Definition of left ventricular remodelling following ST-elevation myocardial infarction: a systematic review of cardiac magnetic resonance studies

Background/Introduction

An increase in left ventricular volumes between baseline and follow-up imaging is the main criteria for the quantification of left ventricular remodeling after ST-elevation myocardial infarction, but without consensual definition.

Purpose

We aimed to review the criterion used for the definition of left ventricular remodeling based on cardiac magnetic resonance imaging in studies including patients with ST-elevation myocardial infarction.

Methods

A systematic literature search was conducted using MEDLINE and the Cochrane Library from January 2010 to August 2019. Thirty-seven studies involving a total of 4209 patients were included.

Results

The median age of the patients was 59 years, 82% were male, and 93% underwent primary percutaneous coronary intervention. The median follow-up duration was 6 months (range, 3–12), and the second cardiac magnetic resonance session was performed at 6 months in 14 (38%) studies. Among these studies, 30 (81%) used a cut-off value for defining left ventricular remodeling, with a pooled left ventricular remodeling prevalence estimate of 22.8%, 95%-CI[19.4%-26.7%], and a major between-study heterogeneity (I2=82%). The seven remaining studies (19%) defined left ventricular remodeling as a continuous variable. A 20% increase in end-diastolic volumes or a 15% increase in end-systolic volumes between a baseline and a follow-up cardiac magnetic resonance imaging were the two most common criterion (13 [35%] and 9 [24%] studies, respectively). Seven studies used both end-diastolic and end-systolic vleft ventricular volumes.

Conclusion(s)

The definition of left ventricular remodeling using cardiac magnetic resonance following ST-elevation myocardial infarction is highly variable, among studies including highly selected patients. The most frequent left ventricular remodeling criterion were a 20% increase in end-diastolic volumes or a 15% increase in end-systolic volumes. A composite cut-off value of a 12% to 15% increase in end-systolic volume and a 12% to 20% increase in end-diastolic volume using a follow-up cardiac magnetic resonance imaging 1 to 3 months after myocardial infarction might be proposed as a consensual cut-off for defining adverse left ventricular remodeling for future large-sized, prospective studies with serial cardiac magnetic resonance imaging and long-term follow-up in unselected patients.

Funding Acknowledgement

Type of funding source: None

Left atrial strain is associated with left ventricular remodeling in patients with ST-elevation myocardial infarction

Background/Introduction

Left ventricular remodeling (LVR) remains common and is associated with outcomes in patients with ST-elevation myocardial infarction (STEMI). Left atrial (LA) volume has been described as a predictor of outcomes in the latter population.

Purpose

To investigate the association between LA mechanical function using speckle tracking imaging and LVR at follow-up in STEMI patients.

Methods

Baseline 3D transthoracic echocardiograms were performed in 121 STEMI patients. LA global longitudinal strain was reported separately for the reservoir (LASr), conduit (LAScd), and contraction (LASct) phases. Follow-up echocardiograms were performed at 6 months.

Results

Mean age was 58.3±12.5 years and 98 (81%) were men. Baseline left ventricular ejection fraction (LVEF) was 46.8% [41.0, 52.9] and significantly improved to 52.1% [45.8, 57.0] at follow-up, (p<0.001). A lower LASct was associated with a significant dilation of left ventricle at follow-up (%end-diastolic volume increase: −1.9% [−11.0, 15.2] in the two higher LASct tertiles group vs. 19.2% [5.0, 34.3] in the lower LASct tertile group, p=0.001). A higher %end-systolic volume increase at follow-up was associated with lower LASct as well: 12.6% [−16.2, 39.8] in the lower LASct group vs. −6.8% [−23.6, 14.4] in the two higher LASct tertiles group (p=0.004). Regarding LVEF, a low LVEF at follow-up was associated with the worst tertile of all LA strains (LASr, p=0.002; LAScd, p=0.01 and LASct, p=0.01).

Conclusion(s)

The three components of baseline LA strain were associated with LVEF at follow-up in patients with STEMI. Some of these components were also significantly associated with lower LVEF at baseline or predictive of a significant increase in left ventricular volumes during follow-up, indicating LVR.

