Presence Of Premature Ventricular Contractions Research Articles

Prognostic implications of premature ventricular contractions and non-sustained ventricular tachycardia in light-chain cardiac amyloidosis.

Premature ventricular contractions (PVC) and non-sustained ventricular tachycardia (NSVT) are commonly observed in light chain cardiac amyloidosis (AL-CA), but their association with prognosis is still unclear. We aimed to evaluate the prognostic value of PVCs and NSVT in patients with moderate-to-advanced AL-CA. We retrospectively included patients with AL-CA at modified 2004 Mayo stages II-IIIb between February 2014 and December 2020. Twenty-four-hour Holter recordings were assessed on admission. The outcomes included (i) new onset of adverse ventricular arrhythmia (VA) or sudden cardiac death (SCD) and (ii) cardiac death during follow-up. Of the 143 patients studied (60.41 ± 11.06 years, male 64.34%), 132 (92.31%) had presence of PVC, and 50 (34.97%) had NSVT on Holter. Twelve (8.4%) patients died in hospital and 131 patients were followed up (median 24.4 months), among whom 71 patients had cardiac death, and 15 underwent adverse VA/SCD. NSVT [hazard ratio (HR): 13.57, 95% confidence interval (CI): 3.06-60.18, P < 0.001], log-transformed PVC counts (HR: 1.46, 95%CI: 1.15-1.86, P = 0.002) and PVC burden (HR: 1.43 95%CI:1.14-1.80, P = 0.002) were predictive of new onset of adverse VA/SCD. The highest tertile of PVC counts (HR: 2.33, 95%CI: 1.27-4.28, P = 0.006) and PVC burden (HR: 2.58, 95%CI: 1.42-4.69, P = 0.002), rather than NSVT (HR: 1.16, 95%CI: 0.67-1.98, P = 0.603), was associated with cardiac death. Higher PVC counts/burden provided incremental value on modified 2004 Mayo stage in predicting cardiac death, with C index increasing from 0.681 to 0.712 and 0.717, respectively (P values <0.05). PVC count, burden, and NSVT significantly correlated with adverse VA/SCD during follow-up in patients with AL-CA. Higher PVC counts/burdens added incremental value for predicting cardiac death.

P349 EARLY DIAGNOSIS OF HEREDITARY CARDIAC AMYLOIDOSIS(ATTRV) IN A CARRIER: WHEN IS ENDOMYOCARDIAL BIOPSY INDICATED?

Abstract Background Hereditary transthyretin amyloidosis (ATTRv) is a rare, adult–onset, autosomal dominant genetic disorder caused by mutations in the TTR gene. The growing availability of effective therapies determining a greater benefit the earlier they start, highlights the importance of identifying cardiac involvement even in the absence of left ventricular hypertrophy. Clinical Case A 58–year–old man came to our observation for exertional dyspnea and received a diagnosis of hereditary transthyretin amyloidosis (Val142Leu). Family screening led to the identification of the 56–year–old brother who was carrier of the same mutation. This patient was symptomatic for palpitations. Blood tests, including cardiac Troponin and NTproBNP, were normal. The ECG showed sinus rhythm, with normal atrioventricular and intraventricular conduction but frequent premature ventricular contractions. Transthoracic echocardiogram was normal, including strain rate evaluation. In order to identify early cardiac involvement, the patient underwent cardiac magnetic resonance imaging and biphosphonate scintigraphy that were negative for cardiac involvement. Neurological examination showed initial bilateral carpal tunnel syndrome. Due to the presence of premature ventricular contractions, the patient underwent to an endomyocardial biopsy which unpredictably showed a slight focal positivity to Congo Red staining, and immunohistochemistry confirmed a slight focal positivity for transthyretin. Therefore, the patient started therapy with Tafamidis. At 12–month follow up cardiac scintigraphy was still negative as well as ventricular thickness resulted within normal limits. Conclusion This case shows that in ATTR mutation carriers, an initial cardiac involvement can be present even in the absence of left ventricular hypertrophy and positive bisphosphonate scintigraphy. In the presence of clinical symptoms and/or suspicious signs of disease, such as arrhythmias, an endomyocardial biopsy may be indicated in order to start disease modifying therapy earlier.

