Giancarlo Casolo

Decreased spontaneous heart rate variability in congestive heart failure

Heart rate (HR) variability is a noninvasive index of the neural activity of the heart. Although also dependent on the sympathetic activity of the heart, HR variability is mainly determined by the vagal outflow of the heart. Several HR abnormalities have been described in patients with congestive heart failure (CHF); however, there are no data on HR variability in CHF patients. In the present study HR variability was assessed in 20 CHF patients and 20 control subjects from 24-hour Holter tapes. HR variability was evaluated by calculating the mean hourly HR standard deviation and by analyzing the 24-hour RR histogram. Mean hourly HR standard deviation was markedly and significantly reduced in CHF patients both over the 24-hour period (97.5 +/- 41 vs 233.2 +/- 26 ms, p less than 0.001) as well as during most of the individual hours examined. The 24-hour RR histogram of CHF patients had a different shape and had a decreased variation compared to control subjects (total variability 356 +/- 102 vs 757 +/- 156 ms, p less than 0.001). Thus, CHF patients with depressed ejection fraction (less than 30%) have a low HR variability compared to normal individuals. This result can be interpreted as adjunctive evidence for decreased parasympathetic activity to the heart during CHF.

Heart rate variability during the acute phase of myocardial infarction.

BACKGROUND After acute myocardial infarction (AMI), several abnormalities of the autonomic control to the heart have been described. Heart rate (HR) variability has been used to explore the neural control to the heart. A low HR variability count measured 7-13 days after AMI is significantly related to a poor outcome. Little information is available on HR variability early after AMI and its relation to clinical and hemodynamic data. METHODS AND RESULTS We studied 54 consecutive patients (42 men and 12 women; mean age, 60.4 +/- 11 years) with evidence of AMI by collecting the 24-hour HR SD from Holter tapes recorded on day 2 or 3. We also measured HR variability in 15 patients with unstable angina and in 35 age-matched normal subjects. HR variability was lower in AMI than in unstable angina patients (57.6 +/- 21.3 versus 92 +/- 19 msec; p less than 0.001) and controls (105 +/- 12 msec; p less than 0.001). Also, HR variability was greater in non-Q-wave than in Q-wave AMI (p less than 0.0001) and in recombinant tissue-type plasminogen activator-treated patients with respect to the rest of the group (p less than 0.02). No difference was found for infarct site. HR variability was significantly related to mean 24-hour HR, peak creatine kinase-MB, and left ventricular ejection fraction (all p less than 0.0001). Patients belonging to Killip class greater than I or who required the use of diuretics or digitalis had lower counts (p less than 0.004, p less than 0.001, and p less than 0.024, respectively). Six patients died within 20 days after admission to the hospital. In these patients, HR variability was lower than in survivors (31.2 +/- 12 versus 60.9 +/- 20 msec; p less than 0.001), and a value less than 50 msec was significantly associated with mortality (p less than 0.025). CONCLUSIONS HR variability during the early phase of AMI is decreased and is significantly related to clinical and hemodynamic indexes of severity. The causes for the observed changes in HR variability during AMI may be reduced vagal and/or increased sympathetic outflow to the heart. It is suggested that early measurements of HR variability during AMI may offer important clinical information and contribute to the early risk stratification of patients.

Assessment and Significance of Left Ventricular Mass by Cardiovascular Magnetic Resonance in Hypertrophic Cardiomyopathy