Funding Acknowledgement

Type of funding source: None

Cost-effectiveness analysis of a telemonitoring program on patients with heart failure in Normandy: an 8-year retrospective analysis (2009–2017)

Background

SCAD is a 3-month telemonitoring program for HF patients, associated with therapeutic education, proposed after an acute HF episode. SCAD is based on an interactive algorithm allowing to generate educative messages and alarms based on patients' responses registered on a digital tablet. It is funded by the French Health Insurance through a pilot program: ETAPES (470€/patient).

Purpose

To describe the profile of patients using SCAD & assess the medico-economic impact of the SCAD system.

Methods

Multicenter retrospective cohort study using SCAD data matched with French Health Insurance data. All patients telemonitored by SCAD in 7 centers have been included, since 01/01/2010 to 12/31/2016. Only direct costs were considered, estimated from a societal perspective limited to reimbursements. Analyses were performed to assess the difference in healthcare consumptions and costs between the year before and the year after inclusion in the SCAD program. Patients who died in the 12 months after SCAD initiation were excluded.

Results

627 patients benefited from SCAD program between 01/01/2010 and 12/31/2016 and were retrieved in French Health Insurance data through probabilistic matching. Out of the 627 patients, 99 died in the 12 months after SCAD initiation. Analyses were performed on 528 patients.72.2% were male, mean age was 66.0 years old and mean BMI 28.2. HFrEF represented 51.9% of patients, HFmrEF 25.9% and HFpEF 22.2%. 58.0% were in NYHA class 2 at baseline, 29.2% in class 3, 8.5% in class 1 and 4.3% in class 4. Mean Charlson Comorbidity Index score was 2.6 at baseline. Patients reported their level of fatigue (10 representing significant fatigue) and morale (10 = good morale) at baseline: mean fatigue=4.0/10 & mean morale=7.4/10. Medico economic results are presented in table 1 and show an important & significant decrease of hospitalizations costs and some transfer of cost toward ambulatory care.

Conclusion

On the year following remote monitoring, total health expenditure has been reduced by 18% on average (mean=3 210€/patient) and 42% in median (5 500€/patient) vs 12 months before.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): This analysis has been funded through an institutional grant from Amgen

Serum neprilysin levels are associated with myocardial stunning after ST-elevation myocardial infarction

Background/Introduction

Left ventricular remodeling following ST-elevation myocardial infarction (STEMI) is associated with poor outcome. Neprilysin inhibition leads to improved outcome in patients with altered left ventricular ejection fraction (LVEF).

Purpose

We aimed to assess the association between serum levels of neprilysin and left ventricular (LV) volumes, function and remodeling in STEMI patients with successful myocardial reperfusion.

Methods

Sixty-eight patients were admitted for STEMI and had both plasma neprilysin measurement at baseline and 3D transthoracic echocardiogram at baseline and at follow-up (7 months). We compared 3 groups: a group with a low-level of plasma neprilysin (<125 pg/mL, i.e. the lower limit of detection of the assay, 38 patients) and the two other groups were defined as being below or above the median value of the remaining samples (15 patients each).

Results

Median age was 58.5±12.8 years and 56 (82.4%) were men. Median LVEF was 45.0±8.5%. Baseline characteristics were comparable among groups. At baseline there was a non-significant trend towards lower end-diastolic volume (p=0.07) but significantly lower LVEF in the high neprilysin group (46.4±8.3%, 47.1±8.1% and 39.1±6.9%, p<0.01). At follow-up, the magnitude of LVEF increase was significantly more important in the high neprilysin group compared to the other groups (p=0.022 for relative change in LVEF and 6.6±7.3%, 3.6±9.0% and 11.3±8.4%, p=0.031 for absolute change in LVEF) resulting in similar LVEF levels at follow-up between all groups (53.0±8.9%, 50.6±9.7% and 50.4±9.9%, p=0.55).

Conclusion(s)

Initial high neprilysin levels may identify patients with stunned myocardium early after STEMI, with a recovery of contractility leading to improved LVEF at follow-up.

