Pheochromocytoma-induced segmental myocardial dysfunction mimicking an acute myocardial infarction in a patient with normal coronary arteries

We report a case of pheochromocytoma-induced segmental myocardial dysfunction and electrocardiographic abnormalities mimicking an acute anterior myocardial infarction, probably due to coronary spasm. Coronary angiography showed normal coronaries, and the electrocardiographic and echocardiographic changes resolved completely after therapy with an alpha-adrenergic blocker and tumor removal. Our case illustrates the importance of maintaining a high index of suspicion in patients presenting with an unexpected myocardial event and a hypertensive crisis.

QT interval, cardiovascular risk factors and risk of death in diabetes

A prolonged QT interval is considered an indicator of increased risk of malignant ventricular arrhythmias and/or sudden death. It has been proposed that autonomic neuropathy in diabetes is related to QT interval prolongation and increased mortality rates. Several studies in Type 1 and Type 2 diabetic patients have confirmed the independent relation between prolonged QT interval duration or increased QT interval dispersion and chronic ischemic heart disease. It has been consistently shown that autonomic neuropathy is related to QT interval duration while more controversies exist on the association with QT interval dispersion. In recent years, studies have confirmed the value of QT interval as a predictor of total mortality in both diabetic and non-diabetic subjects. Moreover, several studies have shown a significant relation between QT interval prolongation and cardiovascular disease risk factors. QT interval could be used to stratify the cardiovascular risk in diabetic patients. We still do not know why QT interval is prolonged and how this abnormality leads to death. Nevertheless, QT interval is a simple, low-cost measure, easily obtainable without the need of the patient's compliance and which could help to select patients who need second level diagnostic procedures and strict observation.

Impaired systemic ventricular relaxation affects postoperative short-term outcome in Fontan patients

OBJECTIVES

Systemic ventricular end-diastolic pressure has been used as a predictor of outcome in patients undergoing the Fontan operation. However, this index only evaluates late diastolic function and does not assess active ventricular relaxation during the phase of early diastole, a key component of systemic venous pathway flow. This study sought to examine whether impaired preoperative systemic ventricular relaxation, expressed as the time constant of isovolumic relaxation (tau), affects short-term postoperative outcome in Fontan patients.

METHODS

All patients who underwent Fontan operation between May 1998 and November 2001 were enrolled. Tau was calculated from digitized preoperative systemic ventricular pressure tracings. Standard preoperative invasive indices were also recorded and analyzed. These independent variables were then entered into a multiple stepwise regression model, with length of intensive care unit stay, length of hospital stay, and prolonged pleural effusion as outcome variables.

RESULTS

Twenty-seven patients fulfilled inclusion criteria. Systemic left ventricle predominated, and all patients had undergone prior staged palliation. Extracardiac Fontan was the commonest operative technique. Of the independent variables examined, tau was the only statistically significant predictor of length of intensive care unit stay (P <.001) and length of hospital stay (P =.002). None of the independent variables predicted pleural effusion greater than 10 days.

CONCLUSIONS

Tau was the only significant preoperative invasive predictor of short-term outcome in the Fontan patients. This illustrates the importance of systemic ventricular relaxation and highlights the need for a more comprehensive assessment of diastolic function before the Fontan operation.

Effects of Repeated Sauna Treatment on Ventricular Arrhythmias in Patients With Chronic Heart Failure

BACKGROUND

The aim of the present study was to determine whether repeated 60 degrees C sauna treatment improves cardiac arrhythmias in chronic heart failure (CHF) patients, because ventricular arrhythmias are an important therapeutic target in CHF.

