History

Fact Explanation
Dizziness/ feeling light headed/ faintness Arises due to reduction in cardiac output as a result of bradycardia[1][2][5]
Syncope Manifests when blood flow to brain is reduced due to sudden but pronounced decrease in the cardiac output, which is caused by reduction in the heart rate[1][2][3][4][5]
History of a recent myocardial infarction There is association of myocardial infarction with bundle branch block. E.g. Right bundle branch block (RBBB) and left anterior hemiblock (LAH) are likely to occur in anterior or anteroseptal infarction.[3][4]
Co-existent cardiovascular disease Studies have shown that cardiovascular diseases such as hypertension (60%), coronary artery disease (10%), and congestive heart failure (4%) are associated with bifascicular and trifascicular block. Therefore these should be looked for when assessing the patient. [1]
Family history of cardiac conduction disorder, permanent pacemaker implantation, sudden cardiac death etc. These can be the presentation of progressive familial heart block (PFHB) type I, which is an autosomal dominantly inherited cardiac conduction disorder. Type I PFHB is characterized by right bundle branch block (RBBB), left anterior fascicular block (LAFB), prolonged PR interval, or complete AV block with broad QRS complexes. [5]
References
  1. MADDALI MM. Cardiac pacing in left bundle branch/bifascicular block patients. Ann Card Anaesth [online] 2010 Jan-Apr, 13(1):7-15 [viewed 06 July 2014] Available from: doi:10.4103/0971-9784.58828
  2. FEMENIA F, CUESTA A, MAURICIO A. A rare form of trifascicular block with intermittent complete atrioventricular block in a patient with Chagas disease. Cardiol J [online] 2009, 16(6):582-4 [viewed 06 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/19950099
  3. ELIZARI MV, ACUNZO RS, FERREIRO M. Hemiblocks revisited. Circulation [online] 2007 Mar 6, 115(9):1154-63 [viewed 06 July 2014] Available from: doi:10.1161/CIRCULATIONAHA.106.637389
  4. MEDRANO GA, DE MICHELI A, ITURRALDE P. Peripheral Heart Blocks Associated with Myocardial Infarcts: Clinical Diagnosis Based on Experimental Findings Curr Cardiol Rev [online] 2008 May, 4(2):140-147 [viewed 06 July 2014] Available from: doi:10.2174/157340308784245784
  5. LEE CK, SHIN DH, JANG JK, JANG KH, KIM EK, CHEONG SS, YOO SY. Progressive Familial Heart Block Type I in a Korean Patient Korean Circ J [online] 2011 May, 41(5):276-279 [viewed 06 July 2014] Available from: doi:10.4070/kcj.2011.41.5.276

Examination

Fact Explanation
Bradycardia Is a sign that can be detected in patients with trifascicular block.[1]
Cannon ‘a’ waves When the atria contract against closed tricuspid and mitral valves, it gives rise to a cannon 'a' wave in the jugular venous pulse, which may be felt as a 'pounding' in the neck.[3]
Variable intensity S1 Intensity of first heart sound may vary according to ventricular rate comparative to atrial rate. It will be heard aloud intermittently when the ventricles happen to contract shortly after the atria.[2]
Hypotension Patient may develop hypotension due to reduced cardiac out put and hypoperfusion.[1][4]
Signs of cardiac failure such as tachypnea, elevated jugular venous pressure, bibasal crackles on lung auscultation These signs may arise in a patient who develops congestive cardiac failure and pulmonary congestion secondary to reduced cardiac out put.[5]
References
  1. MADDALI MM. Cardiac pacing in left bundle branch/bifascicular block patients. Ann Card Anaesth [online] 2010 Jan-Apr, 13(1):7-15 [viewed 06 July 2014] Available from: doi:10.4103/0971-9784.58828
  2. Felner JM. The First Heart Sound. In: Walker HK, Hall WD, Hurst JW, editors. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Boston: Butterworths; 1990. Chapter 22. Available from: http://www.ncbi.nlm.nih.gov/books/NBK333/
  3. Applefeld MM. The Jugular Venous Pressure and Pulse Contour. In: Walker HK, Hall WD, Hurst JW, editors. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Boston: Butterworths; 1990. Chapter 19. Available from: http://www.ncbi.nlm.nih.gov/books/NBK300/
  4. Kapoor WN. Syncope. In: Walker HK, Hall WD, Hurst JW, editors. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Boston: Butterworths; 1990. Chapter 12. Available from: http://www.ncbi.nlm.nih.gov/books/NBK224/
  5. MICHAEL KING, JOE KINGERY, BARETTA CASEY. Diagnosis and Evaluation of Heart Failure. Am Fam Physician.[online] 2012 Jun 15;85(12):1161-1168.[viewed on 6 July 2014] Available from; http://www.aafp.org/afp/2012/0615/p1161.html

