Assessment of the routine reporting of very low-dose exercise-first myocardial perfusion SPECT from a large-scale real-world cohort and correlation with the subsequent reporting of coronary stenosis at angiography

PURPOSE

Our study assesses the routine reporting of exercise ischemia using very low-dose exercise-first myocardial perfusion SPECT in a large number of patients and under real-life conditions, by evaluating correlations with the subsequent routine reporting of coronary stenosis by angiography and with factors that predict ischemia.

METHODS

Data from 13,126 routine exercise MPI reports, from 11,952 patients (31% women), using very low doses of sestamibi and a high-sensitivity cardiac CZT camera, were extracted to assess the reporting of significant MPI-ischemia (> 1 left ventricular segment), to determine the MPI normalcy rate in a group with < 5% pretest probability of coronary artery disease (CAD) (n = 378), and to assess the ability of MPI to predict a > 50% coronary stenosis in patients with available coronary angiography reports in the 3 months after the MPI (n = 713).

RESULTS

The median effective patient dose was 2.51 [IQR: 1.00-4.71] mSv. The normalcy rate was 98%, and the MPI-ischemia rate was independently predicted by a known CAD, the male gender, obesity, and a < 50% LV ejection fraction, ranging from 29.5% with all these risk factors represented to 1.5% when there were no risk factors. A > 50% coronary stenosis was significantly predicted by MPI-ischemia, less significantly for mild (odds ratio [95% confidence interval]: 1.61 [1.26-1.96]) than for moderate-to-severe MPI-ischemia (4.05 [3.53-4.57]) and was also impacted by having a known CAD (2.17 [1.83-2.51]), by a submaximal exercise test (1.48 [1.15-1.81]) and being ≥ 65 years of age (1.43 [1.11-1.76]).

CONCLUSION

Ischemia detected using a very low-dose exercise-first MPI protocol in a large-scale clinical cohort and under real-life routine conditions is a highly significant predictor for the subsequent reporting of coronary stenosis, although this prediction is enhanced by other variables. This weakly irradiating approach is amenable to being repeated at shorter time intervals, in target patient groups with a high probability of MPI-ischemia.

Left ventricle fibrosis associated with nonsustained ventricular tachycardia in an elite athlete: is exercise responsible? A case report

OBJECTIVE

To emphasize the potentially harmful effects of high-intensity exercise on cardiac health and the fine line between physiologic and pathologic adaptation to chronic exercise in the elite athlete. This case also highlights the crucial need for regular evaluation of symptoms that suggest cardiac abnormality in athletes.

BACKGROUND

Sudden cardiac death (SCD) of young athletes is always a tragedy because they epitomize health. However, chronic, high-intensity exercise sometimes has harmful effects on cardiac health, and pathologic changes, such as myocardial fibrosis, have been observed in endurance athletes. In this case, a highly trained 30-year-old cyclist reported brief palpitations followed by presyncope feeling while exercising. Immediate investigations revealed nonsustained ventricular tachycardia originating from the left ventricle on a stress test associated with myocardial fibrosis of the left ventricle as shown with magnetic resonance imaging. Despite complete cessation of exercise, life-threatening arrhythmia and fibrosis persisted, leading to complete restriction from competition. Differential Diagnosis: Hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, myocarditis, postmyocarditis, use of drugs and toxic agents, doping, and systemic disease.

TREATMENT

The arrhythmia could not be treated with catheter ablation procedure or drug suppression. Therefore, the athlete was instructed to withdraw completely from sport participation and to have a medical follow-up twice each year.

UNIQUENESS

To our knowledge, no other report of left ventricle exercise-induced fibrosis associated with life-threatening arrhythmia in a living young elite athlete exists. Only postmortem evidence supports such myocardial pathologic adaptation to exercise.

CONCLUSIONS

To prevent SCD in young athletes, careful attention must be paid to exercise-related symptoms that suggest a cardiac abnormality because they more often are linked to life-threatening cardiovascular disease.

