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]

• Sudden Infant Death Syndrome

  Recent postmortem molecular screening surveys have shown that 10 to 12% of sudden infant death syndrome (SIDS) cases were potentially related to congenital long QT syndrome. Current SIDS etiological surveys fail to diagnose LQTS. [hal.archives-ouvertes.fr]

  We outline the clinical implications for investigation of deaf children and cases of sudden infant death syndrome as well as careful electrocardiographic monitoring of identified mutation carriers to prevent sudden death. Am. J. Med. Genet. (Semin. [doi.org]

  Functional studies have demonstrated that CAV3 mutations are associated with persistent late sodium current, and they have been reported in cases of sudden infant death syndrome (SIDS). [13] LQT9 and LQT4 serve as examples of LQTS with nonchannel mutations [emedicine.medscape.com]

• Severe Pain

  However, strong electrical shocks can damage the heart and cause severe pain. Therefore, we have tested optogenetic defibrillation using expression of the light-sensitive channel channelrhodopsin-2 (ChR2) in cardiac tissue. [ncbi.nlm.nih.gov]

• Nausea

  BACKGROUND AND OBJECTIVE: Domperidone is a drug used globally for relieving nausea and vomiting and stimulating breast milk production. [ncbi.nlm.nih.gov]

  Signs and symptoms of VT include: Chest pain Rapid heartbeat (tachycardia) Dizziness Nausea Shortness of breath Loss of consciousness When to see a doctor If you or someone else is having the above signs and symptoms, seek emergency medical help immediately [mayoclinic.org]

  // Edited by: Alex Koyfman, MD (@EMHighAK, EM Attending Physician, UT Southwestern Medical Center / Parkland Memorial Hospital) and Brit Long, MD (@long_brit, EM Chief Resident at SAUSHEC, USAF) A 66-year-old male presents complaining of persistent “nausea [emdocs.net]

  Also, a precipitating event is usually present, commonly pain, injury, nausea, or an unpleasant or stressful experience. [sads.org]

  About an hour before ventricular fibrillation, some people experience: dizziness nausea pain in the chest tachycardia, or accelerated heartbeat, and palpitations Versus atrial fibrillation The left and right atria form the upper chambers of the heart, [medicalnewstoday.com]

• Diarrhea

  These conditions include the eating disorders anorexia nervosa and bulimia, excessive vomiting or diarrhea, and certain thyroid disorders. [nhlbi.nih.gov]

  Examples of medical conditions that can cause long QT syndrome include excessive diarrhea or vomiting and certain thyroid disorders. [1] Inherited forms of long QT syndrome are caused by changes in genes that control the heart muscle’s electrical activity [rarediseases.info.nih.gov]

  In addition to those patients who had life-threatening events with the 3 main triggers, 15 (37%) suffered a CA/SD associated with “other conditions” (fever, pregnancy, anesthesia, normal daily activities, sepsis with low K +, diarrhea). [doi.org]

• 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]

• 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 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]

  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]

  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]

• Osteoporosis

  INTRODUCTION: Bisphosphonates, including ibandronate, are used in the prevention and treatment of osteoporosis. [ncbi.nlm.nih.gov]

• 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]

• Irritability

  Concerning the causes of premature ventricular contractions, think about the three i’ s: Irritability: The causes of myocardial irritability are hypoxemia and electrolyte abnormalities, including hypokalemia and hypomagnesemia. [dummies.com]

  Using a specialized ablation catheter, radiofrequency, or heat energy, can be delivered to this irritable tissue with eradication of the tachycardia circuit. Not every patient has a benign course or can be offered a catheter ablation procedure. [washingtonhra.com]

  Premature Ventricular Contraction • PVC – Ectopic beat in the ventricle that can occur singly or in clusters – Caused by electrical irritability • Factors influencing electrical irritability – Ischemia – Electrolyte imbalances – Drug intoxication 14. [slideshare.net]

  Possible advantages of cryoablation include the following: No painful sensation if the patient is awake Less irritation of the endocardium with thrombus formation Less chance of perforation Less chance of coronary artery damage if VT origin close to artery [heartracing.com]

  The patient subgroup reported symptoms like extreme cravings for sweets, irritability, weakness, dizziness, shakiness, depression, or mood swings and anxiety or nervousness as well as night awakening and severe night sweats correlating to the exact time [doi.org]

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]

• Biphasic T Wave

  Potassium administration led to resolution of notched T waves in five of six patients (see, for example, Fig 3 ), and the biphasic T waves in the seventh subject became monophasic. [doi.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]

After discontinuing the HCQ, the QT interval was shorter and the patient recovered after treatment with lidocaine and isoproterenol. [ncbi.nlm.nih.gov]

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]

Because of its toxicity, amiodarone should not be used in patients with mild disease or a good prognosis. Simple and monomorphic VPBs have no impact on the prognosis of ChD and do not require specific treatment. [scielo.br]

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]

Pathogenesis Pathophysiology Pedigree analysis suggests autosomal recessive mode of inheritance, although proportion of affected kittens is greater than expected. Failure of ectodermal (hypotrichosis) and entodermal (thymic aplasia) development. [vetstream.com]

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]

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]

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.