Abstract 13613: Prevalence of Atrial Fibrillation and Procedure-Outcome in Patients Undergoing Catheter Ablation for Premature Ventricular Contractions

Introduction: Atrial fibrillation (AF) and premature ventricular contractions (PVC) are common arrhythmias encountered in clinical practice. Theoretically, retrograde atrial conduction can occur in the presence of PVC, causing atrial ectopy. However, the clinical significance of this association is not defined yet. Hypothesis: We investigated the prevalence of AF in patients with PVC and its impact on PVC ablation. Methods:: Consecutive patients undergoing PVC ablation at our institution between 2016 and 2019 were included in this analysis. Patients with structural heart disease, hyperthyroidism, malignancy, alcoholism and advanced renal or hepatic disease were excluded. For all patients, 12-lead ECG was used to diagnose AF and assess PVC morphology. During the index procedure, all PVC morphologies were targeted for ablation. Patients were followed up with remote monitoring as well as ICD interrogations and office visits every 6 months for 2 years. Detection of any PVC in the electrogram was considered as recurrence. Results: A total of 394 patients undergoing PVC ablation were included of which 96 (24%) had the documented evidence of AF. Baseline characteristics of the study population without (group 1, n=298) versus with AF (group 2, n=96) is provided in table 1. Clinical parameters were comparable between the groups except age, which was higher in group 2. PVCs with multiple (≥2) morphology were detected at the index procedure in 41 (13.7%) and 58 (60.4%) patients in group 1 and 2 respectively (p &lt;0.001). At 2 years of follow-up, recurrence rate following PVC-ablation was significantly higher in group 2 compared to group 1 (17 (18%) vs 27 (9%), p=0.026). Conclusions: In this consecutive series, AF was documented in 1/4 th of the population undergoing PVC ablation and presence of AF was associated with lower procedural success at long term, which could be attributed to older age and significantly higher prevalence of multiple morphology’ PVCs in the group 2 population.

Abstract 10221: Premature Ventricular Contractions in Chronic Thromboembolic Pulmonary Hypertension Undergoing Pulmonary Thromboendarterectomy Surgery

Background: Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare and progressive subtype of severe pulmonary hypertension. Premature ventricular contractions (PVC) are common and can be a marker of cardiomyopathy. We aimed to describe the incidence, location and predictors of PVCs in CTEPH patients undergoing Pulmonary Thromboendarterectomy surgery (PTE). Hypothesis: PVCs are common in CTEPH patients and the right ventricle would be the most common location of PVCs. Methods: We reviewed the charts of 883 consecutive patients who were referred for PTE. 12-lead ECGs were reviewed for presence of PVC. Demographics, baseline lab and imaging were extracted from chart review. Predictors of PVCs were analyzed using multivariate backward logistic regression. PVC location was identified using standard location algorithms based on the 12-lead ECG. Results: Overall, 6.5% (n=57) of patients had PVCs. Surprisingly, the majority of PVCs originated from the left ventricle (75.4%, N=43). The most common location was non-outflow tracts with LV non-outflow tract (59.3%, N=34), followed by RV non-out tract (19.3%, N=11). Within the non-outflow tract region, the majority of the PVC location appeared to be septal related (moderator band, posterior fascicle or posterior medial papillary muscle). The mitral annulus was also a common location (15.8%, N=9). In a multivariate model, heart failure (OR 2.8, p=&lt;0.01), coronary artery disease (CAD) (OR 2.8, p=&lt;0.01), sleep apnea (OR 2.2, p=0.02) and obesity (OR 1.6, p=&lt;0.01) increased the odds of having PVCs. Conclusions: PVCs are not uncommon in CTEPH patients undergoing PTE surgery. Overall, 6.5% of patients had PVCs with the majority originating in the left ventricle (75.4%). Using standard ECG criteria, the most common location was the LV non-outflow tract. Heart failure, CAD, sleep apnea and obesity increased the odds of having a PVC.

