scholarly journals Cardiac spinal deafferentation reduces the susceptibility to sustained ventricular tachycardia in conscious rats

2011 ◽  
Vol 301 (3) ◽  
pp. R775-R782 ◽  
Author(s):  
Heidi L. Lujan ◽  
Sandhya Krishnan ◽  
Stephen E. DiCarlo
Keyword(s):  
Ventricular Tachycardia ◽  
Myocardial Ischemia ◽  
Ventricular Arrhythmias ◽  
Clinical Work ◽  
Sustained Ventricular Tachycardia ◽  
Rate Pressure Product ◽  
Sprague Dawley ◽  
Metabolic Demand ◽  
Conscious Rats ◽  
Spinal Afferents

The response to myocardial ischemia is complex and involves the cardio-cardiac sympathetic reflex. Specifically, cardiac spinal (sympathetic) afferents are excited by ischemic metabolites and elicit an excitatory sympathetic reflex, which plays a major role in the genesis of ventricular arrhythmias. For example, brief myocardial ischemia leads to ATP release, which activates cardiac spinal afferents through stimulation of P2 receptors. Clinical work with patients and preclinical work with animals document that disruption of this reflex protects against ischemia-induced ventricular arrhythmias. However, the role of afferent signals in the initiation of sustained ventricular tachycardia has not been investigated. Therefore, we tested the hypothesis that cardiac spinal deafferentation reduces the susceptibility to sustained ventricular tachycardia in adult (12–15 wk of age), conscious, male Sprague-Dawley rats. To test this hypothesis, the susceptibility to ventricular tachyarrhythmias produced by occlusion of the left main coronary artery was determined in two groups of conscious rats: 1) deafferentation (bilateral excision of the T1-T5 dorsal root ganglia) and 2) control (sham deafferentation). The ventricular arrhythmia threshold (VAT) was defined as the time from coronary occlusion to sustained ventricular tachycardia resulting in a reduction in arterial pressure. Results document a significantly higher VAT in the deafferentation group (7.0 ± 0.7 min) relative to control (4.3 ± 0.3 min) rats. The decreased susceptibility to tachyarrhythmias with deafferentation was associated with a reduced cardiac metabolic demand (lower rate-pressure product and ST segment elevation) during ischemia.

scholarly journals Targeted ablation of cardiac sympathetic neurons reduces the susceptibility to ischemia-induced sustained ventricular tachycardia in conscious rats

2010 ◽  
Vol 298 (5) ◽  
pp. H1330-H1339 ◽  
Author(s):  
Heidi L. Lujan ◽  
Gurunanthan Palani ◽  
Lijie Zhang ◽  
Stephen E. DiCarlo
Keyword(s):  
Ventricular Tachycardia ◽  
Sudden Cardiac Death ◽  
Cardiac Death ◽  
Ventricular Arrhythmias ◽  
Antiarrhythmic Drugs ◽  
Sympathetic Neurons ◽  
Left Ventricular ◽  
Sustained Ventricular Tachycardia ◽  
Conscious Rats ◽  
Stellate Ganglia

The Cardiac Arrhythmia Suppression Trial demonstrated that antiarrhythmic drugs not only fail to prevent sudden cardiac death, but actually increase overall mortality. These findings have been confirmed in additional trials. The “proarrhythmic” effects of most currently available antiarrhythmic drugs makes it essential that we investigate novel strategies for the prevention of sudden cardiac death. Targeted ablation of cardiac sympathetic neurons may become a therapeutic option by reducing sympathetic activity. Thus cholera toxin B subunit (CTB) conjugated to saporin (a ribosomal inactivating protein that binds to and inactivates ribosomes; CTB-SAP) was injected into both stellate ganglia to test the hypothesis that targeted ablation of cardiac sympathetic neurons reduces the susceptibility to ischemia-induced, sustained ventricular tachycardia in conscious rats. Rats were randomly divided into three groups: 1) control (no injection); 2) bilateral stellate ganglia injection of CTB; and 3) bilateral stellate ganglia injection of CTB-SAP. CTB-SAP rats had a reduced susceptibility to ischemia-induced, sustained ventricular tachycardia. Associated with the reduced susceptibility to ventricular arrhythmias were a reduced number of stained neurons in the stellate ganglia and spinal cord (segments T1-T4), as well as a reduced left ventricular norepinephrine content and sympathetic innervation density. Thus CTB-SAP retrogradely transported from the stellate ganglia is effective at ablating cardiac sympathetic neurons and reducing the susceptibility to ventricular arrhythmias.