METHODS AND RESULTS

Thirty patients (59+/-3 years) with New York Heart Association functional class II or III CHF and at least 200 premature ventricular contractions (PVCs)/24 h assessed by 24-h Holter recordings were studied. They were randomized into sauna-treated (n=20) or non-treated (n=10) groups. The sauna-treated group underwent a 2-week program of a daily 60 degrees C far infrared-ray dry sauna for 15 min, followed by 30 min bed rest with blankets, for 5 days per week. Patients in the non-treated group had bed rest in a temperature-controlled room (24 degrees C) for 45 min. The total numbers of PVCs/24 h in the sauna-treated group decreased compared with the non-treated group [848+/-415 vs 3,097+/-1,033/24 h, p<0.01]. Heart rate variability (SDNN, standard deviation of normal-to-normal beat interval) increased [142+/-10 (n=16) vs 112+/-11 ms (n=8), p<0.05] and plasma brain natriuretic peptide concentrations decreased [229+/-54 vs 419+/-110 pg/ml, p<0.05] in the sauna-treated group compared with the non-treated group.

CONCLUSION

Repeated sauna treatment improves ventricular arrhythmias in patients with CHF.

Adult Case of Isolated Ventricular Noncompaction Discovered by Complete Atrioventricular Block

A 25-year-old male was admitted to hospital with a 3-day history of worsening faintness. The electrocardiogram showed complete atrioventricular block. Echocardiography showed generalized hypokinesis and prominent trabeculations ranged from the apex to the mid-ventricular lateral wall of the left ventricle as well. Furthermore, trabeculations in the left ventricle were seen in his sister and brother. Thus, isolated ventricular noncompaction (IVNC) was diagnosed and a permanent pacemaker was implanted. Common clinical symptoms of IVNC are heart failure, ventricular arrhythmias, and embolic events. This is the first reported adult case of IVNC disclosed by the presence of complete atrioventricular block.

Ventricular dysfunction in early diabetic heart disease: detection, mechanisms and significance

The detection of preclinical heart disease is a new direction in diabetes care. This comment describes the study by Vinereanu and co-workers in this issue of Clinical Science in which tissue Doppler echocardiography has been employed to demonstrate subtle systolic and diastolic dysfunction in Type II diabetic patients who had normal global systolic function and were free of coronary artery disease. The aetiology of early ventricular dysfunction in diabetes relates to complex intramyocardial and extramyocardial mechanisms. The initiating event may be due to insulin resistance, and involves abnormal myocardial substrate utilization and uncoupling of mitochondrial oxidative phosphorylation. Dysglycaemia plays an important role via the effects of oxidative stress, protein kinase C activation and advanced glycosylation end-products on inflammatory signalling, collagen metabolism and fibrosis. Extramyocardial mechanisms involve peripheral endothelial dysfunction, arterial stiffening and autonomic neuropathy. The clinical significance of the ventricular abnormalities described is unknown. Confirmation of their prognostic importance for cardiac disease in diabetes would justify routine screening for presymptomatic ventricular dysfunction, as well as clinical trials of novel agents for correcting causal mechanisms. These considerations could also have implications for patients with obesity and the metabolic syndrome.

The aminotetraline derivative (+/-)-(R,S)-5,6-dihydroxy-2-methylamino-1,2,3,4-tetrahydro-naphthalene hydrochloride (CHF-1024) displays cardioprotection in postischemic ventricular dysfunction of the rat heart

To analyze the protective effects of the aminotetraline derivative (+/-)-(R,S)-5,6-dihydroxy-2-methylamino-1,2,3,4-tetrahydro-naphthalene hydrochloride (CHF-1024), a compound endowed with DA2-dopaminergic/alpha2-adrenergic receptor agonistic activity, in myocardial ischemia/reperfusion damage. A model of isolated and perfused (15 ml/min) electrically driven (300 beats/min) rat heart subjected to global ischemia (1 ml/min for 20 min) and reperfusion (15 ml/min for 30 min) was followed. Cardiac mechanics changes were evaluated together with biochemical markers of cardiac ischemia in perfusate and tissue tumor necrosis factor-alpha (TNF-alpha). CHF-1024, perfused through the heart for 15 min before ischemia at different molar concentrations (1-100 nM), significantly improved left ventricle developed pressure during reperfusion, and normalized left ventricular end-diastolic pressure and coronary perfusion pressure. This anti-ischemic effect of CHF-1024 was associated to a decrease in creatine kinase and lactate dehydrogenase, both released during heart reperfusion. These events were concomitant with maintenance of a higher production of 6-keto-prostaglandin F1alpha The ability of CHF-1024 to improve postischemic ventricular dysfunction was correlated with a dose-dependent inhibition of the release of both norepinephrine (NE), from sympathetic nerve endings, and TNF-alpha from cardiac tissue. The effect of CHF-1024 on NE release was almost completely antagonized by specific antagonists of presynaptic inhibitory receptors domperidone and rauwolscine. The finding that this new aminotetraline derivative possesses anti-ischemic properties and limits NE release from cardiac nerve endings may bear some therapeutic potential in cardiovascular diseases.