[Knowledge of hypertension among hypertensive patients in general practice, and its relation to achieving therapeutic goals: The Co-HACT study, French West Indies]

OBJECTIVES

Appraisal of the agreement between patients' reports and general practitionners' declaration in a French Caribbean population and relationship with blood pressure normalization.

METHODS

One hundred French Caribbean practitioners participated in this observational survey: each of them included five essential hypertensives treated for more than three months. BP was considered to be normalized if inferior to 140/90 mmHg. We considered that there is a total agreement between patient and GP declaration when SBP and DBP did not differ by more than 5 mmHg and when the eight risk factors or co-morbidity were identical. Identification of independent factors of BP normalization and awareness was performed using logistic regression.

RESULTS

Five hundred and nine hypertensives (57% women) were recruited. Sixty-nine percent (n = 328) were less than 65 years, 75% (n = 341) had an educational level less than high school. The normalisation rate was 39% (n = 185) within the whole population. 63.4% had a high cardiovascular risk. BP normalization appeared to be closely associated to BP awareness.

CONCLUSIONS

In this observational survey, in a French Caribbean hypertensive population, two third had a high cardiovascular risk. The normalization rate was 39%. This BP normalization appeared to be closely associated to BP awareness.

Gated SPECT assessment of left ventricular function is sensitive to small patient motions and to low rates of triggering errors: a comparison with equilibrium radionuclide angiography

BACKGROUND

Patient displacements and errors in R-wave detection are the main causes of inaccurate acquisition for gated single photon emission computed tomography (SPECT) and equilibrium radionuclide angiography (RNA). This study aimed to compare the influences of both factors between gated SPECT and RNA determinations of left ventricular ejection fraction.

METHODS AND RESULTS

On gated SPECT and RNA acquisitions, recorded in 20 patients with coronary artery disease, we simulated the consequences of (1) 3-dimensional patient displacements of low (6.7 mm), moderate (13.4 mm), and high amplitude (20.1 mm) and (2) an erroneous triggering on T waves in 10% to 40% of recorded beats. Absolute values of left ventricular ejection fraction changes from baseline were higher with gated SPECT compared with RNA for patient displacements of low amplitude (5.0% +/- 3.8% vs 1.2% +/- 0.9%, P < .001) or moderate amplitude (10.0% +/- 6.2% vs 3.0% +/- 2.3%, P = .001) but not for patient displacements of high amplitude (12% +/- 9% vs 9% +/- 7%, P = not significant) and inaccurate triggering (for 20% T-wave triggering, 8.9% +/- 3.6% vs 7.9% +/- 3.0%; P = not significant).

CONCLUSION

Contrary to RNA, gated SPECT is vulnerable to small patient displacements, and thus, specific efforts might be useful for limiting this potential cause of erroneous results. Both techniques may be affected by low rates of triggering errors, suggesting that small acceptance windows on cycle length should be recommended not only for RNA but also for gated SPECT.

Utility of transesophageal atrial pacing in the diagnostic evaluation of patients with unexplained syncope associated or not with palpitations

BACKGROUND

Noninvasive studies are often negative in patients with syncope, normal surface ECG and without heart disease. The purpose of the study was to determine the diagnostic impact of an esophageal electrophysiological study performed during a consultation.

METHODS

A total of 154 patients aged from 16 to 87 years were consecutively recruited for unexplained syncope; they had a normal ECG in sinus rhythm, no documented arrhythmia and no patent heart disease. Half of them complained of palpitations. Electrophysiologic study was performed during a consultation by transesophageal route: rate of 2nd d AV block occurrence during atrial pacing and sinus node recovery time were determined; programmed atrial stimulation using one and two atrial extrastimuli were delivered in control state and then after infusion of 0.02-1 microg/min of isoproterenol; arterial blood pressure was monitored.

