Frequency Of Ventricular Extrasystoles Research Articles

Effect of Magnesium on Ventricular Extrasystoles in Children.

Magnesium (Mg) is a crucial element for cardiovascular system and its deficiency results in a variety of cardiac arrhythmias. The aim of this study is to determine the effect of oral Mg supplementation on the frequency of ventricular extrasystoles (VES) in children. Magnesium supplementation was given to 42 children who had VES without structural heart disease. Clinical, electrocardiographic, and Holter monitoring studies were reviewed. The mean baseline 24 h VES burden on Holter monitoring was 10.26% ± 4.13% and it was decreased to 6.62% ± 3.88% after. There was no significant difference between the pre-treatment serum Mg levels and the decrease in the frequency of VES. In conclusion, oral Mg therapy was found to be effective at suppressing VES in children regardless of serum Mg levels. Large and randomized studies are needed to demonstrate the effect of magnesium on VES suppression.

Dynamic changes of heart structural and functional condition in patients with acute myocarditis

Diagnosis and prognosis of myocarditis course, which is an inflammatory heart muscle disease, has been and remains one of the most urgent, complex and unresolved problem in modern cardiology. The purpose of the study – to investigate the dynamic changes in the structural and functional heart state in patients with acute myocarditis and reduced left ventricular ejection fraction. Materials and methods. In total, 74 patients with clinically suspected acute myocarditis (AM) with reduced left ventricular (LV) ejection fraction (EF) ≤40 % and NYHA heart failure (HF) functional class II or higher were examined three times: in the first month of myocarditis debut, after 6 and 12 months of observation. All the patients underwent echocardiography and speckle-tracking echocardiography, Holter electrocardiogram monitoring and cardiac magnetic resonance imaging (MRI). Results. It was found that the debut of AM was characterized by the presence of active inflammatory process according to the cardiac MRI - edema and hyperemia of the myocardium were detected in 54.0 % and 70.2 % of cases, respectively, followed by LV dilation and systolic dysfunction as well as by a significant decrease in longitudinal and circumferential LV global systolic strain. After 12 months of observation, there was a significant increase in LV EF, decrease in end-diastolic volume index and an improvement in the parameters of longitudinal and circumferntial LV systolic strain by 30.8 % and 36.8 %, respectively, (P < 0.01), the frequency of active inflammatory changes in the myocardium was significantly reduced, herewith in 41.8 % of cases, delayed enhancement was noted, indicating fibrotic changes in the myocardium. The presence of delayed enhancement in cardiac MRI after 12 months since myocarditis onset was correlated with the presence of unstable ventricular tachycardia episodes (r = 0.62; P < 0.02) and with the frequency of ventricular extrasystoles (r = 0.53; P < 0.05). A significant influence of fibrotic changes in the myocardium on the presence of unstable ventricular tachycardia episodes in 12 months after the disease onset was confirmed by determining Fisher's exact test, its value was: P = 0.016 (P < 0.05). Conclusions. It was established that the debut of myocarditis was characterized by a significant violation of the structural and functional heart state: an active inflammatory process in the myocardium causedLV dilatation and contractile dysfunction. After 12 months, a decrease in detection of active inflammatory myocardial changes followed by regression ofLV dilation and its contractile function improvement was observed. It was proved that the presence of fibrotic changes in the myocardium in patients with myocarditis was associated with the persistence of ventricular rhythm disorders.

Results of Holter monitoring in patients with angina pectoris treated by combination of trimethazidine with fabomotisol in the area of former armed conflict