[Anatomo-clinical correlation. Case 4/2003 - A 61 year-old patient Chagasic woman, with ventricular dysfunction, recurrent ventricular tachycardia and cardiac pacemaker, presented asystole after surgical resection of apical aneurysm]

A 61 year-old Chagasic woman, with previous left ventricular systolic disfunction, ventricular tachychardia and cardiac pacemaker, presented cardiac arrest in asystolia after surgical ressection of apical aneurysm.

Risk stratification for arrhythmic events in patients with idiopathic dilated cardiomyopathy: a review of the literature and current perspectives

The prognosis for patients with idiopathic dilated cardiomyopathy (DCM) has markedly improved during the last decade, mainly because of advancements in therapeutic strategies. However, sudden death still accounts for a significant part of the total mortality in patients with moderate disease. Recent primary prophylactic trials failed to demonstrate any benefit of cardioverter-defibrillator implantation in an unselected group of idiopathic DCM patients and thus the identification of the subgroup of patients at high arrhythmic risk is crucial. Although different risk stratification methods have been evaluated in risk assessment, the reported clinical value differs in studies, mainly because of differences in either methodology and/or patient selection. The present review focuses on arrhythmic events in idiopathic DCM and on the value of noninvasive methods and electrophysiological study in the risk stratification of this group of patients.

Ventriculophasic sinus arrhythmia in the orthotopic transplanted heart: mechanism of disease revisited

BACKGROUND

Several mechanisms have been proposed for ventriculophasic sinus arrhythmia: phasic changes in baroreceptor mediated vagal input to the sinus node, mechanical effects and pressure changes caused by ventricular systole, and increased blood flow to the sinus node. We attempt to elucidate the role of SA nodal blood flow in the generation of ventriculophasic sinus arrhythmia by measuring phasic changes in PP intervals from the atrial remnants of patients who have received cardiac transplant.

METHODS

A total of 16 atrial electrogram recordings were obtained from the recipient atrial remnant in 12 patients who had undergone heart transplantation at the University of Miami/Jackson Memorial Hospital. Concomitant recordings of the donor surface ECG were also obtained. Recipient atrial PP intervals that contained a QRS were measured. The QP intervals were also measured and plotted against the associated PP interval to assess the relationship between varying QP intervals and the associated PP interval.

RESULTS

A linear relationship between the PP intervals and the associated QP intervals was seen in all patients. Despite widely varying QP intervals, there was little change in the PP intervals suggesting absence of ventriculophasic arrhythmia. Our linear graphs are in contrast to the typical curves seen in ventriculophasic arrhythmia that have been described by Lepeschkin.

CONCLUSIONS

In our study, there appeared to be absence of ventriculophasic arrhythmia despite intact vagal innervation to the atrial remnant suggesting that the lack of pulsatile SA node blood flow may contribute to the absence of ventriculophasic arrhythmia. We conclude that the transplanted heart, when performed by the standard technique, may provide a model to study mechanisms of ventriculophasic arrhythmia.

