Higher Prevalence Of Ventricular Arrhythmias Research Articles

Does scar burden predict sudden cardiac death in patients with cardiac resynchronization therapy? - A Systematic Review and Meta-Analysis

Abstract Background Based on latest guidelines, scar burden assessment may have a crucial role in appropriate device choice in cardiac resynchronization therapy (CRT), but no randomized controlled trials have been made yet.1 Scar burden is associated with a higher prevalence of ventricular arrhythmias (VA) and sudden cardiac death (SCD).2 Late gadolinium enhancement cardiovascular magnetic resonance (LGE-CMR) can accurately evaluate the extent of myocardial scar.3. Purpose Our aim is to investigate the association between scar burden and SCD risk in cardiac resynchronization therapy patients. Methods We performed a systematic literature search on MEDLINE using the PubMed, Embase, Scopus, and CENTRAL databases. Heart failure patients with reduced ejection fraction and CRT therapy were collected. The primary endpoint was sudden cardiac death events. Meta-analyses were performed using the META and DMETAR packages in R, using a random-effects model. The risk of bias was assessed using Quips tool and the quality of evidence was evaluated using the GRADE assessment. Results 18 eligible articles have been included in our study, with a total of 2917 patients, of whom 830, 1324, and 391 have been implanted with an ICD, CRT-D, CRT-P respectively. Altogether 59,05 % of the total population were LGE-CMR positive. The average proportion of appropriate ICD shock was 15,65 % per the total population during the median follow-up time of 39,45 months. Based on the univariant analysis of 14 articles, the cumulative hazard ratio of developing sudden cardiac death events, in the scar burden positive population compared to scar burden negative was 1,95 with CI: 1,29- 2,96 p<0,001. The multivariant analysis shows the HR of 1,88 with CI: 1,20- 2,93 p<0,001. There were 4 articles using the competing risk model which is considered to be the highest evidence level. Based on that analysis we found only a trend with a HR of 1,55 CI: 0,75-2,92. Calculating from the event numbers based on 8 eligible articles, the high scar burden group had 5.55 higher odds of getting SCD events. (OR: 5.55. CI 2,52-12,22 p<0,001). Conclusion In our meta-analysis, LGE-CMR was associated with a trend toward appropriate device therapy and can identify a subgroup of patients with an increased risk of life-threatening VA. Based on our results performing an MRI before device implantation might be important to select high-risk patients for SCD.Forest plot O.R.Forest plot uni. H.R.

Increased Risk of Arrhythmias in Active Acromegaly with Complications and Persistent Uncontrolled Active Acromegaly

Objective: Previous studies showed acromegaly have significant higher prevalence of ventricular arrhythmias and often complicated by diabetes mellitus (DM) and hypertension (HT). Both HT and DM are notoriously associated with the development of arrhythmias. However, the effect of complication (DM and/or HT) in acromegaly on ventricular arrhythmias and the risk of ventricular arrhythmias in acromegaly accept therapy but no control is largely unknown. Methods: A cross-sectional study with 307 acromegaly and 303 patients with non-functional pituitary adenoma as control group. All subjects divided into acromegaly with/without complication and controls with/without complication. In the longitudinal study, 30 persistent uncontrolled active acromegaly with at least three months follow-up. Electrocardiographic Measurements, laboratory examination, and clinical data collection performed in all subjects. QT interval corrected for heart rate (QTc) analysed among groups. Results: QTc in acromegaly population significantly increased compared to controls (p<0.001). Factorial design twoway ANOVA correcting age revealed significant main effects of complication (p=0.016) and acromegaly (p<0.0001), as well as positive interactions between complication and acromegaly (P<0.038) on QTc. Persistent uncontrolled active acromegalic patients after therapy showed QTc significantly increase in follow-up relative to pre-treatment (p<0.0001). The normalized GH level (r=0.11, p<0.05) and complication (r=0.25, p<0.0001) have a significant positive correlation with QTc in acromegaly. Conclusions: Acromegaly is an independent risk factor for ventricular arrhythmias and acromegaly with complication have an elevated risk for ventricular arrhythmia. Persistent uncontrolled acromegaly, who have significantly decreased in serum GH/IGF-1 levels relative to pre-treatment, also enhance the risk of ventricular arrhythmia.