OBJECTIVES Our aim was to assess the distribution and clinical significance of left ventricular (LV) mass in patients with hypertrophic cardiomyopathy (HCM). BACKGROUND Hypertrophic cardiomyopathy is defined echocardiographically by unexplained left ventricular wall thickening. Left ventricular mass, quantifiable by modern cardiovascular magnetic resonance techniques, has not been systematically assessed in this disease. METHODS In 264 HCM patients (age 43 +/- 18 years; 75% men), LV mass by cardiovascular magnetic resonance was measured, indexed by body surface area, and compared with that in 606 healthy control subjects. RESULTS The LV mass index in HCM patients significantly exceeded that of control subjects (104 +/- 40 g/m(2) vs. 61 +/- 10 g/m(2) in men and 89 +/- 33 g/m(2) vs. 47 +/- 7 g/m(2) in women; both p < 0.0001). However, values were within the normal range (< or = mean +2 SDs for control subjects) in 56 patients (21%), and only mildly increased (mean +2 to 3 SDs) in 18 (16%). The LV mass index showed a modest relationship to maximal LV thickness (r(2) = 0.38; p < 0.001), and was greater in men (104 +/- 40 g/m(2) vs. 89 +/- 33 g/m(2) in women; p < 0.001) and in patients with resting outflow obstruction (121 +/- 43 g/m(2) vs. 96 +/- 37 g/m(2) in nonobstructives; p < 0.001). During a 2.6 +/- 0.7-year follow-up, markedly increased LV mass index proved more sensitive in predicting outcome (100%, with 39% specificity), whereas maximal wall thickness >30 mm was more specific (90%, with 41% sensitivity). CONCLUSIONS In distinction to prior perceptions, LV mass index was normal in about 20% of patients with definite HCM phenotype. Therefore, increased LV mass is not a requirement for establishing the clinical diagnosis of HCM. The LV mass correlated weakly with maximal wall thickness, and proved more sensitive in predicting outcome.

Twenty-four-hour spectral analysis of heart rate variability in congestive heart failure secondary to coronary artery disease

Abstract It is well known that heart rate (HR) fluctuates in time and that this variation is closely related to changes in the neural activity to the heart. 1,2 Therefore, HR variability represents a noninvasive parameter for studying the autonomic control to the heart. Recently, it has been shown that HR variability is a powerful independent prognostic factor in patients with coronary artery disease 3 and a low HR variability count has been found to be related to sudden death. 4 Spectrum analysis of HR may provide further information, since HR variability possesses 2 major components that have been shown to relate to different patterns of neural control to the heart. 5,6 Patients with congestive heart failure (CHF) have a complex abnormality of the autonomic control to the heart 7 that also affects some HR characteristics. 8 These abnormalities may be determined either by a selective reduction of the vagal outflow to the heart or by a more complex abnormality. This investigation was undertaken to evaluate the components of HR variability in normal persons and patients with CHF, and their 24-hour behavior.

Transthoracic three-dimensional echocardiographic reconstruction of left and right ventricles: In vitro validation and comparison with magnetic resonance imaging

Two-dimensional (2D) echocardiographic and angiographic measurements of ventricular volumes are limited by geometric assumptions concerning cavity shape. We compared in vitro the accuracy of a three-dimensional (3D) echocardiographic system suitable for transthoracic imaging to magnetic resonance imaging (MRI) in the measurement of left and right ventricular volumes. Ventricular cast volumes from 14 excised formalin-fixed sheep hearts filled with an agarose solution were compared with data derived from 3D echocardiography and MRI. Left and right ventricular volumes from 3D echocardiographic reconstructions agreed well with actual volumes without significant underestimation or overestimation. MRI progressively underestimated left ventricular volumes as these increased and systematically underestimated right ventricular volumes. Our echocardiographic system designed for 3D transthoracic imaging combines excellent measurements of left and right ventricular volumes and the computed reconstruction of tomographic slices with the full spatial resolution of the original 2D images. Thus in this in vitro model, 3D echocardiography exhibited greater accuracy than MRI.

Spatial Relationship Between Coronary Microvascular Dysfunction and Delayed Contrast Enhancement in Patients with Hypertrophic Cardiomyopathy