Increased heart rate due to supra‐ventricular tachycardia triggering premature ventricular contraction

We describe a case wherein the presence of premature ventricular contractions was related to an increased heart rate that occurred due to supra-ventricular tachycardia: atrial tachycardia or atrioventricular nodal reentry tachycardia.

Mitral Valve Prolapse Patients with Less than Moderate Mitral Regurgitation Exhibit Early Cardiac Chamber Remodeling

Mild physiologic mitral regurgitation (MR) is common in normal individuals. Patients with primary MR due to mitral valve prolapse (MVP) may also exhibit less than moderate MR. We sought to determine whether MVP patients with less than moderate MR displayed early cardiac chamber remodeling or factors related to early remodeling and whether early remodeling predicted MR progression. Consecutive MVP patients with less than moderateMR by proximal isovelocity surface area-derived effective regurgitant orifice < 20mm2 and regurgitant volume < 30mL, were matched for age and sex with non-MVP patients (controls) having less than moderate MR. Patients with moderate or greater dysfunctional left- or right-sided valves and left ventricular ejection fraction < 50% were excluded. We evaluated left ventricle (LV) and left atrium (LA) remodeling parameters (LV end-diastolic and end-systolic indexed diameters, LA volume-index, and LV mass-index) as well as determinants of remodeling. The last available transthoracic echocardiography was reviewed to identify progression to moderate-severeMR or more. A total of 253 MVP patients with less than moderate MR were matched to 344 controls (P for age and sex, ≥.18) with less than moderate MR. Patients with MVP (mean effective regurgitant orifice and regurgitant volume, 12±4mm2 and 18±6mL, respectively) had more premature ventricular contractions (PVCs), larger LV and LA remodeling parameters, and more mild-to-moderate MR (all P<.0001). Multivariate linear regression models showed that larger LV remodeling parameters were independently associated with MVP and female sex but not MR severity (all P<.0001). The LA volume index was independently associated with MVP, age, and E/e' (all P<.0001). The LV mass index was associated with MVP, age, and hypertension (all P≤.002). Presence of PVCs was associated with LV end-systolic diameter ≥ 40mm and indexed ≥ 22mm2(P=.005). Among 323 (54%) patients having subsequent transthoracic echocardiography, 17 patients (all MVP) progressed to moderate-severe MR or more at a median of 4.3 (interquartile range, 1.7-6.4) years. Isolated posterior leaflet prolapse was the single factor associated with MR progression (adjusted hazard ratio, 2.70; 95% CI, 0.99-7.34; P=.048) after adjustment for MR severity. At a median of 5.9 (interquartile range, 4.6-7.2) years of follow-up, female sex and MVP (vs controls) were protective factors for mortality. Patients with less than moderate MR due to MVP exhibit early LV and LA remodeling, which does not predict MR progression or mortality. Left ventricle remodeling is associated with MVP, female sex, and presence of PVCs. Early chamber remodeling associated with MVP may be the phenotypical expression of a genetically mediated process and is at least partially related to PVCs.

Abstract P027: Time-updated Premature Ventricular Contractions on 12-lead ECG Are Associated With the Risk of Sudden Cardiac Death: Atherosclerosis Risk in Communities Study and Cardiovascular Health Study