Predictive value of scar burden assessed by cardiac MRI on sudden cardiac death in cardiac resynchronization therapy patients: a systematic review and meta-analysis

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Innovation and the National Research, project no. RRF-2.3.1-21-2022-00003 and Project no. RRF-2.3.1-21-2022-00004 (MILAB) has been implemented with the support provided by the European Union. Background Myocardial fibrosis (MF) is associated with a higher prevalence of ventricular arrhythmias (VA) and sudden cardiac death (SCD). Late gadolinium enhancement cardiovascular magnetic resonance (LGE-CMR) can accurately evaluate the extent of MF. Clinical evidence suggests that scar assessment may help the decision of adding an implantable cardioverter defibrillator (ICD) to cardiac resynchronization therapy (CRT) to reduce the risk of VA and SCD. Purpose In this systematic review and meta-analysis, we collected and analyzed evidence pertaining to the association between scar burden and the risk of VA and SCD, and we evaluated the impact of appropriate device choice for CRT. Methods We performed a systematic literature search on MEDLINE using the PubMed, Embase, Scopus and CENTRAL databases. The target population were adults with heart failure with reduced ejection fraction who underwent CRT. The primary outcome was the association between the incidence of VA and/or SCD and scar burden assessment. Meta-analyses were performed using the META and DMETAR packages in R, using a random-effects model. The risk of bias was assessed using RoB2and the quality of evidence was evaluated using the GRADE assessment. Results 6 eligible articles have been included in our study, with a total of 1548 patients, of whom 465, 696, and 387 have been implanted with an ICD, CRT-D, CRT-P respectively. Altogether 62,68 % of the total population were LGE-CMR positive. The proportion of appropriate ICD shock reached 15,65 % in the total population during the median follow-up time of 51,59 months. The risk of developing appropriate ICD shocks in the LGE positive population was almost 70% higher (Hazard ratio 1,69, 95% Confidence interval: 1,29- 2,21; p<0,001) compared to LGE negative patients. Conclusion In our meta-analysis, LGE-CMR was significantly associated with appropriate device therapy and can identify a subgroup of patients with an increased risk of life-threatening VA. Based on our results performing an MRI before device implantation might be important to select the high-risk patients for SCD in the elderly with ischaemic etiology and older age.

The impact of asymptomatic ventricular arrhythmias on the outcome of heart failure patients with reduced ejection fraction

BackgroundVentricular arrhythmias cause a significant proportion of sudden deaths. Several studies demonstrate a high prevalence of ventricular arrhythmias in patients with heart failure regardless of the etiology. The aim of this study was to determine the prevalence of silent ventricular arrhythmias in ambulatory heart failure patients with reduced left ventricular ejection fraction (HFrEF) and its correlation to the prognosis.ResultsFour hundred (400) ambulatory HFrEF patients on maximum tolerated doses of heart failure medications were included. Holter monitoring for 7 days was done in all patients searching for silent ventricular arrhythmias. The patients were followed-up for one year to detect the occurrence of major adverse cardiovascular events. We divided the study population into 2 groups based on an LVEF cutoff value of 30% (Group A < 30%, Group B ≥ 30%). Holter monitoring revealed ventricular arrhythmias in 304 patients. Patients with left ventricular ejection fraction (EF) < 30% (Group A) had more complex ventricular arrhythmias in the form of frequent Premature ventricular contractions (PVCs) of ≥ 5% and or non-sustained ventricular tachycardia (NSVT) runs. Furthermore, Among Group A, more major cardiovascular events were observed. Multivariate regression analysis showed that frequent PVCs and severely reduced LVEF were the strongest independent predictors of major cardiovascular events.Conclusionsventricular arrhythmias are common in HFrEF patients even in the compensated status. Both, left ventricular systolic function and the PVCs burden were found to be the strongest predictors of major adverse cardiovascular events.

Unfolded Protein Response as a Compensatory Mechanism and Potential Therapeutic Target in PLN R14del Cardiomyopathy.