RESULTS

(1) Electrophysiologic study was positive in 107 patients (69%); (2) sinus node dysfunction was noted in 9 patients (6%); (3) atrioventricular conduction disturbances were noted in 2 patients (1%); (4) vasovagal reaction which associated a junctional bradycardia and a fall of arterial blood pressure and which reproduced spontaneous symptoms was provoked by isoproterenol infusion in 21 patients (14%); (5) sustained atrial fibrillation was induced in 23 patients (15%); and (6) paroxysmal junctional tachycardia was induced in 52 patients (34%). Patients with negative study were younger (44+/-21.5 years) than those with sinus node dysfunction or atrial fibrillation (71+/-9 and 63+/-14 years, respectively). The treatment was guided by these data: patients with inducible atrial fibrillation were treated by antiarrhythmic drugs and those with inducible paroxysmal junctional tachycardia by the radiofrequency ablation of reentrant circuit. Syncope disappeared in all patients but 2.

CONCLUSION

Esophageal electrophysiologic study performed during a consultation was a safe, rapid and economic means to detect an arrhythmia (sinus node dysfunction or supraventricular tachycardia) in patients with dizziness/syncope and palpitations in half cases. Supraventricular tachycardia was clearly an underestimated cause of syncope in this population.

Exercise release of cardiac natriuretic peptides is markedly enhanced when patients with coronary artery disease are treated medically by beta-blockers

OBJECTIVES

This study sought to identify determinants of the exercise rise in plasma levels of cardiac natriuretic peptides (NPs) in patients with coronary artery disease (CAD).

BACKGROUND

During stress, there is a variable rise in the plasma level of NPs, but this rise frequently reaches levels that are known to lower the cardiac load and that thus might be beneficial to CAD patients.

METHODS

Plasma venous concentrations of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) were determined at rest and peak exercise in 104 patients with chronic CAD who were referred to exercise thallium-201 ((201)Tl) single-photon emission computed tomography (SPECT) and radionuclide angiography.

RESULTS

The extent of scarred myocardium by (201)Tl-SPECT and patient age were the best independent predictors of NP concentrations at rest, but also of increases in NP concentration during exercise (all p < 0.001). Moreover, beta-blocking treatment was an additional and strong independent predictor of the increase in NP concentrations at exercise (p < 0.001 for ANP; p = 0.001 for BNP). On average, exercise increases in NP concentrations were more than twice as high in patients with (n = 55) than in those without (n = 49) beta-blocker treatment (ANP: +49 +/- 63 vs. +22 +/- 25 ng/l, p = 0.01; BNP: +24 +/- 5 vs. +11 +/- 15 ng/l, p = 0.04), whereas NP concentrations at rest were equivalent in the two groups (ANP: 34 +/- 34 vs. 30 +/- 33 ng/l, p = NS; BNP: 85 +/- 152 vs. 57 +/- 101 ng/l, p = NS).

CONCLUSIONS

Patients with chronic CAD exhibit much higher exercise releases of ANP and BNP when they are treated with beta-blockers. This enhanced secretion of potent vasodilating and natriuretic agents constitutes an original therapeutic mechanism for further protecting diseased hearts against stress.

Residual exercise SPECT ischemia on treatment is a main determinant of outcome in patients with coronary artery disease treated medically at long-term with beta-blockers

BACKGROUND

Beta-blockers are potent anti-ischemic medications, able to improve prognosis in patients with coronary artery disease (CAD). However, it is not known whether beta-blockers have the same beneficial prognostic effect when residual ischemia persists on treatment.

METHODS AND RESULTS

The prognostic impact of exercise single photon emission computed tomography (SPECT) ischemia was analyzed in 442 patients with chronic CAD, who were treated with beta-blockers and who were referred to exercise thallium 201 SPECT, while they were receiving their daily-life medications. Ischemic and viable myocardium was documented on Tl-201 SPECT in 190 patients (43%), of whom only 23% had angina and only 26% had positive exercise testing results. During a follow-up of 3.8 +/- 1.7 years, 36 patients died and survival curves were progressively divergent between patients with and those without ischemic and viable myocardium: at 5 years, the respective survival rates were 81% +/- 4% and 94% +/- 2% (P =.004). By multivariate analysis, the best independent predictors of death were large extent of necrosis (>25% of left ventricle on Tl-201 SPECT, P <.001) and ischemic and viable myocardium (P =.001).

