Stress Echocardiography in Italian Echocardiographic Laboratories: A Survey of the Italian Society of Echocardiography and Cardiovascular Imaging

Background

The Italian Society of Echography and Cardiovascular Imaging (SIECVI) conducted a national survey to understand the volumes of activity, modalities and stressors used during stress echocardiography (SE) in Italy.

Methods

We analyzed echocardiography laboratory activities over a month (November 2022). Data were retrieved through an electronic survey based on a structured questionnaire, uploaded on the SIECVI website.

Results

Data were obtained from 228 echocardiographic laboratories, and SE examinations were performed in 179 centers (80.6%): 87 centers (47.5%) were in the northern regions of Italy, 33 centers (18.4%) were in the central regions, and 61 (34.1%) in the southern regions. We annotated a total of 4057 SE. We divided the SE centers into three groups, according to the numbers of SE performed: <10 SE (low-volume activity, 40 centers), between 10 and 39 SE (moderate volume activity, 102 centers) and ≥40 SE (high volume activity, 37 centers). Dipyridamole was used in 139 centers (77.6%); exercise in 120 centers (67.0%); dobutamine in 153 centers (85.4%); pacing in 37 centers (21.1%); and adenosine in 7 centers (4.0%). We found a significant difference between the stressors used and volume of activity of the centers, with a progressive increase in the prevalence of number of stressors from low to high volume activity (P = 0.033). The traditional evaluation of regional wall motion of the left ventricle was performed in all centers, with combined assessment of coronary flow velocity reserve (CFVR) in 90 centers (50.3%): there was a significant difference in the centers with different volume of SE activity: the incidence of analysis of CFVR was significantly higher in high volume centers compared to low - moderate - volume (32.5%, 41.0% and 73.0%, respectively, P < 0.001). The lung ultrasound (LUS) was assessed in 67 centers (37.4%). Furthermore for LUS, we found a significant difference in the centers with different volume of SE activity: significantly higher in high volume centers compared to low - moderate - volume (25.0%, 35.3% and 56.8%, respectively, P < 0.001).

Conclusions

This nationwide survey demonstrated that SE was significantly widespread and practiced throughout Italy. In addition to the traditional indication to coronary artery disease based on regional wall motion analysis, other indications are emerging with an increase in the use of LUS and CFVR, especially in high-volume centers.

Organization and Activity of Italian Echocardiographic Laboratories: A Survey of the Italian Society of Echocardiography and Cardiovascular Imaging

Background

The Italian Society of Echocardiography and Cardiovascular Imaging (SIECVI) conducted a national survey to understand better how different echocardiographic modalities are used and accessed in Italy.

Methods

We analyzed echocardiography laboratory activities over a month (November 2022). Data were retrieved via an electronic survey based on a structured questionnaire, uploaded on the SIECVI website.

Results

Data were obtained from 228 echocardiographic laboratories: 112 centers (49%) in the northern, 43 centers (19%) in the central, and 73 (32%) in the southern regions. During the month of observation, we collected 101,050 transthoracic echocardiography (TTE) examinations performed in all centers. As concern other modalities there were performed 5497 transesophageal echocardiography (TEE) examinations in 161/228 centers (71%); 4057 stress echocardiography (SE) examinations in 179/228 centers (79%); and examinations with ultrasound contrast agents (UCAs) in 151/228 centers (66%). We did not find significant regional variations between the different modalities. The usage of picture archiving and communication system (PACS) was significantly higher in the northern (84%) versus central (49%) and southern (45%) centers (P < 0.001). Lung ultrasound (LUS) was performed in 154 centers (66%), without difference between cardiology and noncardiology centers. The evaluation of left ventricular (LV) ejection fraction was evaluated mainly using the qualitative method in 223 centers (94%), occasionally with the Simpson method in 193 centers (85%), and with selective use of the three-dimensional (3D) method in only 23 centers (10%). 3D TTE was present in 137 centers (70%), and 3D TEE in all centers where TEE was done (71%). The assessment of LV diastolic function was done routinely in 80% of the centers. Right ventricular function was evaluated using tricuspid annular plane systolic excursion in all centers, using tricuspid valve annular systolic velocity by tissue Doppler imaging in 53% of the centers, and using fractional area change in 33% of the centers. When we divided into cardiology (179, 78%) and noncardiology (49, 22%) centers, we found significant differences in the SE (93% vs. 26%, P < 0.001), TEE (85% vs. 18%), UCA (67% vs. 43%, P < 0001), and STE (87% vs. 20%, P < 0.001). The incidence of LUS evaluation was similar between the cardiology and noncardiology centers (69% vs. 61%, P = NS).