B-type natriuretic Peptide predicts clinical presentations and ventricular overloading in patients with heart failure

Brain natriuretic peptide (BNP), a neurohormone secreted from the ventricular myocardium in response to hemodynamic load/wall stress, in congestive heart failure (CHF). This study was performed to evaluate the correlation between BNP level and clinical presentations and hemodynamic parameters obtained by echo-Doppler (echo-Doppler) analysis, and its relation with disease severity and ventricular load/wall stress. CHF patients (n=246) were subgrouped by clinical presentations and echo-Doppler findings into 4 groups: diastolic HF only, chronic HF, acute HF, and chronic HF with acute exacerbation. A BNP level of 81.2 pg/ml showed a sensitivity/ specificity of 53.3%/98.4% for detecting CHF (AUC, 0.882; p < 0.0001), and was found to be closely related with the NYHA classification (p < 0.0001). Log BNP was related with LVEF (r2=0.3015, p < 0.0001) and the Meridional wall stress index (r2=0.4052, p < 0.0001). The difference between the BNP levels of the subgroups and BNP control was significant (p < 0.0001), except between the HF group and the controls; control (n=114, 20.9 +/- 31.4 pg/ml), only diastolic HF (n=84, 89.8 +/- 117.6 pg/ml), chronic HF (n=60, 208.2 +/- 210.2 pg/ml), acute HF (n=28, 477.9 +/- 498.4 pg/ml), chronic HF with acute exacerbation (n= 74, 754.1 +/- 419.2 pg/ml). The BNP level was significantly higher in the only diastolic HF group than in the asymptomatic control group with diastolic dysfunction (89.8 +/- 12.8 vs. 22.8 +/- 5.1 pg/ml, p < 0.0001). BNP may be a good indicator for the differential diagnosis of a broad spectrum of heart failures. And, elevated BNP might help to diagnose diastolic HF in patients with diastolic dysfunction.

Reliability of QRS duration and morphology on surface electrocardiogram to identify ventricular dyssynchrony in patients with idiopathic dilated cardiomyopathy

Using Fourier phase analysis of equilibrium radionuclide angiography in both ventricles, inter- and intraventricular delays were correlated with QRS morphology and duration in 103 patients with idiopathic dilated cardiomyopathy. We found that left bundle branch block on the left axis may reflect a high intra-left ventricular dyssynchrony. A precise evaluation of the dyssynchrony appears useful because a high proportion of patients with incomplete bundle branch block, left anterior hemiblock, or "normal" QRS exhibit a marked intra-LV dyssynchrony and may respond to cardiac resynchronization therapy.

Cell transplantation to improve ventricular function in the failing heart

Current therapies for congestive heart failure are limited in efficacy or in applicability. Cardiac cell transplantation offers a novel therapeutic approach to improve heart function. Although significant progress has been made over the past decade in the development of cell transplantation, only recently have investigators studied the changes in ventricular function following cell transplantation. This review article describes the latest research developments, evaluates recent studies of ventricular function after cell transplantation, and discusses the future directions of cell transplantation as a new therapy to 'repair broken hearts'.

Myocardial injury in children following resuscitation after cardiac arrest

BACKGROUND

Myocardial dysfunction occurs immediately after successful cardiac resuscitation. Our purpose was to determine whether measurement of cardiac troponin I in children with acute out-of-hospital cardiac arrest predicts the severity of myocardial injury.