CONCLUSIONS

In the CAD patients treated on a long-term basis with beta-blockers, survival is strongly influenced by persistent exercise SPECT ischemia on treatment. Therefore exercise SPECT on treatment could be a useful tool for selecting those who might benefit from additional anti-ischemic therapeutic interventions.

Postoperative ventricular arrhythmias after cardiac surgery: immediate- and long-term significance

AF is frequent after cardiac surgery. However, ventricular arrhythmias are less known. The purpose of the study was to evaluate the causes and the prognostic significance of severe ventricular arrhythmias occurring after cardiac surgery. For 10 years, among 2,100 cardiac surgeries, 16 (0.8%) patients (13 men, 3 women; age 49-71 years, mean 62 +/- 9 years) without previous ventricular arrhythmias, with preserved left ventricular ejection fraction, and without acute cause of ventricular arrhythmias, developed VF (n = 4) or a sustained VT between 3 days and 3 weeks after cardiac surgery (coronary artery bypass grafting [n = 6], valve replacement [n = 10]). Rapid AF (n = 5) or slow AF (n = 1) were present at the time of VT/VF. Programmed ventricular stimulation occurred after up to three extrastimuli in the basal state and after infusion of 20-30 micrograms of isoproterenol. An echocardiogram, coronary angiography, Holter monitoring with heart rate variability (HRV) study were performed. Ventricular stimulation was negative in six patients (with AF); sustained and clinical VT was induced in 10 patients with a left ventricular ejection fraction > 0.40, except in one patient. Valvular prothesis and coronary bypass graftings were normal. In all patients, HRV was normal before surgery and decreased after cardiac surgery; before versus after surgery, respectively, HR 69 +/- 9 and 89 +/- 30 beats/min (P < 0.01), SDNN 117 +/- 31 and 50 +/- 11 ms (P < 0.001), low frequency (LF) 474 +/- 658 and 51 +/- 40 ms2 (P < 0.05), high frequency (HF) 115 +/- 23 and 33 +/- 32 ms2 (P < 0.05), LF:HF 4 +/- 3 and 1 +/- 0.6 (P < 0.01). Follow-up lasted from 6 months to 10 years (mean 3 +/- 2 years). In patients without induced VT, 1 patient died from asystole, 1 had an ICD but no subsequent events, and the other 4 untreated patients are free of events. Patients with induced VT were treated with amiodarone and beta-blockers except in one patient who died from extracardiac complications. Six of nine patients had no inducible VT with this treatment and are alive; 3 patients had inducible VT, 1 died suddenly before implantation of ICD, and 2 patients are alive with an ICD; recurrent VTs were noted in one patient and received an ICD. In conclusion, recent heart surgery may increase the risk of ventricular arrhythmias. The reduction of indexes reflecting sympathetic and parasympathetic tone could facilitate the occurrence of atrial arrhythmias (and then VT) in patients without ventricular arrhythmogenic substrate or the development of VT/VF in patients with a latent previous ventricular arrhythmogenic substrate. In patients without inducible VT, the prognosis is excellent and an ICD is not recommended in these patients. In those with inducible VT, there is a high incidence of responders to antiarrhythmic drugs with a favorable prognosis.

What is the schizophrenic patients' level of information about their disease and their treatment?