Aim. To assess the effectiveness of trimetazidine and fabomotisol adding to standard treatment in patients with stable angina in the area of former armed conflict in point of improving of Holter monitoring parameters.Material and methods. One hundred and twelve patients with stable angina of the II-III functional classes (FC) living in the area of former armed conflict were randomly divided into two groups. For 6 months 54 patients (control group) received standard treatment (isosorbide dinitrate 40 mg/day, metoprolole tartras 50-100 mg/day, acetylsalicylic acid 100 mg/day, simvastatin 40 mg/day). Fifty eight patients (study group) in addition to a standard treatment, took trimetazidine 70 mg/day and fabomotisol 30 mg/day. Initially and after 6 months they underwent Holter monitoring.Results. In patients of the control group the number of episodes of silent myocardial ischemia was statistically significantly reduced (p&lt;0,05). The duration of episodes of silent and manifest myocardial ischemia, ST segment depression &gt;1 mm, and the number of patients with supraventricular and ventricular extrasystoles decreased not statistically significant (p&gt;0,05). The number of episodes of manifest myocardial ischemia did not change. In the study group, the number of silent ischemia episodes, the duration of silent and manifest myocardial ischemia significantly decreased. ST segment depression and the frequency of ventricular extrasystoles were also decreased (p&lt;0,05). At the same time, the changes in number of supraventricular extrasystoles was not statistically significant (p&gt;0,05). Conclusion. Using a combination of trimetazidine with fabomotisol in comparison with standard treatment in patients with angina reduces the frequency of angina episodes, the duration of myocardial ischemia, ST segment depression, the frequency of supraventricular and ventricular extrasystoles.

Impact of type 2 diabetes mellitus in the course of acute myocardial infarction of the left ventricle with involvement to the right ventricle

The aim. To evaluate the effect of diabetes mellitus (DM) on the clinical course of the acute period of myocardial infarction (MI) of the left ventricle (LV) and the biventricular MI.Materials and methods. 309 patients with Q-MI age 65.5±4.42 years were examined. Patients were divided into 3 groups: the 1st group – 155 patients with MI of the right ventricle (RV) on the background of Q-MI of the posterior wall of the LV, the 2nd group – 53 patients with RV MI due the Q-MI of the LV circular localization, and the 3rd group – 101 patients with Q-MI of the LV posterior wall. Patients with DM were 41 (26.5 %) in the 1st group, 22 (41.5 %) - in the 2nd group, and 26 (25.7 %) patients in the third group. The hospital treatment period was 16.8±2.7 days.Results. Patients with DM in all groups had late admission, usually within 12-24 hours (p &lt;0.05) and after the first day of the MI (p &lt;0.05). Among patients with DM there were more women (p &lt;0.05). The presence of DM was associated with a significantly greater number of ventricular arrhythmias and ventricular fibrillation (p &lt;0.05). The clinical course of the acute MI in patients with DM often complicated of early postinfarction angina (p &lt;0.05), recurrent MI and the LV aneurysms in the 2nd group (p &lt;0.05). The acute heart failure (HF) was more severe in patients with DM with prevalence of the number of cases with Killip II-III (p &lt;0.05) and a higher frequency of cardiogenic shock (p &lt;0.05). Patients with DM had more severe manifestations of chronic HF with greater frequency of the HF IIA, IIB and III NYHA in the total group of patients with MI (p &lt;0.05).Conclusion. The DM in patients with Q-ІМ of the LV and the biventricular MI is accompanied by late admission and is more common in women. The presence of the DM in patients with MI is associated with a higher frequency of ventricular extrasystoles, ventricular tachycardias and ventricular fibrillation, cases of early post-MI angina, the development of recurrent MI and the LV aneurysms. Patients with DM have a high frequency of cardiogenic shock and worse manifestations of acute and chronic HF

Association of silent hypoglycemia with cardiac events in non-diabetic subjects with acute myocardial infarction undergoing primary percutaneous coronary interventions.

BackgroundSome studies have shown that hypoglycemic episodes in diabetic patients might be associated with increased cardiovascular events. It is not clear whether episodes of silent hypoglycemia had greater prognostic value on cardiac events compared with normoglycemia or hyperglycemia in non-diabetic patients, so the aim of this study was to investigate the association of silent hypoglycemia and cardiac events in non-diabetic patients with acute ST-segment elevation myocardial infarction (STEMI) who underwent primary percutaneous coronary intervention (p-PCI).MethodsWe enrolled non-diabetic patients with STEMI who underwent p-PCI and whose clinical and laboratory data were collected. Interstitial glucose values were recorded using a continuous glucose monitoring system (CGMS), and Holter monitoring was recorded for 3 days in parallel. Cardiac ischemia and ventricular arrhythmia was evaluated.ResultsBased on the inclusion and exclusion criteria, we enrolled 164 STEMI patients undergoing p-PCI for final analysis. A total of 280 episodes of silent hypoglycemia (CGMS glucose <70 mg/dl) were recorded. Episodes of silent cardiac ischemia were recorded in 50 of 280 hypoglycemic episodes. The incidence of silent cardiac ischemia during hypoglycemia was significantly higher than the incidence during both hyperglycemia and normoglycemia(P < 0.01). Moreover, we found a significantly higher frequency of ventricular extrasystoles (VESs) or nonsustained ventricular tachycardias (NSVTs) in patients with silent hypoglycemia. The average number of events of silent cardiac ischemia was also significantly increased in the silent hypoglycemia group (0.91 ± 0.82 vs. 0.35 ± 0.54, P < 0.01) compared with either hyperglycemia or normoglycemia group.ConclusionsHypoglycemia was frequent and most of the time asymptomatic in non-diabetic patients with STEMI undergoing p-PCI. Silent hypoglycemia was associated with silent cardiac ischemia. STEMI patients with silent hypoglycemia had a significantly higher frequency of VESs or NSVTs.

