Significance Of Ventricular Arrhythmias Research Articles

Exercise stress tests in the diagnosis and determination of clinical significance of ventricular arrhythmias

Exercise stress tests in the diagnosis and determination of clinical significance of ventricular arrhythmias

Incidence, Predictors, and Significance ofVentricular Arrhythmias in Patients WithContinuous-Flow Left Ventricular Assist Devices: A 15-Year Institutional Experience.

The aim of this study was to evaluate the incidence, predictors, and associated mortality of pre-implantation, early, and late ventricular arrhythmias (VAs) in patients receiving continuous-flow left ventricular assistdevices (CFLVADs). VAs are common both pre- and post-implantation of left ventricular assist devices. Limited data existon their prognostic impact in contemporary CFLVADs. A retrospective review was performed to identify patients who underwent CFLVAD implantation between2000 and 2015 with 2 years of follow-up. All VAs, defined as ventricular fibrillation, ventricular tachycardia lasting >30 s, or a ventricular rhythm requiring defibrillation, were analyzed. VAs occurring within 30 days of implantation were defined as early. Recorded outcomes included death and receipt of cardiac transplant. A total of 517 patients were included for analysis. Early VAs were associated with a significant reduction insurvival (hazard ratio: 1.83; 95% confidence interval: 1.28 to 2.61; p= 0.001) compared with patients with lateornoVAs. Pre-implantation variables independently predictive of early VAs included prior cardiac surgery (oddsratio: 1.90; 95% confidence interval: 1.09 to 3.32; p= 0.023) and pre-CFLVAD ventricular tachycardia storm (oddsratio: 3.15; 95% confidence interval: 1.49 to 6.69; p= 0.003). The incidence of early VAs from 2000 to 2007 was as high as 47%, whereas the highest incidence from 2008 to 2015 was<22%. VAs within 30 days after CFLVAD implantation are associated with an increased risk for death. Predictors of early VAs include prior cardiac surgery and pre-CFLVAD ventricular tachycardia storm. Temporal trends haveshown a decrease in VA from 2000 to 2015. Strategies to reduce arrhythmia burden shortly after CFLVADimplantationwarrant further investigation.

Temporal Evolution and Implications of Ventricular Arrhythmias Associated With Acute Myocardial Infarction

It is important that clinicians have a clear understanding of the significance of ventricular arrhythmias (VAs) that occur in the context of acute myocardial infarction depending on the type of VA and timing in relation to the myocardial injury. This will greatly assist in evaluating prognostic implications and tailoring optimal strategies for management. This review presents an update on the current understanding of the pathogenesis, incidence, and clinical features of postinfarction VAs, and outcomes and potential therapeutic options.

Ventricular Arrhythmias and Implantable Cardioverter-Defibrillator Therapy in Patients With Continuous-Flow Left Ventricular Assist Devices: Need for Primary Prevention?

This study sought to evaluate the prevalence and significance of ventricular arrhythmia (VA) and the role of an implantable cardioverter-defibrillator (ICD) in patients supported by a continuous-flow left ventricular assist device (CF-LVAD). VAs are common in patients supported by CF-LVADs but prospective data to support the routine use of ICDs in these patients are lacking. All patients supported by long-term CF-LVAD receiving care at our institution were enrolled. The ICDs were interrogated at baseline and throughout prospective follow-up. The VA was defined as ventricular tachycardia/fibrillation lasting >30 s or effectively terminated by appropriate ICD tachytherapy. The primary outcome was the occurrence of VA >30 days after CF-LVAD implantation. Ninety-four patients were enrolled; 77 had an ICD and 17 did not. Five patients with an ICD had it deactivated or a depleted battery not replaced during the study. Twenty-two patients had a VA >30 days after LVAD implantation. Pre-operative VA was the major predictor of post-operative arrhythmia. Absence of pre-operative VA conferred a low risk of post-operative VA (4.0% vs. 45.5%; p < 0.001). No patients discharged from the hospital without an ICD after CF-LVAD implantation died during 276.2 months of follow-up (mean time without ICD, 12.7 ± 12.3 months). Patients with pre-operative VA are at risk of recurrent VA while on CF-LVAD support and should have active ICD therapy to minimize sustained VA. Patients without pre-operative VA are at low risk and may not need active ICD therapy.

