Ventricular Complexes Research Articles

DON’T FORGET ABOUT CARDIAC AMYLOIDOSIS: WHEN RED FLAGS MATTER

Abstract Case Report A 78–year–old man came to our attention for worsening dyspnea, asthenia and frequent lipothymic episodes in the last few weeks. Nothing remarkable was reported in anamnesis except for periodic cardiological check–ups ascribed to hypertensive heart disease and moderate aortic stenosis. Other cardiovascular risk factors were obesity, previous smoking habits and dyslipidemia. A recent 24–hours ECG monitoring revealed slow permanent atrial fibrillation (AF) with 3–seconds pauses, frequent premature ventricular complexes (PVCs) and some PVCs couplets. On arrival, NT–proBNP was elevated (2952 pg/mL), while ECG showed AF with a heart rate of 50/m and low voltages in peripheral leads. Transthoracic echocardiogram revealed a biatrial dilatation, a severe left ventricular (LV) concentric hypertrophy with a preserved LV ejection fraction (EF) and a moderate aortic stenosis. In addition, a restrictive LV filling pattern, a decreased longitudinal myocardial contraction and an apical sparing of longitudinal strain were reported. Invasive coronary angiography was performed with evidence of normal coronary arteries. Given the echocardiographic suspicion of amyloidosis, a 99mTc–Hydroxymethylene diphosphonate (HMDP) scintigraphy was performed, showing a moderate cardiac uptake and an attenuated bone uptake (Perugini Score 2). Serum and urine immunofixation resulted negative. Genetic testing did not find any mutations in Transthyretin (TTR) gene. Therefore, the diagnosis of TTR wild–type amyloidosis was made. Before discharge, putting it all together, we opted to implant a leadless pacemaker in order to protect the patient from life–threatening bradyarrhythmias. Discussion Although it is currently considered rare, there is growing evidence that cardiac amyloidosis may be more common than once thought. First of all, it should be investigated in HFpEF–patients (heart failure with preserved EF) with LV hypertrophy. Despite several red flags (low QRS voltages, conduction disorders, elevated NT–proBNP, severe LV hypertrophy and aortic stenosis) and various medical consultations, our patient had to wait 4 years or more to be diagnosed with cardiac amyloidosis. Inevitably, a diagnostic delay means loss of time in treatment initiation. Earlier diagnosis would enable us to improve our patients’ survival and heart failure hospitalization. Awareness alone is not enough, we must be right on target too.

CARDIOPULMONARY SUPPORT WITH EXTRACORPOREAL MEMBRANE OXYGENATION (ECMO) DURING CATHETER ABLATION OF VENTRICULAR FIBRILLATION: A CASE REPORT

Abstract The clinical case deals with a 46–year–old man, severely obese and suffering from type II diabetes mellitus and arterial hypertension, a smoker. He was admitted to our department for iterative ventricular fibrillation (VF) following a recent acute myocardial infarction with ST–segment elevation treated with percutaneous coronary angioplasty (PTCA) and implantation of drug–eluting stents on the anterior interventricular. Control coronary angiography showed good results of previous PTCA. On the echocardiogram, left ventricular pump function moderately reduced (EF 45%) with district alterations of the kinetics and aneurysmal dilatation of the ascending aorta. During hospitalization, iterative episodes of VF despite maximal antiarrhythmic therapy, promptly treated with DC shock. Continuous telemetry monitoring showed frequent early premature ventricular complex (PVC) triggering VF episodes. A 12–lead Holter ECG was performed to better identify the morphology of these PVC, documenting PVC of morphology compatible with origin from Purkinjie fibres. An electrophysiological study and mapping of the left ventricle were performed with extracorporeal membrane oxygenation (ECMO) support. During mapping of the middle left interventricular septum, VF occurred several times and was promptly treated with DC shock. In this area have been documented Purkinje fibers and low voltage and multifragmented areas; ablation was then performed by delivering radiofrequency in this area until the all potentials were completely eliminated. After ablation, no more ventricular arrhythmias were induced. Cardiac magnetic resonance imaging was performed which showed large areas of late gadolinium enhancement. The patient underwent automatic defibrillator implantation. Ventricular arrhythmias were no longer documented during telemetric monitoring. In this complex case of significant arrhythmic instability in ischemic heart disease with moderate left ventricular pump dysfunction, ECMO assistance allowed us to effectively and safely perform the ablation of the arrhythmic substrate triggering the iterative episodes of VF.