Arrhythmogenic right ventricular cardiomyopathy: management of symptoms and prevention of sudden cardiac death

2018 ◽  
Author(s):  
Perry Elliott ◽  
Alexandros Protonotarios
Keyword(s):  
Heart Failure ◽  
Ventricular Tachycardia ◽  
Right Ventricular ◽  
Ventricular Arrhythmias ◽  
Ventricular Dysfunction ◽  
Beta Blockers ◽  
Arrhythmogenic Right Ventricular Cardiomyopathy ◽  
Sustained Ventricular Tachycardia ◽  
Carrier Status ◽  
Ventricular Cardiomyopathy

Patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) have arrhythmia-related symptoms or are identified during screening of an affected family. Heart failure symptoms occur late in the disease’s natural history. As strenuous exercise has been associated with disease acceleration and worsening of ventricular arrhythmias, lifestyle modification with restricted athletic activities is recommended upon disease diagnosis or even identification of mutation carrier status. An episode of an haemodynamically unstable, sustained ventricular tachycardia or ventricular fibrillation as well as severe systolic ventricular dysfunction constitute definitive indications for implantable cardioverter defibrillator (ICD) implantation, which should also be considered following tolerated sustained or non-sustained ventricular tachycardia episodes, syncope, or in the presence of moderate ventricular dysfunction. Antiarrhythmic medications are used as an adjunct to device therapy. Catheter ablation is recommended for incessant ventricular tachycardia or frequent appropriate ICD interventions despite maximal pharmacological therapy. Amiodarone alone or in combination with beta blockers is most effective for symptomatic ventricular arrhythmias. Beta blockers are considered for use in all patients with a definite diagnosis but evidence for their prognostic benefit is sparse. Heart failure symptoms are managed using standard protocols and heart transplantation is considered for severe ventricular dysfunction or much less commonly uncontrollable ventricular arrhythmias.

scholarly journals Short‐Term Variability of the QT Interval Can be Used for the Prediction of Imminent Ventricular Arrhythmias in Patients With Primary Prophylactic Implantable Cardioverter Defibrillators

2020 ◽  
Vol 9 (23) ◽  
Author(s):  
Agnieszka Smoczyńska ◽  
Vera Loen ◽  
David J. Sprenkeler ◽  
Anton E. Tuinenburg ◽  
Henk J. Ritsema van Eck ◽  
...  
Keyword(s):  
Ventricular Tachycardia ◽  
Ventricular Arrhythmia ◽  
Qt Interval ◽  
Ventricular Arrhythmias ◽  
Sustained Ventricular Tachycardia ◽  
Control Group ◽  
Implantable Cardioverter Defibrillators ◽  
Short Term ◽  
Cardioverter Defibrillators ◽  
Holter Recordings

Background Short‐term variability of the QT interval (STV QT ) has been proposed as a novel electrophysiological marker for the prediction of imminent ventricular arrhythmias in animal models. Our aim is to study whether STV QT can predict imminent ventricular arrhythmias in patients. Methods and Results In 2331 patients with primary prophylactic implantable cardioverter defibrillators, 24‐hour ECG Holter recordings were obtained as part of the EU‐CERT‐ICD (European Comparative Effectiveness Research to Assess the Use of Primary Prophylactic Implantable Cardioverter Defibrillators) study. ECG Holter recordings showing ventricular arrhythmias of >4 consecutive complexes were selected for the arrhythmic groups (n=170), whereas a control group was randomly selected from the remaining Holter recordings (n=37). STV QT was determined from 31 beats with fiducial segment averaging and calculated as , where D n represents the QT interval. STV QT was determined before the ventricular arrhythmia or 8:00  am in the control group and between 1:30 and 4:30  am as baseline. STV QT at baseline was 0.84±0.47 ms and increased to 1.18±0.74 ms ( P <0.05) before the ventricular arrhythmia, whereas the STV QT in the control group remained unchanged. The arrhythmic patients were divided into three groups based on the severity of the arrhythmia: (1) nonsustained ventricular arrhythmia (n=32), (2) nonsustained ventricular tachycardia (n=134), (3) sustained ventricular tachycardia (n=4). STV QT increased before nonsustained ventricular arrhythmia, nonsustained ventricular tachycardia, and sustained ventricular tachycardia from 0.80±0.43 ms to 1.18±0.78 ms ( P <0.05), from 0.90±0.49 ms to 1.14±0.70 ms ( P <0.05), and from 1.05±0.22 ms to 2.33±1.25 ms ( P <0.05). This rise in STV QT was significantly higher in sustained ventricular tachycardia compared with nonsustained ventricular arrhythmia (+1.28±1.05 ms versus +0.24±0.57 ms [ P <0.05]) and compared with nonsustained ventricular arrhythmia (+0.34±0.87 ms [ P <0.05]). Conclusions STV QT increases before imminent ventricular arrhythmias in patients, and the extent of the increase is associated with the severity of the ventricular arrhythmia.

