead configuration does not reduce the ADFT. Shocks from larger capacitors defibrillate with lower voltage and current but pts still perceive low energy subthreshold shocks as painful or uncomfortable.

[The concurrent implantation of a last-generation automatic defibrillator and a 2-chamber pacemaker]. / Impianto concomitante di defibrillatore automatico di ultima generazione e pacemaker bicamerale.

BACKGROUND: Potentially lethal interactions between concomitantly implanted pacemaker and automatic first-generation cardioverter-defibrillator have been reported. We therefore evaluated the reliability and safety of simultaneous implantation of dual-chamber pacemakers with a fourth generation cardioverter-defibrillator incorporating an improved arrhythmia detection system. METHODS: Concomitant implantation of an automatic cardioverter defibrillator and a dual-chamber pacemaker was performed in four patients for malignant tachyarrhythmias and symptomatic bradycardia. Two Jewel 7219C and two Micro Jewel 7223 (Medtronic Inc.) implantable cardioverter defibrillators were connected to an endocardial lead (Medtronic Mod. 6936). In 2 patients with a previously implanted cardioverter-defibrillator, the pacemaker was connected to bipolar atrial and ventricular leads. In the 2 patients who already had a dual-chamber pacemaker, the unipolar pacing leads implanted previously were used. At the time of implantation of the second device, interaction testing was performed evaluating ventricular fibrillation detection during high-output asynchronous pacing. Testing for malfunctions, reprogramming or variations of pacing thresholds of the pacemakers after electric shocks was also carried out. Moreover, intracavitary signals, stimulation thresholds and electrical therapies delivered were evaluated during follow-up. RESULTS: During interaction testing, induced ventricular fibrillation was detected, with no delay, in 4/4 cases (100%). After a mean follow-up of 6.3 +/- 5 months (range 2-13), 5 shocks for ventricular fibrillation, 10 shocks for fast ventricular tachycardia and 72 antitachycardia pacings were delivered. All these electrical therapies were considered appropriate. No symptomatic sustained tachyarrhythmia remained undetected. CONCLUSIONS: These data suggest that concomitant implantation of a fourth-generation automatic cardioverter-defibrillator and a dual-chamber pacemaker using either unipolar or bipolar leads can be performed safely. Extreme caution and rigorous interactions testing is nevertheless advised when considering this device combination.

[Improvement of postinfarct left myocardial contractile function after administration of diltiazem]. / Ripresa contrattile di asinergie miocardiche postinfartuali indotta dalla somministrazione acuta di diltiazem.

BACKGROUND: The impairment of intracellular calcium homeostasis is an important biochemical alteration in stunned and hibernating myocardium. These different forms of viable myocardium frequently occur after myocardial infarction and their recognition may modify the therapeutic program and prognosis. Experimental studies and experiences on male subjects have demonstrated that calcium-channel blockers exert a protective action on myocardial reperfusion injury and reduce infarct size. OBJECTIVES: The aim of the present study was to evaluate the efficacy of i.v. diltiazem (i.e. a calcium-channel blocker with negative inotropic effect) in enhancing the contractility of viable akinetic myocardium in patients after myocardial infarction. METHODS: Sixty patients (52 males and 8 females, age 57 +/- 10 years) with the first acute myocardial infarction were evaluated with dobutamine-echocardiography 9 +/- 2 days after admission and on the following day with diltiazem-echocardiography. Diltiazem was administered i.v. using repeated boluses of 0.25 mg/kg up to the maximum dose of 1 mg/kg. Before and during the infusion, left ventricular regional function was scored and the Wall Motion Score Index (WMSI) was calculated; ECG and arterial blood pressure were also monitored. Results were compared with low-dose dobutamine-echocardiography. In a subset of 13 patients who underwent myocardial revascularization (7 coronary artery by-pass graftings and 6 percutaneous transluminal angioplasties), post-procedure echocardiograms were performed to evaluate whether regional left ventricular function had improved. RESULTS: Low-dose dobutamine and diltiazem enhanced regional left ventricular contractility in 28 and 31 patients, respectively; both tests were positive in 26 cases. Conversely, dobutamine-test was negative in 32 patients and diltiazem in 29, with concordance in 27. A good correlation was found between diltiazem and dobutamine WMSI at the basal evaluation (r = 0.91; p < 0.000) as well as during the pharmacological test (r = 0.86; p < 0.000). In patients who underwent myocardial revascularization, the same good correlation was found between diltiazem-WMSI and WMSI evaluated after the procedure (r = 0.91; p < 0.000). CONCLUSIONS: Acute i.v. administration of diltiazem about ten days after myocardial infarction may enhance the contractility of viable akinetic ventricular wall segments, as evaluated with echocardiography. The results of this study may have some physiopathological and therapeutical implications that could lead to reconsidering the use of calcium-channel blockers, particularly diltiazem, in selected patients after myocardial infarction.