A LABILE EQUILIBRIUM: THE CONTROVERSIAL ROLE OF BETA–BLOCKERS IN A CASE OF MID–VENTRICULAR TAKOTSUBO SYNDROME

Abstract Case Report Takotsubo syndrome (TTS) is a non–ischemic heart disease mimicking acute coronary syndrome. The mid–ventricular variant is almost rare (15% of TTS cases). A 62 years old woman was referred to our hospital for oppressive chest pain radiating to the jaw lasting at least 30 minutes after an attempted strangulation by a family member. She denied any conventional cardiovascular risk factor; she was taking beta–blockers (BB) to reduce symptomatic and idiopathic premature ventricular complexes (PVCs) burden. On arrival, the patient was hemodynamically stable, reporting only swallowing difficulties. Physical examination revealed neck bruising and irregular pulse. The initial ECG showed sinus rhythm with a heart rate of 62 bpm, PVCs and a biphasic T wave in lead aVL. Hs–cTnI first dosage was 145 pg/mL. Transthoracic echocardiography (TTE) found moderate left ventricular (LV) dysfunction and severe hypokinesis of mid septal and mid inferior segments. Coronary angiography revealed normal coronary arteries. Left ventriculogram showed hypokinesis of the midventricular section with a hyperdynamic base and apex suggestive of mid–ventricular variant of TTS. After a few hours, she experienced a lipothymic episode and telemetry showed marked sinus bradycardia followed by multiple sinus pauses. A TTE was immediately performed, demonstrating a worsening LV ejection fraction with new development of severe symmetrical akinesia of the LV apex. Successively, psychotherapy was started. Wall motion abnormalities and LV systolic function completely recovered over a few days. At present the patient is in good health status. Discussion domestic violence against women is prevalent, but it is often omitted as a potential stress trigger that affects their hearts. In Italy, it’s reported that 32% of women had experienced physical violence. Strangulation is very uncommon as cause of TTS and psychotherapy may prevent recurrences and recover in a shorter time. Bradycardia due to atrioventricular block and asystole has been described in the acute phase of TTS and it is often attributed to BB therapy. Although BB have been proposed to add further benefit of blunting the effect of catecholamine excess, their use should be used cautiously in the acute phase of TTS. Moreover, beta–adrenoceptor hypersensitivity may generate a parasympathetic drive when on BB infusion, provoking a worsening LV dysfunction and a transient sick sinus syndrome as we described.

PERCUTANEOUS LEFT STELLATE GANGLION BLOCK TO INCREASE VENTRICULAR FIBRILLATION THRESHOLD AND DEFIBRILLATION SUCCESS RATE IN ACUTE FULMINANT MYOCARDITIS WITH ELECTRICAL STORM

Abstract Introduction Acute fulminant myocarditis represents a predisposing substrate for life–threatening ventricular arrhythmias (VAs). Percutaneous left stellate ganglion block (PLSGB) usage has been reported for the prevention of recurrent VAs, but clinical data on its acute effect on ongoing ventricular fibrillation (VF) are missing. Case A 57–years–old man suffering gastroenteritis and fever in the past week presented in the ED with typical chest pain. ECG depicted infero–lateral ST–segment elevation, cardiac ultrasound showed a mildly reduced LVEF and coronary angiography ruled out coronary lesions. In the following hours the patient developed frequent premature ventricular complexes with R on T phenomenon triggering short coupled torsade de pointes with rapid degeneration into VF. VAs episodes, initially responsive to single DC shock, kept recurring despite intravenous (iv) amiodarone, iv lidocaine and iv correction of potassium and magnesium. The patient was therefore treated with deep sedation, intubation and ECMO VA placement; still, he reached a status of persistently ongoing VF, refractory even to DC shocks (n=20). Therefore, ultrasound–guided PLSGB using a local bolus of lidocaine 150 mg + ropivacaine 50 mg was performed. After 5 minutes, a single DC shock was delivered, effective in achieving a stable sinus rhythm at 35 bpm with no more recurrences. Despite electrical stabilization, the patient developed a severe cardiogenic shock due to bradycardia and severe biventricular disfunction, treated with vasopressin and dobutamine. In the next 48 hours we observed a significant improvement, resumption of biventricular contractility and absence of VAs recurrences, so the patient was slowly weaned off ECMO and vasopressors. Immunological tests showed Enterovirus IgM positivity, while endomyocardial biopsy was negative for inflammatory infiltrates in the analyzed sections. Cardiac MRI (performed 10 days after onset) showed edema and non–ischemic LGE in the antero–lateral and infero–lateral basal subepicardial regions of the left ventricle, LVEF was 55%. After 15 days from admission, despite ongoing amiodarone and bisoprolol, the patient developed a run of monomorphic VA of 30 beats at 170 bpm, therefore he underwent sICD implantation. Conclusion PLSGB played a key role for the acute management of refractory VF unresponsive to DC shocks, allowing for acute stabilization. More clinical data are needed on acute neuromodulation for electrical storm.