Conclusions

This nationwide survey demonstrated that digital infrastructures and advanced echocardiography modalities, such as 3D and STE, are widely available in Italy with a notable diffuse uptake of LUS in the core TTE examination, a suboptimal diffusion of PACS recording, and conservative use of UCA, 3D, and strain. There are significant differences between northern and central-southern regions and echocardiographic laboratories that pertain to the cardiac unit. This inhomogeneous distribution of technology represents one of the main issues that must be solved to standardize the practice of echocardiography.

Early echocardiographic findings in patients hospitalized for COVID-19 pneumonia: a prospective, single center study

BACKGROUND

Cardiac dysfunction, mainly assessed by biomarker alterations, has been described in COVID-19 infection. However, there are still areas of uncertainty regarding its effective role in disease evolution. Aim of this study was to evaluate early echocardiographic parameters in COVID pneumonia and their association with severity disease and prognosis.

METHODS

An echocardiographic examination was performed within 72 h from admission in 64 consecutive patients hospitalized for COVID-19 pneumonia in our medium-intensity care unit, from March 30th to May 15th 2020. Six patients were excluded for inadequate acoustic window.

RESULTS

Fifty-eight consecutive patients were finally enrolled, with a median age of 58 years. Twenty-two (38%) were classifiable as severe COVID-19 disease. Eight out of 58 patients experienced adverse evolution (six died, two were admitted to ICU and received mechanical ventilation), all of them in the severe pneumonia group. Severe pneumonia patients showed higher troponin, IL-6 and D-Dimer values. No significant new onset alterations of left and right ventricular systolic function parameters were observed. Patients with severe pneumonia showed higher mean estimated systolic pulmonary artery pressure (sPAP) (30.7 ± 5.2 mmHg vs 26.2 ± 4.3 mmHg, p = 0.006), even if in the normality range values. No differences in echocardiographic parameters were retrieved in patients with adverse events with respect to those with favorable clinical course.

CONCLUSION

A mild sPAP increase in severe pneumonia patients with respect to those with milder disease was the only significant finding at early echocardiographic examination, without other signs of new onset major cardiac dysfunction. Future studies are needed to deepen the knowledge regarding minor cardiac functional perturbation in the evolution of a complex systemic disorder, in which the respiratory involvement appears as the main character, at least in non-ICU patients.

Lung ultrasonography: A prognostic tool in non-ICU hospitalized patients with COVID-19 pneumonia

BACKGROUND

High diagnostic accuracy for pneumonia, absence of radiation exposure and repeatability are intrinsic features of lung ultrasonography making it an attractive tool in the assessment of patients with COVID-19 pneumonia. The aim of our prospective, observational study was to detect COVID-19-associated sonographic features and assess the potential value of LUS in predicting adverse events.

METHODS

From March 12th to April 20th 2020 patients admitted to two medium-intensive wards with a discharge diagnosis of COVID-19 pneumonia were enrolled and underwent lung ultrasonography. The prognostic value of several ultrasonographic scores at admission and after 72 hours from the first examination (the total score, the anterolateral score, the number of positive region and the presence of consolidation) were analysed with logistic regression along with other potential prognostic factors. The primary outcome was a composite of death and transfer to Intensive Care Unit (ICU), while the secondary was continuous positive airways pressure (CPAP) support.