Phospholamban (PLN) is a critical regulator of calcium cycling and contractility in the heart. The loss of arginine at position 14 in PLN (R14del) is associated with dilated cardiomyopathy with a high prevalence of ventricular arrhythmias. How the R14 deletion causes dilated cardiomyopathy is poorly understood, and there are no disease-specific therapies. We used single-cell RNA sequencing to uncover PLN R14del disease mechanisms in human induced pluripotent stem cells (hiPSC-CMs). We used both 2-dimensional and 3-dimensional functional contractility assays to evaluate the impact of modulating disease-relevant pathways in PLN R14del hiPSC-CMs. Modeling of the PLN R14del cardiomyopathy with isogenic pairs of hiPSC-CMs recapitulated the contractile deficit associated with the disease in vitro. Single-cell RNA sequencing revealed the induction of the unfolded protein response (UPR) pathway in PLN R14del compared with isogenic control hiPSC-CMs. The activation of UPR was also evident in the hearts from PLN R14del patients. Silencing of each of the 3 main UPR signaling branches (IRE1, ATF6, or PERK) by siRNA exacerbated the contractile dysfunction of PLN R14del hiPSC-CMs. We explored the therapeutic potential of activating the UPR with a small molecule activator, BiP (binding immunoglobulin protein) inducer X. PLN R14del hiPSC-CMs treated with BiP protein inducer X showed a dose-dependent amelioration of the contractility deficit in both 2-dimensional cultures and 3-dimensional engineered heart tissues without affecting calcium homeostasis. Together, these findings suggest that the UPR exerts a protective effect in the setting of PLN R14del cardiomyopathy and that modulation of the UPR might be exploited therapeutically.

Abstract 13662: The Arrhythmogenic Impact of Heart Failure With Preserved Ejection Fraction on Diabetics: Insights From A Nationally Representative Sample

Introduction: Heart failure with preserved ejection fraction (HFpEF) is emerging as a significant clinical concern among people with DM with recent studies showing that 45% of patients with HFpEF have DM. Sudden death accounts for around 20% of deaths in the HFpEF population, with diabetics running the highest risk. DM and HFpEF are associated with endothelial dysfunction, interstitial fibrosis, and repolarization changes that may predispose to ventricular arrhythmias (VA). However, the burden of VA in people with DM and HFpEF is not well elucidated. Hypothesis: We hypothesize that patients with DM and HFpEF have a higher prevalence of VA than patients with DM only. Methods: We queried the national inpatient sample (NIS) from 2012 to 2014 for patients age&gt;=18years. We excluded heart failure with reduced ejection fraction and hypertrophic cardiomyopathy. Subsequently, we used ICD-9-CM codes to identify discharges associated with HFpEF, DM, VT, VF, and QTc prolongation. We divided patients into two groups: DM/HFpEF vs. DM/non-HFpEF. 1ry-outcome was VT Prevalence. 2ry-outcomes are VF prevalence, QTc prolongation, length of stay (LOS), and in-hospital mortality. We used multivariate logistic regression (MLR) to devise the propensity scores. Propensity score matching (PSM) was performed. Standardized mean difference &lt;0.1 indicates covariate homogeneity. Results: We Identified 326545 hospitalizations among the HFpEF group and 3625130 among the non-HFpEF group. HFpEF group tended to be older, females, and had higher rates of obesity and other comorbidities and. On PSM+MLR, HFpEF group had higher Odds of VT (2.1% vs. 1.9%; OR, 1.06; 95%CI, 1.03-.10; P, &lt;0.001) and higher LOS. Nonetheless, VF and In-hospital mortality were surprisingly higher in the non-HFpEF group. No difference in QTc prolongation between both groups. Conclusions: HFpEF was associated with higher rates of VT among patients with diabetes, although there was no change in in-hospital mortality.

The effect of revascularization of a chronic total coronary occlusion on electrocardiographic variables. A sub-study of the EXPLORE trial

IntroductionChronic total coronary occlusions (CTOs) have been associated with a higher prevalence of ventricular arrhythmias compared to patients without a CTO. We evaluated the effect of CTO revascularization on electrocardiographic (ECG) variables. MethodsWe studied a selection of ST-elevation myocardial infarction patients with a concomitant CTO enrolled in the EXPLORE trial. ECG variables and cardiac function were analysed at baseline and at 4 months follow-up. ResultsPatients were randomized to percutaneous coronary intervention (PCI) of their CTO (n = 77) or to no-CTO PCI (n = 81). At follow-up, median QT dispersion was significantly lower in the CTO PCI group compared to the no-CTO PCI group (46 ms [33–58] vs. 54 ms [37–68], P = 0.043). No independent association was observed between ECG variables and cardiac function. ConclusionRevascularization of a CTO after STEMI significantly shortened QT dispersion at 4 months follow-up. These findings support the hypothesis that CTO revascularization reduces the pro-arrhythmic substrate in CTO patients.