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The Influence of Subclinical Hyperthyroidism on Blood Pressure, Heart Rate Variability, and Prevalence of Arrhythmias

The impact of subclinical hyperthyroidism (sHT) on the cardiovascular system still needs to be elucidated. The aim of the study was to prospectively assess blood pressure (BP), variability in heart rate, and the prevalence of arrhythmias in patients with sHT, both before and after they are restored to the euthyroid state.The study group consisted of 44 normotensive patients (37 women, 7 men), aged 22-65 years (mean±SD: 45.9±11.0) with sHT. Enrolled patients were drawn from 1080 patients referred to our department for treatment of hyperthyroidism. Study patients were treated with radioiodine treatment to restore the euthyroid state. Ambulatory BP monitoring and Holter electrocardiography were performed (i) when sHT was diagnosed and (ii) at least 6 months after they became euthyroid.sHT in comparison to the euthyroid state was associated with higher (109.3±7.1 vs. 107.1±7.7 mmHg) nocturnal systolic mean BP (p=0.035) and BP load (14.8 vs. 10.2%, p=0.033), mean diastolic BP (66.4±6.6 vs. 64.8±6.6 mmHg, p=0.047), and mean arterial pressure (80.8±43.1 vs. 79.3±43.6 mmHg, p=0.049). Moreover, significant changes in both the time and frequency domain measures of heart rate variability (HRV) were observed: decrease of the square root of the mean squared differences of successive NN intervals (rMSSD) (45.68±34.1 vs. 65.09±50.6 ms, p=0.03) and the low frequency power (LF) (5.71±0.99 vs. 6.0±1.01 ms(2), p=0.049) as well as increase of QT interval dispersion (58.25±28.5 vs. 46.90±12.1 ms, p=0.020). This was accompanied by a clinically insignificant increase in the frequency of ventricular extrasystoles (VES) (3.1±7.4 vs. 0.6±1.2 per hour, p=0.048) and increased mean heart rate (78.4±6.8 vs. 76.0±8.0 beats/min, p=0.004). Some of the parameters correlated positively with thyroid hormones: nocturnal diastolic BP with free triiodothyronine (FT(3)) (r=0.397, p=0.008), rMSSD with free thyroxine (FT(4)) (r=0.389, p=0.013), and QT interval dispersion with FT(4) (r=0.450, p=0.004).The study suggests that sHT in comparison to euthyroid status may be associated with a statistically significant but probably clinically insignificant increase of QT interval dispersion, prevalence of VES, elevated nocturnal arterial BP, and changes in HRV. These findings broaden our understanding of the cardiovascular effects of sHT.

Control of Pain Trough Epidural Block and Incidence of Cardiac Dysrhythmias in Postoperative Period of Thoracic and Major Abdominal Surgical Procedures: a Comparative Study