Fragmented Ventricular Complexes and Blood Pressure Variability Assessed by Ambulatory Blood Pressure Monitoring in Patients With Metabolic Syndrome

Fragmented Ventricular Complexes and Blood Pressure Variability Assessed by Ambulatory Blood Pressure Monitoring in Patients With Metabolic Syndrome

Coronary Sinus Metabolite 12,13-diHOME Is a Novel Biomarker for Left Atrial Remodeling in Patients With Atrial Fibrillation.

12,13-dihydroxy-9Z-octadecenoic acid (12,13-diHOME) has shown potential in protecting against heart disease, but its relationship with atrial fibrillation (AF) remains unknown. Coronary sinus (CS) and femoral vein blood samplings were synchronously collected from AF and non-AF subjects (paroxysmal supraventricular tachycardia or idiopathic premature ventricular complexes) who underwent catheter ablation. First, untargeted metabolomic profiling was performed in a discovery cohort (including 12 AF and 12 non-AF subjects) to identify the most promising CS or femoral vein metabolite. Then, the selected metabolite was further measured in a validation cohort (including 119 AF and 103 non-AF subjects) to confirm its relationship with left atrium remodeling and 1-year postablation recurrence of AF. Finally, the biological function of the selected metabolite was validated in a rapid-paced cultured HL-1 atrial cardiomyocytes model. Metabolomic analysis identified CS 12,13-diHOME as the most pronounced change metabolite correlated with left atrium remodeling in the discovery cohort. In the validation cohort, CS 12,13-diHOME was significantly lower in patients with AF than non-AF controls (84.32±20.13 versus 96.24±23.56 pg/mL; P<0.01), and associated with worse structural, functional, and electrical remodeling of left atrium. Multivariable regression analyses further demonstrated that decreased CS 12,13-diHOME was an independent predictor of 1-year postablation recurrence of AF (odds ratio, 0.754 [95% CI, 0.648-0.920]; P=0.005). Biological function validations showed that 12,13-diHOME treatment significantly protect the cell viability, improved the expression of MHC (myosin heavy chain) and Cav1.2 (L-type calcium channel α1c), and attenuated mitochondrial damage in the rapid-paced cultured HL-1 cardiomyocytes model. CS metabolite 12,13-diHOME is decreased in patients with AF and can serve as a novel biomarker for left atrium remodeling.

The Association between Exercise-Induced Ventricular Premature Contractions and Long-Term Mortality in Patients without Obstructive Coronary Artery Disease.

The treadmill exercise test is widely used to determine cardiovascular risk and mortality. Premature ventricular complexes (PVCs) are frequently observed during exercise stress testing. The literature on the role of PVCs observed during treadmill exercise testing in predicting prognosis is controversial. Hence, we aimed to evaluate the clinical results of PVCs seen during exercise testing in patients without obstructive coronary artery disease confirmed by coronary angiography (CAG). The study population consisted of 1624 consecutive patients who were considered high risk according to the Duke treadmill risk score and had no significant stenosis on CAG from January 2016 to April 2021. The primary endpoints of the study were long-term all-cause mortality of patients who had PVCs during the exercise test or during the resting phase. Long-term mortality was observed in 53 of the 1624 patients after a mean follow-up of 47 months. PVCs were observed in 293 (18.7%) patients without long-term mortality, and in 24 (45.3%) patients with long-term mortality (p < 0.001). The model adjusted for all covariates showed that the presence of PVCs in the recovery phase [p < 0.007, hazard ratio (HR) (95% confidence interval (CI)) 2.244 (1.244-4.047)] and advanced age [p < 0.001, HR (95% CI) 1.194 (1.143-1.247)] were associated with long-term all-cause mortality. PVCs observed during treadmill exercise testing and the recovery phase were related to long-term mortality in patients without obstructive coronary artery disease.