RESULTS

190 patients were enrolled in the study. The primary outcome was seen in 25 patients (13%), the secondary outcome in 36 (22%). At multivariate regression no sonographic score at admission was independently correlated with the primary outcome while the total score, the anterolateral score, the number of positive regions were associated with CPAP support. When considering the subgroup of patients undergoing lung ultrasonography after 72 hours (128 patients) the total score was independently associated with both the primary and secondary outcome.

CONCLUSION

Lung ultrasonography can be a promising prognostic tool in patients admitted to non-ICU units for COVID-19 pneumonia.

Residual congestion and long-term prognosis in acutely decompensated heart failure patients

AIMS

Recent studies have established the role of residual congestion evaluated by lung ultrasound in estimating short-term risk of readmission or death in patients admitted for heart failure (HF) decompensation. However, if lung ultrasounds maintain a prognostic role of in long-term survival is still unknown. Aim of our study was to evaluate if residual congestion could predict all-cause mortality during 4 year follow up in a cohort of unselected patients admitted for acute decompensated HF.

METHODS

One-hundred fifty patients were enrolled. The anterolateral chest was scanned to evaluate the presence of B-lines. A sonographic score was calculated attributing 1 to each positive sector (≥ 3 B-lines). Clinical, biochemical and echocardiographic data were recorded. A Cox proportional hazard regression analysis was performed to evaluate the association between variables and 4-year survival.

RESULTS

During the follow-up, 86 patients (58%) died. Univariate analysis showed a significant correlation between the sonographic score at discharge and events occurrence at long term follow up (HR 1.21; CI 1.11-1.31; p < 0.001) suggesting that, on average, the increase of 1 point in the sonographic score was associated with an increase of approximately 20% in the risk of death.

CONCLUSIONS

Our results suggest the role of LUS in the identification of more congested HF patients, that will be at risk for worse long term outcome.

Three-month mortality in permanently bedridden medical non-oncologic patients. The BECLAP study (permanently BEdridden, creatinine CLearance, albumin, previous hospital admissions study)

OBJECTIVE

To predict the 3-months mortality in permanently bedridden medical non-oncologic inpatients.

PATIENTS AND METHODS

2788 consecutive patients admitted in 5 Italian Internal Medicine units from January 2016 through January 2017 were prospectively screened; 644 oncologic patients were excluded; 2144 non-oncologic patients (1021 female) were followed-up for mortality for 6 months. Main outcome was 3-months mortality in permanently bedridden inpatients with at least 2 of: creatinine clearance <35 ml/min; albumin < 2.5 g/dl; at least 2 hospital admissions in the previous 6 months. Advanced dementia and dysphagia were also recorded.

RESULTS

Mean age of the 2144 patients was 73.9 (SD, 14.9) years; 374 (17%) were permanently bedridden, 435 (20%) had a creatinine clearance <35 ml/min, 217 (10%) albumin <2,5 g/dl, 112 (5%) at least 2 hospital admissions in the previous 6 months. Seventy-seven (4%) patients were permanently bedridden with at least 2 of the above mentioned items, and 48 of them died within 3 months (62%) (p < 0.001;95% CI 51-73%). Regression coefficients of the variables associated with 3-months mortality in multivariate analysis in 998 patients of unit 1 (training cohort) were used to create a simple score, which was validated in the 1146 patients of the other units (validation cohort) and performed well in predicting the 3-months mortality (https://www.ejcrim.com/beclap/).

CONCLUSIONS

Approximately two out of three non-oncologic medical patients permanently bedridden having 2 of the abovementioned items are dead 3 months after index admission; a simple score including bedridden status, creatinine clearance, albumin, dysphagia, age and sex may help discuss management priorities.

Lung ultrasonography in pulmonary tuberculosis: A pilot study on diagnostic accuracy in a high-risk population

OBJECTIVES

The validity of lung ultrasound (LUS) in the diagnosis of interstitial or focal lung pathologies is well documented, we assessed its accuracy in the diagnosis of pulmonary tuberculosis (PTB).