Introduction: The association between premature ventricular contractions (PVCs) and Sudden Cardiac Death (SCD) remains controversial. Hypothesis: We hypothesized that PVCs are associated with SCD. Methods: Presence of PVCs was detected on 12-lead ECG recorded at baseline or any of 4 follow-up visits in 15,667 participants (pts) (mean age: 54.2 + 5.8 Yrs; 55% female; 73% Whites) of the Atherosclerosis Risk in Communities (ARIC) study. For validation cohort, we included baseline and 9 follow-up visits ECG data in 5,846 pts (mean age: 72.8+ 5.6 yrs; 57.7% female, 84.2% whites) from Cardiovascular Health Study (CHS). Competing risk analyses models were constructed to test the association between time-updated PVCs and SCD risk. Model 1 was adjusted for age, sex, race and study center. Model 2 in addition was adjusted for time-updated coronary heart disease, heart failure, atrial fibrillation, stroke, and hypertension. Results: In ARIC pts, across all study visits, PVCs were observed in 2.6% of the ECGs; 99.7% of pts were PVC-free at least once; 8.8% of pts had PVC at least once. 97.7% of pts without PVCs remained PVC-free at the next visit; 19.1% of pts with detected PVC had PVC at the next visit; 2.4% of pts who were PVC-free on previous ECG, transitioned to having PVC on subsequent visit ECG. In CHS, across all 10 yearly study visits, on average, PVC was observed on 4.85% of ECG recordings; 99.4% of participants were PVC-free at least once; 21.9% of pts had PVC at least once. 96.4% of PVC-free pts remained free from PVC at the next visit. 30.6% of pts with detected PVC on a given ECG had PVC at the next visit. 3.6% of pts who did not have PVC on previous ECG, transitioned to having PVC at the next visit. 69.4% of pts with PVC on a given ECG transitioned to being PVC-free next year. In adjusted competing risk analysis PVC was associated with SCD, but not with non-sudden cardiac death or non-cardiac death (Table). Conclusions: Time-updated presence of PVC on a short 10-sec resting 12-lead ECG is associated with SCD.

Ambulatory blood pressure results and heart rate variability in patients with premature ventricular contractions

ABSTRACTBackground: The presence of premature ventricular contractions (PVCs) is a sign of arrhythmia and typically trigerred by over stimulation of the sympathetic nervous system. This study examined the relationships among PVCs, heart rate variability (HRV), and 24-hour ambulatory blood pressure (ABP) results. Methods: This observational clinical study evaluated a cohort of 100 consecutive patients (58 women and 42 men) with PVCs. The individuals were split into occasional (n = 50) and frequent (n = 50) PVCs groups. All Holter recordings were performed during a working day. Results: Daytime low-frequency power (LFP), daytime low frequency/high frequency (LF/HF), nighttime LFP, and nighttime LF/HF and 24-hour systolic blood pressure (SBP) were slightly higher in the frequent PVCs group (p = 0.046, p = 0.027, p = 0.038, p = 0.032, and p < 0.001, respectively). Hypertension, LF, LF/HF, 24-hour SBP were positively correlated with PVCs (r = 0.305, p = 0.002; r = 0.269, p = 0.007; r = 0.403, p < 0.001, respectively). Conclusion: Frequent PVCs reflect dominance of the sympathetic system according to the results of Holter recordings. This study showed that PVC had a significant association with high blood pressure values. Assessment of ABP and HRV in patients with PVCs is part of a comprehensive approach to the assessment of cardiovascular regulation.

Abstract 12465: Association of Markers of Electrical Heterogeneity With Premature Ventricular Contractions on 12-Lead Electrocardiogram

Introduction: It was recently shown that independent electrophysiological substrate, quantified by global electrical heterogeneity (GEH) measures on ECG, is associated with Sudden Cardiac Death (SCD). However, mechanisms of GEH development are incompletely understood. Hypothesis: We hypothesized that the presence of premature ventricular contractions (PVCs) on 12-lead ECG is associated with GEH. Methods: We analyzed 20,288 participants from the Atherosclerosis Risk in Communities (ARIC) and Cardiovascular Health Studies (CHS). Linear regression models were adjusted for demographics, structural heart disease and its risk factors to assess the association between PVCs and GEH. In a subsequent analysis, we included only those participants (n =478) who had both (a): monomorphic (if multiple) or single PVCs and (b): normal median sinus beat . The distance between PVC’s QRS vector and sinus T vector was calculated assuming the heart as a global structure. Prematurity index (PI) was defined as coupling interval (CI) divided by mean sinus-beat RR interval. SAI QRST (sum absolute interval of QRST interval) was measured as the arithmetic sum of areas under the QRST curve. Results: After adjusting for structural heart disease and its risk factors, the presence of PVCs was associated with a QRS-T angle widening by 6.9 (95% CI: 4.41-9.41) degrees (p &lt; 0.0001), and SAI QRST increase by 7.03 mV*ms (95% CI: 2.58-11.48, p = 0.002). On comprehensive adjustment using our linear regression model, among those with PVCs, 1 standard deviation of decrease in the distance between PVC’s QRS-vector and sinus beat’s T-vector was associated with spatial QRS-T angle increase by 3.6 (95% CI: 0.3-7.2) degrees (p =0.048). In the same model increase in PI by 10% was associated with spatial QRS-T angle increase by 3.0 (95%CI 0.7-4.9) degrees (P=0.010). Conclusions: The presence of PVCs is independently associated with an increase in the GEH. Better alignment between PVC’s QRS-vector and sinus beat’s T-vector (presumed cardiac memory) and less premature PVC was independently associated with wider spatial QRS-T angle.