To clarify the spatial relationship between coronary microvascular dysfunction and myocardial fibrosis in hypertrophic cardiomyopathy (HCM), we compared the measurement of hyperemic myocardial blood flow (hMBF) by PET with the extent of delayed contrast enhancement (DCE) detected by MRI. Methods: In 34 patients with HCM, PET was performed using 13N-labeled ammonia during hyperemia induced by intravenous dipyridamole. DCE and systolic thickening were assessed by MRI. Left ventricular myocardial segments were classified as with DCE, either transmural (DCE-T) or nontransmural (DCE-NT), and without DCE, either contiguous to DCE segments (NoDCE-C) or remote from them (NoDCE-R). Results: In the group with DCE, hMBF was significantly lower than in the group without DCE (1.81 ± 0.94 vs. 2.13 ± 1.11 mL/min/g; P < 0.001). DCE-T segments had lower hMBF than did DCE-NT segments (1.43 ± 0.52 vs. 1.91 ± 1 mL/min/g, P < 0.001). Similarly, NoDCE-C segments had lower hMBF than did NoDCE-R (1.98 ± 1.10 vs. 2.29 ± 1.10 mL/min/g, P < 0.01) and had no significant difference from DCE-NT segments. Severe coronary microvascular dysfunction (hMBF in the lowest tertile of all segments) was more prevalent among NoDCE-C than NoDCE-R segments (33% vs. 24%, P < 0.05). Systolic thickening was inversely correlated with percentage transmurality of DCE (Spearman ρ = −0.37, P < 0.0001) and directly correlated with hMBF (Spearman ρ = 0.20, P < 0.0001). Conclusion: In myocardial segments exhibiting DCE, hMBF is reduced. DCE extent is inversely correlated and hMBF directly correlated with systolic thickening. In segments without DCE but contiguous to DCE areas, hMBF is significantly lower than in those remote from DCE and is similar to the value obtained in nontransmural DCE segments. These results suggest that increasing degrees of coronary microvascular dysfunction might play a causative role for myocardial fibrosis in HCM.

Diagnostic accuracy of 64-slice computed tomography coronary angiography in patients with low-to-intermediate risk

PurposeOur aim was to evaluate the diagnostic accuracy of 64-slice computed tomography coronary angiography (MSCT-CA) for detecting significant stenosis (≥50% lumen reduction) in a population of patients at low to intermediate risk.Materials and methodsWe studied 72 patients (38 men, 34 women, mean age 53.9±8.0 years) with atypical or typical chest pain and stratified in the low-to intermediate risk category. MSCT-CA (Sensation 64 Cardiac, Siemens, Germany) was performed after IV administration of 100 ml of iodinated contrast material (Iomeprol 400 mgI/ml, Bracco, Italy). Two observers, blinded to the results of conventional coronary angiography (CAG), assessed the MSCT-CA scans in consensus. Diagnostic accuracy for detecting significant stenosis was calculated.ResultsCAG demonstrated the absence of significant disease in 70.1% of patients (51/72). No patient was excluded from MSCT-CA. There were 37 significant lesions on 1,098 available coronary segments. Sensitivity, specificity and positive and negative predictive value of MSCT-CA for detecting significant coronary artery on a per-segment basis were 100%, 98.6%, 71.2% and 100%, respectively. All patients with at least one significant lesion were correctly identified by MSCT-CA. MSCT-CA scored 15 false positives on a per-segment base, which affected only marginally the per-p.atient performance (only one false positive).ConclusionsWe concluded that 64-slice CT-CA is a diagnostic modality with high sensitivity and negative predictive value in patients at low to intermediate risk.RiassuntoObiettivoValutare l’accuratezza diagnostica dell’angiografia coronarica non invasiva con tomografia computerizzata (AC-TC) a 64 strati nell’individuazione delle stenosi coronariche significative (riduzione del lume coronarico ≥ 50%) in una popolazione di pazienti a basso-intermedio rischio cardiovascolare.Materiali e metodiSono stati studiati 72 pazienti (38 maschi, 34 donne, età media 53,9±8,0 anni) che presentavano dolore toracico atipico o angina pectoris stabile e che venivano stratificati nella categoria del rischio basso-intermedio. Per la scansione AC-TC sono stati iniettati endovena 100 ml di mezzo di contrasto (Iomeprolo 400 mgI/ml, Bracco, Italia). Due osservatori, in cieco rispetto alla coronarografia convenzionale CAG), hanno valutato in consenso le immagini dell’AC-TC. Sono stati quindi calcolati i valori di accuratezza diagnostica per la rilevazione di stenosi significative.RisultatiL’angiografia coronarica invasiva ha dimostrato l’assenza di malattia o la presenza di malattia non critica nel 70,1% dei pazienti (51/72). Nessun paziente è stato escluso dalla popolazione studiata. Sono state individuate 37 lesioni significative su 1098 segmenti disponibili. Sensibilità, specificità, valore predittivo positivo e negativo dell’AC-TC nella determinazione delle stenosi significative utilizzando un’analisi per segmenti sono risultate, rispettivamente, del 100%, 98,6%, 71,2% e 100%. Tutti i pazienti con almeno una lesione significativa sono stati correttamente identificati anche nella valutazione con AC-TC. L’AC-TC ha generato 15 falsi postivi su base segmentale che però si riducono a un solo falso positivo nell’analisi per paziente.ConclusioniL’AC-TC a 64 strati rappresenta una metodica diagnostica ad elevata sensibilità e valore predittivo negativo nei pazienti con rischio basso o intermedio.

