The clinical presentation depends on the underlying subtype of arrhythmia [1] [2]:

• Outflow tract arrhythmia (OTA) - Developing on the grounds of aberrant cyclic adenosine monophosphate (cAMP) activity, this type is most frequently encountered in individuals between 20-40 years, with a slight predilection toward female gender [1]. Symptoms seem to be aggravated by emotional stress or exertion, most common being palpitations, dyspnea, chest pain and syncope [1]. Cardiac arrest has been rarely associated with OTA [1].
• Ventricular tachycardia (VT) - Defined as 3 or more ventricular beats at a heart rate of more than 120 beats per minute [3], VT is strongly associated with heart disease (eg. myocardial infarction, cardiomyopathies), while electrolyte abnormalities (hypokalemia or hypomagnesemia) or metabolic changes, including acidosis or hypoxemia, can also induce VT [3]. Monomorphic or polymorphic (the ectopic beat arises from one or multiple foci) and sustained or nonsustained subtypes exist. Nonsustained forms may be asymptomatic, as they are of short duration, but sustained VT is universally symptomatic, manifesting with palpitations, hemodynamic instability, and sudden cardiac death [3], which is not uncommon in severe structural heart disease (SHD).
• Long QT and Brugada syndromes - Two ventricular arrhythmias induced by genetic events present usually in early life (mean onset of symptoms in long QT syndrome is 12 years of age) manifest through syncope, seizures, palpitations, and cardiac arrest [1] [3]. The nocturnal appearance of symptoms is characteristic of Brugada syndrome [3].
• Ventricular fibrillation - Considered as the most severe form of arrhythmia, chaotic ventricular conduction leads to immediate syncope and death within minutes without adequate therapeutic measures [3].

• Falling

  Blood pressure tends to fall, and heart failure follows. Sustained ventricular tachycardia is also dangerous because it can worsen until it becomes ventricular fibrillation —a form of cardiac arrest. [merckmanuals.com]

  The QT interval is markedly prolonged (at least 600ms), with each PVC falling on the preceding T wave (= ‘R on T’ phenomenon). This ECG is extremely high risk for TdP – in fact this patient had a TdP cardiac arrest shortly after this ECG was taken. [lifeinthefastlane.com]

  His description is as follows: "The ventricular muscle is thrown into a state of irregular arrhythmic contraction, whilst there is a great fall in the arterial blood pressure, the ventricles become dilated with blood as the rapid quivering movement of [en.m.wikipedia.org]

  The QTc interval in men decreases at puberty and then gradually increases as androgen levels fall ; this is also the reason women typically have a longer QT interval than men. [pharmaceutical-journal.com]

  Such patients when they experience VT can try vagal maneuvers at home or even try to fall asleep in hopes that the VT will go away on its own. [heartracing.com]

• Heart Disease

  A total of 123 consecutive patients confirmed ischemia heart disease with ICD were examined. After device implantation, the occurrence of appropriate ICD therapy was noted. [ncbi.nlm.nih.gov]

  Ventricular tachycardia (VT) - Defined as 3 or more ventricular beats at a heart rate of more than 120 beats per minute, VT is strongly associated with heart disease (eg. myocardial infarction, cardiomyopathies), while electrolyte abnormalities (hypokalemia [symptoma.com]

  Inflammatory, rheumatic and valvular heart diseases 11.1 Myocarditis 11.2 Endocarditis 11.3 Rheumatic heart disease. 11.4 Pericarditis 11.5 Cardiac sarcoidosis 11.6 Valvular heart disease 12. [escardio.org]

  CONTINUE SCROLLING OR CLICK HERE FOR RELATED ARTICLE Reviewed on 12/27/2018 A Visual Guide to Heart Disease Medical Illustrations of the Heart Image Collection Take the Heart Disease Quiz! [medicinenet.com]

• Ventricular Bigeminy

  In this paper, we propose a new method for detection and classification of shockable ventricular arrhythmia (VT/VF) and non-shockable ventricular arrhythmia (normal sinus rhythm, ventricular bigeminy, ventricular ectopic beats, and ventricular escape [ncbi.nlm.nih.gov]