Premature Ventricular Contraction-Induced Cardiomyopathy: Contemporary Evidence from Risk Stratification, Pathophysiology, and Management.

Premature ventricular complexes (PVCs) are commonly encountered problems in clinical settings. The range of symptoms can be from asymptomatic to palpitations, fatigue, or heart failure symptoms. A higher burden of PVCs is a risk factor for development of PVC-induced cardiomyopathy (PIC). Rhythm evaluation by 12-lead ECG and an ambulatory monitoring device are essential. Currently, several imaging modalities, such as echocardiography and cardiac magnetic resonance imaging, are utilized to evaluate the underlying structure that may be related to PIC. Beta blockers and antiarrhythmic drugs are typically part of the initial management strategy. If these fail, catheter ablation of PVCs is typically the next step. The purpose of this article is to summarize the current evidence/knowledge about PIC.

Ventricular bigeminy associated with myocardial ischemia in a dog with a colonic torsion: a case report

BackgroundVentricular bigeminy due to myocardial ischemia has been reported in humans as well as in canine patients with obstructive gastrointestinal diseases. This is the first case report of ventricular bigeminy in a dog with a colonic torsion that resolved after fluid resuscitation and restoration of myocardial perfusion.Case presentationAn 11-year-old, male neutered mixed breed dog presented with a one day history of vomiting, tenesmus, and lethargy. Physical examination identified an irregular heart rhythm and intermittent pulse deficits. A ventricular arrhythmia represented by ventricular premature complexes (VPCs) organized in bigeminy, was appreciated on a 3-lead electrocardiogram (ECG) with a single lead (II) view. Abdominal radiographs confirmed a colonic torsion. Prior to anesthetic induction, ventricular bigeminy was non responsive to fentanyl or lidocaine. The patient was anesthetized and intravascular volume deficit was identified by dampened plethysmographic wave amplitude (plethysomographic variability), audible softening of the Doppler sound, and more pronounced pulse deficits. Fluid resuscitation was achieved with a combination of intravenous crystalloid and colloid fluid therapy comprising 7.2% hypertonic saline and 6% hetastarch. The patient’s cardiac rhythm converted to normal sinus after fluid resuscitation. The colonic torsion was surgically corrected. The patient recovered well from anesthesia and was ultimately discharged from the hospital 5 days later.ConclusionsThe present case report highlights that myocardial ischemia can lead to ventricular arrythmias, such as ventricular bigeminy. This is the first documented case of ventricular bigeminy in the canine patient with a colonic torsion. Assessment of patient volume status and appropriate fluid resuscitation along with continuous electrocardiogram (ECG) monitoring are vital to patient stability under general anesthesia.

Del Nido versus cold crystalloid cardioplegia for myocardial protection during ventricular septal defect repair in children under one year of age: a prospective randomized trial