Role of non-invasive assessment in prediction of preclinical cardiac affection in multi-transfused thalassaemia major patients

BackgroundThe principal cause of mortality and morbidity in β-thalassemia major (β-TM) is the iron overload as these patients receive about 20 times the normal intake of iron, which leads to iron accumulation and damage in the liver, heart, and endocrine organs. Chronically transfused patients used to die from cardiac iron overload in their teens and twenties. Monitoring of iron status through cardiac magnetic resonance imaging (CMRI) has replaced the conventional methods of assessment, yet this modality is not readily available in centers where the disease distribution is maximal.ObjectivesThe aim of this work is to study some simple non-invasive tools and their abilities to predict preclinical cardiac affection reflecting cardiac iron deposition (CID) in multi-transfused β-TM patients taking the T2* CMRI as a gold standard reference test.MethodsOne hundred consecutive multi-transfused, clinically stable β-TM patients with age ranging from 16 to 30 years (mean ± SD, 21.1 ± 3.9) were included in this study. Assessment of serum ferritin, serum hepcidin, and high-sensitivity C-reactive protein as well as cardiac assessment by echo-doppler and 24-hour Holter were used to predict CID, and consequently predict preclinical cardiac affection, in reference to CMRI results as the standard method of cardiac iron assessment.ResultsAccording to CMRI results, patients were subdivided into a group of 42 patients with detectable myocardial iron (T*≤ 20 ms) and a group of 58 patients with no detectable myocardial iron (T* > 20 ms). No differences in age, gender, or distribution of splenectomized patients were observed between both groups. Patients with detectable myocardial iron received significantly higher number of transfusions per year than those with no detectable myocardial iron (mean ± SD, 14.6 ± 1.7 vs. 12.5 ± 1.7; P < 0.001) yet comparable levels of serum ferritin, serum hepcidin, and hepcidin/ferritin ratio (P > 0.05) were noted. Cardiac iron detection was associated with significantly lower heart rate (mean ± SD, 75 ± 6.1 vs. 80 ± 6.9; P < 0.001), lower left ventricular ejection fraction (LVEF) (mean ± SD 60.1 ± 3.2 vs. 70.1 ± 2.8; P < 0.001), and higher total number of premature ventricular contractions (PVCs) (median 78 vs. 14; P < 0.001). The group with CID comprised significantly more patients with left ventricular diastolic dysfunction (15/42, 35.7% vs. 3/58, 5.2%; P < 0.001); PVCs ≥10/hour (13/42, 31% vs. 2/58, 3.4%; P < 0.001); episodes of sinus pauses (6/42, 14.3% vs. 1/58, 1.7%; P < 0.05); episodes of high-grade atrio-ventricular block (5/42, 11.9% vs. 1/58, 1.7%; P < 0.05) compared to the group with no (CID). In presence of normal LVEF, detection of 10 or more PVCs per hour was the most predictive of cardiac iron loading with a positive predictive value of 86.7% and specificity of 96.6%, and the highest likelihood ratio (9.09). Detection of more than 22 PVCs/24 hours had the best sensitivity (81%) and the best negative predictive value (84%). The positive likelihood ratio of the studied parameters was highest in case of presence of PVCs ≥10/hour and lowest in case of average heart rate with a cut-off level of ≤77.5 bpm (9.09 and 1.46, respectively).ConclusionOur results support our hypothesis that monitoring β-TM patients with echo and Holter electrocardiogram can help in the detection of preclinical cardiac affection in centers lacking cardiac MRI; however, due to relatively low sensitivity they can not fully replace CMRI. Further work is needed to identify additional simple parameters that can form a diagnostic model with adequate sensitivity.