  Bigeminy, Trigeminy, Quadrigeminy, etc. - ventricular bigeminy is the occurrence of a PVC every other beat, trigeminy is every third beat, quadrigeminy every fourth beat. [heartpoint.com]

  Example 5 R on T phenomenon: There is sinus rhythm with frequent PVCs in a pattern of ventricular bigeminy. The QT interval is markedly prolonged (at least 600ms), with each PVC falling on the preceding T wave (= ‘R on T’ phenomenon). [lifeinthefastlane.com]

  A premature ventricular complex is usually followed by a full compensatory pause. The term “ventricular bigeminy” refers to alternating normal sinus and premature ventricular complexes. [aafp.org]

  [ edit ] Premature ventricular contractions (PVCs), sometimes called ventricular extra beats (VEBs) Premature ventricular beats occurring after every normal beat are termed " ventricular bigeminy " PVCs that occur at intervals of 2 normal beats to 1 [en.wikipedia.org]

• Irregular Heart Rhythm

  Ventricular Fibrillation (VF) is a rapid, irregular heart rhythm caused by abnormal electrical signals from the ventricles (lower chambers of the heart). Most cardiac arrest patients suffer from ventricular fibrillation (VF). [altabatessummit.org]

  Ventricular fibrillation is a serious cardiac disturbance that causes abnormal heart rhythms. It can be fatal. For many people with this condition, irregular heart rhythms are the first and only sign of coronary artery disease. [medicalnewstoday.com]

  By looking at an ECG, a doctor can gain insights about your heart rhythm and look for irregularities. [support.apple.com]

• Palpitations with Skipped Beats

  Common symptoms include the following: Palpitations, feeling "skipped beats" Thumping or fluttering in the chest Sensation of the heart racing In addition, some can experience symptoms that are more generalized, including the following: Feeling faint [emedicinehealth.com]

• Seizure

  Patients usually present with hypocalcemia-induced seizures or tetany, whereas no case of hypocalcemia-induced cardiac arrhythmia in PHP has been described to date. [ncbi.nlm.nih.gov]

  Long QT and Brugada syndromes - Two ventricular arrhythmias induced by genetic events present usually in early life (mean onset of symptoms in long QT syndrome is 12 years of age) manifest through syncope, seizures, palpitations, and cardiac arrest. [symptoma.com]

  If the ventricular tachycardia persists longer, patients may then manifest a generalized seizure. In both syncope and seizure presentations, the heart eventually catches itself, reverts back to normal sinus rhythm, and the "spell" stops. [sads.org]

  […] disorder should be suspected when the electrocardiogram shows characteristic QT abnormalities, or when there is a family history of long QT syndrome or of an event that raises suspicion of long QT syndrome, such as sudden death, syncope, or ill-defined “seizure [mdedge.com]

  Primary symptoms of long QT syndrome may include palpitations, syncope and seizures. [pharmaceutical-journal.com]

Prompt diagnostic workup is mandatory in defining the exact type of arrhythmia, starting with a thorough physical examination and a detailed patient history that could reveal the presence of comorbidities, use of pro-arrhythmogenic drugs, structural heart disease, or positive family history [4]. A 12-lead electrocardiogram (ECG) should be performed immediately in patients who present with symptoms suggestive of arrhythmia, followed by a transthoracic echocardiogram in order to evaluate cardiac structure and exclude structural heart disease as a possible cause [4] [5]. ECG findings may include a widened QRS complex (both prolongation and change in shape), ST elevation and inversion of T waves in the case of ventricular tachycardia and fibrillation, while prolonged QT intervals and coving of the ST-segment are seen in long QT syndrome and Brugada syndrome, respectively [1] [4] [5]. In addition to ECG and echocardiography, laboratory workup should comprise a complete blood count, cardiac markers (troponin, creatine kinase MB, and myoglobin), serum electrolytes (potassium, sodium, magnesium, calcium) and renal function tests, to determine optimal therapy and perform electrolyte correction [3] [4]. If symptoms appear in childhood, genetic testing to confirm mutations characteristic for Brugada or long QT syndromes is necessary [4]. If the cause of arrhythmia remains unresolved, coronary arteriography, exercise stress testing and cardiac magnetic resonance imaging (MRI) have been suggested as additional diagnostic methods [4].