Upper abdomen and thorax surgeries cause intense pain. Some of postoperative pain main complications are cardiocirculatory complications. The objective of this study was to test the hypothesis that postoperative analgesia with employment of local anesthetics plus spinal opioids may reduce the incidence of cardiovascular complications in postoperative period of patients in these conditions, comparing with classical methods of postoperative analgesia, opioids and NSAIDs, administered upon patient's demand. Eighty adult patients, ASA I and II, without ECG alterations, were allocated into two groups of 40: Group A, patients under general anesthesia with propofol, cisatracurium and isoflurane, associated with epidural anesthesia with catheter and control of postoperative analgesia with bupivacaine and epidural morphine; and Group B, patients under general anesthesia with the same drugs and doses of A, plus postoperative analgesia carried out with NSAIDs and intravenous morphine at the end of surgery and in regular intervals. In both groups Holter was applied for 24 hours. Pain evaluation was carried out through visual analog scale. In pain evaluation, an evident predominance of 0 score (p<0.001) was observed in Group A and there was also reduction of blood pressure levels in postoperative period in a more accentuated way. Ventricular and supraventricular dysrhythmias were five times more frequent in Group B (p=0.00001), in which a tendency to a higher frequency of ventricular extrasystoles in age>50 years (22.2% versus 0.0%. p=0.26) was also detected. No significative difference of heart rate among groups (p>0.05) was observed. The best quality of analgesia in postoperative period, carried out in Group A, reduced the incidence of cardiovascular complications.

Potential value of automated daily screening of cardiac resynchronization therapy defibrillator diagnostics for prediction of major cardiovascular events: results from Home‐CARE (Home Monitoring in Cardiac Resynchronization Therapy) study

AimTo investigate whether diagnostic data from implanted cardiac resynchronization therapy defibrillators (CRT-Ds) retrieved automatically at 24 h intervals via a Home Monitoring function can enable dynamic prediction of cardiovascular hospitalization and death.Methods and resultsThree hundred and seventy-seven heart failure patients received CRT-Ds with Home Monitoring option. Data on all deaths and hospitalizations due to cardiovascular reasons and Home Monitoring data were collected prospectively during 1-year follow-up to develop a predictive algorithm with a predefined specificity of 99.5%. Seven parameters were included in the algorithm: mean heart rate over 24 h, heart rate at rest, patient activity, frequency of ventricular extrasystoles, atrial–atrial intervals (heart rate variability), right ventricular pacing impedance, and painless shock impedance. The algorithm was developed using a 25-day monitoring window ending 3 days before hospitalization or death. While the retrospective sensitivities of the individual parameters ranged from 23.6 to 50.0%, the combination of all parameters was 65.4% sensitive in detecting cardiovascular hospitalizations and deaths with 99.5% specificity (corresponding to 1.83 false-positive detections per patient-year of follow-up). The estimated relative risk of an event was 7.15-fold higher after a positive predictor finding than after a negative predictor finding.ConclusionWe developed an automated algorithm for dynamic prediction of cardiovascular events in patients treated with CRT-D devices capable of daily transmission of their diagnostic data via Home Monitoring. This tool may increase patients’ quality of life and reduce morbidity, mortality, and health economic burden, it now warrants prospective studies.ClinicalTrials.gov NCT00376116.

Cardiac Arrhythmias and Conduction Disturbances in Patients With Ankylosing Spondylitis

Conduction disturbances, aortic incompetence, and myocardial fibrosis are known complications in adult patients with ankylosing spondylitis (AS). Its incidence has been reported to be 10% to 30%; however, less attention has been paid to all cardiac arrhythmias. The aim of this study was to evaluate arrhythmias and conduction disturbances in patients with AS using electrocardiograms and Holter monitoring (including heart rate variability analysis) and to estimate its relationships with age, gender, clinical features, and duration of AS. Thirty-one patients with AS (20 to 69 years old, mean 50 +/- 14) and 22 healthy volunteers (26 to 69 years old, mean 49 +/- 13) underwent rheumatologic and cardiologic evaluations. Ventricular extrasystoles were present in 55% of AS patients and in 28% of controls. Supraventricular extrasystoles were present in 94% of AS patients and 100% of controls. The frequency of ventricular extrasystoles was found to be higher in the AS patients than in the control subjects. Significant differences were found in heart rate variability analyses: ultra low-frequency power and root mean square recessive difference (r-MSSD) were lower in the AS group. When the AS group was divided into subgroups (stages 3 and 4), significant differences were found between control subjects and stage 3 patients in PR interval, heart rate (HR), T-wave duration, ultra low frequency, and r-MSSD and between controls and stage 4 patients in HR, T-wave duration, and r-MSSD. QTc and QTd were not significantly different in groups and subgroups and were not correlated with any other clinical or electrocardiographic parameter. Cardiac arrhythmias were more frequent in patients with AS than in the healthy population. Simple electrocardiograms and Holter parameters do not correlate with the incidence of VESs, age, gender, clinical features, and duration of AS.