Prevalence of Cardiac Arrhythmias in Hypothyroid and Euthyroid Patients.

The thyroid functions as a regulator of cardiac function and rhythm through genomic and nongenomic actions of triiodothyronine (T3) in cardiac myocytes. Atrial fibrillation is a common complication of thyrotoxicosis. Hypothyroidism is not considered a risk factor for arrhythmias despite well-known EKG changes in this condition. This case control study was conducted to analyze the differences, if any, in the prevalence of cardiac arrhythmias between hypothyroid patients and euthyroid controls. Three hundred and four consecutive patients admitted at our medical center for a period of one year were included in the study. The study population was divided into 2 groups (age, gender and race matched): patients with hypothyroidism and euthyroid subjects as a control group. Major arrhythmia data were obtained from telemetry recordings and from known past medical history. There were 152 subjects in each arm of the study. The mean age was 61.9 years. Mean TSH in hypothyroid group was 40.4 mIU/l (95% CI 33.3-47.5) (range 10.09-304, SE 3.62) and in euthyroid group was 0.89 mIU/l (95% CI 0.82-0.96). Chi-square analysis revealed a higher prevalence of ventricular tachycardia (p=0.04) and any ventricular arrhythmia in the hypothyroid group (p=0.007). This relatively large case control study revealed a statistically higher prevalence of ventricular arrhythmias in hypothyroidism. Our study has thrown light on the prevalence of arrhythmias in hypothyroidism and the observation of increased ventricular arrhythmias necessitates future large scale prospective studies to better define the risk of such ventricular arrhythmias and the effects of thyroid supplementation on this risk.

Magnetic Resonance Imaging in Hypertrophic Cardiomyopathy

.The analysis of the data retrieved from defibrillators and implantable pacemakers in patients with HCM demonstrates that the mechanism of sudden death is ventricular tachycardia, followed by ventricular fibrillation 4 . Cardiac structural changes resulting from HCM such as cellular disorganization (misaligned myocytes), fibrosis and cell death are the most probable causes of arrhythmias. There is not an isolated test identifying with a reasonable degree of accuracy those patients at risk of sudden death, which makes stratification complex and imprecise. A study in patients with HCM who underwent routine 24-hour Holter 5 showed that 90% of patients had ventricular arrhythmias, and more than 20% had ventricular extrasystoles higher than 200/24h; more than 40% had paired ventricular extrasystoles; and perhaps the most important finding in the study, 20% to 30% of patients had non-sustained ventricular tachycardia. This high prevalence of ventricular arrhythmias on Holter is certainly disproportionate to the relatively low incidence of sudden death in patients with HCM 2

Prevalence of ventricular arrhythmias and heart rate variability pattern in chronic heart failure

This study was carried out to determine the prevalence of ventricular arrhythmias and heart rate variability pattern in patients on treatment for chronic heart failure. Twenty four hour ambulatory electrocardiograms were recorded in 60 patients with chronic heart failure and echocardiography left ventricular ejection fraction of less than 45%.Sixty age and sex- matched individuals with no obvious evidence of underlying cardiac disease were also evaluated for comparison. Premature ventricular complexes (PVCs) were evident in all subjects being infrequent [ < 30 PVCs per hour], in 21 (35%) and frequent [ > 30 PVCs per hour] in 39 (65%).Multiform extra systoles were recorded in 44 (73.3%) subjects, ventricular couplets in 50 (83.4%), and non-sustained ventricular tachycardia (NSVT) in 28 (46.7%) of the 60 subjects. Among the controls, PVCs were seen in 27(45%) and were all infrequent. None of the controls had multiform extra systole, ventricular couplets or NSVT. Significant inverse relationships were found between ejection fraction and PVC per h ( P-value < 0.001), ventricular couplet per 24h (P-value < 0.001) and NSVT per hour (P-value 0.002).Time domain heart rate variability measures i.eMean Standard Deviation of Normal to Normal RR Interval (SDNN), mean Percentage of Adjacent NN Intervals in a 24 hour recording which differ by at least 50ms (pNN550) , mean Root Mean Square Successive Difference in RR Interval (rMSSD) were significantly lower in the subjects compared to the controls. The corresponding P-values were < 0.001, < 0.001, < 0.001 respectively. A significant positive correlation was found between EF and SDNN ( P-value < 0.001), pNN50 (P-value 0.044) and rMSSD (P-value < 0.001). This study showed that ambulant out patients with chronic heart failure, have significantly higher prevalence of ventricular arrhythmias and narrow heart rate variability compared to healthy individuals of comparable age and gender.