• Wide QRS Complex

  An overview of ventricular tachycardias, follow the Approach to the Wide Complex Tachycardia example regularity atrial frequency ventricular frequency origin (SVT/VT) p-wave effect of adenosine Wide complex (QRS>0.12) Ventricular Tachycardia regular [en.ecgpedia.org]

  (wide QRS complex), or ventricular (wide QRS complex). [msdmanuals.com]

  Therefore, late premature wide QRS complexes (after the T wave, for example) are most often ventricular ectopic in origin. [ecg.utah.edu]

  Ventricular tachycardia refers to a wide QRS complex heart rhythm — that is, a QRS duration beyond 120 milliseconds — originating in the ventricles at a rate of greater than 100 beats per minute. [healio.com]

• Ventricular Bigeminy

  In this paper, we propose a new method for detection and classification of shockable ventricular arrhythmia (VT/VF) and non-shockable ventricular arrhythmia (normal sinus rhythm, ventricular bigeminy, ventricular ectopic beats, and ventricular escape [ncbi.nlm.nih.gov]

  Bigeminy, Trigeminy, Quadrigeminy, etc. - ventricular bigeminy is the occurrence of a PVC every other beat, trigeminy is every third beat, quadrigeminy every fourth beat. [heartpoint.com]

  Example 5 R on T phenomenon: There is sinus rhythm with frequent PVCs in a pattern of ventricular bigeminy. The QT interval is markedly prolonged (at least 600ms), with each PVC falling on the preceding T wave (= ‘R on T’ phenomenon). [lifeinthefastlane.com]

  A premature ventricular complex is usually followed by a full compensatory pause. The term “ventricular bigeminy” refers to alternating normal sinus and premature ventricular complexes. [aafp.org]

  [ edit ] Premature ventricular contractions (PVCs), sometimes called ventricular extra beats (VEBs) Premature ventricular beats occurring after every normal beat are termed " ventricular bigeminy " PVCs that occur at intervals of 2 normal beats to 1 [en.wikipedia.org]

• T Wave Alternans

  Catecholamine provoked microvoltage T wave alternans in genotyped long QT syndrome. Pacing & Clinical Electrophysiology. 2003;26(8):1660–7. Google Scholar 104. Nemec J, Hejlik JB, Shen WK, Ackerman MJ. [doi.org]

  Other noninvasive tests, such as T-wave alternans, signal-averaged ECG, and heart rate variability, do not provide diagnostic confirmation, but might be helpful in defining arrhythmia risk in patients with CAD. 17 Electrocardiographic Findings During [revespcardiol.org]

• Electrocardiogram Change

  If the VA occur during or less than 10 seconds after injection and some typical electrocardiogram changes (such as bradycardia, QT interval prolongation, T-wave amplitude, rotation of QRS axis, and PR prolongation) are simultaneously observed before the [revespcardiol.org]

We suggest that this treatment should be seriously considered in those patients with SSc and malignant ventricular arrhythmias unresponsive to drug therapy. [ncbi.nlm.nih.gov]

Most episodes are self-limited and do not require treatment. Premature ventricular complexes do not usually require treatment. [aafp.org]

We evaluate the clinical and electrocardiographic characteristics of these patients as well as their prognosis. [ncbi.nlm.nih.gov]

Prognosis matters when weighing up the benefit versus risk of an ICD implant for secondary prevention (3-6% implanting complication and 10% inappropriate shock rate) 36. [bhrs.com]

[…] and Recommendations [ edit ] The prognosis for patients with ventricular tachycardia is largely dependent on whether or not there is an underlying structural heart condition. [en.wikibooks.org]

Ventricular arrhythmia originating from outflow tract diverticulum is even rarer and its etiology, epidemiology and proper treatment still remain controversial. [ncbi.nlm.nih.gov]