[Atrial thrombosis following the low-energy DC internal countershock of chronic AF: considerations of a clinical case]. / Trombosi auricolare post dc-shock interno a bassa energia della FA cronica: considerazioni su un caso clinico.

Embolism may occur after cardioversion of atrial arrhythmias, especially atrial fibrillation, despite the apparent exclusion of preexisting atrial thrombus. This is related to the now well-known phenomenon of "atrial stunning" following either electrical or pharmacological cardioversion. It has also been suggested that "de novo" atrial thrombus formation after cardioversion could be responsible for the embolic event. We report a case of low-energy internal cardioversion of chronic atrial fibrillation in a patient with recurrent episodes of heart failure followed by a de novo left appendage thrombus formation. The patient, followed clinically and by repeated transesophageal echocardiograms, did not show any clinical sign of thromboembolism and the left appendage thrombus regressed completely, as demonstrated on the transesophageal echocardiogram.

Internal cardioversion of chronic atrial fibrillation in patients.

Transvenous internal cardioversion of chronic AF using a right atrium (RA) coronary sinus (CS) vector requires more energy than cardioversion of paroxysmal AF. Chronic AF is not terminated in 25% of patients using biphasic shocks up to 10 J. We therefore evaluated efficacy, safety, and tolerability of internal cardioversion using a "unipolar" configuration (RA to skin patch) and biphasic shocks in patients with long-lasting AF and different heart disease. In each patient, biphasic R wave synchronous shocks were delivered between a large defibrillating surface area electrode in the RA and a skin patch in the left prepectoral position. Defibrillation protocol started with a test shock of 0.4 J. Shocks were repeated and increased until termination of AF or a maximum of 34 J. Sedation was used when the patient described the shock as painful. This study included 11 patients with a mean age of 67 +/- 8 years (range 56-83). AF duration was > or = 1 month in all patients with a mean duration of 11 +/- 11 months (range 2-36). Underlying heart disease was present in all patients and the mean left atrial dimension was 43 +/- 9 mm (range 26-57). AF was terminated in 10 of 11 patients (91%) with a mean delivered energy of the successful shocks of 18.7 +/- 8.7 J (median energy 16.9 J; range 7.3-32.5) and a mean leading edge voltage of 564 +/- 129 V. The mean shock impedance at the defibrillation threshold was 71 +/- 13 omega (range 59-103). A total of 131 shocks were delivered without any complication and proarrhythmia episodes. We conclude that low energy "unipolar" internal cardioversion is a simple, safe, and effective technique for termination of chronic AF in patients with heart disease. The procedure is often tolerated under light sedation.

Transesophageal echocardiographic color Doppler evaluation of pulmonary vein flow during ventricular pacing.