Funding Acknowledgement

Type of funding source: None

Prostaglandins in renovascular and renal hypertension

PG A1, B1, E2, F1,2alpha and PRA have been measured in 8 hypertensive patients with unilateral renal arterial stenosis, 7 hypertensive patients with unilateral renal atrophy and 20 control normotensive subjects. PRA and PGA1 were significantly increased in patients with renovascular hypertension but not in patients with atrophy. PGE2 and PGF1,2alpha were increased in both groups of patients, especially on the stenotic or atrophic side. The increase of PGA1 and PGE2, represents a secondary antihypertensive, diuretic and natriuretic mechanism, the increase of PGF1,2alpha a direct hypertensive mechanism.

Longitudinal left ventricular strain impairment in type 1 diabetes children and adolescents: a 2D speckle strain imaging study

AIM

Type 1 diabetes (T1D) involves complex metabolic disturbances in cardiomyocytes leading to morphological and functional abnormalities of the myocardium. The relationship between T1D and cardiac structure and function in children is not well established. Our study investigated whether T1D is associated with early subclinical myocardial disturbances in children and adolescents, and whether the state of metabolic control and diabetes duration are influential factors.

METHODS

Standard echocardiography, tissue Doppler imaging (TDI) and two-dimensional (2D) strain imaging were prospectively performed in 100 T1D children (age: 11.3 ± 3.6 years, 52 boys) and compared with 79 controls.

RESULTS

The diabetic and control children were comparable with respect to age, gender, heart rate and blood pressure. There were no significant differences between the two groups in left ventricular (LV) ejection fraction, LV remodelling and TDI parameters. Conventional mitral Doppler demonstrated significantly fewer diastolic filling abnormalities with an early filling wave in the diabetes group. Global longitudinal strain (GLS) was also significantly lower in the T1D children, while circumferential strain and radial strain did not differ. GLS correlated with HbA1c (r=0.52; P<0.01), but there was no correlation with diabetes duration.

CONCLUSION

Our results suggest that LV longitudinal myocardial deformation is decreased in young patients with T1D, and glycaemic control may be the main risk factor for these changes. Further follow-up is now necessary to precisely determine the clinical significance of these myocardial changes detected by 2D strain imaging in T1D children.

Urinary aldosterone-to-active-renin ratio: a useful tool for predicting resolution of hypertension after adrenalectomy in patients with aldosterone-producing adenomas

BACKGROUND

The purpose of this study was to determine the preoperative clinical and biological factors that predict the clinical outcomes after surgery, in subjects with aldosterone-producing adenomas (APAs).

METHODS

Fifty-eight patients (mean age 52 +/- 11 years) with APA were followed up for 43 +/- 13 months after they had undergone unilateral adrenalectomy. The subjects were classified as "cured" (n = 23) if the blood pressure (BP) was <140/90 mm Hg without postoperative medication, "normalized" (n = 20) if BP was <140/90 mm Hg with antihypertensive therapy, and "uncontrolled" (n = 15) if a BP of < or =140/90 mm Hg was not achieved despite intensive therapy.

RESULTS

The cured patients had a significantly lower mean preoperative age, cardiac mass, and serum creatinine (P < 0.001) than the other subjects. The main independent predictors of surgical curability were: age (P < 0.01), low serum potassium (P < 0.0001), and the urinary aldosterone-to-active-renin (UAAR) ratio (P < 0.008). Among the hormonal parameters, the UAAR ratio provided the best area under the receiver operating-characteristics curve (0.802 (confidence interval (CI) 95%: 0.676-0.944)). For a cutoff value of 15, the positive and negative predictive values of the UAAR ratio were 85 and 92%, respectively. In the study population as a whole, surgical treatment restored the age-systolic BP (SBP) relationship (P < 0.006), which was insignificant before surgery.

CONCLUSIONS

Although all the subjects showed lowering of BP after surgery, and the age-BP relationship was restored, the long-term cure rate of APA subjects was 40%. The UAAR ratio, by comparison with other classical hormonal features of primary aldosteronism, was the best independent predictor of the cure of hypertension after adrenalectomy.