METHODS

Sonographic signs suggestive of PTB and their diagnostic accuracy were evaluated in patients admitted with clinical suspicion of PTB. Consolidations, subpleural nodules, pleural thickenings or irregularities and pleural effusion were assessed. LUS signs significantly associated with PTB in the univariate analysis (p < .05) were entered in a multivariate logistic regression model.

RESULTS

PTB was confirmed in 51 out of 102 patients. Multiple consolidations (OR 3.54, 95%CI 1.43-8.78), apical consolidations (OR 9.65, 95%CI 3.02-30.78), superior quadrant consolidations (OR 4.01, 95%CI 1.76-9.14), and subpleural nodules (OR 5.29, 95%CI 2.27-12.33) were significantly associated with PTB diagnosis. Apical consolidation (OR 9.67, 95%CI 2.81-33.25, p 0.003) and subpleural nodules (OR 5.30, 95%CI 2.08-13.52, p 0.005) retained a significant association in a multivariate model, with an overall accuracy of 0.799.

CONCLUSIONS

Our data suggest a possible role of LUS in the diagnosis of PTB, a high burden pathological condition for which the delay in diagnosis still represents a critical point in the control of the disease.

Chagas disease knocks on our door: a cross-sectional study among Latin American immigrants in Milan, Italy

OBJECTIVES

We aimed to assess the prevalence and risk factors for Chagas disease (CD) in Latin American immigrants and to evaluate the accuracy of diagnostic tests. Moreover, we offered to all positive subjects a complete free-of-charge clinical/instrumental evaluation as well as benznidazole treatment in order to stage the disease and verify drug tolerability.

METHODS

A cross-sectional survey of CD among Latin Americans living in Milan and its metropolitan area was conducted between July 2013 and July 2014. Blood samples were tested for serologic evidence of CD together with a questionnaire covering demographic and clinical-epidemiological information.

RESULTS

Forty-eight (9.6%) of the 501 tested subjects were conclusively diagnosed as having CD. The highest prevalence of CD was among those from Bolivia (43/169, 25.4%) and El Salvador (4/68, 5.9%). Older age (adjusted odds ratio (aOR)] 1.05, p =0.004), a Bolivian origin (aOR 8.80; p =0.003), being born in the department of Santa Cruz (aOR 3.72, p =0.047), having lived in mud houses (aOR 2.68; p =0.019), and having an affected relative (aOR 12.77, p =0.001) were independently associated with CD. The ARCHITECT Chagas test showed the highest sensitivity (100%) and specificity (99.8%). Twenty-nine of the subjects with CD (60.4%) underwent disease staging, 10 of whom (35.7%) showed cardiac and/or digestive involvement. Benznidazole treatment was associated with high frequency of adverse reactions (19/27, 70.4%) and permanent discontinuation (8/27, 29.6%).

CONCLUSIONS

CD is highly prevalent among Bolivians and Salvadorans living in Milan. Regions with a large Latin American immigrant population should implement programmes of active detection and treatment.

Bedside echocardiography in internal medicine: which key questions and answers for our decision-making?

The advent of portable equipment in the last years has brought ultrasound technology available at patient bedside, giving the opportunity to non-cardiologists to extend cardiac assessment based on physical examination. Bedside echocardiography is a ‘question-driven’ examination, where simple and often dichotomic answers are searched. It is performed using phased-array probes and bidimensional images are visually evaluated to obtain information regarding cardiac size and function, presence of pericardial effusion, gross valvular diseases. Although this approach can not in any case substitute a standard 2D color-doppler echocardiography, bedside echocardiography has been demonstrated to maintain a good diagnostic accuracy when limited to basic questions, even in the hands of short-trained non cardiologist physicians. At present the bedside ultrasound approach is widely used in different settings and focused echocardiography takes part together with US explorations of lung, abdomen and deep veins in an integrated perspective that perfectly fit with the holistic approach of the internist. In this context we address two typical scenarios encountered in the internal medicine divisions -the patient presenting with dyspnea or non-post-traumatic hypotension- showing the main questions we can ask to bedside echocardiography for a rapid identification of the determinants of symptoms and consequently for a therapeutic choice based on more objective evidences.