A high-fat diet increases risk of ventricular arrhythmia in female rats: enhanced arrhythmic risk in the absence of obesity or hyperlipidemia

Obesity increases the incidence of cardiac arrhythmias and impairs wound healing. However, it is presently unknown whether a high-fat diet affects arrhythmic risk or wound healing before the onset of overt obesity or hyperlipidemia. After 8 wk of feeding a high-fat diet to adult female rats, a nonsignificant increase in body weight was observed and associated with a normal plasma lipid profile. Following ischemia/reperfusion injury, scar length (standard diet 0.29 +/- 0.09 vs. high-fat 0.32 +/- 0.13 cm), thickness (standard diet 0.047 +/- 0.02 vs. high-fat 0.059 +/- 0.01 cm), and collagen alpha(1) type 1 content (standard diet 0.21 +/- 0.04 vs. high-fat 0.20 +/- 0.04 arbitrary units/mm(2)) of infarcted hearts were not altered by the high-fat diet. However, the mortality rate was greatly increased 24 h postinfarction (from 5% to 46%, P < 0.01 for ischemia/reperfusion rats; from 20% to 89%, P < 0.0001, in complete-occlusion rats) in high-fat fed rats, in association with a higher prevalence of ventricular arrhythmias. Ventricular arrhythmia inducibility was also significantly increased in noninfarcted rats fed a high-fat diet. In the hearts of rats fed a high-fat diet, connexin-40 expression was absent, connexin-43 was hypophosphorylated and lateralized, and neurofilament-M immunoreactive fiber density (standard diet 2,020 +/- 260 vs. high-fat diet 2,830 +/- 250 microm(2)/mm(2)) and tyrosine hydroxylase protein expression were increased (P < 0.05). Thus, in the absence of overt obesity and hyperlipidemia, sympathetic hyperinnervation and an aberrant pattern of gap junctional protein expression and regulation in the heart of female rats fed a high-fat diet may have contributed in part to the higher incidence of inducible cardiac arrhythmias.

Electrophysiological effects of short-term antihypertensive therapy

Evaluation of: Porthan K, Viitasalo M, Hiltunen TP et al. Short-term electrophysiological effects of losartan, bisoprolol, amlodipine, and hydrochlorothiazide in hypertensive men. Ann. Med. DOI: 10.1080/07853890802195211 (2008) (Epub ahead of print).Left ventricular hypertrophy (LVH) detected by ECG has been shown to be associated with a higher prevalence of ventricular arrhythmias in members of the general population, in a case–control series of hypertensive patients and in never-treated hypertensive patients. In-keeping with this, it has been observed that hypertension-induced LVH increases the risk of sudden cardiac death. Furthermore, a consistent bulk of data suggests antihypertensive therapy targeted at regression or prevention of electrocardiographic LVH may reduce the incidence of arrhythmias. In this regard, recent clinical trials showed that antihypertensive therapy may delay or prevent the occurrence of cardiac arrhythmias and sudden cardiac death in patients with hypertension. Porthan et al. hypothesized that an antihypertensive therapy might also rapidly affect ventricular repolarization and sought to investigate the short-term electrophysiological effects of four common antihypertensive drugs, represented by an angiotensin II receptor blocker (losartan), a β-blocker (bisoprolol), a calcium channel blocker (amlodipine) and a thiazide diuretic (hydrochlorothiazide) in hypertensive men. Porthan et al. showed that losartan and bisoprolol favorably affected ventricular repolarization, with beneficial effects on ECG parameters of ventricular repolarization duration and heterogeneity. On the contrary, hydrochlorothiazide significantly increased repolarization heterogeneity, while amlodipine administration did not affect ECG repolarization measures. Thus, the observed findings suggest an intriguing hypothesis on the possible role of antihypertensive therapy in favouring or preventing cardiac arrhythmias.