[Recommendations for sports participation in patients with arrhythmia]

Nowadays, sports are a wonderful mean for social success, and the high-level athlete is the symbol of a perfect hygiene of life. Despite this, the occurrence of unexplained sudden death (SD) is not exceptional, especially during training and competition. In this context, it is important to intensify medical controls for these athletes, especially in a very early phase, in order to detect subjects at risk. In case of detection of a cardiac disease prone to cardiovascular or arrhythmic event, the practice of any high-level sportive activity or even any sustained sportive activity must be forbidden without hesitation, with the aim of protecting these subjects. Even though a total interdiction of sports practice can be a tough decision to be accepted, it should prevail on the dramatic consequences of sudden death. Physicians' responsibility issues in the screening and management of competition or leisure-time sportsmen are of high importance since in case of sudden death, the physician and the medical community liabilities can be considered. As a consequence, the medical community set up recommendations on the screening, treatment and even interdiction of sportive activity for athletes, which should also be applied to leisure-time sportsmen. In the first part of this article, the different causes (especially the arrhythmia-related) of sudden death occurring in sportsmen are reviewed. In the second part, the recommendations on practice of high-level sports in case of arrhythmia or genetic arrhythmic cardiac disease are summarized.

[Value and limitations of programmed ventricular stimulation]

The electrocardiogramme and methods of prolonged ECG recording are sufficient for diagnosing most cardiac arrhythmias. They also provide some prognostic information and allow evaluation and follow-up of treatment. However, in some situations, endocavitary electrophysiological investigations are required when the diagnosis is uncertain, that more prognostic information is required or interventional techniques (endocavitary ablation) are envisaged. The aim of this report is to summarise the value and limitations of programmed ventricular stimulation. Many of its indications have been abandoned in terms of rhythm stratification in the face of more robust parameters, in particular the left ventricular ejection fraction. However, it retains a potential utility in terms of prognosis in arrhythmogenic right ventricular dysplasia, the Brugada syndrome and operated Tetralogy of Fallot. In any event, it is important to remember that studies resulting in diagnostic or therapeutic recommendations were performed with strict protocols of stimulation in selected patients and that these recommendations can only be applied when the evaluation protocols are respected. The indications of programmed ventricular stimulation will increase in the therapeutic field with the development of new techniques of 3D mapping, new systems of catheter guiding which should extend the indications of endocavitary ablation.

[Primary anomalies of ventricular repolarisation]

The duration of repolarisation is the main determinant of the refractory period and therefore plays a major electrophysiological role. Ventricular repolarisation can be influenced or modified by very many extrinsic factors responsible for so-called secondary changes or anomalies. On the contrary, primary anomalies of ventricular repolarisation correspond to intrinsic anomalies of ionic conduction which in turn affect repolarisation. Primary anomalies of ventricular repolarisation are the consequences of vascular disease, which is the origin of both electrocardiographic anomalies and rhythm disorders, and which can result in sudden death from ventricular fibrillation. Three clinical syndromes correspond with these definitions: long QT syndrome, short QT syndrome, and Brugada syndrome. Much of the experimental work seems to show that arrhythmogenic action results mostly from an increase in the heterogeneity of the refractory periods, whether this involves a prolonged, short or even normal repolarisation time. The various experimental models also give a better understanding of the repolarisation changes observed on the electrocardiogram. Knowledge of the mechanisms responsible for arrhythmias due to primary anomalies of ventricular repolarisation could provide a model for secondary anomalies.

[Comparison between three-dimensional electro-anatomical mapping and conventional mapping in the ablation of atrial tachycardias]

In atrial tachycardias, catheter ablation using conventional mapping system is associated with high immediate success and low recurrence. Three-dimensional electroanatomical mapping system combined to catheter ablation of atrial tachycardias has reached, in small uncontroled series, success rates of 100%. However, limited data are available about rates of recurrence or complication using this approach. In order to compare both mapping systems, we have conducted a study of 65 consecutive patients (36 women and 29 men) that underwent both electrophysiologic study and catheter ablation for suspected atrial tachycardias. Pre-existing heart disease was noted in 43%, hypertension in 32% and a history of atrial fibrillation of flutter in 52%. Catheter ablation guided by conventional mapping was undertaken in 44 patients and by three-dimensional electroanatomical mapping in 21. Successful ablation was performed in 68% of patients with conventional mapping and in 90% with three-dimensional electroanatomical mapping. No complication and recurrence were observed with the latter approach, while 5 patients had a recurrence and 2 had immediate complication with conventional mapping. Catheter ablation of atrial tachycardias combined with three-dimensional electroanatomical mapping appeared to be effective and safe, however, conventional mapping system still remains a reliable approach that must be considered as the first choice for atrial tachycardias ablation.