Hemodynamic changes induced by ventriculo-atrial retroconduction has been considered an important factor in pacemaker syndrome. The contraction of atrial muscles, when the mitral valve is closed, induces a reverse systolic flow into the pulmonary veins, because the outlet of the pulmonary vein in the left atrium is not protected by a valve. The profile of the pulmonary vein forward flow of 25 patients was examined using transesophageal echocardiography (TEE) technique. Doppler evaluation of velocity-time integrals of forward flow (fVTI) and reverse flow (rVTI) was measured both during sinus rhythm or fully automatic (DDD) pacing, and ventricular demand pacing (VVI) accompanied by ventriculoatrial (VA) retroconduction or atrioventricular (AV) dissociation. The mean fVTI was reduced from 21.1 cm +/- 6.2 cm in DDD or sinus rhythm (SR) to 16.4 cm +/- 6.6 cm in VVI (p < 0.001). The mean rVTI was increased from 1.4 cm +/- 0.8 cm in DDD or SR to 4.3 cm +/- 1.8 cm in VVI (p < 0.001). The degree of such alterations varied considerably from patient to patient and this may explain the variability of clinical symptoms reported for pacemaker syndrome. It has not been possible to establish a direct correlation between the magnitude of hemodynamic changes and the severity of the symptoms observed because all the patients were in sequential stimulation or in SR and were temporarily submitted to VVI stimulation during the echocardiographic examination.

[A reduction of left ventricular hypertrophy and an improvement in diastolic function after therapy with nifedipine retard in patients with hypertensive cardiopathy]. / Riduzione dell'ipertrofia ventricolare sinistra e miglioramento della funzione diastolica dopo terapia con nifedipina retard in pazienti con cardiopatia ipertensiva.

Left ventricular (LV) hypertrophy with increased LV mass is associated with abnormal LV diastolic filling in patients with hypertension. To assess the effect of antihypertensive therapy on LV mass (M), LV wall stress (SS) and rapid LV filling, 16 patients (12 males, 4 females), mean age 57 +/- 8 years, were treated with nifedipine slow release (NSR, 20 mg bid) for 12 months and evaluated by Doppler echocardiography at baseline and at 3, 6, 9, 12 months from the beginning of treatment. No other cardiovascular drugs were given during the study. Systolic and diastolic blood pressure (SBP, DBP), LVM/m2 body surface (bs; M/m2), LVSS, LV end-diastolic and end-systolic diameters (EDD/m2, ESD/m2) bs, left atrial diameter (LAD), fractional shortening index (FS%), isovolumic relaxation time (IVRT), E/A velocities ratio at mitral Doppler spectrum (E/A) were measured at each examination. During treatment, systolic and diastolic blood pressure, LVM, LVSS, LV end-systolic diameter and isovolumic relaxation time decreased and FS% and E/A significantly increased as compared with baseline values, EDD and LAD did not change significantly. The reduction of LVSS was of greater extent compared with that of LVM, at short and at mid-term, probably for a fibrotic component of LVM induced by chronic systolic overload. Changes of ESD and FS% were less evident compared with LVSS, possibly depending on their contribution to LVSS normalization. In conclusion, our experience indicates that NSR is an effective antihypertensive agent at short and mid-term.(ABSTRACT TRUNCATED AT 250 WORDS)

Life expectancy in Italian track and field athletes.

Nine hundred eighty-three top Italian track and field athletes (700 males and 283 females) were examined for survival, mortality and causes of death for an average follow-up period of 18.6 years starting from their last year of competition as members of the national team. Overall mortality rates were compared to the rates expected on the basis of the life tables for Italian people of the same age, sex and time period. Thirty-four deaths were observed among males (vs 46.6 expected) with a O/E ratio of 0.73, while 3 deaths were observed among women (vs 6.2 expected) with a O/E ratio of 0.48. Neither of these differences was significant, but the O/E ratio for the group as a whole was quite significant (p = 0.0296). Some of the athletes demonstrated behavioural characteristics developed during their active careers that might have contributed to their low mortality rate.

[The diameter of the common trunk of the left coronary artery and left ventricular mass in athletes. An echocardiographic study]. / Diametria del tronco comune della coronaria sinistra e massa ventricolare sinistra in atleti. Studio ecocardiografico.