Understanding congenital heart defects through abdominal fetal electrocardiography: Case reports and clinical implications

Congenital heart defects are the most common fetal structural anomalies of which a significant number remain unrecognized during postnatal life. Fetal electrocardiography (FECG) is an ideal clinical tool to complement ultrasonography for the screening and management of these cases where early and accurate diagnoses would allow definite rather than palliative treatment. The objective of this report was to correlate the particular FECG results found with the different types of congenital heart defects involved and to further demonstrate the usefulness of FECG in clinical settings. This is a report of four cases of prenatally diagnosed congenital heart defects seen at a university hospital in Sendai, Japan. Their complete and thorough evaluation included, among other tests, abdominal FECG analysis. The presence of premature ventricular contractions, a prolonged pre-ejection period (PEP > 75 msec), and prolonged QTc intervals (QTc > 440 msec) served as markers of hemodynamic alteration but were unlikely determinants of disease severity precluding further investigation. In practice, similar findings found on FECG should raise the index of suspicion for the presence of congenital heart disease and prompt a targeted ultrasound scan.

Rest Premature Ventricular Contractions on Routine ECG and Prognosis in Heart Failure Patients

Premature ventricular contractions (PVC) at rest are frequently seen in heart failure (HF) patients but conflicting data exist regarding their importance for cardiovascular (CV) mortality. This study aims to evaluate the prognostic value of rest PVCs on an electrocardiogram (ECG) in patients with a history of clinical HF. We considered 352 patients (64 + or - 11 years; 7 females) with a history of clinical HF undergoing treadmill testing for clinical reasons at the Veterans Affairs Palo Alto Health Care System (VAPAHCS) (1987-2007). Patients with rest PVCs were defined as having > or = 1 PVC on the ECG prior to testing (n = 29; 8%). During a median follow-up period of 6.2 years, there were 178 deaths of which 76 (42.6%) were due to CV causes. At baseline, compared to patients without rest PVCs, those with rest PVCs had a lower ejection fraction (EF) (30% vs 45%) and the prevalence of EF < or = 35% was higher (75% vs 41%). They were more likely to have smoked (76% vs 55%).The all-cause and CV mortality rates were significantly higher in the rest PVCs group (72% vs 49%, P = 0.01 and 45% vs 20%, P = 0.002; respectively). After adjusting for age, beta-blocker use, rest ECG findings, resting heart rate (HR), EF, maximal systolic blood pressure, peak HR, and exercise capacity, rest PVC was associated with a 5.5-fold increased risk of CV mortality (P = 0.004). Considering the presence of PVCs during exercise and/or recovery did not affect our results. The presence of PVC on an ECG is a powerful predictor of CV mortality even after adjusting for confounding factors.

Prognostic Significance of PVCs and Resting Heart Rate

We sought to evaluate the prognostic significance of premature ventricular contractions (PVCs) on a routine electrocardiogram (ECG) and to evaluate the relationship between heart rate and PVCs. Computerized 12-lead ECGs of 45,402 veterans were analyzed. Vital status was available through the California Health Department Service. There were 1731 patients with PVCs (3.8%). Compared to patients without PVCs, those with PVCs had significantly higher all-cause (39% vs 22%, P < 0.001) and cardiovascular mortality (20% vs 8%, P < 0.001). PVCs remain a significant predictor even after adjustment for age and other ECG abnormalities. The presence of multiple PVCs or complex morphologies did not add significant additional prognostic information. Those patients with PVCs had a significantly higher heart rate than those without PVCs (mean +/- SD: 78.6 +/- 15 vs 73.5 +/- 16 bpm, P < 0.001). When patients were divided into groups by heart rate (<60, 60-79, 80-99 and >100 bpm) and by the presence or absence of PVCs, mortality increased progressively with heart rate and doubled with the presence of PVCs. Using regression analysis, heart rate was demonstrated to be an independent and significant predictor of PVCs. PVCs on a resting ECG are a significant and independent predictor of all-cause and cardiovascular mortality. Increased heart rate predicts mortality in patients with and without PVCs and the combination dramatically increases mortality. These findings together with the demonstrated independent association of heart rate with PVCs suggest that a hyperadrenergic state is present in patients with PVCs and that it likely contributes to their adverse prognosis.