A prospective study to determine the significance of ventricular late potentials in children with mitral valvar prolapse.

We aimed prospectively to determine the incidence of ventricular arrhythmias and ventricular late potentials in children with mitral valvar prolapse, and to assess whether signal-averaged electrocardiography could identify which such children were at high risk of developing ventricular tachycardia. In all, we examined 151 children with mitral valvar prolapse, at an age of 12.2 +/- 3.1 years, and 164 healthy subjects aged 12.3 +/- 3.7 years. All children underwent 24-hour ambulatory Holter monitoring and echocardiography. The children with mitral valvar prolapse were followed prospectively for a mean of 64 months. There was a significantly higher prevalence of ventricular arrhythmias in those with prolapse than in the controls (p < 0.0001). Runs of ventricular tachycardia were observed in 3 children with mitral valvar prolapse compared with one from the control group. Late potentials were more frequently observed in the children with mitral valvar prolapse than in those who were healthy (p < 0.0001), and also in those with prolapse suffering ventricular arrhythmias compared with those without ventricular arrhythmias (p < 0.02). During follow-up, 24 children with prolapsing mitral valves developed non-sustained ventricular tachycardia, giving a frequency of 3.1/100 subject-years. The sensitivity of late potentials was low, at 52%, for the identification of children with mitral valvar prolapse who developed ventricular tachycardia, although the specificity was high at 90%. This gave a positive predictive value of 50%, and a negative predictive value of 91%. We conclude that prolapse of the mitral valve predisposes to the development of ventricular arrhythmias and late potentials in children. An abnormal signal-averaged electrocardiogram is a specific, but not very sensitive, predictor for the development of ventricular tachycardia in such children.

Evaluation of the ventricular arrhythmogenic profile of patients with dilated cardiomyopathy and reduced ejection fraction

To evaluate the arrhythmogenic profile of patients with dilated cardiomyopathy of low ejection fraction and its prognostic significance. Data from 40 patients (30 males; mean age: 52 +/- 13 years) were analysed including ventricular arrhythmias (24h - Holter monitoring), autonomic balance from heart rate variability in time domain (rMSSD and pNN50 indexes), ventricular late potentials (signal averaged electrocardiogram (ECG) and dispersion of ventricular repolarization measured from 12-lead ECG. There was a high prevalence of ventricular arrhythmias with at least one episode of nonsustained ventricular tachycardia (VT) in 60% of the patients. Depressed vagal activity was observed in more than half of the patients. In only 30% of the patients the signal-averaged ECG was positive. The dispersion of ventricular repolarization ranged from 20 to 100 ms. The presence of > 30 ventricular premature beats or nonsustained VT on Holter monitoring was the most significant predictor of cardiac death and sudden cardiac death with a relative risk of 1.9 and 3.2, respectively (p = 0.01 and 0.000). In this study population it was noted that patients with dilated cardiomyopathy and low ejection fraction had an abnormal electrical and autonomic cardiac behaviour. These findings could represent risk factors for the occurrence of life-threatening arrhythmias or fatal events.

Study of late potentials and ventricular arrhythmias in hypertensive patients with normal electrocardiograms.