Electroacupuncture treatment of arrhythmias in myocardial ischemia

integrative medicine, sometimes also called complementary and alternative medicine (or CAM), has been classified by the National Center for Complementary and Alternative Medicine into five domains, including 1 ) alternative systems of medical practice, like traditional Chinese medicine; 2 ) mind-

Changes in frequency of premature complexes and heart rate variability related to shift work

OBJECTIVESTo investigate whether an increased risk of cardiovascular disease might be caused by increased arrhythmogeneity and by unfavourable changes in autonomic cardiac control the changes in the occurrence of premature...

QT dispersion as a predictor of arrhythmic events in patients with ankylosing spondylitis.

The aim of the study was to evaluate QT dispersion (QTd), an indicator of repolarization heterogeneity, and its relation to ventricular arrhythmias in patients with ankylosing spondylitis (AS). A full history, clinical examination, electrocardiograms and 24-h Holter monitoring were performed in 88 AS patients and 31 volunteers of similar age and sex. Groups were compared based on electrocardiographic abnormality, QTd, arrhythmias and heart blocks. QTd and corrected QTd (QTcd) were significantly greater in AS patients than controls (QTd, 52.8 +/- 15.1 vs 35.5 +/- 8.9 ms, P: < 0.0001; QTcd, 60.3 +/- 16.1 vs 39.4 +/- 10.7 ms, P: < 0.0001). The magnitudes of these parameters were associated with the duration of the disease (QTd, r = 0.56, P: < 0.01; QTcd, r = 0.60, P: < 0.001). The frequency of ventricular extrasystoles was found to be correlated with QTd (r = 0.35, P: < 0.01) and QTcd (r = 0.33, P: < 0. 01). Involvement of the heart may be seen in AS during the early clinical course of the disease. QTd may give clues about the presence of arrhythmias and can be used as a new technique for the evaluation of asymptomatic patients. Earlier detection of cardiac involvement could alter the prognosis of the patients.

Silent myocardial ischemia in glaucoma and cataract patients.

Glaucoma and cataract are multifactorial diseases. They have been described to be associated with cardiovascular risk factors. Twenty-four-hour ECG monitoring was done in 22 normal-tension glaucoma patients, 27 open-angle glaucoma patients, 25 cataract patients, and 20 normal controls. The frequency of silent myocardial ischemia (SMI) as well as that of ventricular extrasystoles (VES) was evaluated. At least one episode of significant asymptomatic ST-T segment depression occurred in 45% of the normal-tension glaucomas, in 25.9% of open-angle glaucomas, in 12% of cataract patients, and in 5% of normal controls. The frequency of VES was not significantly different among the groups. Glaucoma, especially normal-tension glaucoma, is significantly associated with the occurrence of episodic asymptomatic myocardial ischemias. Cataract patients, however, had only a slightly, statistically not significantly increased frequency of both SMI and VES compared with normals.

The beneficial effects of atrial natriuretic peptide on arrhythmias and myocardial high-energy phosphates after reperfusion.

The aim of this investigation was to test whether the administration of atrial natriuretic peptide (ANP) has cardioprotective effects against ischaemic and reperfusion injury. Thoracotomized dogs underwent a 30 min left circumflex coronary artery occlusion and 60 min of reperfusion (control group; n = 16). The ANP group (n = 9) received a 20 micrograms bolus injection of synthetic alpha human ANP (SUN 4936) followed by infusion at a dose of 0.1 microgram/kg/min from the beginning of coronary occlusion to the end of the procedure. Administration of exogenous ANP increased plasma ANP immediately and maintained levels at 3000 pg/ml, resulting in an 8-fold increase in plasma cyclic guanosine monophosphate (cGMP) levels. Plasma ANP and plasma cGMP levels did not change at all in controls. There were no significant differences in haemodynamic parameters during ischaemia and reperfusion between the groups. In the ANP group, the prevalence and frequency of ventricular extrasystoles within 10 min after reperfusion decreased markedly [ANP 22% vs. control 100%, P < 0.01, and ANP 1 (1) vs. control 92 (50), P < 0.05, respectively]. No dog in the ANP group had ventricular fibrillation (VF), but the incidence of VF was not statistically significant between the groups [ANP 0% vs. control 25%]. ATP content in the inner layers of the ischaemic myocardium in the ANP group was higher than in controls (P < 0.05) [1.92 (0.28) vs. 1.18 (0.13) mumol/g wet weight]. There was no significant difference in the content of myocardial tissue angiotensin II between the groups. These data show that the infusion of ANP has cardioprotective effects on myocardial ischaemia and reperfusion in this model. These beneficial effects are probably due to direct effects through cGMP rather than haemodynamic changes.