Autologous skeletal myoblasts restore the myocardial electrical impedance, but not the refractory period of infarcted myocardium: engraftment versus integration?

Introduction: Autologous skeletal myoblasts (ASM) can survive within areas of myocardial infarct. However, little evidence exists as to whether these skeletal fibers develop and become integrated (electromechanically coupled) with the host myocardium. Myocardial electrical impedance (MEI) is sensitive to physiological changes in regional tissue metabolism, while the myocardial refractory period (RP) is sensitive to changes in integrated intercellular electrochemistry of the myocardium. Methods: Myocardial infarction was created in sheep (N = 7) by means of coronary microembolization. Myocardial impedance electrodes were placed in remote (CTRL) and infarcted areas. Animals were injected (in the infarct) with up to 5.0 × 10^8 ASM (INF+ASM; N = 4) or cell-media (INF; N = 3). MEI and RP were measured in awake, unsedated animals at 1, 7, 14 and 21 days following ASM/cell-media injection. Random night-time ECG (telemetry) monitoring was conducted to evaluate for the presence of premature ventricular contractions (PVCs) or other ectopy. Results: ASM-derived myofibers were found aligned and apposed to cardiac myocytes, however, no connexin 43 was identified in skeletal myocytes. At Day 1, the MEI and RP of infarcted myocardium (361±20Ω & 178±4ms) differed (P<0.05) from that of remote myocardium (480±25Ω & 205±8ms). After 21 days, the MEI difference remained unchanged in cell-media animals (470±71Ω vs. 584±27Ω) but decreased significantly with ASM, reaching control (remote) values (503±20Ω vs. 522±24Ω, see figure). However, no significant change in RP or PVC count (21 pvc/hr; range: 3–38) was observed after Day 1. Discussion: The normalization of passive electrical properties (MEI) of the infarcted myocardium after ASM injection may represent ASM development, engraftment, and the revitalization of myocardial scar by skeletal myofibers. However, the lack of changes in measured RP suggests that engrafted skeletal myofibers may not impact active electrochemical properties of the myocardium.

Ventricular arrhythmias after repair of congenital heart disease: Who needs treatment?

Sudden death occurs in patients after repair of congenital heart disease. In those with tetralogy of Fallot, or a similar lesion, ventricular tachycardia has been hypothesized as the major arrhythmic mechanism for sudden death. It would be desirable to identify individuals at risk for sudden death, to determine which arrhythmia would be likely to cause sudden death, and to treat those individuals with an appropriate antiarrhythmic to prevent sudden death. For the last 10 years, physicians have been treating patients with antiarrhythmic drugs, based on a number of criteria, the most common of which is the presence of premature ventricular contractions.1,2 The practice has recently been called into question by the CAST trial. It is the purpose of this paper to review the evidence that repair causes ventricular arrhythmias, that ventricular arrhythmias cause sudden death, and that ventricular arrhythmias should be treated prophylactically.