The feasibility of two-dimensional echocardiographic visualization of the coronary artery was re-evaluated in adults in the light of technological advances and development of new imaging planes. Athletes are a good model for this type of study. The aim of our study was to visualize in athletes the coronary arteries, particularly the left main artery, and to see if a correlation exists between left-ventricular mass and coronary diameter. Twenty-one endurance athletes, aged between 17 and 30 years, and 21 control subjects, matched for age, sex and body surface area, were examined. All the subjects were examined with mono- and two-dimensional echocardiography, with annular array (3.5 and 5 MHz), with parasternal and apical projections modified in order to visualize the left main coronary artery. Wall thickness, left ventricular internal dimension and left ventricular mass were calculated. Interventricular septum thickness was 10.8 +/- 1.5 mm for athletes (A) versus 8.2 +/- 0.9 mm for controls (C); p less than 0.01. Posterior wall thickness was 10.4 +/- 1.5 mm (A) versus 8.2 +/- 0.6 mm (C); p less than 0.01. The left ventricular diastolic diameter was 54.6 +/- 5.1 mm (A) versus 49.5 +/- 3.4 mm (C); p less than 0.01. The mean left ventricular mass was 278.2 +/- 85.2 g (A) versus 165.6 +/- 35.4 g (C); p less than 0.01. The mean diameter of the left main coronary artery was 4.9 +/- 0.8 mm (A) versus 3.1 +/- 0.4 mm (C); p less than 0.01.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of nifedipine on left ventricular diastolic function in hypertension; echo Doppler study.

Hypertensive cardiac disease shows early alteration of left ventricular diastolic filling, characterized by a longer isovolumetric relaxation period and by an altered E/A ratio on the mitral spectral Doppler. We chose ten hypertensive patients who had left ventricular hypertrophy, but no left ventricular dilatation or mitral valve insufficiency and had a good left ventricular shortening fraction (greater than 26%). After the washout period we studied each of the above-mentioned parameters before and after the acute administration of nifedipine, dinitrate isosorbide, and captopril. While captopril and dinitrate isosorbide induced a prolongation of the isovolumic relaxation time and an impairment of the E/A ratio in mitral spectral Doppler (i.e., left ventricular filling), nifedipine induced an improvement in both parameters. The three drugs also induced a similar reduction in systemic blood pressure values (i.e., similar afterload). We therefore suggest that changes in diastolic function in hypertrophied cardiac fibers, induced by nifedipine, may be the result of a double action: one mediated by hemodynamic changes, the other directly affecting the cellular calcium ion exchange.

Positive inotropic effects of ibopamine in patients with congestive heart failure. A multicenter investigation.

A multicenter double-blind placebo-controlled investigation was carried out in 42 patients with severe congestive heart failure who were given ibopamine (SB-7505), the 3,4-diisobutyryl ester of N-methyldopamine, for a period of 10 days in addition to previous treatment with digitalis and diuretics. Symptoms were evaluated by using a suitable score; some patients were submitted to an exercise test along with other clinical tests. Compared with placebo, ibopamine induced no significant changes in heart rate and arterial blood pressure. Clinical scores were lower after ibopamine than after placebo (p less than 0.01). Functional capacity, defined as the duration (in s) of a maximum symptom-limited exercise test using the ergometric bicycle with a constant 25-W workload, was significantly higher after ibopamine than after placebo (p less than 0.05). So a clear symptomatic improvement was observed after ibopamine in cardiac patients with prolongation of exercise time and reduced clinical scores. In conclusion, the results obtained, along with the slight improvement in the systolic time intervals, indicate that ibopamine is capable of improving cardiac performance in patients with advanced heart failure who display symptoms despite treatment with digitalis and diuretics.

[Clinical, electrocardiographic and echocardiographic findings in a case of vasospastic angina with alternating pseudonormalization of the ST segment]. / Rilievi clinici, elettrocardiografici ed ecocardiografici in un caso di angina vasospastica con pseudo-normalizzazione alternante del tratto ST.

During Ergonovine-test a patient with Prinzmetal angina presented (in I, aVL, V3-V6) ST downsloping which, after a temporary phase of alternative normalization (AST) beat to beat in V5, progressed to ST upsloping with typical angina. The M-mode echo-study first discovered, before than ecg, septal impairment (hypokinesia which increased to akinesia in the AST phase) and also asynergy of posterior wall of left ventricle. After intravenous nitrate echo-alterations reversed more rapidly than ecg one (transitional phase of ST decrease). The authors relate the AST to temporary alternative pseudonormalization caused by a phase of electrical instability during progressive vasospastic ischemia involving first the endocardial layers and after the epicardium of a single myocardiocoronary district. Probably also other partially opposite ischaemic districts, as suggested from echo data of posterior wall asynergy took a part in these events. This rare ST-alternans type as new pseudonormalization phenomenon and the usefulness of echo-study during ischaemic attacks are stressed.