Usefulness of reperfusion ventricular arrhythmias in non-invasive prediction of early reperfusion and sustained coronary artery patency in acute myocardial infarction.

Established tenets of occurrence of reperfusion ventricular arrhythmias in acute myocardial infarction (AMI) do not provide insight into the timing of achieving reperfusion or whether coronary artery patency is sustained. We assessed the significance of ventricular arrhythmias in the non-invasive prediction of timely reperfusion and sustained restoration of coronary patency after thrombolysis in patients with AMI. 24-hour Holter monitors were placed in 163 patients with an AMI before administration of thrombolytic therapy. Patients were classified into 3 groups of early (within 2 hours) or late reperfusion, or no-reperfusion, according with clinical and continuous ST-segment electrocardiographic criteria. Ventricular fibrillation, ventricular tachycardia (VT) and accelerated idioventricular rhythm (AIVR) were also categorized as having occurred early (within the first 2 hours) or late (after the first 2-hour period). Angiographic confirmation of coronary patency was determined 2 to 6 days after AMI. Early reperfusion was predicted by early sustained AIVR in 86% of patients and early non-sustained AIVR in 62.5% of patients, with sensitivity 38% and 77%, and specificity 96% and 69%, respectively; p<0.0001. Late non-sustained AIVR was commonly seen in early and late reperfused patients (92-97%) as well as in non-reperfused patients (74%). Sustained coronary patency was predicted by early sustained AIVR in 93% of patients, as well as by early non-sustained AIVR in 86% of patients and late non-sustained AIVR in 79% of patients, with sensitivity 22%, 55% and 94%, and specificity 95%, 71% and 18%, respectively; p<0.05. Only the occurrence of sustained AIVR, and probably early non-sustained AIVR convey useful information about both early reperfusion and sustained coronary artery patency. The absence of AIVR does not preclude successful thrombolysis.

Ischemia, metabolic disturbances, and arrhythmogenesis: mechanisms and management.

The development of ventricular arrhythmias is often a consequence of the interaction between structural abnormalities of the heart and transient disturbances in the electrophysiologic milieu. The critically ill patient is particularly susceptible to arrhythmias given the metabolic, ischemic, and neurohormonal stressors present in the intensive care unit. The significance of ventricular arrhythmias in the acute care setting is related to the presence of reversible causes and the extent of underlying heart disease. Long-term management of these patients is guided by an assessment of the risk for recurrent arrhythmias and the degree of left ventricular systolic dysfunction. In the absence of a reversible cause, symptomatic sustained arrhythmias are usually treated with an implantable cardioverter-defibrillator, a therapy that improves survival in this patient population. In many cases, however, proper long-term management of patients with ventricular arrhythmias is less clear, and the approach must be guided by a thorough understanding of the pathophysiology and the fundamental mechanisms of arrhythmogenesis.

Significance of ventricular arrhythmias in systemic hypertension with left ventricular hypertrophy

Hypertensive patients with the electrocardiographic (ECG) pattern of left ventricular (LV) hypertrophy and strain are at increased risk of sudden death. It has been suggested that ventricular arrhythmias may be responsible. The prevalence and significance of ventricular arrhythmias was therefore studied in 90 hypertensive patients with LV hypertrophy and strain by undertaking 48-hour ambulatory ECG monitoring, ECG signal-averaging and programmed ventricular stimulation. Complex ventricular ectopic activity (Lown grade ≥3) was detected in 59 patients (66%). Eleven patients (12%) had episodes of nonsustained ventricular tachycardia. There were no sustained arrhythmias either on ambulatory ECG monitoring or induced by programmed ventricular stimulation. Only 1 patient had ventricular late potentials recorded by the signal-averaged electrocardiogram. Therefore, there was little to suggest an underlying arrhythmogenic substrate in these patients. In conclusion, whereas ventricular arrhythmias occur often in patients with LV hypertrophy associated with systemic hypertension, their significance, if any, remains to be established.