Meta-analysis of Empirical Long-term Antiarrhythmic Therapy After Myocardial Infarction

SUDDEN cardiac death remains a major cause of mortality and a significant public health concern. At least 40% of sudden deaths occur in people with clinically overt heart disease, and among patients with coronary heart disease, the risk of sudden death is relatively greater for those patients who have had a myocardial infarction (MI) than for those who have not. 1 Approximately 50% of MI-related deaths are sudden and usually caused by ventricular arrhythmias. 2,3 Although the majority of these deaths occur in the earliest phases of MI, 4 the risk of mortality beyond 1 year after MI remains four to eight times greater than that for comparable patients who did not have an MI. 5,6 Approximately 35% to 40% of deaths that occur late after MI will be caused by sudden death. 7 The presence of premature ventricular contractions (PVCs) after MI has been shown to be a risk

Clinical evaluation of the enhancement of vagal tone in acute myocardial infarction by edrophonium hydrochloride: Effects on ventricular arrhythmias, His bundle electrography, and left ventricular function

Enhanced electrical stability of acutely ischemic myocardium with vagal stimulation and acetylcholinesterase inhibition has been demonstrated experimentally. To extend these findings clinically, within 24 hours of acute myocardial infarction, 11 patients underwent continuous 10 hour Holter monitoring: 2.5 hour control before and after 5 hour constant edrophonium infusion (0.25 to 2.00 mg./minute). Continuous infusion of the agent lowered heart rate 92 to 78 b.p.m. (p less than 0.01). Although mean total ventricular extrasystoles (PVC's) per 5 hours per patient (131) and PVC's per 1,000 beats (4.7) were unchanged (p greater than 0.05), potentially lethal tachyarrhythmias (malignant PVC's: multifocal, R on T, paried, greater than 5 per minute or ventricular tachycardia) were terminated in six of 10 patients by edrophonium. However, serious ventricular arrhythmias continued in three patients and appeared in four despite the agent. Ventricular fibrillation did not occur during the 10 hour period of study. In addition, the patients were evaluated hemodynamically and by His bundle electrograms before and after a 10 mg. bolus of edrophonium prior to the 10 hour constant infusion: heart rate declined (88 to 72 b.p.m., p less than 0.01), while mean arterial pressure (98 mm. Hg), left ventricular filling pressure (14 mm. Hg), cardiac index (2.4 L. per minute per square meter), and stroke work index (36 Gm.m./M.2) were unchanged (p greater than 0.05). The edrophonium bolus prolonged the A-H interval (117 to 135 msec., p less than 0.01) while the H-Q interval was unaltered (48 msec; p greater than 0.05). It is concluded that increased vagal tone with edrophonium did not reduce the over-all presence of premature ventricular contractions in the entire study group; however, the malignant nature of PVCs and ventricular tachycardia appeared to be lessened by the parasympathomimetic agent in certain patients. In addition, no adverse hemodynamic or intraventricular conduction effects were produced by edrophonium administration.

Correlation of the standard electrocardiogram and continuous ambulatory monitoring in the detection of ventricular arrhythmias in coronary patients

To evaluate the efficacy of ventricular arrhythmia detection in ambulatory patients with stable coronary artery disease, 101 coronary patients documented by arteriography or remote myocardial infarction underwent concurrent evaluation by 10-hour portable ambulatory ECG monitoring and standard 12-lead electrocardiograms (ECGs) obtained serially over 24 months. Portable ECG recorded premature ventricular contractions (PVCs) in 77 patients: 50% serious PVCs (multifocal, paired, >5/minute, R on T) and 9% patients with ventricular tachycardia. Standard ECG was insensitive (p<.001) in arrhythmia detection both by one tracing (PVC prevalence 17%) obtained within 12 hours of portable ECG or by four serial standard ECGs during the subsequent two weeks (PVC prevalence 18%). Although a total of 1,414 standard ECGs during 24 months recorded PVCs in 49% of patients, serious PVCs were limited (p<.001) to 25% and ventricular tachycardia to 1% of patients. However, ventricular ectopy present by any standard ECG (10 per patient) within three months of ambulatory monitoring was associated with high prevalence of hazardous ectopics by portable ECG (p<.05): serious PVC 92%; ventricular tachycardia 17% patients. Even in patients free of ventricular ectopy by 24-month serial standard ECG, portable ECG detected serious PVCs in 62% and ventricular tachycardia in 6% of patients. Thus stable coronary patients manifested frequent ventricular ectopics by portable ECG which were usually undetected by even multiple serial standard ECGs. Importantly, presence of PVCs by standard ECG was related to increased risk of hazardous ventricular arrhythmias by portable ECG.