0:00 Arithmogenic right ventricular cardiomyopathy, or ARVC, is a heritable, under- 0:17 recognized 0:18 heart muscle disorder that predominantly affects the right ventricle, 0:23 increasing the risk 0:24 of arrhythmias. 0:27 It's loss of right ventricular myocardium, and its replacement by fibrophatic 0:33 tissue is 0:33 the pathological hallmark of this disease. 0:38 The cardiac muscle cells, or fibers, have a single nucleus, they are branched 0:42 and joined 0:42 to one another by intraclated discs. 0:46 The intraclated discs contain gap junctions. 0:50 The intraclated discs and gap junctions form a syncedium of cardiac cells, 0:54 allowing the 0:54 heart to contract in a coordinated, unified manner. 0:59 Now, mutations in genes encoding for desmosomal proteins, which, again, are the 1:06 structures 1:07 important for cell to cell adhesion, play a key role in the pathogenesis of AR 1:18 VC. 1:19 Issues with cell to cell adhesion as the pathological basis of arithmogenic 1:24 right ventricular cardiomyopathy 1:26 was first described in patients with an axos disease, who had, you know, arithm 1:34 ogenic right 1:35 ventricular cardiomyopathy, palmo-plantic keratosis, and woolly hair. 1:41 Now an axos disease is a mutation of the plaqueoglobin, a component of the des 1:47 mosomal 1:47 complex. 1:49 It was then found that mutations of the other components of the desmosomal 1:53 complex was associated 1:55 with autosomal dominant forms of arithmogenic right ventricular cardiomyopathy, 1:59 including 2:00 mutations of the ismoplacin, a plaque of fill-in 2, which is the most common 2:06 mutation found 2:07 in this cardiomyopathy, as well as mutations of desmosglane 2 and desmoscolin 2 2:23 . 2:25 Abnormal desmosomal complex proteins results in a number of things. 2:30 So, firstly, desmosomes are responsible for holding cells together, thus 2:35 abnormal desmosomal 2:37 complex results in myoside detachment and remodeling of cardiomyosides, and 2:44 possibly 2:45 cardiomyoside death. 2:47 Desmosomal complexes are also important mediators of intracellular signaling. 2:53 Changes in signaling is thought to reduce genes for muscle activity, but they 2:58 will promote 2:59 this expression of adipogenic and fibrogenic genes that contribute to the fibro 3:06 fati myocardial 3:07 scarring I talked about earlier. 3:10 And so this fibrofati tissue that replaces the myocardium is what is thought to 3:15 contribute 3:15 to the arrhythmias, the ventricular arrhythmias. 3:19 Loss of desmosomal complexes causes remodeling of gap junctions, interclated 3:24 discs, and the 3:25 surrounding ion channels. 3:28 Denoting of the gap junctions and surrounding channels can also play a role in 3:32 triggering 3:33 ventricular arrhythmias. 3:36 The abnormal desmosomal complex and cardiac remodeling that occurs results in 3:41 the features 3:41 of arrhythmogenic right ventricular cardiomyopathy, which includes right vent 3:47 ricular dilation 3:49 and right ventricular dysfunction. 3:52 You can get regional right ventricular war motion abnormalities, and there may 3:57 be involvement 3:58 of the left ventricle as well. 4:01 Again, these right ventricular changes are what triggers arrhythmias. 4:15 The clinical manifestation. 4:18 This condition is actually not that uncommon, one in 5,000 people, 50% of which 4:24 have some 4:25 form of family history. 4:28 This condition is usually asymptomatic, but symptoms become apparent in the 4:32 second to 4:33 fourth decade of life. 4:35 The most common presentation is palpitations or effort induced syncope in young 4:42 adults. 4:43 The ECG changes. 4:44 You can get T-wave inversion in the right pre-chordial lead, so V1 to V4, as 4:50 well as 4:51 presence of the epsilon wave. 4:58 The most common arrhythmias found in ARVC include ventricular tachycardia, left 5:09 bundle 5:10 branch block, however you can also frequently find ventricular topics. 5:16 The fiberfetti tissue that replaces the myocardium is thought to contribute to 5:20 ventricular arrhythmias 5:21 by slowing conduction through the myocardium, and also acts as a scar-related 5:26 macro-entry 5:27 circuit triggering the ventricular tachycardia. 5:32 Investigations to perform in someone with cardiomyopathy, as well as suspected 5:38 arrhythmogenic 5:39 right ventricular cardiomyopathy include an electrocardiogram, which we talked 5:44 about the 5:44 signs, echocardiogram, MRI of the heart is the preferred imaging technique, and 5:51 this 5:52 is important to evaluate the heart's structure, as well as the heart function. 5:56 It's also important to take a family history of any cardiac problems. 6:01 Arithmogenic right ventricular cardiomyopathy can present a sudden cardiac 6:06 death, however 6:07 there is no data, really, to support the use of implantable cardioverter defibr 6:14 illator 6:14 as primary prevention, especially if the person are asymptomatic and have never 6:21 had 6:21 any ventricular arrhythmias. 6:23 Rather, the ICDs, the implantable cardioverter defibrillator, is used for 6:29 secondary prevention 6:31 in ARVC. 6:34 People with arrhythmogenic right ventricular cardiomyopathy should also be in a 6:40 beta blocker. 6:41 Catheter ablation is a therapeutic option for patients who have had an episode 6:46 of sustained 6:46 VT. 6:48 Finally, patients with ARVC should not participate in competitive or endurance 6:55 activities. 6:56 Cardiac transplantation is the ultimate therapy for patients with untreatable 7:00 arrhythmias 7:00 or heart failure that is refractory to treatment.