[Pulsed Doppler echocardiography in the study of tricuspid valve insufficiency]. / L'ecocardiografia Doppler ad onda pulsante nello studio della insufficienza tricuspidale.

The value of pulsed Doppler echocardiography in assessing the presence and severity of tricuspid regurgitation (TR) has been studied in three groups of subjects, 12 without cardiovascular disease (Group I), 38 with TR (Group II) and 16 patients with aortic and mitral valve disease but no TR (Group III). The presence and severity of TR was also independently evaluated by clinical examination, jugular vein pulse recording and/or hemodynamic investigation. Left parasternal, sub-xyphoid and apical views were adapted for the pulsed Doppler echocardiographic examination. The sample volume was placed in the right atrium at varying distances from the tricuspid valve. We tried to quantitate the degree of TR according to: 1) the diameter and maximal distance from the tricuspid valve of the regurgitant stream, 2) the duration of reguritation through systole, and 3) the degree of turbolence as demonstrated by the time interval histograms. On the basis of above mentioned criteria, three subgroups of subjects with TR, i.e. mild, moderate and severe were recognised. These results were compared to hemodynamic and/or clinical-poligraphic evaluation. In 34 Group II subjects (89%), the Doppler study revealed the presence of TR and allowed an acceptable quantitative assessment. Falsely positive diagnoses were not made in any of the subjects of Group I. Identification of organic TR in patients with atrial fibrillation was possible only when regurgitation was moderate or severe.

[Clinical application of echocardiokymography for detection of global and sectorial dyskinesias (author's transl)]. / Applicazioni dell'ecocardiochimografia nello studio delle ipo-discinesie globali e settoriali.

The clinical application of a new ultrasonic technique, echocardiokymography (ECKG), has been showed particularly useful in the detection of myocardial and pericardial dyskinesias. In patients with congestive cardiomyopathy, the global hypokynesia was confirmed by the ECKG; regional impairment of parietal wall motion after myocardial infarction is clearly demonstrated by the technique; acute and chronic pericarditis show peculiar kymographic patterns. The ECKG is a kind of two-dimensional examination, that keeps some of the advantages of the time-motion, in the comparative study of cardiac walls dynamics.

[Two-dimensional contrast echocardiography of hepatic veins in the diagnosis of tricuspid regurgitation (author's transl)]. / Ecocontrastografia bidimensionale delle vene sovraepatiche nella identificazione e valutazione dell'insufficienza tricuspidale.

The diagnosis of tricuspid regurgitation (TR) is often controversial. We used peripheral venous contrast echocardiography for the detection and the quantitative assessment of valvular regurgitation. We studied 10 normal subjects, 7 patients with atrial fibrillation, but without tricuspid lesions, 36 patients with TR confirmed by right heart catheterization, divided in three subgroups, according to ventriculography and jugular pulse recording: 10 cases with mild TR, 17 cases with moderate TR, 9 with severe regurgitation. After the injection of contrast medium (CM) (saline solution), the regurgitant flow was visualized in the hepatic veins (HV) and in the inferior vena cava (IVC), by two-dimensional subxiphoid projections; the time of disappearance of the CM was studied by time-motion echograms. The appearance of CM in the HV and in IVC wasn't demonstrated in any normal case. Subjects with atrial fibrillation alone, showed, in 71,5% of cases of persistence of CM in IVC for less than 10 cardiac beats. The diagnosis of severe TR was correctly made in 100% of cases; in all the patients the CM was showed in the HV for more than 40 beats. In patients with mild TR, the diagnosis was correct in 60% of cases with a short persistence of the CM in the HV. In the other cases of mild TR, the presence of CM in HV was misinterpreted as due to atrial fibrillation. Moderate TR was correctly recognized in 70.5% of patients, while in the remainder it was under or overestimated. The method shows a good sensitivity; some cases with atrial fibrillation, in the absence of TR, may cause "false-positive" diagnosis.