Lung ultrasonography for the assessment of rapid extravascular water variation: evidence from hemodialysis patients

Chest ultrasonography is a useful tool to assess extravascular lung water at bedside. In presence of interstitial-alveolar imbibition, vertical artifacts arising from the pleura are detected; these are called B-lines. Although a positive linear correlation between B-lines and extravascular lung water has been shown in symptomatic heart failure patients, the subclinical phase of pulmonary imbibition and the clearance of B-lines after rapid body fluid removal have been less investigated. The aim of this study was to assess if chest ultrasound could detect lung water imbibition and its variations induced by dialysis, an experimental model of controlled rapid fluid loss. Forty-one patients undergoing hemodialysis were studied. Total number of B-lines from ultrasound chest scanning and vena cava diameters were measured before and after treatment. Before dialysis, most of the patients presented ultrasound signs of pulmonary imbibition despite the absence of dyspnea; the number of B-lines was associated with the accumulated weight before treatment (p < 0.05) as well as with the residual weight after dialysis (p < 0.01); B-lines and end-inspiratory and end-expiratory vena cava diameters were also significantly reduced after dialysis. Moreover, B-lines reduction was significantly related to weight loss. Ultrasound performed at the bedside can detect lung water and intravascular overload and their reduction after dialysis in yet asymptomatic patients. These observations add further evidence regarding the use of lung ultrasound and inferior vena cava measurement in estimating volume overload and monitoring the response to therapy both in hemodialysis and congestive heart failure patients.

Target organ damage in a population at intermediate cardiovascular risk, with adjunctive major risk factors: CArdiovascular PREvention Sacco Study (CAPRESS)

The objective of the study is to assess the prevalence of target organ damage (TOD) at carotid, cardiac, renal and peripheral vascular levels in a population at intermediate cardiovascular risk, with adjunctive major risk factors (AMRF). From March 2007 to July 2009 we examined 979 subjects at intermediate cardiovascular risk, as indicated by the Italian algorithm "Progetto Cuore"; the patients were aged 40-69 years, sensitized by one or more AMRF such as family history for cardiovascular disease (CVD), being overweight or obese, and smoking habit (more than 10 cigarettes/day). We measured common carotid intima-media thickness (cc-IMT) and plaque at any level, left ventricular mass index (LVMI), urine albumin/creatinine ratio (UACR), and ankle-brachial index (ABI). The prevalence of at least one TOD was 63% (617 subjects), cc-IMT was high in 48.2% (472), UACR abnormal in 14.1% (138), LVMI high in 12.6% (117) and ABI pathological in 9.1% (89). In those with carotid damage 423 had a plaque, amounting to 43.2% of the total population. Of note, carotid damage was present in all subjects with 3 TODs, and in 92% of subjects with 2 TODs. A multivariate logistic regression model including conventional factors and AMRF indicated that age 50-69 years, systolic blood pressure, relevant smoking and CV risk score ≥15 were independently and significantly associated with at least one TOD, and at least, with carotid damage. Among the AMRF, peripheral arterial disease was associated with relevant smoking, with an odds ratio (OR) of 3 [confidence interval (CI) 1.80-4.97, p < 0.0001]; overweight and obesity both had selective associations with cardiac damage with OR 2.75 (CI 1.2-6.3, p < 0.01) and OR 3.89 (CI 1.61-9.73, p < 0.01). A substantial proportion of people at intermediate risk, with at least one AMRF have at least one TOD, a major predictor of cardiovascular outcomes.