[Ventricular extrasystoles]

Ventricular extrasystoles result from premature excitation of the heart from a site beyond the bifurcation of the bundle of His, at the level of the conductive tissue or myocardial cells. In practice they represent a daily problem for cardiologists due to their frequent occurrence. They can be detected in symptomatic patients and also in asymptomatic subjects, for example during routine health checks. It is therefore important to distinguish benign ventricular extrasystoles from those which are potentially serious, so that a useless or even dangerous treatment is not undertaken and severe anxiety is not caused in patients who have become 'medicalised'. The decision about treatment is only made following electrocardiographic and echographic clinical investigation, with the presence of cardiopathy being one of the major deciding factors.

[Recent concepts of the Brugada syndrome, the long QT syndrome and adrenergic ventricular tachycardias]

The clinical syndromes responsible for sudden death have benefited from spectacular advances in recent years. The authors propose a brief review of the genetic, electrophysiological, physiopathological and clinical characteristics of the long QT syndrome, Brugada's syndrome, adrenergic ventricular tachycardias and the short QT syndrome. The initial concept of one gene responsible for one pathology has uncovered new zones of complexity within diseases considered to be monogenetic in origin. These new findings have impacted on diagnostic and therapeutic strategies of these conditions. However, the assessment of the arrhythmic risk and the choice of treatment in individual cases still remain almost exclusively the domain of clinical judgement. Similarly, the better understanding of the mechanisms of the arrhythmias in these syndromes has opened up new specific therapeutic approaches which require validation by clinical trial.

Aldosterone and anti-aldosterone effects in cardiovascular diseases and diabetic nephropathy

Cells in the cortical collecting duct of distal nephron have been considered for a long time as the unique cellular targets of aldosterone. However, it is now clear that other cell types in non-epithelial tissues are also potential targets for aldosterone. The functions that this hormone controls in non-epithelial tissues are still a matter of debate. Clinical and experimental studies have established that aldosterone plays a major role in the pathophysiology of cardiovascular and renal diseases. The aldosterone receptor antagonists spironolactone and eplerenone have demonstrated specific effects not related to their hypotensive properties in hypertension or cardiac diseases. It appears that a key action of these molecules is related to prevention or treatment of end-organ damage. The latter fact, and the recognition of aldosterone escape on long-term treatment of heart failure, diabetic nephropathy and some forms of hypertension with ACE inhibitors, justify the clinical use of aldosterone receptor antagonists provided that kaliemia is controlled. Experimental studies have allowed to draw a still incomplete but comprehensive scheme of aldosterone cardiovascular actions in pathological conditions. When elevated, aldosterone has deleterious effects in blood vessels, in the heart and in kidney, which are secondary to the induction of inflammatory and oxidative processes and necrosis, that induce the increased synthesis of extracellular matrix proteins.

Aldosterone-synthase overexpression in heart: a tool to explore aldosterone's effects

Clinical observations indicate that elevated aldosterone impairs cardiovascular function. The mechanisms, however, are not totally understood although total and cardiovascular mortality are decreased by aldosterone antagonists. Experimentally, increased plasma aldosterone induces pericoronary inflammation and cardiac fibrosis. Our laboratory has discovered that aldosterone is synthesized in the rat heart, and has demonstrated that this cardiac aldosterone is involved in post-infarction cardiac remodeling. In man, activated cardiac aldosterone production has been described in patients with heart failure. In transgenic mice that overexpress aldosterone-synthase in the heart, we observe a normal cardiac function but a major coronary dysfunction, more pronounced in males. These observations converge to a potential physiological and pathological relevance of this system. Beneficial effects of anti-aldosterone treatment in heart failure may thus be secondary in part to blockade of cardiac aldosterone action.