Heart rate variability and its relation to ventricular arrhythmias in congestive heart failure.

It has been shown that heart rate variability is decreased in patients with congestive heart failure and that depressed heart rate variability is associated with a propensity to ventricular arrhythmias. Little is known, however, about heart rate variability in patients with both congestive heart failure and ventricular arrhythmias. Spectral heart rate variability was analysed from 24 hour ambulatory electrocardiograms in 15 controls, 15 patients with non-sustained ventricular tachycardia associated with clinically normal hearts (NHVT group), and 40 patients with congestive heart failure (CHF group) secondary to either ischaemic heart disease (n = 15) or idiopathic dilated cardiomyopathy (n = 25). Of the 40 patients with congestive heart failure 15 had no appreciable ventricular arrhythmias (ventricular extrasystoles < 10 beats/h and no salvos) and formed the CHF-VA- group. Another 15 patients with congestive heart failure and non-sustained ventricular tachycardia formed the CHF-NSVT group. Heart rate variability was significantly lower in the CHF group than in controls (mean (SD) total frequency 23 (12) v 43 (13) ms; low frequency 12 (8) v 28 (9) ms; high frequency 8 (5) v 14 (7) ms; p < 0.001). The differences in heart rate variability between controls and the NHVT group, between ischaemic heart disease and dilated cardiomyopathy, and between the CHF-VA- and CHF-NSVT groups were not significant. In the CHF group heart rate variability was significantly related to left ventricular ejection fraction but not associated with ventricular arrhythmias. The frequency of ventricular extrasystoles was significantly related to the high frequency component of heart rate variability (r = 0.54, p < 0.05) in the NHVT group. Stepwise multiple regression analysis showed that in the CHF group, heart rate variability was predominantly related to left ventricular ejection fraction (p < 0.05). There was no significant difference in heart rate variability between survivors (n = 34) and those who died suddenly (n = 6) at one year of follow up in the CHF group. In patients with congestive heart failure, heart rate variability is significantly decreased. The depressed heart rate variability is principally related to the degree of left ventricular impairment and is independent of aetiology and the presence of ventricular arrhythmias. The data suggest that analysis of heart rate variability does not help the identification of patients with congestive heart failure at increased risk of sudden death.

A field study on the immediate effects of exposure to low-altitude flights on heart rate and arrhythmia in patients with cardiac diseases.

Noise from low-altitude military flights differs from most other sources of noise by virtue of its unpredictability in space and time, its very high maximal levels, and the fast increase in noise level at high flight speeds. While this makes low-altitude flights a frightening and annoying experience, the potential immediate health hazards for exposed individuals with preexisting cardiovascular disease are unclear. A field study on the immediate effects of exposure to low-altitude flights on heart rate and arrhythmia was conducted among patients of a rehabilitation clinic for cardiac diseases in the summer of 1990 in Bad Rothenfelde, Germany. Twenty-four hour electrocardiograms of 68 patients taken on days when low-altitude overflights with peak sound pressure levels above 95 dB(A) were registered on the flat roof of the clinic were analyzed for changes in the heart rate or the occurrence of ventricular extrasystoles in four 2-min periods before, around, and after the overflights. Overall, 149 "overflight events" were included in the analysis. No major changes in the heart rate or in the frequency of ventricular extrasystoles were observed, but this could be partly due to problems inherent in the field approach. Nevertheless, the potential effects on heart rate and arrhythmia of low-altitude flights appear to be of limited magnitude compared to the potential effects of other factors, such as psychological or physical exposures, and they are probably too small to be proven under field conditions in an observational epidemiologic study in Germany following the limitations placed on the frequency and altitude of flights in September 1990.