Rationale: The choice of strategy for myocardial protection during procedures with cardiopulmonary bypass and cardioplegic arrest in children is not regulated by clinical guidelines due to insufficient data from clinical studies. The issue of methods to assess myocardial injury remains unresolved.&#x0D; Aim: To assess the frequency and specifics of the development of intraoperative myocardial injury syndrome in children of the first year of life with ventricular septal defect depending on the strategy for cardioplegia.&#x0D; Materials and methods: In a single center, prospective, randomized controlled trial we compared two cardioplegia strategies during surgical closure of ventricular septal defect in infants aged from 1 to 12 months: del Nido blood cardioplegia (n = 102) and cold crystalloid cardioplegia with Custodiol solution (n = 102). The primary endpoint was a persistent over 10-fold increase above the upper limit of the normal in the plasma concentration of high-sensitivity troponin I at 6 hours after surgery persisting after 24 hours. The secondary combined endpoint was myocardial damage verified by persistent increase in troponin I level more than 10-fold above the upper limit of the normal, persisting at 6 and 24 hours, accompanied by new pathological Q waves, acute complete left bundle branch block, abnormalities of the end part of the ventricular complex on the electrocardiography (ST segment elevation 1 mm or ST depression of 1 mm in more than 2 adjacent leads), and a decrease in the global longitudinal strain of the left ventricle by 50% from the initial value at 6 hours after surgery.&#x0D; Results: In 53/204 (26%) patients, the increase in troponin I persisted at 24 hours after the surgery and was associated with electrocardiography abnormalities, changes in the parameters of left ventricle longitudinal mechanics, and in some cases required greater inotropic support. By the end of the 1st postoperative 24 hours, the longitudinal strain of the left ventricle showed more negative changes over time in the Custodiol group compared to that in the del Nido group (-10 [-14.1; -6.27] versus -14.8 [- 16.5; -10]%; p 0.0001). The same was true for the left ventricle global strain rate (-0.71 [-0.9; -0.52] s-1 in the del Nido group and -0.57 [-0.760; - 0.44] s-1 in the Custodiol group; p = 0.0049). The primary endpoint was achieved by 21 (20.6%) and 55 (53.9%) patients in the del Nido and Custodiol groups, respectively (p = 0.032). The combined endpoint in the Custodiol group was achieved by 34 (33.3%) versus 19 (18.6%) patients in the del Nido group (p = 0.049, χ2 = 3.875, DF = 1, φ = 0.191).&#x0D; Conclusion: Del Nido blood cardioplegia compared to cold crystalloid cardioplegia with Custodiol has advantages in terms of preventing intraoperative myocardial damage and minimizing its severity. When assessing myocardial damage, such indicators as left ventricle global longitudinal strain and left ventricle global strain rate are informative, along with an increase in the troponin I level.

Real World Data from Catheter Ablation of Ventricular Tachycardias and Premature Ventricular Complexes in a Tertiary Care Center.

Background: Catheter ablation in patients with ventricular arrhythmias (VA), such as ventricular tachycardias (VT) or frequent premature ventricular complexes (PVC), is increasingly considered an effective and safe therapy when performed in experienced centers. This study sought to determine acute success rates and complication rates of ablation procedures for patients with VA in a Swiss tertiary care center. Methods: All patients who underwent ablation therapy for VT and PVC at the University Heart Center in Zurich, Switzerland, between March 2012 and April 2017 were included in this analysis. Results: A total of 120 patients underwent catheter ablation for VT and PVC (69 and 51, respectively). Seventy percent of patients were male, and the mean age was 55.3 years. The most common indication for ablation was high PVC burden (47.5%), followed by paroxysmal VT (38.3%), ICD shocks (23.3%), incessant VT (12.5%), electrical storm (7.5%), and syncope (3.3%). Acute success rates for VT and PVC ablations were 94.2% and 92.2%, respectively. Rates for complications (including major and minor) for VT and PVC were 10.1% and 7.8%, respectively. Complications occurred only in patients with structural heart disease; no complications were noted in structurally normal hearts. Conclusions: Our results suggest that catheter ablation for VT and PVC has high acute success rates with a reasonable risk for complications in the setting of tertiary care centers, comparable to those reported in other studies.

Echocardiographic and electrocardiographic findings in Irish Wolfhounds eating high-pulse or low-pulse diets.

Apparently healthy dogs of various breeds eating nontraditional, high-pulse diets can have larger left ventricular diameter, lower systolic function, and more ventricular premature complexes (VPCs) compared with dogs eating traditional, low-pulse diets. It is unknown whether Irish Wolfhounds eating high-pulse diets have similar cardiac abnormalities. To compare electrocardiographic and echocardiographic findings between Irish Wolfhounds eating high- or low-pulse diets. Ninety-seven Irish Wolfhounds. Retrospective study of Irish Wolfhounds that had echocardiography performed at dog shows between October 2018 and May 2021. Demographic information, echocardiographic measurements, cardiac rhythm (1-minute lead II rhythm strip), and main diet were recorded retrospectively. Diets were classified as high-pulse or low-pulse based on the presence and location of pulses (peas, lentils, chickpeas, or dry beans) on the ingredient list. Thirty-five of 97 Irish Wolfhounds (36%) were eating high-pulse diets and 62 of 97 (64%) were eating low-pulse diets. There were no significant differences between diet groups in echocardiographic measurements. A significantly higher percentage of dogs in the high-pulse diet group (6/35 [17%]) had VPCs compared with those in the low-pulse diet group (1/62 [2%]; effect size = 0.15 [95% confidence interval: 0.004-0.31]; P = .005). In this retrospective study of apparently healthy Irish Wolfhounds, high-pulse diets were associated with a higher prevalence of VPCs which could represent early cardiac abnormalities.