Improved compliance with antipsychotic medication is a major issue in schizophrenic management. For this purpose educational programs have been used, but up to now, little or no information has been gathered or published in France concerning schizophrenic patients' opinion on information they have about their disease and their treatment. Thus we conducted a survey in concert with 78 psychiatrists from the French psychiatric health service. From this cross sectional survey we assessed 336 outpatients (male: 72%; mean age: 36 +/- 10.4 years) with schizophrenia according to the DSM IV (paranoid sub type: 57%, disorganized: 12%, catatonic: 1%, undifferentiated: 12%, residual: 18%). The mean duration of the illness was 11.6 years (sd: 8.5) and the mean duration of the follow up with the same psychiatrist was 5.4 years (sd: 5.1). Patients completed a questionnaire which assessed their level of information on mental illness and treatment. The diagnosis of schizophrenia has been told to their patients by 39% of the psychiatrists, and treatment has been explained to the patients by 96% of the practitioners. Results indicate less than half of the patients (45%) felt ill, only 46% thought they knew their illness well or very well (nevertheless only 31% of them named spontaneously the diagnosis of schizophrenia or psychosis), and 61% considered that they had been given sufficient information. Most of the patients (79%) were persuaded that their treatment was useful, and 75% of patients were completely satisfied with their treatment. Surprisingly 92% reported taking their medication regularly. Most patients think that a high level of information about their illness (74%) and treatment (79%) help them to cope better with their schizophrenia. Analysis performed according to patients characteristics indicated that paranoid patients felt more ill (p = 0.035) than others, thought to know less about their illness (p = 0.0065), and were less satisfied with their treatment (p = 0.04) and their level of information (p = 0.03). Patients with a duration of their illness longer than 10 years were more convinced of the utility of their treatment (p = 0.02) and had debated more on the choice of their treatment with their psychiatrist (p = 0.047). Patients older than 35 years were more satisfied with their information (p = 0.002). More patients with atypical antipsychotics accepted to take their treatment on a regular basis (p = 0.035) compared to patients under classical neuroleptics. This survey underlines that mental health consumers' opinions can be obtained even in the field of schizophrenia, and argues in favour of further such investigations. It also highlights the need for educational programs on schizophrenia and antipsychotic medications.

[What information do patients with schizophrenia have about their illness and treatment?]

Improved compliance with antipsychotic medication is a major issue in schizophrenic management. For this purpose educational programs have been used, but up to now, little or no information has been gathered or published in France concerning schizophrenic patients' opinion on information they have about their disease and their treatment. Thus we conducted a survey in concert with 78 psychiatrists from the French psychiatric health service. From this cross sectional survey we assessed 336 outpatients (male: 72%; mean age: 36 +/- 10.4 years) with schizophrenia according to the DSM IV (paranoid sub type: 57%, disorganized: 12%, catatonic: 1%, undifferentiated: 12%, residual: 18%). The mean duration of the illness was 11.6 years (sd: 8.5) and the mean duration of the follow up with the same psychiatrist was 5.4 years (sd: 5.1). Patients completed a questionnaire which assessed their level of information on mental illness and treatment. The diagnosis of schizophrenia has been told to their patients by 39% of the psychiatrists, and treatment has been explained to the patients by 96% of the practitioners. Results indicate less than half of the patients (45%) felt ill, only 46% thought they knew their illness well or very well (nevertheless only 31% of them named spontaneously the diagnosis of schizophrenia or psychosis), and 61% considered that they had been given sufficient information. Most of the patients (79%) were persuaded that their treatment was useful, and 75% of patient were completely satisfied with their treatment. Surprisingly 92% reported taking their medication regularly. Most patients think that a high level of information about their illness (74%) and treatment (79%) help them to cope better with their schizophrenia. Analysis performed according to patients characteristics indicated that paranoid patients felt more ill (p = 0.035) than others, thought to know less about their illness (p = 0.0065), and were less satisfied with their treatment (p = 0.04) and their level of information (p = 0.03). Patients with a duration of their illness longer than 10 years were more convinced of the utility of their treatment (p = 0.02) and had debated more on the choice of their treatment with their psychiatrist (p = 0.047). Patients older than 35 years were more satisfied with their information (p = 0.002). More patients with atypical antipsychotics accepted to take their treatment on a regular basis (p = 0.035) compared to patients under classical neuroleptics. This survey underlines that mental health consumers' opinions can be obtained even in the field of schizophrenia, and argues in favour of further such investigations. It also highlights the need for educational programs on schizophrenia and antipsychotic medications.