Cardiac dysrhythmias during cardiovascular autonomic reflex tests.

To assess the possible dysrhythmogenic effect of cardiovascular autonomic function tests, ECG tracings of 925 consecutive subjects, taken during a battery of cardiovascular autonomic reflex tests were analyzed. The battery included the Valsalva manoeuvre, deep breathing test, orthostatic and isometric handgrip. The frequency of ventricular extrasystoles increased during or after the tests, compared with the resting phase, in 11% of healthy subjects, in 11% of diabetic subjects and in 23% of subjects with a previous myocardial infarction (p = 0.001 vs healthy subjects). In patients with previous myocardial infarction, the most dysrhythmogenic individual tests were orthostatic and isometric handgrip. In nine subjects, other cardiac rhythm disturbances were detected (including nonsustained ventricular tachycardia, conduction block, and atrial fibrillation). In all cases, the dysrhythmias were asymptomatic and resolved without medical intervention. In conclusion, we consider the cardiovascular reflex test battery safe for the patient. However, due to occasional potentially significant dysrhythmias we recommend continuous monitoring of the electrocardiogram and immediate access to resuscitation facilities during cardiovascular autonomic testing.

Influence of age on the relation between heart rate variability, left ventricular ejection fraction, frequency of ventricular extrasystoles, and sudden death after myocardial infarction.

To examine the influence of age on the prediction of sudden death after acute myocardial infarction based on heart rate variability (HRv), left ventricular ejection fraction (LVEF), and the frequency of ventricular extrasystoles. Autonomic and left ventricular function and the frequency of ventricular extrasystoles change with age but the influence of age on the prediction of sudden death from these variables has not been examined. The 477 patients who had been through an early postinfarction risk stratification protocol and followed up for a mean of 790 days were dichotomised at 60 years of age. Sudden deaths occurred with similar frequency in both age groups (12 (4.7%) of the 256 patients aged < 60 years and seven (3.2%) of the 221 older patients). Sudden death, however, accounted for 52% of all deaths in the young group but only 18.4% of all deaths in the older group (p < 0.01). An HRv index of < 20 units combined with an average of more than 10 ventricular extrasystoles an hour on Holter monitoring (VE10) had a sensitivity of 50%, a positive predictive accuracy of 33%, and a risk ratio of 18 in the young group (p < 0.001) but was not significantly predictive in older patients. The situation was similar when the combination of an LVEF < 40% with VE10 was considered. This combination had a sensitivity of 44%, positive predictive accuracy of 36.4%, and a risk ratio of 16.1 in young patients (p < 0.001), but was not significantly predictive in older patients. The combination of VE10 with either LVEF < 40% or HRv < 20 units gave a sensitivity of 75%, positive predictive accuracy of 30%, and a risk ratio of 30 in young patients (p < 0.001), but the relation between this combination and sudden death in older patients was not statistically significant. In postinfarction patients aged < 60 sudden death was a more predominant mode of death and was more reliably predicted from a depressed HRv index, an LVEF < 40%, and VE10 than in older postinfarction patients. These findings may have important implications for post-infarction risk stratification and management.

Heartbeat and arrhythmia perception in diabetic autonomic neuropathy

A comparative study of diabetics with autonomic neuropathy (N = 13) as against non-neuropathic diabetics (N = 16) and healthy control persons (N = 20) was carried out with respect to heart rate both at rest and under stress, frequency of cardiac arrhythmias in a 24-h ECG and accuracy of heartbeat and arrhythmia perception. In the subjects with diabetic autonomic neuropathy, the spontaneous variability and stress-induced reactivity of the heart rate as well as the number of tachycardic episodes were reduced, whereas the frequency of ventricular extrasystoles was somewhat increased. Impaired heartbeat perception and a complete loss of perception of arrhythmias as a consequence of neuropathic deafferentation could be demonstrated. Cardiac perception disorders also play a vital role in other clinical problems, e.g. silent myocardial infarction and lack of awareness of hypoglycaemia in diabetes mellitus.