Temporal association of ventricular arrhythmias and respiratory events in heart failure patients with central sleep apnoea

In contrast to obstructive sleep apnoea, the peak of sympathetic tone in central sleep apnoea occurs during the hyperventilation phase. To explore the temporal association of premature ventricular complex (PVC) burden in the context of the apnoea/hypopnoea-hyperpnoea cycle, the duration of apnoea/hypopnoea was defined as 100 %. We assessed the PVC burden throughout the apnoea/hypopnoea-hyperpnoea cycle during the periods of ±150 % in 50 % increments before and after the apnoea/hypopnoea phase. In this subanalysis of 54 SERVE-HF patients, PVC burden was 32 % higher in the late hyperventilation period (50–100 % after apnoea/hypopnoea) compared to the apnoea/hypopnoea phase.

Catheter ablation of parahisian premature ventricular complexes in patients with and without cardiac scar

BackgroundAblation of premature ventricular complexes (PVCs) originating from the parahisian area is challenging. Late gadolinium-enhanced cardiac magnetic resonance (LGE-CMR) scar may influence procedural outcomes; the impact of cardiac scar on parahisian PVCs has not been described. ObjectiveThe objective of this study was to examine the incidence and significance of LGE-CMR scarring in patients undergoing ablation for parahisian PVCs. MethodsConsecutive patients who underwent preprocedure LGE-CMR imaging and ablation of parahisian PVCs were included. Acute and long-term outcomes were examined. ResultsForty-eight patients were included (male, n = 37; age, 66 ± 10 years; ejection fraction, 50% ± 12%; preprocedure PVC burden, 21% ± 12%). Intramural LGE-CMR scar was present in 33 of 48 (69%) patients. Cryoablation was used in 9 patients; ablation in multiple chambers was required in 28 (58%) patients. The PVC site of origin (SOO) was intramural (n = 25 patients), left ventricular (n = 5), and right ventricular (n = 18). Patients with LGE-CMR scar were more likely to have intramural PVCs (64% vs 27%; P < .04) and to require ablation in multiple cardiac chambers (58% vs 13%; P < .02). Patients with intramural scar required longer duration of ablation delivery (31 ± 20 minutes vs 17 ± 8 minutes; P < .02). Acute procedural success was 69%; PVC burden on follow-up was 6% ± 9% and similar for those with and without scar. ConclusionAblation of parahisian PVCs often requires mapping and ablation of multiple cardiac chambers, with an intramural SOO identified in most patients. An intramural scar was associated with an intramural SOO of the PVCs requiring more extensive ablation procedures, with similar long-term outcomes compared with those without scar.

Unlocking the enigma: decoding premature ventricular complexes for effective clinical assessment and risk management.

The identification of ventricular premature complexes during a cardiological evaluation necessitates the implementation of diagnostic processes aimed at discerning the clinical context that may predispose individuals to a high risk of sudden cardiac death. Epidemiological studies reveal that ventricular premature beats occur in approximately 75% of healthy (or seemingly healthy) individuals, as long as there is no evidence of underlying structural heart disease, such as benign idiopathic ventricular extrasystole originating from the right and left ventricular outflow tracts. In the real world, however, ventricular ectopic beats with morphologies very similar to seemingly benign occurrences are not uncommon. They are notable in subjects exhibiting rapid and complex repetitive forms during exercise testing and Holter electrocardiogram. Additionally, these subjects may display more or less extensive scarring signs on cardiac magnetic resonance and may have a family history of cardiomyopathy and/or sudden cardiac death. Therefore, the purpose of this review is to critically analyse the process of evaluating premature ventricular complexes, which is crucial for accurate risk stratification. The latter cannot overlook some inevitable elements, including morphology, origin, complexity, and the associated clinical setting (absence or presence of structural heart disease).

Abnormal conduction-induced cardiomyopathy: a poorly explored entity.