Arrhythmogenic right ventricular cardiomyopathy: management of symptoms and prevention of sudden cardiac death

ESC CardioMed ◽  
2018 ◽  
pp. 1502-1505
Author(s):  
Alexandros Protonotarios ◽  
Perry Elliott
Keyword(s):  
Heart Failure ◽  
Ventricular Tachycardia ◽  
Right Ventricular ◽  
Ventricular Arrhythmias ◽  
Ventricular Dysfunction ◽  
Beta Blockers ◽  
Arrhythmogenic Right Ventricular Cardiomyopathy ◽  
Pharmacological Therapy ◽  
Sustained Ventricular Tachycardia ◽  
Ventricular Cardiomyopathy

Patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) have arrhythmia-related symptoms or are identified during screening of an affected family. Heart failure symptoms occur late in the disease’s natural history. As strenuous exercise has been associated with disease acceleration and worsening of ventricular arrhythmias, lifestyle modification with restricted athletic activities is recommended upon disease diagnosis or even identification of mutation carrier status. An episode of an haemodynamically unstable, sustained ventricular tachycardia or ventricular fibrillation as well as severe systolic ventricular dysfunction constitute definitive indications for implantable cardioverter defibrillator (ICD) implantation, which should also be considered following tolerated sustained or non-sustained ventricular tachycardia episodes, syncope, or in the presence of moderate ventricular dysfunction. Antiarrhythmic medications are used as an adjunct to device therapy. Catheter ablation is recommended for incessant ventricular tachycardia or frequent appropriate ICD interventions despite maximal pharmacological therapy. Amiodarone alone or in combination with beta blockers is most effective for symptomatic ventricular arrhythmias. Beta blockers are considered for use in all patients with a definite diagnosis but evidence for their prognostic benefit is sparse. Heart failure symptoms are managed using standard protocols and heart transplantation is considered for severe ventricular dysfunction or much less commonly uncontrollable ventricular arrhythmias.

Relationship between myocardial amiodarone concentration and antiarrhythmic effect in dogs with myocardial infarction and electrically induced ventricular arrhythmias

1991 ◽  
Vol 69 (6) ◽  
pp. 812-817 ◽  
Author(s):  
Hoshiar Abdollah ◽  
F. James Brennan ◽  
Sandra Jimmo ◽  
James F. Brien
Keyword(s):  
Ventricular Tachycardia ◽  
Ventricular Fibrillation ◽  
Ventricular Arrhythmias ◽  
Dose Group ◽  
Low Dose ◽  
Antiarrhythmic Effect ◽  
Baseline Data ◽  
Sustained Ventricular Tachycardia ◽  
Control Group ◽  
High Dose