METHODS AND RESULTS

This prospective, observational study was performed in the Pediatric Intensive Care Unit (PICU) on 24 patients following arrest, ranging in age from 8 months to 17 years. Troponin measurements were obtained on admission, and at 12, 24, and 48 h. Transthoracic echocardiograms were performed within 24 h after admission. Survival to hospital discharge was 29% (7/24). The mean age was 5.9+/-4.6 years for survivors and 4.2+/-5.3 years for non-survivors. The median (range) duration of cardiac arrest times for survivors was 6 min (3 to 63 min) versus 34 min (4 to 70 min) for nonsurvivors (P=0.02). Survivors received 1.3+/-2.2 doses of epinephrine (adrenaline) compared with 2.9+/-1.6 doses for non-survivors (P=0.02). Only one patient had ventricular fibrillation and defibrillation was unsuccessful. The ejection fraction for survivors averaged 73.2+/-11.2%, but for nonsurvivors only 55.4+/-19.8% (P=0.04). Ejection fraction correlated inversely with troponin at 12 h (r=-0.54, P=0.01) and at 24 h (r=-0.59, P=0.02). Circumferential fiber shortening for survivors was 37.5+/-7.8 and 25.5+/-10.7% for nonsurvivors (P=0.02). It also correlated inversely with troponin (r=-0.46, P=0.03 for survivors and r=-0.65, P=0.01, for nonsurvivors).

CONCLUSION

After cardiac arrest and resuscitation in pediatric patients, the severity of myocardial dysfunction was reflected in troponin I levels.

Identification of hibernating myocardium with quantitative intravenous myocardial contrast echocardiography: comparison with dobutamine echocardiography and thallium-201 scintigraphy

BACKGROUND

There are currently no data on the accuracy of intravenous myocardial contrast echocardiography (MCE) in detecting myocardial hibernation in man and its comparative accuracy to dobutamine echocardiography (DE) or thallium 201 (Tl(201)) scintigraphy.

METHODS AND RESULTS

Twenty patients with coronary artery disease and ventricular dysfunction underwent MCE 1 to 5 days before bypass surgery and repeat echocardiography at 3 to 4 months. Patients also underwent DE (n=18) and rest-redistribution Tl(201) tomography (n=16) before revascularization. MCE was performed using continuous Optison infusion (12 to 16 cc/h) with intermittent pulse inversion harmonics and incremental triggering (1:1 to 1:8). Myocardial contrast intensity (MCI) replenishment curves were constructed to derive quantitative MCE indices of blood velocity and flow. Recovery of function occurred in 38% of dysfunctional segments. MCE parameters of perfusion in hibernating myocardium were similar to segments with normal function and higher than dysfunctional myocardium without recovery of function (P<0.001). The best MCE parameter for predicting functional recovery was Peak MCIxbeta, an index of myocardial blood flow (area under the curve, 0.83). MCE parameters were higher in segments with contractile reserve and Tl(201) uptake > or =60% (P<0.05) and identified viable segments without contractile reserve by DE. The sensitivity of Peak MCIxbeta >1.5 dB/s for recovery of function was 90% and was similar to Tl(201) scintigraphy (92%) and any contractile reserve (80%); specificity was higher than for Tl(201) and DE (63%, 45%, and 54%, respectively; P<0.05).

CONCLUSIONS

MCE with intravenous contrast identifies myocardial hibernation in humans. Prediction of viable myocardium with MCE is best using quantification of myocardial blood flow and provides improved accuracy compared with DE and Tl(201) scintigraphy.

Myocardial infarction and transient ventricular dysfunction in an adolescent with sickle cell disease

We report a case of an adolescent who had sickle cell disease and previous evidence of myocardial damage and presented with abdominal pain and rapid progression to cardiogenic shock and subsequent development of myocardial infarction. To our knowledge, this represents only the second report of a case of acute myocardial ischemia and subsequent infarction resulting transient ventricular dysfunction reported in a child with sickle cell disease successfully treated with exchange transfusion. The pathophysiology of this complication remains unclear, and cardiac complications may remain undetected as lung, bone, and brain infarcts are more common and the pain associated with sickle cell crisis may mask the ischemic symptoms. Multiple factors may contribute to ischemia in addition to the presence of a vaso-occlusive crisis or infection. Acute or chronic myocardial ischemia are probably more prevalent than currently known.