Current SIDS etiological surveys fail to diagnose LQTS. Specific questioning and electrocardiographic screening of first-degree relatives could greatly facilitate LQTS diagnosis. We propose adding these to screening modalities after a SIDS incident. [hal.archives-ouvertes.fr]

Etiology The physiopathology of this type of VT is unknown but it has been suggested that microscopic tumors such as myocardial hamartomas, also known as histiocytoid cardiomyopathy (see this term), are responsible. [orpha.net]

This arrhythmia may be either of congenital etiology or may occur after cardiac surgery. Sudden death is uncommon in children with arrhythmias but when it occurs, is frequently caused by ventricular arrhythmias. [af-ablation.org]

The patient underwent a successfully surgical repair by semitotal resection of the right ventricle free wall, tricuspid annuloplasty, and one and one-half ventricular repair. 1 Introduction Uhl's anomaly, a very rare anomaly with unknown etiology, is [academic.oup.com]

BIPS GmbH (Garbe, Schink), Bremen, Germany; Department of Medical and Surgical Sciences (Poluzzi), University of Bologna, Bologna, Italy; Department of Clinical Epidemiology (Frøslev), Aarhus University Hospital, Aarhus, Denmark; Department of Primary [ncbi.nlm.nih.gov]

Definitions, epidemiology and future perspectives for the prevention of sudden cardiac death 3.1 Epidemiology of sudden cardiac death 3.2 Indications for autopsy and molecular autopsy in sudden death victims 3.3 Risk prediction of sudden cardiac death [escardio.org]

Rafik Tadros, Anh-Tuan Ton, Céline Fiset and Stanley Nattel, Sex Differences in Cardiac Electrophysiology and Clinical Arrhythmias: Epidemiology, Therapeutics, and Mechanisms, Canadian Journal of Cardiology, 30, 7, (783), (2014) . [doi.org]

The pathophysiology of arrhythmias in this population is complex and seems to be related to structural cardiac abnormalities caused by CKD, associated with several triggers, such as water and electrolyte disorders, hormonal conditions, arrhythmogenic [ncbi.nlm.nih.gov]

Kass, Molecular Pathophysiology of Congenital Long QT Syndrome, Physiological Reviews, 97, 1, (89), (2017). Amara Greer-Short, Sharon A. George, Steven Poelzing and Seth H. [doi.org]

This elimination of the atrial fibrillation with ablation implies APs have some pathophysiologic role in the development of a-fib in the WPW patient. [4] Functionally defined re-entry does not require the alternative anatomically defined circuit accessory [en.wikipedia.org]

METHODS: In this study, 93 patients who received ICDs for secondary prevention, had an LVEF of < 45%, and underwent echocardiographic follow-up assessment after receiving an ICD were enrolled. [ncbi.nlm.nih.gov]

3.4 Prevention of sudden cardiac death in special settings 4. [escardio.org]

Sometimes antiarrhythmic drugs can help in preventing recurrent ventricular tachycardia, but unfortunately, these drugs often do not work well enough. [heartdisease.about.com]

1. Prystowsky EN, Padanilam BJ, Joshi S, Fogel RI. Ventricular Arrhythmias in the Absence of Structural Heart Disease. J Am Coll Cardiol. 2012;59(20):1733-1744.
2. Roberts-Thomson KC1, Lau DH, Sanders P. The diagnosis and management of ventricular arrhythmias. Nat Rev Cardiol. 2011;8(6):311-321.
3. Hebbar AK, Hueston WJ. Management of common arrhythmias: Part II. Ventricular arrhythmias and arrhythmias in special populations. Am Fam Physician. 2002;65(12):2491-2496.
4. Pedersen CT, Kay GN, Kalman J, Borggrefe M, Della-Bella P, Dickfeld T, et al. EHRA/HRS/APHRS expert consensus on ventricular arrhythmias. Europace. 2014;16(9):1257-1283.
5. Porter RS, Kaplan JL. Merck Manual of Diagnosis and Therapy. 19th Edition. Merck Sharp & Dohme Corp. Whitehouse Station, N.J; 2011.