Linear and nonlinear dynamics of heart rate variability after acute myocardial infarction with normal and reduced left ventricular ejection fraction

We analyzed heart rate variability (HRV) in 2 groups of patients after acute myocardial infarction with normal and reduced ejection fraction (EF) by considering both the power of the 2 major harmonic components at low and high frequency and 2 indexes of nonlinear dynamics, namely the 1/f slope and the correlation dimension D2. HRV of patients with a reduced EF was characterized by a diminished RR variance as well as a different distribution of the residual power in all frequency ranges, with lower values of the low-frequency component expressed in both absolute and normalized units, and of the low- to high-frequency ratio. In these patients we also observed a steeper slope of the negative regression line between power and frequency in the very low frequency range. The presence of a smaller fractal dimension was suggested by a lower D2. Thus, in patients after acute myocardial infarction with a reduced EF, the reduction in HRV is associated with a different distribution of the residual power in the entire frequency range, which suggests a diminished responsiveness of sinus node to neural modulatory inputs.

Heart rate variability in the early hours of an acute myocardial infarction

The occurrence of an autonomic disturbance early in acute myocardial infarction (AMI) has been reported: signs of sympathetic activation were mainly observed in relation to an anterior localization, whereas signs of vagal overactivity were more frequent in inferior wall AMI. Information is limited in relation to the persistence of these alterations during the early hours of AMI. We studied 33 patients with an AMI within 188 +/- 16 minutes from the onset of symptoms and 1 week after hospital admission. From a 20-minute Holter recording, we computed with autoregressive methodology, time and frequency domain indexes of heart rate variability. At admission, patients with an anterior wall AMI exhibited a smaller RR variance (593 +/- 121 ms2) than did those with an inferior wall AMI (1,122 +/- 191 ms2). In both groups the spectral profile was characterized by a predominant (73 +/- 4 and 61 +/- 4 normalized units) low frequency and by a small (13 +/- 2 and 22 +/- 3 normalized units) high-frequency component, indicating the presence of a sympathetic excitation and of a diminished vagal modulation. Although signs of sympathetic activation were more evident in patients with anterior wall AMI, no evidence of a vagal hyperactivity was observed in patients with inferior wall AMI. In the latter group, we noticed 1 week after the acute event an increase in the low-frequency component, which reached the values observed in patients with anterior wall AMI. Thrombolysis did not affect heart rate variability parameters. Thus, this study suggests the presence of an autonomic disturbance characterized by signs of sympathetic excitation and of a reduced vagal modulation, which was more evident in patients with an anterior localization early after AMI.

Spectral analysis of short term R-Tapex interval variability during sinus rhythm and fixed atrial rate

Analysis of heart rate variability has been proven useful in stratifying post myocardial patients at risk and in evaluating autonomic dysfunction. Recently augmented inter-lead variability of the QT interval has been associated with increased mortality as a result of arrhythmia and proposed as a marker of dispersion of ventricular repolarization. As the duration of the QT interval is largely dependent upon the length of the preceding cardiac cycle it is tempting to analyse whether neural mechanisms might also directly exert additional modulation. Using autoregressive algorithms we therefore analysed RR and R-Tapex interval variabilities in 15 normal subjects during sinus rhythm and in six patients with a fixed atrial rate. In controls mean R-Tapex interval and variance measured on the vector magnitude were, respectively, 245 +/- 6 ms and 5.1 +/- 0.7 ms2. Spectral analysis of R-Tapex indicated the presence of two spectral components which corresponded to the low and high frequency components of heart rate variability. In R-Tapex variability, high frequency (44 +/- 4 nu) was predominant over low frequency (29 +/- 4 nu). During controlled respiration, a manoeuvre associated with enhanced vagal modulation of sinus node, there was a further increase in high frequency (58 +/- 4 nu) whereas during tilt the low frequency component of R-Tapex variability became predominant (57 +/- 6 nu). In patients with a fixed atrial rate, variance was extremely low (3 +/- 0.9 ms2) and only a respiration-related high frequency component was recognizable in spectral analysis of RR and R-Tapex variabilities. This component was likely to depend upon mechanically induced changes in cardiac vector orientation. These data indicate that during sinus rhythm short-term R-Tapex interval variability is characterized by the same rhythmical components present in RR variability. However, the presence of a very low variance and of only a high frequency component in patients in whom the physiological variability of sinus node is abolished by atrial pacing. suggests that neural modulatory mechanisms do not exert a direct effect on the length of the R-Tapex interval.