A dyssynchronous biventricular activation, which can be determined by left bundle branch block, chronic right ventricular pacing, frequent premature ventricular complexes, or pre-excitation, can cause a global abnormal contractility, thus leading to systolic dysfunction and left ventricular remodelling in a unique nosological entities: abnormal conduction-induced cardiomyopathies. In this clinical scenario, the mainstay therapy is eliminating or improving LV dyssynchrony, removing the trigger. This usually ensures the improvement and even recovery of cardiac geometry and left ventricular function, especially in the absence of genetic background. A multidisciplinary approach, integrating advanced multimodal imaging, is essential for the systematic aetiological definition and the subsequent evaluation and aetiology-guided therapies of patients and their families. This review aims to describe mechanisms, prevalence, risk factors, and diagnostic and therapeutic approach to the various abnormal conduction-induced cardiomyopathies, starting from reasonable certainties and then analysing the grey areas requiring further studies.

Premature ventricular complexes: Assessing burden density in a large national cohort to better define optimal ECG monitoring duration

BackgroundPremature ventricular contraction (PVC) burden is a risk factor for heart failure and cardiovascular death in patients with structural heart disease. Long-term electrocardiographic monitoring can have a significant impact on PVC burden evaluation by further defining PVC distribution patterns. ObjectiveThis study aimed to ascertain the optimal duration of electrocardiographic monitoring to characterize PVC burden and to understand clinical characteristics associated with frequent PVCs and nonsustained ventricular tachycardia in a large US cohort. MethodsCommercial data (iRhythm’s Zio patch) from June 2011 to April 2022 were analyzed. Inclusion criteria were age >18 years, PVC burden ≥5%, and wear period ≥13 days. PVC burden cutoffs were determined on the basis of AHA/ACC/HRS guidelines for very frequent PVCs (10,000–20,000 during 24 hours). Patients were assigned to categories by PVC densities: low, <10%; moderate, 10% to <20%; and high, ≥20%. Mean measured error was assessed at baseline and daily until the wear period’s end for overall PVC burden and different PVC densities. ResultsAnalysis of 106,705 patch monitors revealed a study population with mean age of 70.6 ± 14.6 years (33.6% female). PVC burden was higher in male patients and those >65 years of age. PVC burden mean error decreased from 2.9% at 24 hours to 1.3% at 7 days and 0.7% at 10 days. Number of ventricular tachycardia episodes per patient increased with increasing PVC burden (P < .0001). ConclusionExtending ambulatory monitoring beyond 24 hours to 7 days or more improves accuracy of assessing PVC burden. Ventricular tachycardia frequency and duration vary by initial PVC density, highlighting the need for prolonged cardiac monitoring.

Curvature-mediated source and sink effects on the genesis of premature ventricular complexes in long QT syndrome.

Premature ventricular complexes (PVCs) are spontaneous excitations occurring in the ventricles of the heart that are associated with ventricular arrhythmias and sudden cardiac death. Under long QT conditions, PVCs can be mediated by repolarization gradient (RG) and early afterdepolarizations (EADs), yet the effects of heterogeneities or geometry of the RG or EAD regions on PVC genesis remain incompletely understood. In this study, we use computer simulation to systematically investigate the effects of the curvature of the RG border region on PVC genesis under long QT conditions. We show that PVCs can be either promoted or suppressed by negative or positive RG border curvature depending on the source and sink conditions. When the origin of oscillation is in the source region and the source is too strong, a positive RG border curvature can promote PVCs by causing the source area to oscillate. When the origin of oscillation is in the sink region, a negative RG border curvature can promote PVCs by causing the sink area to oscillate. Furthermore, EAD-mediated PVCs are also promoted by negative border curvature. We also investigate the effects of wavefront curvature and show that PVCs are promoted by convex but suppressed by concave wavefronts; however, the effect of wavefront curvature is much smaller than that of RG border curvature. In conclusion, besides the increase of RG and occurrence of EADs caused by QT prolongation, the geometry of the RG border plays important roles in PVC genesis, which can greatly increase the risk of arrhythmias in cardiac diseases.NEW & NOTEWORTHY The effects of the curvature or geometry of the repolarization gradient region and wavefront curvature on the genesis of premature ventricular complexes are systematically investigated using computer modeling and simulation. Premature ventricular complexes can be promoted by either positive or negative curvature of the gradient region depending on the source and sink conditions. The underlying mechanisms of the curvature effects are revealed, which provides mechanistic insights into arrhythmogenesis in cardiac diseases.