Coronary calcium score as gatekeeper for 64-slice computed tomography coronary angiography in patients with chest pain: per-segment and per-patient analysis

We sought to investigate the performance of 64-slice CT in symptomatic patients with different coronary calcium scores. Two hundred patients undergoing 64-slice CT coronary angiography for suspected coronary artery disease were enrolled into five groups based on Agatston calcium score using the Mayo Clinic risk stratification: group 1: score 0, group 2: score 1–10, group 3: score 11–100, group 4: score 101–400, and group 5: score > 401. Diagnostic accuracy for the detection of significant (≥50% lumen reduction) coronary artery stenosis was assessed on a per-segment and per-patient base using quantitative coronary angiography as the gold standard. For groups 1 through 5, sensitivity was 97, 96, 91, 90, 92%, and specificity was 99, 98, 96, 88, 90%, respectively, on a per-segment basis. On a per-patient basis, the best diagnostic performance was obtained in group 1 (sensitivity 100% and specificity 100%) and group 5 (sensitivity 95% and specificity 100%). Progressively higher coronary calcium levels affect diagnostic accuracy of CT coronary angiography, decreasing sensitivity and specificity on a per-segment base. On a per-patient base, the best results in terms of diagnostic accuracy were obtained in the populations with very low and very high cardiovascular risk.

Prevalence and characteristics of coronary artery disease in a population with suspected ischaemic heart disease using CT coronary angiography: correlations with cardiovascular risk factors and clinical presentation