Effects of beta blockers (atenolol or metoprolol) on heart rate variability after acute myocardial infarction

This study analyzed, with spectral techniques, the effects of atenolol or metoprolol on RR interval variability in 20 patients 4 weeks after the first uncomplicated myocardial infarction. Beta blocker-induced bradycardia was associated with a significant increase in the average 24-hour values of RR variance (from 13,886 +/- 1,479 to 16,728 +/- 1,891 ms2) and of the normalized power of the high-frequency component (from 22 +/- 1 to 28 +/- 2 normalized units), whereas the low-frequency component was greatly reduced (from 60 +/- 3 to 50 +/- 3 normalized units). When considering day and nighttime separately, the effects of both drugs were more pronounced in the daytime. In addition, a marked attenuation was observed in the circadian variation of the low-frequency component after beta blockade. As a result, the early morning increase of the spectral index of sympathetic modulation was no longer detectable. These results indicate that beta-blocker administration has important effects on RR interval variability and on its spectral components. The observed reduction in signs of sympathetic activation and the increase in vagal tone after beta blockade help to explain the beneficial effects of these drugs after myocardial infarction. However, the potential clinical relevance of the increase in RR variance remains to be established.

Evidence of functional alterations in sympathetic activity after myocardial infarction

To assess whether the presence of areas of efferent sympathetic denervation might contribute to alterations in sympathetic and vagal neural regulatory activities observed after myocardial infarction, we attempted to correlate the changes in the spectral components of RR variability with the I-123 MIBG and Thallium-201 uptake defects. Ten patients with first and uncomplicated myocardial infarction were studied. Thallium-201 and I-123 MIBG scintigraphy as well as spectral analysis of heart rate variability were performed 7 days, 4, 12 and 30 months after the acute event. Regional abnormalities in I-123 MIBG uptake were more extensive than the perfusion defects indicated by Thallium-201 images and remained constant throughout the entire period of observation. In the early post-infarction period, spectral analysis of RR variability was characterized by a predominant LF (74 +/- 6 nu) and a smaller HF (16 +/- 3 nu) component indicating a sympathetic predominance. Thereafter, we observed a progressive reduction in LF and a gradual increase in HF which were consistent with a normalization of sympatho-vagal balance. These data indicate that after a myocardial infarction, the presence and persistence of areas of sympathetic functional denervation do not seem to play a major role in determining the changes in sympathetic and vagal neural regulatory activities directed to the heart.

Beta-blocking effect of propafenone based on spectral analysis of heart rate variability

RR variability was analyzed in 15 patients with ventricular arrhythmias to evaluate whether the antiarrhythmic action of propafenone is associated with alteration of neural control mechanisms. Before drug administration, spectral analysis of RR variability was characterized by 2 major components at low and high frequency, which are considered to reflect sympathetic and parasympathetic modulation of the heart period. After propafenone (600 to 900 mg/day), there was a marked reduction in RR variance (826 +/- 184 to 412 +/- 77 ms2; p < 0.05), although the mean RR interval was unchanged. The drug significantly reduced the low-frequency component (52 +/- 6 to 28 +/- 4 nu) and augmented the high-frequency component (39 +/- 6 to 55 +/- 5 nu). As a result, the low-/high-frequency ratio (an index of sympathovagal balance) decreased from 2.0 +/- 0.4 to 0.6 +/- 0.1. A positive correlation between serum levels and drug-induced changes in the low-frequency component was also observed. Furthermore, the increase in the low-frequency component induced by tilt (53 +/- 5 to 79 +/- 3 nu) was markedly attenuated after drug administration (27 +/- 5 to 54 +/- 7 nu). Thus, propafenone administration is associated with changes in spectral components that are consistent with a beta-blocking effect of the drug.