Class 1C Antiarrhythmics for Premature Ventricular Complex Suppression in Nonischemic Cardiomyopathy With Implantable Cardioverter-Defibrillators

BackgroundPremature ventricular complexes (PVCs) are common and associated with worse outcomes in patients with heart failure. Class 1C antiarrhythmic drugs (AADs) effectively suppress PVCs, but guidelines currently restrict their use in structural heart disease. ObjectivesThis study aimed to assess the safety and efficacy of class 1C AADs in patients with nonischemic cardiomyopathy (NICM) and implantable cardioverter-defibrillators (ICDs). MethodsAll patients with NICM and an ICD treated with flecainide or propafenone at the Hospital of the University of Pennsylvania between 2014 and 2022 were identified. PVC burden, left ventricular ejection fraction (LVEF), and biventricular pacing percentage were compared before and during class 1C AAD treatment. Safety outcomes included sustained atrial and ventricular arrhythmias, heart failure admissions, and death. ResultsWe identified 34 patients, 23 receiving flecainide and 11 propafenone. Most patients (62%) had failed other AADs or catheter ablation (68%) prior to class 1C AAD initiation. PVC burden decreased from 20% ± 13% to 6% ± 7% (P < 0.001), LVEF increased from 33% ± 9% to 37% ± 10% (P = 0.01), and biventricular pacing percentage increased from 85% ± 9% to 93% ± 7% (P = 0.01). Sustained ventricular tachycardia (2 vs 9 patients) and admissions for decompensated heart failure (2 vs 3 patients) decreased compared with the 12 months prior to class 1C AAD initiation. ConclusionsClass 1C AADs effectively suppressed PVCs in patients with NICM and ICDs, leading to increases in LVEF and biventricular pacing percentage. In this limited sample, their use was safe. Larger studies are needed to confirm the safety of this approach.

Three-Day Monitoring of Adhesive Single-Lead Electrocardiogram Patch for Premature Ventricular Complex: Prospective Study for Diagnosis Validation and Evaluation of Burden Fluctuation.

Wearable electrocardiogram (ECG) monitoring devices are used worldwide. However, data on the diagnostic yield of an adhesive single-lead ECG patch (SEP) to detect premature ventricular complex (PVC) and the optimal duration of wearing an SEP for PVC burden assessment are limited. We aimed to validate the diagnostic yield of an SEP (mobiCARE MC-100, Seers Technology) for PVC detection and evaluate the PVC burden variation recorded by the SEP over a 3-day monitoring period. This is a prospective study of patients with documented PVC on a 12-lead ECG. Patients underwent simultaneous ECG monitoring with the 24-hour Holter monitor and SEP on the first day. On the subsequent second and third days, ECG monitoring was continued using only SEP, and a 3-day extended monitoring was completed. The diagnostic yield of SEP for PVC detection was evaluated by comparison with the results obtained on the first day of Holter monitoring. The PVC burden monitored by SEP for 3 days was used to assess the daily and 6-hour PVC burden variations. The number of patients additionally identified to reach PVC thresholds of 10%, 15%, and 20% during the 3-day extended monitoring by SEP and the clinical factors associated with the higher PVC burden variations were explored. The recruited data of 134 monitored patients (mean age, 54.6 years; males, 45/134, 33.6%) were analyzed. The median daily PVC burden of these patients was 2.4% (IQR 0.2%-10.9%), as measured by the Holter monitor, and 3.3% (IQR 0.3%-11.7%), as measured in the 3-day monitoring by SEP. The daily PVC burden detected on the first day of SEP was in agreement with that of the Holter monitor: the mean difference was -0.07%, with 95% limits of agreement of -1.44% to 1.30%. A higher PVC burden on the first day was correlated with a higher daily (R2=0.34) and 6-hour burden variation (R2=0.48). Three-day monitoring by SEP identified 29% (12/42), 18% (10/56), and 7% (4/60) more patients reaching 10%, 15%, and 20% of daily PVC burden, respectively. Younger age was additionally associated with the identification of clinically significant PVC burden during the extended monitoring period (P=.02). We found that the mobiCARE MC-100 SEP accurately detects PVC with comparable diagnostic yield to the 24-hour Holter monitor. Performing 3-day PVC monitoring with SEP, especially among younger patients, may offer a pragmatic alternative for identifying more individuals exceeding the clinically significant PVC burden threshold.