Differential Diagnoses

Fact Explanation
Atrioventricular block Can present with syncope, pre syncope, dizziness etc. similar to trifascicular block.[2]
Bifascicular block Can progress to trifascicular block and complete heart block. Can have clinical features similar to trifascicular block[1]
References
  1. MADDALI MM. Cardiac pacing in left bundle branch/bifascicular block patients. Ann Card Anaesth [online] 2010 Jan-Apr, 13(1):7-15 [viewed 06 July 2014] Available from: doi:10.4103/0971-9784.58828
  2. CHICHE P, HAIAT R, STEFF P. Angina pectoris with syncope due to paroxysmal atrioventricular block: role of ischaemia. Report of two cases. Br Heart J [online] 1974 Jun, 36(6):577-81 [viewed 06 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/4850578

Investigations - for Diagnosis

Fact Explanation
12-lead electrocardiogram (ECG) Trifascicular block is diagnosed when there is right bundle branch block (RBBB) with either left anterior fascicular block (hemi block) or left posterior fascicular block (hemi block) usually associated with first degree atrioventricular block. According to recommendations of the Criteria Committee of the New York Heart Association, RBBB is diagnosed when QRS duration is greater than or equal to 0.12 s and the QRS complex in V 1 has 'rsR' configuration or is a solitary notched R wave, left bundle branch block is (LBBB) is diagnosed when QRS duration is greater than or equal to 0.12 s and QRS complex is notched and splintered in leads 1 and V6 and has a QS or rS deflection in lead V1, left anterior fascicular block is diagnosed when frontal plane QRS axis is within minus 45 to minus 90 degrees, left posterior fascicular block is diagnosed when frontal plane QRS axis is between plus 90 to plus 120 degrees and first-degree A-V block is diagnosed when P-R interval greater than 0.21 s and one-to-one A-V conduction is present. [1][2][3][4][5]
24 hour Holter monitoring 24 hour Holter monitoring is done to detect ECG abnormalities in symptomatic patients with normal initial ECG. A device called a Holter monitor which continuously records the heart's rhythm is usually worn for 24 - 48 hours during normal activity.[5]
References
  1. MEDRANO GA, DE MICHELI A, ITURRALDE P. Peripheral Heart Blocks Associated with Myocardial Infarcts: Clinical Diagnosis Based on Experimental Findings Curr Cardiol Rev [online] 2008 May, 4(2):140-147 [viewed 06 July 2014] Available from: doi:10.2174/157340308784245784
  2. SEEWOODHARY J, GRIFFIN L. Trifascicular block and a raised Troponin 'T' in acute cholecystitis. QJM [online] 2010 Feb, 103(2):121-3 [viewed 06 July 2014] Available from: doi:10.1093/qjmed/hcp156
  3. MADDALI MM. Cardiac pacing in left bundle branch/bifascicular block patients. Ann Card Anaesth [online] 2010 Jan-Apr, 13(1):7-15 [viewed 06 July 2014] Available from: doi:10.4103/0971-9784.58828
  4. FEMENIA F, CUESTA A, MAURICIO A. A rare form of trifascicular block with intermittent complete atrioventricular block in a patient with Chagas disease. Cardiol J [online] 2009, 16(6):582-4 [viewed 06 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/19950099
  5. EL-SHERIF N. Intraventricular trifascicular block. Observations on conduction disturbance in bundle-branch system. Br Heart J [online] 1971 Jul, 33(4):626-8 [viewed 06 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/5557505

Management - Specific Treatments

Fact Explanation
Permanent pacemaker implantation According to American College of Cardiology/American Heart Association permanent pacing in chronic trifascicular block is considered in the presence of intermittent third degree AV block, type 11 second degree block, alternating bundle branch block, incidental ECG finding of markedly prolonged HV interval in asymptomatic patients, fascicular block without AV block, fascicular block with first degree AV block etc[1][2]
Temporary cardiac pacing Any patient presenting with acute hemodynamic compromise caused by bradycardia should be considered for temporary cardiac pacing[1]
References
  1. MADDALI MM. Cardiac pacing in left bundle branch/bifascicular block patients. Ann Card Anaesth [online] 2010 Jan-Apr, 13(1):7-15 [viewed 06 July 2014] Available from: doi:10.4103/0971-9784.58828
  2. LEE CK, SHIN DH, JANG JK, JANG KH, KIM EK, CHEONG SS, YOO SY. Progressive familial heart block type I in a korean patient. Korean Circ J [online] 2011 May, 41(5):276-9 [viewed 06 July 2014] Available from: doi:10.4070/kcj.2011.41.5.276