Accessory pathways (AP)

• Some people are born with an extra piece of heart muscle tissue [1]
• That connects directly between the atria and the ventricles, bypassing the AV node altogether[1]
• This abnormal piece of muscle is referred to as a bypass tract or an accessory pathway [1]

1. Kent - WPW [ delta wave, PQ<0.12 ] [LA-RA or RA-RV]
2. James - LGL [ no delta wave, PQ<0.12 ] [ LA-Hiss ]
3. Mahaim - [ small delta wave ] [ Hiss - V ]

• Accessory pathways (AP) typical, atypical, non-evident. [3]
• Typical
• Left sided (Left atrium - left ventricle)
• ECG changes (PR < 0.12 and pre-excitated wide QRS) [3]
• delta wave - manifest
• Atypical 
• Right sided(right atrium - right ventricle)
• ECG changes (PR > 0.12 and normal or pre-excitated wide QRS) [3]
• Non-evident - ECG normal [3]
• interatrial conduction delays (enlarged or diseased atria) [3]
• accessory pathway conduction delay (Ebstein anomaly, atriofasicular track etc.) [3]
• anterograd directed conduction. ECG changes (normal PR and normal QRS) [3]
• no delta wave - concealed
• if there is delta wave then it called manifes, else concealed.
• WPW Type A
• 
• WPW Type B
• 

• 

References

1. Wolff-Parkinson-White Syndrome and Accessory Pathways James Kulig, Bruce A. Koplan. Circulation 2010
2. Basic of Pre-excitation syndrome, Leonardo Paskah. Slideshare
3. The Esc Textbook of cardiovascular medicine, 2nd edition. page 1061.

Myocardial infarction and complete heart block

• Inferior MI
• a block above the bifurcation [1]
• Complete Heart Block (III AV block) is transitory [1]
• dont require pacing [1]
• the patients had no Stokes-Adams attacks** [1]
• Pacemakers generally should not be implanted with inferior MI if the peri-infarctional AV block is expected to resolve or is not expected to negatively affect long-term prognosis [2]
• Anteroseptal myocardial infarction
• a bilateral bundle branch block (below the bifurcation) [1]
• severe Stokes-Adams attacks [1]
• require pacing [1]

**Stokes Adams attack: Sudden collapse into unconsciousness due to a disorder of heart rhythm

References

1. Can Med Assoc J. 1970 Apr 11; 102(7): 705–708. Myocardial Infarction and Complete Heart Block J. F. Lopez, M. Mori, and B. L. Baltzan
2. ACC/AHA/HR, Guidedline Device-Based Therapy of Cardiac Rhythm Abnormalities

Hiatal Hernia and Heart

• hiatal hernia occurs when the upper part of your stomach bulges through the large muscle separating your abdomen and chest (diaphragm) [1]
• Hiatus hernia can present as acute chest pain [3]
• In echocardiography Hiatal Hernia Masquerading as Left Atrial Mass [2]
• 
• after drinking carbonated solution echo-free space replaced the mass in left atrium [2]
• 
• Youtube video
• Another example image
•  [3]
•  [4]
• Discussion and recommendations: [4]
• various origin can impress the left atrium
• These structures generally grow slowly
• When a structure behind the left atrium is diagnosed using TTE
• additional CT scan can give a more comprehensive view

References

1. Mayo Clinic, Hiatal Hernia
2. Hiatal Hernia Masquerading as Left Atrial Mass, Circulation 1996
3. Echocardiographic manifestation of hiatus hernia simulating a left atrial mass: Case report. Cardiovasc Ultrasound. 2008; 
4. Left atrial impression: a sign of extra-cardiac pathology Johan M. van Rooijen Lambert F.M. van den Merkhof European Journal of Echocardiography, Volume 9, Issue 5, 1 September 2008, Pages 661–664

Lyme disease, Lyme cardit, Reversible complete heart block

• Lyme disease also known as "Lyme borreliosis" [1]
• Lyme disease is a systemic illness caused by the spirochete Borrelia burgdorferi [3]
• caused by bacteria of the Borrelia type which is spread by ticks [1]
• The most common sign of infection is an expanding area of redness on the skin, known as erythema migrans [1]
  
• Blood test - Screening Lyme serology - positive [2]
• Lyme carditis is a complication of Lyme disease [3]
• The Lyme bacterium can infect all parts of the heart, including the conduction system around the atrioventricular node, the outer or inner membranes of the heart, the cardiac muscle [4]
• impairment of conduction system cause heart block [ 1st degree, 2nd degree and complete heart block]
• Ceftriaxone started after 24 hours rash is resolved [2]
• After 48 hours of observation, he underwent a temporary VVI (ventricular pacing and sensing mode) pacemaker insertion [2]
• On ceftriaxone, the AV block converted to first degree 2 days after starting antibiotics and then completely resolved by day 11, at which point the pacemaker was removed [2]
• He completed a total 21-day course of treatment with oral doxycycline [2]

References

1. Lyme disease - Wikipedia
2. Case of Reversible Complete Heart Block - The American Journal of Medicine, Vol 130, No 8, August 2017
3. Lyme carditis with complete heart block: management with an external pacemaker, Muhammad Ali Chaudhry. Pubmed
4. Lyme Disease and the Heart. - Peter J. Krause, Linda K. Bockenstedt. Circulation, 2013