The relationship between the antiarrhythmic effect of amiodarone and its myocardial concentration was studied in dogs with 1-week-old myocardial infarction and reproducibly inducible sustained ventricular tachycardia or ventricular fibrillation. Three groups of animals (n = 10/group) received amiodarone, 40 mg∙kg−1∙day−1 (low-dose amiodarone), amiodarone 60 mg∙kg−1∙day−1 (high-dose amiodarone), or no amiodarone (control group). After 1 week of treatment, programmed electrical stimulation was repeated, and plasma and myocardial amiodarone and desethylamiodarone concentrations were measured. In the control group, sustained ventricular tachycardia or ventricular fibrillation was induced in six dogs (p = NS) when compared with baseline data. In the low-dose amiodarone group, sustained ventricular tachycardia or ventricular fibrillation was induced only in two dogs after 1 week of treatment (p < 0.01 vs. baseline data). Sustained ventricular tachycardia or ventricular fibrillation was induced in seven dogs after treatment with high-dose amiodarone (p = NS vs. baseline data). Plasma amiodarone concentration in the low-dose amiodarone group (2.54 ± 1.9 μg/mL) was significantly less (p < 0.01) than that in the high-dose amiodarone group (4.64 ± 1.66 μg/mL). Similarly, the plasma desethylamiodarone in the low-dose amiodarone group (0.32 ± 0.16 μg/mL) was significantly less (p < 0.001) than that in the high-amiodarone dose group (0.56 ± 0.23 μg/mL). The myocardial amiodarone concentration in the low-dose amiodarone group (49.7 ± 23.1 μg/g) was significantly lower (p < 0.001) than that in the high-dose group (98.4 ± 32.1 μg/g). There was no significant difference in the myocardial desethylamiodarone concentrations between the two treatment groups (25.1 ± 12.2 μg/g in the low-dose amiodarione group vs. 37.4 ± 16.4 μg/g in the high-dose amiodarone group). These data show that the high-dose amiodarone regimen, which produced high myocardial amiodarone concentration, didn't suppress sustained ventricular arrhythmias.Key words: amiodarone, ventricular arrhythmias, plasma and myocardial drug concentrations.

scholarly journals RESULTS OF NON-INVASIVE ACTIVATION MAPPING OF THE HEART IN “IDIOPATHIC” VENTRICULAR ARRHYTHMIAS IN COMPARISON WITH STRUCTURAL CHARACTERISTICS OF MYOCARDIUM BY MAGNETIC RESONANCE IMAGING

2018 ◽  
pp. 32-40
Author(s):  
N. A. Mironova ◽  
L. H. Yeghiazaryan ◽  
О. P. Aparina ◽  
T. A. Malkina ◽  
O. V. Stukalova ◽  
...  
Keyword(s):  
Ventricular Tachycardia ◽  
Magnetic Resonance ◽  
Ventricular Arrhythmias ◽  
Structural Characteristics ◽  
Magnetic Resonance Tomography ◽  
Late Enhancement ◽  
Morphological Type ◽  
Sustained Ventricular Tachycardia ◽  
Ventricular Ectopic Activity ◽  
Non Invasive

Aim.To compare the results of non-invasive activational mapping in patients with “idiopathic” ventricular arrhythmias (IVA) with the data on myocardial structure obtained by late enhancement magnetic resonance tomography (MRI).Material and methods.Twenty eight IVA patients, mean age 37 y. o. [26; 45], with ventricular arrhythmias of the heart (VA) of 2nd or higher grade by Lown, and 5 healthy volunteers (HV), mean age 29 [29; 30], underwent surface epiand endocardial non-invasive mapping (SEENIM) of the heart with the system for noninvasive electrophysiological investigation of the heart “Amicard 01C” with the analysis of duration of the activation-recovery interval (ARI) of the ventricles, and high resolution MRI (voxel 1,25x1,25x2,5mm) with delayed contrasting.Results.The number of VA in IVA group was 20196 [11479; 29834] for 24 hours. In 11 patients there were episodes of non-sustained ventricular tachycardia (VT). By SEENIM, predominating morphological type of ventricular ectopic activity in 22 patients sourced from the right ventricle myocardium (RV), of those in 20 from outflow tract of the LV (OTLV). There was significantly prolonged ARI in OTLV patients with IVA comparing to HV (p<0,05). In IVA and non-sustained ventricular tachycardia patients, by contrast MRI of the heart, in LV myocardium there were small foci of contrast retention found. There was no correlation of the areas of contrast retention and topography of VA sources.Conclusion.In most of IVA patients the source of VA was outflowing tract of the RV. The revealed prolongation of the ARI of this area in IVA patients can be an important factor of IVA onset. Small foci of LV fibrosis, found in late enhancement MRI of the heart and episodes of so called idiopathic VT, might be the earliest presentation of the “tachycardiopathy” at the step of pathology development when there are no signs of LV dilation.