Although an increase in the occurrence of ventricular arrhythmias has been observed in hypertensive patients, some basic questions remain unresolved regarding the prevalence and the pathophysiology of these arrhythmias. The basic aims of this study were as follows: (1) to examine the incidence and severity of ventricular arrhythmias in a substantial number of hypertensive patients without electrocardiographic indications of hypertrophy; and (2) to examine the correlation between late potentials, hypertrophy, and ventricular arrhythmias in these patients. We studied 78 consecutive patients (31 men, 47 women), aged 60.5 +/- 7.8 years, with a history of hypertension but a normal electrocardiogram. All patients had an echocardiographic study, 24-hour ambulatory monitoring, exercise test, and signal-averaged electrocardiogram. The latter was analyzed using a 40- to 250-Hz filter and with a noise level < or = 0.3 microV. Of the 78 patients studied, 21 (26.9%) had severe ventricular arrhythmias, while 57 (73.1%) had either no ventricular ectopics or sporadic isolated ventricular extrasystoles. Left ventricular hypertrophy, defined by echocardiography, was found in 58 patients (74.3%), of which 16 (27.58%) had severe ventricular arrhythmias. Five (25%) of the 20 patients without hypertrophy also had severe ventricular arrhythmias (P = NS). Ventricular late potentials were recorded in 19 (24.5%) of the 78 patients. Of these, 11 (57.89%) had severe arrhythmias, while of the 59 patients without late potentials 10 (16.94%) had severe ventricular ectopic activity. In hypertensive patients without electrocardiographic signs of hypertrophy, the higher prevalence of ventricular arrhythmias does not appear to be related to left ventricular hypertrophy but is correlated with the existence of ventricular late potentials.

Ventricular arrhythmias and four-year mortality in haemodialysis patients

127 randomly selected patients on haemodialysis showed a high prevalence of ventricular arrhythmias, the frequency of which rose significantly during and after dialysis. These patients have now been followed up for 4 years. Only age and ischaemic heart disease correlated independently with mortality. Although ventricular arrhythmias are often associated with cardiac disease in patients on chronic haemodialysis, they do not seem to predict overall mortality.

Determinants of Ventricular Arrhythmias in Cardiac Hypertrophy

Ventricular arrhythmias occur with increased frequency in both experimental and human cardiac hypertrophy. Although the process of hypertrophy itself may be arrhythmogenic, other factors may contribute to the high prevalence of arrhythmias in hypertensive patients with left ventricular hypertrophy (LVH). Disease of the large epicardial coronary arteries or of the small intramyocardial vessels (coronary microangiopathy) may lead to myocardial ischemia and thus predispose to arrhythmia. Myocardial fibrosis, a common sequelae of cardiac hypertrophy, has also been shown to be associated with ventricular arrhythmias in experimental models. Other possible determinants of ventricular arrhythmias in this group of patients include metabolic abnormalities; studies relating to the importance of hypokalemia in particular have yielded conflicting results. Thus a number of factors may combine to explain the high prevalence of ventricular arrhythmias in hypertensive patients with LVH.

Effect of Congestive Heart Failure Treatment on Incidence and Prognosis of Ventricular Tachyarrhythmias

The prognosis for patients with congestive heart failure (CHF) is poor, with a mortality exceeding 50% within 5 years from diagnosis. This poor prognosis remains despite improved pharmacological therapy. Because the prevalence of sudden death among these patients is high, reported to exceed 40%, the prognostic importance of ventricular tachyarrhythmias has attracted much interest. Long-term electrocardiographic monitoring of patients with CHF reveals a high prevalence of ventricular premature beats, which in many patients occur frequently or are complex according to Lown criteria. Ventricular tachycardia (three or more consecutive beats) has been recorded in 40% or more of the patient population. Whether the occurrence and/or severity of ventricular tachyarrhythmia detected on Holter electrocardiograms relates to the subsequent prognosis is, however, debated. The occurrence of ventricular tachyarrhythmia may just be an expression of severely compromised left ventricular function, which, in turn, decides the subsequent outcome of the disease. Besides myocardial injury, patients with CHF have many factors that may contribute to the high prevalence of ventricular arrhythmias. Among these are elevated levels of plasma norepinephrine. Angiotensin II may increase the sensitivity to sympathetic nervous system arousal but also promotes renal loss of potassium and magnesium. Treatment with digitalis and diuretic drugs may provoke arrhythmias as well. Heart failure therapy may, however, also improve ventricular arrhythmias. Accordingly, it has been demonstrated that captopril therapy significantly reduces ventricular prematurity, compared with digitalis. In contrast, however, enalapril improvement of mortality was due to a reduction of progressive heart failure, with no difference seen in the incidence of sudden cardiac death (the CONSENSUS study).(ABSTRACT TRUNCATED AT 250 WORDS)