[Bidirectional ventricular tachycardias]

Bidirectional tachycardias are rare arrhythmias. Nevertheless in the sixties and seventies these arrhythmias prompted much work relating to their mechanism. Discussions about the supposed supra-ventricular origin of certain bidirectional tachycardias essentially rested on presumptive arguments based on electrocardiographic analysis. All the electrophysiological investigations which could be performed in tachycardia showed a ventricular origin. The current hypotheses concerning the electrophysiological mechanism favour non-unifocal mechanisms as well as a very diverse aetiology: an automatic focus, or the triggered activities being associated with alternating conduction, or re-entry between the left hemibranches. Although the classic context is of excess digitalis with advanced cardiopathy, readily in atrial fibrillation with a poor prognosis as a corollary, the most recent description of catecholergic ventricular tachycardias with the very characteristic appearance of bidirectional tachycardias justifies updating the understanding of these unusual tachycardias.

[Characteristic electrocardiographic procedures of isthmic-dependent atrial flutter; influence of clinical and echocardiographic procedures]

The appearance of the F waves on the ECG is considered to be related to the type of circuit of the anti-clockwise flutters and the clockwise isthmic-dependant flutters. In the authors' experience, the usual ECG description of these two types of flutter is not always observed. This study was undertaken to analyse the different appearances of anti-clockwise and clockwise flutters and to try and explain the reasons for these differences. Over a 4 year period, 139 patients with an ECG of atrial flutter required electro-physiological studies and echocardiography of the 156 flutters analysed: 130 were anti-clockwise and 26 clockwise. Three types of anti-clockwise flutter were observed: type 1 with exclusively negative F waves in the inferior leads: type 2 and 3 with negative F waves in the inferior leads and a small (type 2) or large (type 3) positive terminal components. The types 2 and 3 were associated with a higher incidence of left atrial dilatation, cardiac disease and atrial fibrillation than type 1. Two types of clockwise flutter were observed: type 1 with positive notched F waves in the inferior leads with a return to the iso-electric line and type 2 with wide F waves in the inferior leads with two components, predominantly positive and negative, without return to the iso-electric line. There are different ECG appearances of anti-clockwise and clockwise flutter which seem to be correlated with structural cardiac abnormalities. The anti-clockwise flutters with a positive terminal component of the F waves in the inferior leads corresponds to a subgroup with a high probability of cardiac disease and left atrial dilatation.

[Brugada syndrome]

The Brugada syndrome is characterised clinically by the occurrence of syncope or sudden death due to ventricular arrhythmias in patients with structurally normal hearts and electrocardiographic signs of right bundle branch block and ST elevation in the right precordial leads (V1 to V3). The transmission of the condition is autosomal dominant with variable penetration. Mutations have been identified in a gene coding for the alpha sub-unity of the sodium channel (SCN5A) on chromosome 3 in only 30% of cases. This mutation is responsible for a reduction of the density of the sodium current and explains the aggravation of the electrocardiographic anomalies by antiarrhythmic drugs which block the sodium channels. The prognosis is poor in symptomatic patients and depends on the prevention of sudden death by the implantation of an automatic defibrillator. The therapeutic decision is much more difficult in asymptomatic patients without a family history. The authors propose a decisional algorithm. The management may have to be modified in the months or years to come depending on advances in the understanding of this syndrome.

[Indications for implantable automatic defibrillators: critical analysis]

The implantable automatic defibrillator (IAD), invented in 1980, has revolutionised the management of patients with malignant ventricular arrhythmias resistant to medical treatment or ablation procedures. The number of devices implanted continues to increase in the industrialised countries and, based on the results of clinical trials, the indications for IAD are now well codified and increase as new clinical studies are published. However, the absolute number of implantations in France remains low (about 1200 to 2000, about 20 per million population) for a number of reasons: cost of IAD, absence of reimbursement by the health service which has restrained the implantation to public hospitals, and information of cardiologists for whom IAD may seem to be reserved for a few exceptional cases. Several factors suggest that the number of implantations will increase in the near future. First of all, the procedures of implantation have become much more simple due mainly to technical improvements. Then, the results of recent studies have validated prophylactic implantations of these devices in primary prevention in the post-infarction period (MADIT, MUSTT, MADIT II studies) and have demonstrated the superiority of IAD over antiarrhythmic drug therapy in terms of global survival in patients with severe ventricular arrhythmias (AVID, CIDS, CASH studies).