Prevalence, characteristics and significance of ventricular premature complexes and ventricular tachycardia detected by 24-hour continuous electrocardiographic recording in the Cardiac Arrhythmia Suppression Trial

The prevalence, characteristics and significance of ventricular arrhythmias detected by ambulatory electrocardiography were evaluated in 1,498 patients who were randomized to encainide, flecainide or placebo in the Cardiac Arrhythmia Suppression Trial. The mean ventricular premature complex (VPC) frequency at baseline was 133 ± 257 VPCs/hour. Nonsustained ventricular tachycardia (VT) (rate ≥120 beats/min) was present in 22% of patients. Accelerated idioventricular rhythm (rate <120 beats/min) occurred in 22% of subjects. There were 63 deaths/resuscitated cardiac arrests in the active treatment (encainide/flecainide) group and 26 in the placebo group. In the treatment group mortality increased with increasing VPC frequency, (p = 0.006), whereas in the placebo group such a relation was not present. Mortality/resuscitated cardiac arrest increased in patients with ≥2 VT episodes than in those with ≤1 episode in the active treatment group (p = 0.04). There was no significant association between VT and mortality/resuscitated cardiac arrest in the placebo group. The presence of accelerated idioventricular rhythm was not associated with increased mortality/resuscitated cardiac arrest in either the active treatment or placebo groups. However, mortality was lower in patients with accelerated idioventricular rhythm rates <100 beats/ min than in those with rates ≥100 beats/min (p = 0.05). Thus, in the Cardiac Arrhythmia Suppression Trial the previously described association between mortality/resuscitated cardiac arrest and ventricular arrhythmias (VPC and VT) were only observed in the active treatment group. In addition, based on the results obtained in this highly selected population, it is suggested that the definition of accelerated idioventricular rhythm should be a rate <100 beats/min, and at a rate ≥100 beats/min it should be categorized as VT.

Dilated Cardiomyopathy

Dilated Cardiomyopathy

Long-Term Treatment After Acute Myocardial Infarction

Even if the prognostic significance of ventricular arrhythmias (VA) has been documented in post-AMI CAD, which post-AMI patient showing VA should be treated is still controversial, because no beneficial effects of antiarrhythmic treatment has ever been proved in clinical trials using phenytoin, aprindine, tocainide, mexiletine, and the drugs recently utilized in the CAPS for EVBs. Probably, the rationale for antiarrhythmic therapy is more conclusive in patients with ventricular arrhythmias other than EVBs, and the need for antiarrhythmic drugs should be evaluated in each case, considering other clinical variables of prognostic importance (EF%, extent of coronary lesions, etc.). The type of antiarrhythmic drugs to be used is discussed, considering that, while many traditional antiarrhythmic agents are undoubtedly effective in the treatment of an acute arrhythmia, in the chronic setting, most of the time, a significant reduction in ventricular arrhythmias on Holter monitoring can be proved, without a significant reduction in total mortality. Conversely, we comment on the positive results of some empirical studies showing beneficial effects of antiarrhythmic therapy in high-risk patients reported by Lown's group. Furthermore, it can be stated that patients showing efficacy of antiarrhythmic therapy by both noninvasive and invasive evaluation of antiarrhythmic therapy efficacy had better long-term outcomes. To confirm these data, we report the results of a clinical study of the treatment of complex and frequent EVBs in cardiac patients. A different mortality on follow-up was observed in responders and nonresponders vs. patients not receiving drugs (2.2, 28, and 24%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Ventricular arrhythmias late after aortic and/or mitral valve replacement.

Since it is not yet known whether ventricular arrhythmias in patients with valve replacement are associated with an increased risk of sudden death, as in patients with coronary artery disease, a total of 46 patients who were long-term survivors of aortic and/or mitral valve replacement were examined with 24-hour ambulatory electrocardiographic monitoring, and the factors influencing the occurrence of ventricular arrhythmias were analyzed. The significance of ventricular arrhythmias in the prognosis of valve replacement is discussed. The occurrence of ventricular arrhythmias was significantly higher: 1) in patients with aortic stenosis than in those with aortic regurgitation, 2) in patients with multiple valve surgery than in those with single valve replacement and 3) in patients with larger heart size. Pre- and postoperative hemodynamics, including left ventricular function, were not significantly related to the incidence of ventricular arrhythmias. A review of the patients who died suddenly, late after valve replacement suggests that frequent ventricular arrhythmias and thromboembolism are the most important factors in the late mortality of these patients. The prognostic significance of postoperative ventricular arrhythmias in patients with valve replacement requires additional study.

Significance of ventricular arrhythmias on low level exercise testing two weeks after acute myocardial infarction

Significance of ventricular arrhythmias on low level exercise testing two weeks after acute myocardial infarction