Abstract 16223: Cardiac Arrhythmias in Hospitalized Patients With COVID-19

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Jae Hyung Cho ◽  
Ali Namazi ◽  
Richard Shelton ◽  
Archana Ramireddy ◽  
Ashkan Ehdaie ◽  
...  
Keyword(s):  
Ventricular Tachycardia ◽  
Ventricular Fibrillation ◽  
Interleukin 6 ◽  
Cardiac Arrhythmias ◽  
Ventricular Arrhythmias ◽  
Sinus Tachycardia ◽  
Sustained Ventricular Tachycardia ◽  
Rhythm Disorder ◽  
Baseline Characteristics

Introduction: Arrhythmias have been reported frequent in COVID-19 patients, but the incidence and nature have not been well characterized. Hypothesis: Atrial and ventricular arrhythmias are common complications of patients with COVID-19. Methods: Patients admitted with COVID-19 and monitored by telemetry were prospectively enrolled in the study. Baseline characteristics, hospital course, treatment and complications were collected from the patients’ medical records. Telemetry was monitored to detect the incidence of cardiac arrhythmias. The incidence and types of cardiac arrhythmias were analyzed and compared between survivors and non-survivors. Results: Among 143 patients admitted with telemetry monitoring, overall in-hospital mortality was 23.1% (33/143 patients) during the period of observation (mean follow up 19.9 ± 13.7 days). Survivors were younger (68.1 ± 17.2 vs. 77.6 ± 15.9 years old, p=0.006), had higher body mass index (28.1 ± 8.3 vs. 24.3 ± 6.2, p=0.019), were less tachycardic on initial presentation (heart rate 90.6 ± 19.4 vs. 99.8 ± 23.7 bpm, p=0.026) and had lower troponin (peak troponin 0.03 vs. 0.14 ng/ml. p=0.006) and interleukin-6 levels (peak interleukin-6 32 vs. 264 pg/ml, p=0.001). Sinus tachycardia, the most common arrhythmia (occurring in 39.9% [57/143] of patients), occurred more frequently in non-survivors (57.6% vs. 34.5% in survivors, p=0.018). Premature ventricular complexes occurred in 28.7% (41/143), and non-sustained ventricular tachycardia in 15.4% (22/143) of patients, with no difference between survivors and non-survivors. Sustained ventricular tachycardia and ventricular fibrillation were rare (seen only in 1.4% and 0.7% of patients, respectively). Conclusions: In this prospective observational study of hospitalized and monitored patients with COVID-19, sinus tachycardia was the most common rhythm disorder, and its presence was associated with higher mortality. Sustained ventricular tachycardia or ventricular fibrillation were infrequent, contradicting previous reports that malignant ventricular arrhythmias are commonly seen in patients hospitalized with COVID-19.

Electroacupuncture decreases the susceptibility to ventricular tachycardia in conscious rats by reducing cardiac metabolic demand

2007 ◽  
Vol 292 (5) ◽  
pp. H2550-H2555 ◽  
Author(s):  
Heidi L. Lujan ◽  
Victoria J. Kramer ◽  
Stephen E. DiCarlo
Keyword(s):  
Ischemia Reperfusion ◽  
Rate Pressure Product ◽  
Therapeutic Effects ◽  
Ventricular Tachyarrhythmias ◽  
Metabolic Demand ◽  
Experimental Conditions ◽  
St Segment Elevation ◽  
Conscious Rats ◽  
Clinical Observations ◽  
St Segment

Reperfusion after a brief period of cardiac ischemia can lead to potentially lethal arrhythmias. Clinical observations and experimental work with animals suggest that acupuncture may have therapeutic effects for individuals with coronary heart disease, certain arrhythmias, and myocardial ischemia. Therefore, we tested the hypothesis that electroacupuncture reduces the susceptibility to ischemia-reperfusion-mediated ventricular tachyarrhythmias. To test this hypothesis, we measured the susceptibility to ventricular tachyarrhythmias produced by 3 min of occlusion and reperfusion of the left main coronary artery in conscious rats under two experimental conditions: 1) control and 2) with electroacupuncture. Acupuncture was simulated by electrically stimulating the median nerves, corresponding to the Jianshi-Neiguan [pericardial meridian (P) 5-6] acupoints. Results document a significantly lower incidence of ventricular tachyarrhythmias with electroacupuncture (2 of 8, 25%) relative to control (14 of 14, 100%) rats. The decreased susceptibility to tachyarrhythmias with electroacupuncture was associated with a reduced cardiac metabolic demand (lower rate-pressure product and ST-segment elevation) during ischemia.

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