Different patterns of interatrial conduction in clockwise and counterclockwise atrial flutter

BACKGROUND

The terms counterclockwise (CC) and clockwise (C) atrial flutter (Afl) are used to describe right atrial activation around the tricuspid valve in the left anterior oblique view. The manner in which the left atrium is activated, as reflected by coronary sinus (CS) recordings, has not been systematically evaluated.

METHODS AND RESULTS

Nine patients with both CC and C Afl underwent electrophysiological study with CS recordings during both rhythms with the use of a decapolar catheter with the tip placed in the distal CS. Patterns of CS activation during each type of Afl as well as during during sinus rhythm were categorized into 1 of 3 patterns: sequential proximal-to-distal, sequential distal-to-proximal, and fused, indicating activation from different directions. In 7 of 9 patients, the pattern of CS activation in CC Afl and C Afl differed, with a proximal-to-distal pattern in CC Afl and a fused pattern in C Afl. In 2 patients, pacing the high right atrial septum near the presumed site of Bachmann's bundle in sinus rhythm showed a similar fused pattern of CS activation.

CONCLUSIONS

These results demonstrate different patterns of CS activation in CC Afl and C Afl in the majority of patients and are consistent with a model in which the left atrium is activated predominantly over Bachmann's bundle during C Afl and over the CS os in CC Afl. These findings may have implications for maintenance of Afl, interpretation of flutter wave morphology on surface ECG, and left atrial mechanical function in Afl.

[New markers for the risk of sudden death: analysis of ventricular repolarization]

The identification of patients at high risk of sudden cardiac death is one of the greatest challenges for cardiologists. Non-invasive methods have, characteristically, low predictive sensitivities and specificities. The role of abnormalities of ventricular repolarisation (QT interval) in the genesis of ventricular arrhythmias has been well established by experimental data. For this reason, parameters of ventricular repolarisation on the surface electrocardiogram have been proposed. However, taken in isolation, these markers are limited in terms of arrhythmic risk stratification. This report analyses the value of the different parameters of ventricular repolarisation in the identification of high risk: QT dispersion, QT dynamics and T wave alternans. The dispersion of the QT interval is a marker of unhomogenous ventricular depolarisation. This concept must be applied differently in such pathologically dissimilar diseases such as myocardial infarction, cardiomyopathy or the long QT syndrome. Moreover, methodological problems make the interpretation of many experimental studies very delicate. Frequency dependence of the QT helps select high risk patients after myocardial infarction or with dilated cardiomyopathy. A common feature of pathological ventricular myocardium is the more pronounced frequency-dependency of the QT interval. The predictive value of this new index should be evaluated and compared with other non-invasive risk factors in prospective trials. Studies of T wave alternans in selected high risk populations, essentially patients with coronary artery disease and dilated cardiomyopathy, have shown this parameter to be predictive of arrhythmia. The predictive value requires confirmation in much larger populations at lower levels of risk of arrhythmia and sudden death in prospective trials. A new field of research has opened up in the study of ventricular repolarisation. Many studies have been undertaken on the duration of the QT interval, the morphology of the QT (including T wave alternans and post-pause changes) and, finally, the dynamics of the QT interval. By regrouping, analysing and using these data correctly, we should be able to identify new markers of high arrhythmic risk.

[Conn adenoma manifesting as reversible tetraparesis and rhabdomyolysis]

INTRODUCTION

Primary hyperaldosteronism is an uncommon cause of hypertension which classically features hypokaliemia, metabolic alkalosis and excessive urinary potassium excretion. Clinical manifestations of hypokalemia rarely reveal the diagnosis.

EXEGESE

We report the case of a hypertensive patient who developed quadriparesis and rhabdomyolysis induced by a severe hypokalemia. Clinical manifestations were reversible after potassium supplementation. Laboratory and radiological findings led to the diagnosis of an aldosterone-producing adenoma. Surgical treatment allowed correction of electrolyte abnormalities and improvement of hypertension.

CONCLUSION

Although primary aldosteronism is rare, it should be systematically considered when arterial hypertension is associated with hypokalemia, even if the potassium depletion is due to diuretic therapy.