Nitric oxide deficiency in fenfluramine- and dexfenfluramine-induced pulmonary hypertension

Dexfenfluramine and fenfluramine greatly increase the risk of developing pulmonary hypertension (PHT). The mechanism of anorexigen-associated PHT (AA-PHT) and the reason PHT occurs in a minority of people exposed are unknown. Anorexigens are weak pulmonary vasoconstrictors, but they become potent when synthesis of the endogenous vasodilator nitric oxide (NO) is suppressed. We hypothesized NO deficiency predisposes affected individuals to develop AA-PHT. A prospective, case-control, study was performed on consecutive patients with AA-PHT (n = 9). Two sex-matched control groups were selected: patients with primary PHT (P-PHT, n = 8) and normal volunteers (n = 12). Lung NO production (VNO) and systemic plasma oxidation products of NO (NOx) were measured at rest and during exercise. AA-PHT developed 17 +/- 6 mo after a short course of anorexigen (6 +/- 2 mo) and was irreversible. VNO was lower in AA-PHT than in P-PHT and correlated inversely with PVR (p < 0.05). The apparent VNO deficiency may have resulted from increased oxidative inactivation of NO in patients with AA-PHT, as their NOx levels were elevated (p < 0.05) in inverse proportion to VNO (r2 = 0. 55; p < 0.02). In susceptible persons, anorexigens can cause an irreversible syndrome of PHT, hypoxemia, and systemic vascular complications after brief exposures. These patients have a relative NO deficiency years after discontinuing the anorexigen, perhaps explaining their original susceptibility.

[Evaluation of high amplification ECG and the study of sinus variability in the detection of patients at risk of sudden death]

In order to define the best strategy of prognostic evaluation in relation to patients in heart failure, 415 patients with impaired left ventricular function (ejection fraction < 40%) were prospectively included, between June 1993 and 1996, in a study comparing the respective value of high amplification ECG and Holter analysis of sinus variability, 308 patients in sinus rhythm and narrow QRS complexes were included. The patients were distributed into 4 groups according to the presence or absence of late potentials and altered sinus variability (group I with 2 normal examinations, group II with late potentials and normal variability, group III without late potentials, but with altered variability and group IV with 2 abnormal examinations). The sudden and overall mortality was significantly greater in groups III (28 and 11%) and IV (28 and 9%) than in group I (7 and 3%) and II (11 and 2%). The presence of potential was unable to identify patients at risk of ventricular tachycardia and sudden death. In another 60 patients with complete branch block, the prognosis was also correlated with the alteration of sinus variability. In conclusion, high amplification ECG correctly evaluated the prognosis of subjects in heart failure. However, analysis of sinus variability should be systematically proposed to detect subjects at high risk of mortality, whether the subject has large or narrow QRS complexes.

[Can signal-averaged electrocardiograms be interpreted in cases of complete bundle branch block?]

The aim of this study was to evaluate the results of signal-averaged (SA) ECG in cases of complete right (RBBB) or left bundle branch block (LBBB). One hundred and seven patients had RBBB; 42 without cardiac disease (0), 56 with chronic myocardial infarction (MI) and 9 with primary cardiomyopathy (CMP). Seventy-four patients had LBBB: 20 without cardiac disease, 26 with chronic myocardial infarction and 28 with primary cardiomyopathy. A SA ECG (Cardionics, Fidelity) was performed with a 40 Hz band pass and compared with the recordings of 72 healthy controls without bundle branch block. The duration of the averaged QRS (QRS dur), the voltage of the last 40 milliseconds (RMS40) and duration of terminal activity < 40 microV (LAS) were measured. The analysis of results showed that QRS dur was significantly longer in subjects with ventricular tachycardia (VT) (p < 0.05) and in those with advanced cardiac disease (p < 0.05), whatever the type of bundle branch block, and that only the RMS40 distinguished patients with VT from those without VT, irrespective of the underlying cardiac disease and the type of bundle branch block. However, the study of the diagnostic value of each parameter showed very mediocre results: RMS 40 < 20 microV in myocardial infarction and < 17 microV in cardiomyopathy had sensitivities and specificities in RBBB of 73% and 50% respectively, incalculable in CMP, in LBBB 70% and 33%, 77% and 60% respectively; the LAS was unusable. The authors conclude that it is hazardous to interprete SA ECG in bundle branch block, especially in advanced cardiac disease where the specificity of the criteria becomes very low (< 50%).