Treatment of high-risk African American patients: left ventricular dysfunction, heart failure, renal disease, and postmyocardial infarction

African Americans experience more mortality and morbidity from hypertension-related complications than other racial groups. Although angiotensin-converting enzyme (ACE) inhibitors have clearly been shown to reduce mortality and morbidity in hypertensive white patients with heart failure, renal dysfunction, stroke, and acute myocardial infarction, African American patients have been underrepresented in these trials. The lack of direct evidence of the benefit of ACE inhibitors in these individuals and the suggestion that ACE inhibitors are less efficacious in this group has resulted in a reluctance to use ACE inhibitors in African Americans. However, retrospective analyses in black patients with heart failure and a recent randomized clinical trial in African Americans with renal dysfunction suggest that a regimen based on ACE inhibitors is efficacious in this racial group. Although diuretics remain first-line therapy, data now suggest that ACE inhibitors provide additional benefit and should be considered for use in patients with high-risk complications regardless of race.

[Utility of verapamil in the treatment of diastolic dysfunction in patients with acromegaly]

INTRODUCTION

Diastolic dysfunction is a common complication in patients with acromegaly. By using the metabolic treatment for acromegaly, an improvement in diastolic function is not always achieved and a group of these patients could obtain some benefit from a specific treatment for such a condition. The objective of the present study was to evaluate the utility of verapamil therapy in acromegalic patients with diastolic dysfunction.

METHODS

Fourteen patients (7 males and 7 females) with the diagnosis of acromegaly and diastolic dysfunction confirmed by echocardiogram were studied. After six months of treatment with verapamil (240 mg/day) the echo-cardiographic parameters and the functional class (NYHA) of patients were reevaluated.

RESULTS

All patients showed an increased basal measurement of the cardiac mass (mean [percentiles 25-75]: 149 g/m2 [128-264]) and no improvement was observed after treatment (182 g/m2 [123-328]). Also, no improvement was found regarding the studied diastolic function parameters: E/A relationship of left ventricle (0.70 [0.54-0.83] versus 0.61 [0.54-0.86]) and isovolumetric relaxation time (146 [119-193] versus 120 [97-169]). A trend towards improvement was indeed found in the functional class, although no statistical differences were observed.

CONCLUSION

Our results did not demonstrate a benefit derived from the treatment with verapamil upon the diastolic function in patients with acromegaly.

Ventricular dyssynchrony and risk markers of ventricular arrhythmias in nonischemic dilated cardiomyopathy: a study with phase analysis of angioscintigraphy

Biventricular pacing is a new form of treatment for patients with dilated cardiomyopathy and ventricular dyssynchrony. Limited information is available regarding the relationship between ventricular dyssynchrony and risk markers of ventricular arrhythmias in idiopathic dilated cardiomyopathy (IDC). In 103 patients with IDC, Fourier phase analysis of both ventricles was performed from equilibrium radionuclide angiography (ERNA). The difference between the mean phase of the LV and RV was a measure of interventricular dyssynchrony, and the standard deviations of the mean phases in each ventricle measured intraventricular dyssynchrony. There were no significant differences in inter- and intraventricular dyssynchrony between patients with versus without histories of sustained VT or VF, nonsustained VT, abnormal signal-averaged ECG, or induced sustained monomorphic VT. Dyssynchrony was not related to decreased heart rate variability (HRV). LV and interventricular dyssynchrony were weakly related to QT duration and QT dispersion. During a follow-up of 27 +/- 23 months, 21 patients had major adverse cardiac events (MACE), including 7 cardiac deaths, 11 progression of heart failure leading to cardiac transplantation, and 3 sustained VT/VF. The only independent predictors of MACE were an increased standard deviation of LV mean phase (P = 0.003), a decreased HRV (standard deviation of normal-to-normal intervals, P = 0.004), and histories of previous VT/VF (P = 0.03) or nonsustained VT (P = 0.04). In conclusion, left intraventricular dyssynchrony evaluated with ERNA was an independent predictor of MACE in IDC and was not related to usual risk markers of ventricular arrhythmias. This may have implications for resynchronization therapy and/or the use of implantable cardioverter defibrillators in IDC.