Purpose . This study was undertaken to describe the correlation between the distribution of coronary artery disease (CAD) in a symptomatic population with suspected ischaemic heart disease, cardiovascular risk factors (RF) and clinical presentationMaterials and methods . We studied 163 patients (mean age 65.5 years; 101 men and 62 women) referred for multidetector computed tomography coronary angiography (MDCT-CA) to rule out CAD. The patients had no prior history of revascularisation or myocardial infarction. We analysed how the characteristics of CAD (severity and type of plaque) can change with the increase in RF and how they are related to different clinical presentationsResults . Patients were divided into three groups according to the number of RF: zero or one, two or three, and four or more. The percentage of coronary arteries with no plaque, nonsignificant disease and significant disease was 55%, 41% and 4%, respectively, in patients with zero or one RF; 27%, 51% and 22%, respectively, in patients with two or three RF; and 19%, 38% and 44%, respectively, in patients with four or more RF. Plaque in patients with nonsignificant disease was mixed in 65%, soft in 18% and calcified in 17%. The percentage of coronaries with no plaque in the three RF groups was 50%, 20% and 0% in patients with typical chest pain and 46%, 24% and 12% in those with atypical pain. The percentage of significant disease in patients with typical pain was 0%, 47% and 86% and in those with atypical pain 4%, 20% and 29%Conclusions . MDCT plays an important role in the identification of CAD in patients with suspected ischaemic heart disease. Severity and type of disease is highly correlated with RF number and assumes different characteristics according to clinical presentationRiassuntoObiettivo . Descrivere la correlazione esistente tra la distribuzione della patologia coronarica, in una popolazione sintomatica con sospetta cardiopatia ischemica, i fattori di rischio (FDR) cardiovascolari e la presentazione clinicaMateriali e metodi . Abbiamo studiato 163 pazienti (età media 65,5±10,6 anni; 101 maschi e 62 femmine) che hanno eseguito una angiografia coronarica mediante tomografia computerizzata multistrato (TCMS) con lo scopo di escludere la presenza di patologia coronarica; tutti i pazienti erano sintomatici e nessuno aveva storia di rivascolarizzazione o infarto miocardio. Abbiamo analizzato come le caratteristiche della malattia (severità e tipo di placca) possono cambiare con l’aumentare dei FDR e come sono correlate alle differenti presentazioni clinicheRisultati . Sono stati suddivisi i pazienti in tre gruppi in base al numero dei FDR: con 0 o 1, con 2 o 3 e con 4 o più FDR. La percentuale di coronarie indenni, malattia non significativa e malattia significativa era, rispettivamente, del 55%, 41%, 4% nei pazienti con 0 o 1 FDR, del 27%, 51%, 22% nei pazienti con 2 o 3 FDR e del 19%, 38%, 44% nei pazienti con 4 o più FDR. La placca nei pazienti con malattia non significativa era mista nel 65%, soft nel 18% e calcifica nel 17%. La percentuale di coronarie indenni nei tre gruppi di FDR era 50%, 20%, 0% nei pazienti con dolore tipico e 46%, 24%, 12% in quelli con dolore atipico, mentre la percentuale di malattia significativa nei pazienti con dolore tipico era 0%, 47%, 86% e in quelli con dolore atipico era 4%, 20%, 29%Conclusioni . La TCMS ha un ruolo importante nella identificazione della patologia coronarica nei pazienti con sospetta cardiopatia ischemica. La severità e il tipo di malattia è fortemente correlato al numero dei FDR e assume caratteristiche differenti in base alla presentazione clinica

Three-dimensional simultaneous strain-volume analysis describes left ventricular remodelling and its progression: a pilot study.

Aims Three-dimensional (3D)-echocardiography speckle imaging allows the evaluation of frame-by-frame strain and volume changes simultaneously. The aim of the present investigation was to describe the strain–volume combined assessment in different patterns of cardiac remodelling. Methods and results Fifty patients received a 3D acquisition. Patients were classified as follows: healthy subjects (CNT), previous AMI, and normal ejection fraction (EF; group A); ischaemic cardiomyopathy with reduced EF (group B); hypertrophic/infiltrative cardiomyopathy (group C). Values of 3D strain were plotted vs. volume for each frame to build a strain–volume curve for each case. Peak of radial, longitudinal, and circumferential systolic strain (Rɛp, Lɛp, and Cɛp, respectively), slopes of the curves (RɛSl, LɛSl, CɛSl), and strain to end-diastolic volume (EDV) ratio (Rɛ/V, Lɛ/V, Cɛ/V) were computed for the analysis. Strain–volume curves of the CNT group were steep and clustered, whereas, due to progressive dilatation and reduction of strains, progressive flattening could be demonstrated in groups A and B. Quantitative data supported visual assessment with progressive lower slopes (P< 0.05 for RɛSl, CɛSl, P= 0.06 for LɛSl) and significantly lower ratios (P< 0.01 for Rɛ/V, Lɛ/V, and Cɛ/V). Group C showed an opposite behaviour with slopes and ratios close to those of normal subjects. Correlation coefficients between EDV and slopes of the curves were significant for all the directions of strain (CɛSl: r = 0.891; RєSl: r = 0.704; LєSl: r = 0.833; P< 0.0001 for all). Conclusion We measured left ventricular volumes and strain by 3D-echo and obtained strain–volume curve to evaluate their behaviour in remodelling. A distinctive and progressive pattern consistent with pathophysiology was observed. The analysis here shown could represent a new non-invasive method to assess myocardial mechanics and its relationship with volumes.